Papillomaviridae

Last updated
Papillomaviridae
Papillomavirus.jpg
Electron micrograph of papillomavirus, scale bar 70 nm
Virus classification OOjs UI icon edit-ltr.svg
(unranked): Virus
Realm: Monodnaviria
Kingdom: Shotokuvirae
Phylum: Cossaviricota
Class: Papovaviricetes
Order: Zurhausenvirales
Family:Papillomaviridae
Subfamilies and genera

Papillomaviridae is a family of non-enveloped DNA viruses whose members are known as papillomaviruses. [1] Several hundred species of papillomaviruses, traditionally referred to as "types", [2] have been identified infecting all carefully inspected mammals, [2] but also other vertebrates such as birds, snakes, turtles and fish. [3] [4] [5] Infection by most papillomavirus types, depending on the type, is either asymptomatic (e.g. most Beta-PVs) or causes small benign tumors, known as papillomas or warts (e.g. human papillomavirus 1, HPV6 or HPV11). Papillomas caused by some types, however, such as human papillomaviruses 16 and 18, carry a risk of becoming cancerous. [6]

Contents

Papillomaviruses are usually considered as highly host- and tissue-tropic, and are thought to rarely be transmitted between species. [7] Papillomaviruses replicate exclusively in the basal layer of the body surface tissues. All known papillomavirus types infect a particular body surface, [2] typically the skin or mucosal epithelium of the genitals, anus, mouth, or airways. [8] For example, human papillomavirus (HPV) type 1 tends to infect the soles of the feet, and HPV type 2 the palms of the hands, where they may cause warts. Additionally, there are descriptions of the presence of papillomavirus DNA in the blood and in the peripheral blood mononuclear cells.

Papillomaviruses were first identified in the early 20th century, when it was shown that skin warts, or papillomas, could be transmitted between individuals by a filterable infectious agent. In 1935 Francis Peyton Rous, who had previously demonstrated the existence of a cancer-causing sarcoma virus in chickens, went on to show that a papillomavirus could cause skin cancer in infected rabbits. This was the first demonstration that a virus could cause cancer in mammals.

Taxonomy of papillomaviruses

Selected papillomavirus types PapillomavirusTree3.png
Selected papillomavirus types

There are over 100 species of papillomavirus recognised, [9] though the ICTV officially recognizes a smaller number, categorized into 53 genera, as of 2019. [10] [11] [12] All papillomaviruses (PVs) have similar genomic organizations, and any pair of PVs contains at least five homologous genes, although the nucleotide sequence may diverge by more than 50%. Phylogenetic algorithms that permit the comparison of homologies led to phylogenetic trees that have a similar topology, independent of the gene analyzed. [13]

Phylogenetic studies strongly suggest that PVs normally evolve together with their mammalian and bird host species, but adaptive radiations, occasional zoonotic events and recombinations may also impact their diversification. [13] Their basic genomic organization appears maintained for a period exceeding 100 million years, and these sequence comparisons have laid the foundation for a PV taxonomy, which is now officially recognized by the International Committee on Taxonomy of Viruses. All PVs form the family Papillomaviridae, which is distinct from the Polyomaviridae thus eliminating the term Papovaviridae . Major branches of the phylogenetic tree of PVs are considered genera, which are identified by Greek letters. Minor branches are considered species and unite PV types that are genomically distinct without exhibiting known biological differences. This new taxonomic system does not affect the traditional identification and characterization of PV "types" and their independent isolates with minor genomic differences, referred to as "subtypes" and "variants", all of which are taxa below the level of "species". [14] Additionally, phylogenetic groupings at higher taxonomic level have been proposed. [15]

This classification may need revision in the light of the existence of papilloma–polyoma virus recombinants. [16] Additional species have also been described. Sparus aurata papillomavirus 1 has been isolated from fish. [17]

Human papillomaviruses

Over 170 human papillomavirus types have been completely sequenced. [18] They have been divided into 5 genera: Alphapapillomavirus, Betapapillomavirus, Gammapapillomavirus, Mupapillomavirus and Nupapillomavirus. At least 200 additional viruses have been identified that await sequencing and classification.[ citation needed ]

Animal papillomaviruses

Viral papilloma in a dog Viral papilloma 1.JPG
Viral papilloma in a dog

Individual papillomavirus types tend to be highly adapted to replication in a single animal species. In one study, researchers swabbed the forehead skin of a variety of zoo animals and used PCR to amplify any papillomavirus DNA that might be present. [19] Although a wide variety of papillomavirus sequences were identified in the study, the authors found little evidence for inter-species transmission. One zookeeper was found to be transiently positive for a chimpanzee-specific papillomavirus sequence. However, the authors note that the chimpanzee-specific papillomavirus sequence could have been the result of surface contamination of the zookeeper's skin, as opposed to productive infection.[ citation needed ]

Cottontail rabbit papillomavirus (CRPV) can cause protuberant warts in its native host, the North American rabbit genus Sylvilagus . These horn-like warts may be the original basis for the urban legends of the American antlered rabbit the Jackalope and European Wolpertinger . [20] European domestic rabbits (genus Oryctolagus) can be transiently infected with CRPV in a laboratory setting. However, since European domestic rabbits do not produce infectious progeny virus, they are considered an incidental or "dead-end" host for CRPV. [21]

Inter-species transmission has also been documented for bovine papillomavirus (BPV) type 1. [22] In its natural host (cattle), BPV-1 induces large fibrous skin warts. BPV-1 infection of horses, which are an incidental host for the virus, can lead to the development of benign tumors known as sarcoids. The agricultural significance of BPV-1 spurred a successful effort to develop a vaccine against the virus.[ citation needed ]

A few reports have identified papillomaviruses in smaller rodents, such as Syrian hamsters, the African multimammate rat and the Eurasian harvest mouse. [23] However, there are no papillomaviruses known to be capable of infecting laboratory mice. The lack of a tractable mouse model for papillomavirus infection has been a major limitation for laboratory investigation of papillomaviruses.[ citation needed ]

Four papillomaviruses are known to infect birds: Fringilla coelebs papillomavirus 1, Francolinus leucoscepus papillomavirus 1, Psittacus erithacus papillomavirus 1 and Pygoscelis adeliae papillomavirus 1. [24] All these species have a gene (E9) of unknown function, suggesting a common origin.

Evolution

The evolution of papillomaviruses is thought to be slow compared to many other virus types, but there are no experimental measurements currently available. This is probably because the papillomavirus genome is composed of genetically stable double-stranded DNA that is replicated with high fidelity by the host cell's DNA replication machinery.[ citation needed ]

It is believed that papillomaviruses generally co-evolve with a particular species of host animal over many years, although there are strong evidences against the hypothesis of coevolution. [13] [25] In a particularly speedy example, HPV-16 has evolved slightly as human populations have expanded across the globe and now varies in different geographic regions in a way that probably reflects the history of human migration. [26] [27] Cutaneotropic HPV types are occasionally exchanged between family members during the entire lifetime, but other donors should also be considered in viral transmission. [28]

Other HPV types, such as HPV-13, vary relatively little in different human populations. In fact, the sequence of HPV-13 closely resembles a papillomavirus of bonobos (also known as pygmy chimpanzees). [29] It is not clear whether this similarity is due to recent transmission between species or because HPV-13 has simply changed very little in the six or so million years since humans and bonobos diverged. [27]

The most recent common ancestor of this group of viruses has been estimated to have existed 424  million years ago. [30]

There are five main genera infecting humans (Alpha, Beta, Gamma, Mu and Nu). The most recent common ancestor of these genera evolved 49.7  million years ago- 58.5  million years ago. [31] The most recent ancestor of the gamma genus was estimated to have evolved between 45.3  million years ago and 67.5  million years ago.[ citation needed ]

Structure

Papillomavirus capsid from bovine papillomavirus Bovine Papillomavirus Capsid.png
Papillomavirus capsid from bovine papillomavirus

Papillomaviruses are non-enveloped, meaning that the outer shell or capsid of the virus is not covered by a lipid membrane. A single viral protein, known as L1, is necessary and sufficient for formation of a 55–60 nanometer capsid composed of 72 star-shaped capsomers (see figure). Like most non-enveloped viruses, the capsid is geometrically regular and presents icosahedral symmetry. Self-assembled virus-like particles composed of L1 are the basis of a successful group of prophylactic HPV vaccines designed to elicit virus-neutralizing antibodies that protect against initial HPV infection. As such, papillomaviridæ are stable in the environment.[ citation needed ]

The papillomavirus genome is a double-stranded circular DNA molecule ~8,000 base pairs in length. It is packaged within the L1 shell along with cellular histone proteins, which serve to wrap and condense DNA.[ citation needed ]

The papillomavirus capsid also contains a viral protein known as L2, which is less abundant. Although not clear how L2 is arranged within the virion, it is known to perform several important functions, including facilitating the packaging of the viral genome into nascent virions as well as the infectious entry of the virus into new host cells. L2 is of interest as a possible target for more broadly protective HPV vaccines.

The viral capsid consists of 72 capsomeres of which 12 are five-coordinated and 60 are six-coordinated capsomeres, arranged on a T = 7d icosahedral surface lattice. [32]

Tissue specificity

Papillomaviruses replicate exclusively in keratinocytes. Keratinocytes form the outermost layers of the skin, as well as some mucosal surfaces, such as the inside of the cheek or the walls of the vagina. These surface tissues, which are known as stratified squamous epithelia, are composed of stacked layers of flattened cells. The cell layers are formed through a process known as cellular differentiation, in which keratinocytes gradually become specialized, eventually forming a hard, crosslinked surface that prevents moisture loss and acts as a barrier against pathogens. Less-differentiated keratinocyte stem cells, replenished on the surface layer, are thought to be the initial target of productive papillomavirus infections. Subsequent steps in the viral life cycle are strictly dependent on the process of keratinocyte differentiation. As a result, papillomaviruses can only replicate in body surface tissues.[ citation needed ]

Life cycle

Infectious entry

Papillomaviruses gain access to keratinocyte stem cells through small wounds, known as microtraumas, in the skin or mucosal surface. Interactions between L1 and sulfated sugars on the cell surface promote initial attachment of the virus. [33] [34] The virus is then able to get inside from the cell surface via interaction with a specific receptor, likely via the alpha-6 beta-4 integrin, [35] [36] and transported to membrane-enclosed vesicles called endosomes. [37] [38] The capsid protein L2 disrupts the membrane of the endosome through a cationic cell-penetrating peptide, allowing the viral genome to escape and traffic, along with L2, to the cell nucleus. [39] [40] [41]

Viral persistence and latency

After successful infection of a keratinocyte, the virus expresses E1 and E2 proteins, which are for replicating and maintaining the viral DNA as a circular episome. The viral oncogenes E6 and E7 promote cell growth by inactivating the tumor suppressor proteins p53 and pRb. Keratinocyte stem cells in the epithelial basement layer can maintain papillomavirus genomes for decades. [8]

Production of progeny virus

The current understanding is that viral DNA replication likely occurs in the G2 phase of the cell cycle and rely on recombination-dependent replication supported by DNA damage response mechanisms (activated by the E7 protein) to produce progeny viral genomes. [42] Papillomavirus genomes are sometimes integrated into the host genome, especially noticeable with oncogenic HPVs, but is not a normal part of the virus life cycle and a dead-end that eliminates the potential of viral progeny production. [42]

The expression of the viral late genes, L1 and L2, is exclusively restricted to differentiating keratinocytes in the outermost layers of the skin or mucosal surface. The increased expression of L1 and L2 is typically correlated with a dramatic increase in the number of copies of the viral genome. Since the outer layers of stratified squamous epithelia are subject to relatively limited surveillance by cells of the immune system, it is thought that this restriction of viral late gene expression represents a form of immune evasion.[ citation needed ]

New infectious progeny viruses are assembled in the cell nucleus. Papillomaviruses have evolved a mechanism for releasing virions into the environment. Other kinds of non-enveloped animal viruses utilize an active lytic process to kill the host cell, allowing release of progeny virus particles. Often this lytic process is associated with inflammation, which might trigger immune attack against the virus. Papillomaviruses exploit desquamation as a stealthy, non-inflammatory release mechanism.[ citation needed ]

GenusHost detailsTissue tropismEntry detailsRelease detailsReplication siteAssembly siteTransmission
DyoxipapillomavirusVertebratesNoneCell receptor endocytosisLysisNucleusNucleusContact
OmikronpapillomavirusPorpoisesEpithelial: mucous; epithelial: skinCell receptor endocytosisLysisNucleusNucleusContact
DyodeltapapillomavirusVertebratesNoneCell receptor endocytosisLysisNucleusNucleusContact
OmegapapillomavirusVertebratesEpithelial: mucous; epithelial: skinCell receptor endocytosisLysisNucleusNucleusContact
NupapillomavirusHumansEpithelial: mucous; epithelial: skinCell receptor endocytosisLysisNucleusNucleusContact
DyomupapillomavirusVertebratesNoneCell receptor endocytosisLysisNucleusNucleusContact
DyozetapapillomavirusVertebratesNoneCell receptor endocytosisLysisNucleusNucleusContact
KappapapillomavirusRabbitsEpithelial: mucous; epithelial: skinCell receptor endocytosisLysisNucleusNucleusContact
UpsilonpapillomavirusVertebratesEpithelial: mucous; epithelial: skinCell receptor endocytosisLysisNucleusNucleusContact
DyoetapapillomavirusVertebratesNoneCell receptor endocytosisLysisNucleusNucleusContact
SigmapapillomavirusVertebratesEpithelial: mucous; epithelial: skinCell receptor endocytosisLysisNucleusNucleusContact
LambdapapillomavirusCats; dogsEpithelial: mucous; epithelial: skinCell receptor endocytosisLysisNucleusNucleusContact
TaupapillomavirusVertebratesEpithelial: mucous; epithelial: skinCell receptor endocytosisLysisNucleusNucleusContact
BetapapillomavirusHumansEpithelial: mucous; epithelial: skinCell receptor endocytosisLysisNucleusNucleusContact
XipapillomavirusBovinesEpithelial: mucous; epithelial: skinCell receptor endocytosisLysisNucleusNucleusContact
DyoepsilonpapillomavirusVertebratesNoneCell receptor endocytosisLysisNucleusNucleusContact
ThetapapillomavirusBirdsEpithelial: mucous; epithelial: skinCell receptor endocytosisLysisNucleusNucleusContact
EtapapillomavirusBirdsEpithelial: skinCell receptor endocytosisLysisNucleusNucleusContact
RhopapillomavirusVertebratesEpithelial: mucous; epithelial: skinCell receptor endocytosisLysisNucleusNucleusContact
DyothetapapillomavirusVertebratesNoneCell receptor endocytosisLysisNucleusNucleusContact
DyoomikronpapillomavirusVertebratesNoneCell receptor endocytosisLysisNucleusNucleusContact
GammapapillomavirusHumansEpithelial: mucous; epithelial: skinCell receptor endocytosisLysisNucleusNucleusContact
AlphapapillomavirusHumans; monkeysEpithelial: mucous; epithelial: skinCell receptor endocytosisLysisNucleusNucleusSex; contact
ZetapapillomavirusHorsesEpithelial: mucous; epithelial: skinCell receptor endocytosisLysisNucleusNucleusContact
DeltapapillomavirusRuminantsEpithelial: mucous; epithelial: skinCell receptor endocytosisLysisNucleusNucleusContact
DyolambdapapillomavirusVertebratesNoneCell receptor endocytosisLysisNucleusNucleusContact
DyosigmapapillomavirusVertebratesNoneCell receptor endocytosisLysisNucleusNucleusContact
DyorhopapillomavirusVertebratesNoneCell receptor endocytosisLysisNucleusNucleusContact
PsipapillomavirusVertebratesEpithelial: mucous; epithelial: skinCell receptor endocytosisLysisNucleusNucleusContact
DyokappapapillomavirusVertebratesNoneCell receptor endocytosisLysisNucleusNucleusContact
PipapillomavirusHamstersEpithelial: mucous; epithelial: skinCell receptor endocytosisLysisNucleusNucleusContact
IotapapillomavirusRodentsEpithelial: mucous; epithelial: skinCell receptor endocytosisLysisNucleusNucleusContact
EpsilonpapillomavirusBovinesEpithelial: skinCell receptor endocytosisLysisNucleusNucleusContact
PhipapillomavirusVertebratesEpithelial: mucous; epithelial: skinCell receptor endocytosisLysisNucleusNucleusContact
DyonupapillomavirusVertebratesNoneCell receptor endocytosisLysisNucleusNucleusContact
DyopipapillomavirusVertebratesNoneCell receptor endocytosisLysisNucleusNucleusContact
DyoiotapapillomavirusVertebratesNoneCell receptor endocytosisLysisNucleusNucleusContact
MupapillomavirusHumansEpithelial: mucous; epithelial: skinCell receptor endocytosisLysisNucleusNucleusContact

Association with cancer

Although some papillomavirus types can cause cancer in the epithelial tissues they inhabit, cancer is not a typical outcome of infection. The development of papillomavirus-induced cancers typically occurs over the course of many years. Papillomaviruses have been associated with the development of cervical cancer, penile cancer [43] and oral cancers. [44] An association with vulval cancer and urothelial carcinoma with squamous differentiation in patients with neurogenic bladder has also been noted. [45] [46] There are cancer causing papillomavirus genome that encodes two small proteins called E6 and E7 that mimic cancer causing oncogenes. The way they work is that they stimulate unnatural growth of cells and block their natural defenses. Also they act on many signaling proteins that control proliferation and apoptosis. [47]

Laboratory study

The fact that the papillomavirus life cycle strictly requires keratinocyte differentiation has posed a substantial barrier to the study of papillomaviruses in the laboratory, since it has precluded the use of conventional cell lines to grow the viruses. Because infectious BPV-1 virions can be extracted from the large warts the virus induces on cattle, it has been a workhorse model papillomavirus type for many years. CRPV, rabbit oral papillomavirus (ROPV) and canine oral papillomavirus (COPV) have also been used extensively for laboratory studies. As soon as researchers discovered that these viruses cause cancer, they worked together to find a vaccine to it. Currently, the most effective way to go about it is to mimic a virus that is composed of L1 protein but lack the DNA. Basically, our immune system builds defenses against infections, but if these infections do not cause disease they can be used as a vaccine. PDB entry 6bt3 shows how antibodies surfaces attack the surface of the virus to disable it. [48]

Some sexually transmitted HPV types have been propagated using a mouse "xenograft" system, in which HPV-infected human cells are implanted into immunodeficient mice. More recently, some groups have succeeded in isolating infectious HPV-16 from human cervical lesions. However, isolation of infectious virions using this technique is arduous and the yield of infectious virus is very low.[ citation needed ]

The differentiation of keratinocytes can be mimicked in vitro by exposing cultured keratinocytes to an air/liquid interface. The adaptation of such "raft culture" systems to the study of papillomaviruses was a significant breakthrough for in vitro study of the viral life cycle. [49] However, raft culture systems are relatively cumbersome and the yield of infectious HPVs can be low. [50]

The development of a yeast-based system that allows stable episomal HPV replication provides a convenient, rapid and inexpensive means to study several aspects of the HPV lifecycle (Angeletti 2002). For example, E2-dependent transcription, genome amplification and efficient encapsidation of full-length HPV DNAs can be easily recreated in yeast (Angeletti 2005).

Recently, transient high-yield methods for producing HPV pseudoviruses carrying reporter genes has been developed. Although pseudoviruses are not suitable for studying certain aspects of the viral life cycle, initial studies suggest that their structure and initial infectious entry into cells is probably similar in many ways to authentic papillomaviruses.

Human papillomavirus binds to heparin molecules on the surface of the cells that it infects. Studies have shown that the crystal of isolated L1 capsomeres has the heparin chains recognized by lysines lines grooves on the surface of the virus. Also those with the antibodies show that they can block this recognition. [51]

Genetic organization and gene expression

Genome organization of Human papillomavirus type 16 HPV-16 genome organization.png
Genome organization of Human papillomavirus type 16

[52]

The papillomavirus genome is divided into an early region (E), encoding six open reading frames (ORF) (E1, E2, E4, E5, E6, and E7) that are expressed immediately after initial infection of a host cell, and a late region (L) encoding a major capsid protein L1 and a minor capsid protein L2. All viral ORFs are encoded on one DNA strand (see figure). This represents a dramatic difference between papillomaviruses and polyomaviruses, since the latter virus type expresses its early and late genes by bi-directional transcription of both DNA strands. This difference was a major factor in establishment of the consensus that papillomaviruses and polyomaviruses probably never shared a common ancestor, despite the striking similarities in the structures of their virions.[ citation needed ]

After the host cell is infected, HPV16 early promoter is activated and a polycistronic primary RNA containing all six early ORFs is transcribed. This polycistronic RNA contains three exons and two introns and undergoes active RNA splicing to generate multiple isoforms of mRNAs. [52] One of the spliced isoform RNAs, E6*I, serves as an E7 mRNA to translate E7 oncoprotein. [53] In contrast, an intron in the E6 ORF that remains intact without splicing is necessary for translation of E6 oncoprotein. [53] However, viral early transcription subjects to viral E2 regulation and high E2 levels repress the transcription. HPV genomes integrate into host genome by disruption of E2 ORF, preventing E2 repression on E6 and E7. Thus, viral genome integration into host DNA genome increases E6 and E7 expression to promote cellular proliferation and the chance of malignancy.[ citation needed ]

A major viral late promoter in viral early region becomes active only in differentiated cells and its activity can be highly enhanced by viral DNA replication. The late transcript is also a polycistronic RNA which contains two introns and three exons. Alternative RNA Splicing of this late transcript is essential for L1 and L2 expression and can be regulated by RNA cis-elements and host splicing factors. [52] [54] [55]

Technical discussion of papillomavirus gene functions

Genes within the papillomavirus genome are usually identified after similarity with other previously identified genes. However, some spurious open reading frames might have been mistaken as genes simply after their position in the genome, and might not be true genes. This applies specially to certain E3, E4, E5 and E8 open reading frames.[ citation needed ]

E1

Encodes a protein that binds to the viral origin of replication in the long control region of the viral genome. E1 uses ATP to exert a helicase activity that forces apart the DNA strands, thus preparing the viral genome for replication by cellular DNA replication factors.

E2

The E2 protein serves as a master transcriptional regulator for viral promoters located primarily in the long control region. The protein has a transactivation domain linked by a relatively unstructured hinge region to a well-characterized DNA binding domain. E2 facilitates the binding of E1 to the viral origin of replication. E2 also utilizes a cellular protein known as Bromodomain-4 (Brd4) to tether the viral genome to cellular chromosomes. [56] This tethering to the cell's nuclear matrix ensures faithful distribution of viral genomes to each daughter cell after cell division. It is thought that E2 serves as a negative regulator of expression for the oncogenes E6 and E7 in latently HPV-infected basal layer keratinocytes. Genetic changes, such as integration of the viral DNA into a host cell chromosome, that inactivate E2 expression tend to increase the expression of the E6 and E7 oncogenes, resulting in cellular transformation and possibly further genetic destabilization.

E3

This small putative gene exists only in a few papillomavirus types. The gene is not known to be expressed as a protein and does not appear to serve any function.

E4

Although E4 proteins are expressed at low levels during the early phase of viral infection, expression of E4 increases dramatically during the late phase of infection. In other words, its "E" appellation may be something of a misnomer. In the case of HPV-1, E4 can account for up to 30% of the total protein at the surface of a wart. [57] The E4 protein of many papillomavirus types is thought to facilitate virion release into the environment by disrupting intermediate filaments of the keratinocyte cytoskeleton. Viral mutants incapable of expressing E4 do not support high-level replication of the viral DNA, but it is not yet clear how E4 facilitates DNA replication. E4 has also been shown to participate in arresting cells in the G2 phase of the cell cycle.

E5

The E5 are small, very hydrophobic proteins that destabilise the function of many membrane proteins in the infected cell. [58] The E5 protein of some animal papillomavirus types (mainly bovine papillomavirus type 1) functions as an oncogene primarily by activating the cell growth-promoting signaling of platelet-derived growth factor receptors. The E5 proteins of human papillomaviruses associated to cancer, however, seem to activate the signal cascade initiated by epidermal growth factor upon ligand binding. HPV16 E5 and HPV2 E5 have also been shown to down-regulate the surface expression of major histocompatibility complex class I proteins, which may prevent the infected cell from being eliminated by killer T cells.

E6

Structure of Sap97 PDZ3 bound to the C-terminal peptide of HPV18 E6 2i0i bio r 250.jpg
Structure of Sap97 PDZ3 bound to the C-terminal peptide of HPV18 E6

E6 is a 151 amino-acid peptide that incorporates a type 1 motif with a consensus sequence –(T/S)-(X)-(V/I)-COOH. [60] [61] It also has two zinc finger motifs. [60]

E6 is of particular interest because it appears to have multiple roles in the cell and to interact with many other proteins. Its major role, however, is to mediate the degradation of p53, a major tumor suppressor protein, reducing the cell's ability to respond to DNA damage. [62] [63]

E6 has also been shown to target other cellular proteins, thereby altering several metabolic pathways. One such target is NFX1-91, which normally represses production of telomerase, a protein that allows cells to divide an unlimited number of times. When NFX1-91 is degraded by E6, telomerase levels increase, inactivating a major mechanism keeping cell growth in check. [64] Additionally, E6 can act as a transcriptional cofactor—specifically, a transcription activator—when interacting with the cellular transcription factor, E2F1/DP1. [60]

E6 can also bind to PDZ-domains, short sequences which are often found in signaling proteins. E6's structural motif allows for interaction with PDZ domains on DLG (discs large) and hDLG (Drosophila large) tumor suppressor genes. [61] [65] Binding at these locations causes transformation of the DLG protein and disruption of its suppressor function. E6 proteins also interact with the MAGUK (membrane-associated guanylate kinase family) proteins. These proteins, including MAGI-1, MAGI-2, and MAGI-3 are usually structural proteins, and can help with signaling. [61] [65] More significantly, they are believed to be involved with DLG's suppression activity. When E6 complexes with the PDZ domains on the MAGI proteins, it distorts their shape and thereby impedes their function. Overall, the E6 protein serves to impede normal protein activity in such a way as to allow a cell to grow and multiply at the increased rate characteristic of cancer.

Since the expression of E6 is strictly required for maintenance of a malignant phenotype in HPV-induced cancers, it is an appealing target of therapeutic HPV vaccines designed to eradicate established cervical cancer tumors.

E7

In most papillomavirus types, the primary function of the E7 protein is to inactivate members of the pRb family of tumor suppressor proteins. Together with E6, E7 serves to prevent cell death (apoptosis) and promote cell cycle progression, thus priming the cell for replication of the viral DNA. E7 also participates in immortalization of infected cells by activating cellular telomerase. Like E6, E7 is the subject of intense research interest and is believed to exert a wide variety of other effects on infected cells. As with E6, the ongoing expression of E7 is required for survival of cancer cell lines, such as HeLa, that are derived from HPV-induced tumors. [66]

E8

Only a few papillomavirus types encode a short protein from the E8 gene. In the case of BPV-4 (papillomavirus genus Xi), the E8 open reading frame may substitute for the E6 open reading frame, which is absent in this papillomavirus genus. [67] These E8 genes are chemically and functionally similar to the E5 genes from some human papillomaviruses, and are also called E5/E8.

L1

L1 spontaneously self-assembles into pentameric capsomers. Purified capsomers can go on to form capsids, which are stabilized by disulfide bonds between neighboring L1 molecules. L1 capsids assembled in vitro are the basis of prophylactic vaccines against several HPV types. Compared to other papillomavirus genes, the amino acid sequences of most portions of L1 are well-conserved between types. However, the surface loops of L1 can differ substantially, even for different members of a particular papillomavirus species. This probably reflects a mechanism for evasion of neutralizing antibody responses elicited by previous papillomavirus infections. [68]

L2

L2 exists in an oxidized state within the papillomavirus virion, with the two conserved cysteine residues forming an intramolecular disulfide bond. [69] In addition to cooperating with L1 to package the viral DNA into the virion, L2 has been shown to interact with a number of cellular proteins during the infectious entry process. After the initial binding of the virion to the cell, L2 must be cleaved by the cellular protease furin. [70] The virion is internalized, probably through a clathrin-mediated process, into an endosome, where acidic conditions are thought to lead to exposure of membrane-destabilizing portions of L2. [39] The cellular proteins beta-actin [71] and syntaxin-18 [72] may also participate in L2-mediated entry events. After endosome escape, L2 and the viral genome are imported into the cell nucleus where they traffic to a sub-nuclear domain known as an ND-10 body that is rich in transcription factors. [40] Small portions of L2 are well-conserved between different papillomavirus types, and experimental vaccines targeting these conserved domains may offer protection against a broad range of HPV types. [73]

See also

Related Research Articles

<span class="mw-page-title-main">Human papillomavirus infection</span> Human disease

Human papillomavirus infection is caused by a DNA virus from the Papillomaviridae family. Many HPV infections cause no symptoms and 90% resolve spontaneously within two years. In some cases, an HPV infection persists and results in either warts or precancerous lesions. These lesions, depending on the site affected, increase the risk of cancer of the cervix, vulva, vagina, penis, anus, mouth, tonsils, or throat. Nearly all cervical cancer is due to HPV, and two strains – HPV16 and HPV18 – account for 70% of all cases. HPV16 is responsible for almost 90% of HPV-positive oropharyngeal cancers. Between 60% and 90% of the other cancers listed above are also linked to HPV. HPV6 and HPV11 are common causes of genital warts and laryngeal papillomatosis.

<span class="mw-page-title-main">Poliovirus</span> Enterovirus

Poliovirus, the causative agent of polio, is a serotype of the species Enterovirus C, in the family of Picornaviridae. There are three poliovirus serotypes: types 1, 2, and 3.

<i>Hepadnaviridae</i> Family of viruses

Hepadnaviridae is a family of viruses. Humans, apes, and birds serve as natural hosts. There are currently 18 species in this family, divided among 5 genera. Its best-known member is hepatitis B virus. Diseases associated with this family include: liver infections, such as hepatitis, hepatocellular carcinomas, and cirrhosis. It is the sole accepted family in the order Blubervirales.

<i>Polyomaviridae</i> Family of viruses

Polyomaviridae is a family of viruses whose natural hosts are primarily mammals and birds. As of 2020, there are six recognized genera and 117 species, five of which are unassigned to a genus. 14 species are known to infect humans, while others, such as Simian Virus 40, have been identified in humans to a lesser extent. Most of these viruses are very common and typically asymptomatic in most human populations studied. BK virus is associated with nephropathy in renal transplant and non-renal solid organ transplant patients, JC virus with progressive multifocal leukoencephalopathy, and Merkel cell virus with Merkel cell cancer.

<span class="mw-page-title-main">Oncovirus</span> Viruses that can cause cancer

An oncovirus or oncogenic virus is a virus that can cause cancer. This term originated from studies of acutely transforming retroviruses in the 1950–60s, when the term "oncornaviruses" was used to denote their RNA virus origin. With the letters "RNA" removed, it now refers to any virus with a DNA or RNA genome causing cancer and is synonymous with "tumor virus" or "cancer virus". The vast majority of human and animal viruses do not cause cancer, probably because of longstanding co-evolution between the virus and its host. Oncoviruses have been important not only in epidemiology, but also in investigations of cell cycle control mechanisms such as the retinoblastoma protein.

<span class="mw-page-title-main">Adeno-associated virus</span> Species of virus

Adeno-associated viruses (AAV) are small viruses that infect humans and some other primate species. They belong to the genus Dependoparvovirus, which in turn belongs to the family Parvoviridae. They are small replication-defective, nonenveloped viruses and have linear single-stranded DNA (ssDNA) genome of approximately 4.8 kilobases (kb).

<i>Herpesviridae</i> Family of DNA viruses

Herpesviridae is a large family of DNA viruses that cause infections and certain diseases in animals, including humans. The members of this family are also known as herpesviruses. The family name is derived from the Greek word ἕρπειν, referring to spreading cutaneous lesions, usually involving blisters, seen in flares of herpes simplex 1, herpes simplex 2 and herpes zoster (shingles). In 1971, the International Committee on the Taxonomy of Viruses (ICTV) established Herpesvirus as a genus with 23 viruses among four groups. As of 2020, 115 species are recognized, all but one of which are in one of the three subfamilies. Herpesviruses can cause both latent and lytic infections.

<i>Cardiovirus</i> Genus of viruses

Cardiovirus are a group of viruses within order Picornavirales, family Picornaviridae. Vertebrates serve as natural hosts for these viruses.

<span class="mw-page-title-main">Herpes simplex virus</span> Species of virus

Herpes simplex virus1 and 2, also known by their taxonomic names Human alphaherpesvirus 1 and Human alphaherpesvirus 2, are two members of the human Herpesviridae family, a set of viruses that produce viral infections in the majority of humans. Both HSV-1 and HSV-2 are very common and contagious. They can be spread when an infected person begins shedding the virus.

Simian foamy virus (SFV) is a species of the genus Spumavirus that belongs to the family of Retroviridae. It has been identified in a wide variety of primates, including prosimians, New World and Old World monkeys, as well as apes, and each species has been shown to harbor a unique (species-specific) strain of SFV, including African green monkeys, baboons, macaques, and chimpanzees. As it is related to the more well-known retrovirus human immunodeficiency virus (HIV), its discovery in primates has led to some speculation that HIV may have been spread to the human species in Africa through contact with blood from apes, monkeys, and other primates, most likely through bushmeat-hunting practices.

<span class="mw-page-title-main">Bovine papillomavirus</span> Group of viruses

Bovine papillomaviruses (BPV) are a paraphyletic group of DNA viruses of the subfamily Firstpapillomavirinae of Papillomaviridae that are common in cattle. All BPVs have a circular double-stranded DNA genome. Infection causes warts of the skin and alimentary tract, and more rarely cancers of the alimentary tract and urinary bladder. They are also thought to cause the skin tumour equine sarcoid in horses and donkeys.

<span class="mw-page-title-main">Shope papilloma virus</span> Papilloma virus which infects certain leporids

The Shope papilloma virus (SPV), also known as cottontail rabbit papilloma virus (CRPV) or Kappapapillomavirus 2, is a papillomavirus which infects certain leporids, causing keratinous carcinomas resembling horns, typically on or near the animal's head. The carcinomas can metastasize or become large enough to interfere with the host's ability to eat, causing starvation. Richard E. Shope investigated the horns and discovered the virus in 1933, an important breakthrough in the study of oncoviruses. The virus was originally discovered in cottontail rabbits in the Midwestern U.S. but can also infect brush rabbits, black-tailed jackrabbits, snowshoe hares, European rabbits, and domestic rabbits.

Gyrovirus is a genus of viruses, in the family Anelloviridae. Until 2011, chicken anemia virus was the only Gyrovirus identified, but since then gyroviruses have also been identified in humans. Diseases associated with this genus include: chicken infectious anemia, which is associated with depletion of cortical thymocytes and erythroblastoid cells.

HspE7 is an investigational therapeutic vaccine candidate being developed by Nventa Biopharmaceuticals for the treatment of precancerous and cancerous lesions caused by the human papillomavirus (HPV). HspE7 uses recombinant DNA technology to covalently fuse a heat shock protein (Hsp) to a target antigen, thereby stimulating cellular immune system responses to specific diseases. HspE7 is a patented construct consisting of the HPV Type 16 E7 protein and heat shock protein 65 (Hsp65) and is currently the only candidate using Hsp technology to target the over 20 million Americans already infected with HPV.

<span class="mw-page-title-main">Virus</span> Infectious agent that replicates in cells

A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898, more than 11,000 of the millions of virus species have been described in detail. The study of viruses is known as virology, a subspeciality of microbiology.

<span class="mw-page-title-main">Late protein</span>

A late protein is a viral protein that is formed after replication of the virus. One example is VP4 from simian virus 40 (SV40).

<span class="mw-page-title-main">Agnoprotein</span> Viral protein found in some polyomaviruses

Agnoprotein is a protein expressed by some members of the polyomavirus family from a gene called the agnogene. Polyomaviruses in which it occurs include two human polyomaviruses associated with disease, BK virus and JC virus, as well as the simian polyomavirus SV40.

A kinetic class, also known as a temporal class, is a grouping of genes in a viral genome that are expressed at the same time during the viral replication cycle. Five of the human DNA viral families have multiple kinetic classes: Poxviridae, Herpesviridae, Adenoviridae, Papillomaviridae, and Polyomaviridae. All of the genes in a particular kinetic class are activated by the same mechanism: either by the process of the virus entering the cell and uncoating, or by the products of an earlier kinetic class in what is known as a transcriptional cascade. Generally speaking, earlier kinetic classes code for enzymes that direct the viral replication process, and later kinetic classes code for structural proteins to be packaged into virions

<i>Woolly monkey hepatitis B virus</i> Species of virus

The woolly monkey hepatitis B virus (WMHBV) is a viral species of the Orthohepadnavirus genus of the Hepadnaviridae family. Its natural host is the woolly monkey (Lagothrix), an inhabitant of South America categorized as a New World primate. WMHBV, like other hepatitis viruses, infects the hepatocytes, or liver cells, of its host organism. It can cause hepatitis, liver necrosis, cirrhosis, and hepatocellular carcinoma. Because nearly all species of Lagothrix are threatened or endangered, researching and developing a vaccine and/or treatment for WMHBV is important for the protection of the whole woolly monkey genus.

Michelle Adair Ozbun is an American molecular virologist who is the Maralyn S. Budke Endowed Professor in Viral Oncology at the University of New Mexico School of Medicine. Her research considers cancer biology and how human papillomavirus infections cause pathology including their contributions to cancers.

References

  1. ↑ Van Doorslaer, K; Chen, Z; Bernard, HU; Chan, PKS; DeSalle, R; Dillner, J; Forslund, O; Haga, T; McBride, AA; Villa, LL; Burk, RD; Ictv Report, Consortium (August 2018). "ICTV Virus Taxonomy Profile: Papillomaviridae". The Journal of General Virology. 99 (8): 989–990. doi:10.1099/jgv.0.001105. PMC   6171710 . PMID   29927370.
  2. 1 2 3 de Villiers EM, Fauquet C, Broker TR, Bernard HU, zur Hausen H (June 2004). "Classification of papillomaviruses". Virology. 324 (1): 17–27. doi: 10.1016/j.virol.2004.03.033 . PMID   15183049.
  3. ↑ Herbst LH, Lenz J, Van Doorslaer K, Chen Z, Stacy BA, Wellehan JF, Manire CA, Burk RD (January 2009). "Genomic characterization of two novel reptilian papillomaviruses, Chelonia mydas papillomavirus 1 and Caretta caretta papillomavirus 1". Virology. 383 (1): 131–5. doi: 10.1016/j.virol.2008.09.022 . PMID   18973915.
  4. ↑ Drury SE, Gough RE, McArthur S, Jessop M (December 1998). "Detection of herpesvirus-like and papillomavirus-like particles associated with diseases of tortoises". The Veterinary Record. 143 (23): 639. PMID   9881444.
  5. ↑ Lange CE, Favrot C, Ackermann M, Gull J, Vetsch E, Tobler K (September 2011). "Novel snake papillomavirus does not cluster with other non-mammalian papillomaviruses". Virology Journal. 8: 436. doi: 10.1186/1743-422X-8-436 . PMC   3179961 . PMID   21910860.
  6. ↑ Muñoz N, Castellsagué X, de González AB, Gissmann L (August 2006). "Chapter 1: HPV in the etiology of human cancer". Vaccine. 24 Suppl 3 (3): S3/1–10. doi:10.1016/j.vaccine.2006.05.115. PMID   16949995.
  7. ↑ Mistry N, Wibom C, Evander M (October 2008). "Cutaneous and mucosal human papillomaviruses differ in net surface charge, potential impact on tropism". Virology Journal. 5: 118. doi: 10.1186/1743-422X-5-118 . PMC   2571092 . PMID   18854037.
  8. 1 2 Doorbar J (March 2005). "The papillomavirus life cycle". Journal of Clinical Virology. 32 (Suppl 1): S7–15. doi:10.1016/j.jcv.2004.12.006. PMID   15753007.
  9. ↑ Kocjan BJ, Hosnjak L, Seme K, Poljak M (May 2013). "Complete Genome Sequence of a Novel Human Betapapillomavirus, HPV-159". Genome Announcements. 1 (3): e00298–13. doi:10.1128/genomeA.00298-13. PMC   3668007 . PMID   23723399.
  10. ↑ "Virus Taxonomy: 2018b Release". International Committee on Taxonomy of Viruses. February 2019. Retrieved 26 March 2019.
  11. ↑ "Virus Taxonomy: 2014 Release". ICTV. Retrieved 15 June 2015.
  12. ↑ Bernard HU, Burk RD, Chen Z, van Doorslaer K, zur Hausen H, de Villiers EM (May 2010). "Classification of papillomaviruses (PVs) based on 189 PV types and proposal of taxonomic amendments". Virology. 401 (1): 70–9. doi:10.1016/j.virol.2010.02.002. PMC   3400342 . PMID   20206957.
  13. 1 2 3 Gottschling M, Stamatakis A, Nindl I, Stockfleth E, Alonso Á, Bravo IG (2007). "Multiple evolutionary mechanisms drive papillomavirus diversification". Molecular Biology and Evolution. 24 (5): 1242–58. doi: 10.1093/molbev/msm039 . PMID   17344207.
  14. ↑ Campo MS, ed. (2006). Papillomavirus Research: From Natural History To Vaccines and Beyond. Caister Academic Press. ISBN   978-1-904455-04-2. .
  15. ↑ Bravo IG, de Sanjosé Llongueras S, Gottschling M (2010). "The clinical importance of knowledge about papillomavirus evolution". Trends in Microbiology. 18 (10): 432–8. doi:10.1016/j.tim.2010.07.008. PMID   20739182.
  16. ↑ Rector A, Van Ranst M (October 2013). "Animal papillomaviruses". Virology. 445 (1–2): 213–23. doi: 10.1016/j.virol.2013.05.007 . PMID   23711385.
  17. ↑ López-Bueno A, Mavian C, Labella AM, Castro D, Borrego JJ, Alcami A, Alejo A (October 2016). "Concurrence of Iridovirus, Polyomavirus, and a Unique Member of a New Group of Fish Papillomaviruses in Lymphocystis Disease-Affected Gilthead Sea Bream". Journal of Virology. 90 (19): 8768–79. doi:10.1128/JVI.01369-16. PMC   5021401 . PMID   27440877.
  18. ↑ Chouhy D, Bolatti EM, Pérez GR, Giri AA (November 2013). "Analysis of the genetic diversity and phylogenetic relationships of putative human papillomavirus types". The Journal of General Virology. 94 (Pt 11): 2480–8. doi: 10.1099/vir.0.055137-0 . hdl: 2133/9862 . PMID   23997181.
  19. ↑ Antonsson A, Hansson BG (December 2002). "Healthy skin of many animal species harbors papillomaviruses which are closely related to their human counterparts". Journal of Virology. 76 (24): 12537–42. doi:10.1128/JVI.76.24.12537-12542.2002. PMC   136724 . PMID   12438579.
  20. ↑ Holliday, Chuck. "Prof. Chuck Holliday's www page at Lafayette College » Jackalopes". Archived from the original on 2014-07-18. Retrieved 2014-07-13.
  21. ↑ Christensen ND (2005). "Cottontail rabbit papillomavirus (CRPV) model system to test antiviral and immunotherapeutic strategies". Antiviral Chemistry & Chemotherapy. 16 (6): 355–62. doi: 10.1177/095632020501600602 . PMID   16331841.
  22. ↑ Coggins LW, Ma JQ, Slater AA, Campo MS (June 1985). "Sequence homologies between bovine papillomavirus genomes mapped by a novel low-stringency heteroduplex method". Virology. 143 (2): 603–11. doi:10.1016/0042-6822(85)90398-8. PMID   2998027.
  23. ↑ Van Ranst M, Tachezy R, Pruss J, Burk RD (June 1992). "Primary structure of the E6 protein of Micromys minutus papillomavirus and Mastomys natalensis papillomavirus". Nucleic Acids Research. 20 (11): 2889. doi:10.1093/nar/20.11.2889. PMC   336941 . PMID   1319576.
  24. ↑ Varsani A, Kraberger S, Jennings S, Porzig EL, Julian L, Massaro M, Pollard A, Ballard G, Ainley DG (June 2014). "A novel papillomavirus in Adélie penguin (Pygoscelis adeliae) faeces sampled at the Cape Crozier colony, Antarctica". The Journal of General Virology. 95 (Pt 6): 1352–65. doi: 10.1099/vir.0.064436-0 . PMID   24686913. S2CID   206218507.
  25. ↑ Gottschling M, Göker M, Stamatakis A, Bininda-Emonds OR, Nindl I, Bravo IG (July 2011). "Quantifying the phylodynamic forces driving papillomavirus evolution". Molecular Biology and Evolution. 28 (7): 2101–13. doi: 10.1093/molbev/msr030 . PMID   21285031.
  26. ↑ Ho L, Chan SY, Burk RD, Das BC, Fujinaga K, Icenogle JP, Kahn T, Kiviat N, Lancaster W, Mavromara-Nazos P (November 1993). "The genetic drift of human papillomavirus type 16 is a means of reconstructing prehistoric viral spread and the movement of ancient human populations". Journal of Virology. 67 (11): 6413–23. doi:10.1128/JVI.67.11.6413-6423.1993. PMC   238076 . PMID   8411343.
  27. 1 2 Calleja-Macias IE, Villa LL, Prado JC, Kalantari M, Allan B, Williamson AL, Chung LP, Collins RJ, Zuna RE, Dunn ST, Chu TY, Cubie HA, Cuschieri K, von Knebel-Doeberitz M, Martins CR, Sanchez GI, Bosch FX, Munoz N, Bernard HU (November 2005). "Worldwide genomic diversity of the high-risk human papillomavirus types 31, 35, 52, and 58, four close relatives of human papillomavirus type 16". Journal of Virology. 79 (21): 13630–40. doi:10.1128/JVI.79.21.13630-13640.2005. PMC   1262609 . PMID   16227283.
  28. ↑ Gottschling M, Göker M, Köhler A, Lehmann MD, Stockfleth E, Nindl I (2009). "Cutaneotropic β-/γ-HPV types are rarely shared between family members". Journal of Investigative Dermatology. 129 (10): 2427–34. doi: 10.1038/jid.2009.94 . PMID   19516265.
  29. ↑ Van Ranst M, Fuse A, Fiten P, Beuken E, Pfister H, Burk RD, Opdenakker G (October 1992). "Human papillomavirus type 13 and pygmy chimpanzee papillomavirus type 1: comparison of the genome organizations". Virology. 190 (2): 587–96. doi:10.1016/0042-6822(92)90896-W. PMID   1325697.
  30. ↑ Willemsen A, Bravo IG (2019) Origin and evolution of papillomavirus (onco)genes and genomes. Philos Trans R Soc Lond B Biol Sci. 374(1773):20180303
  31. ↑ Murahwa AT, Nindo F, Onywera H, Meiring TL, Martin DP, Williamson AL (2019) Evolutionary dynamics of ten novel Gamma-PVs: insights from phylogenetic incongruence, recombination and phylodynamic analyses. BMC Genomics 20(1):368
  32. ↑ Rayment I, Baker TS, Caspar DL, Murakami WT (January 1982). "Polyoma virus capsid structure at 22.5 A resolution". Nature. 295 (5845): 110–5. Bibcode:1982Natur.295..110R. doi:10.1038/295110a0. PMC   4144041 . PMID   6276752.
  33. ↑ Joyce JG, Tung JS, Przysiecki CT, Cook JC, Lehman ED, Sands JA, Jansen KU, Keller PM (February 1999). "The L1 major capsid protein of human papillomavirus type 11 recombinant virus-like particles interacts with heparin and cell-surface glycosaminoglycans on human keratinocytes". The Journal of Biological Chemistry. 274 (9): 5810–22. doi: 10.1074/jbc.274.9.5810 . PMID   10026203.
  34. ↑ Giroglou T, Florin L, Schäfer F, Streeck RE, Sapp M (February 2001). "Human papillomavirus infection requires cell surface heparan sulfate". Journal of Virology. 75 (3): 1565–70. doi:10.1128/JVI.75.3.1565-1570.2001. PMC   114064 . PMID   11152531.
  35. ↑ Evander M, Frazer IH, Payne E, Qi YM, Hengst K, McMillan NA (March 1997). "Identification of the alpha6 integrin as a candidate receptor for papillomaviruses". Journal of Virology. 71 (3): 2449–56. doi:10.1128/JVI.71.3.2449-2456.1997. PMC   191355 . PMID   9032382.
  36. ↑ McMillan NA, Payne E, Frazer IH, Evander M (September 1999). "Expression of the alpha6 integrin confers papillomavirus binding upon receptor-negative B-cells". Virology. 261 (2): 271–9. doi: 10.1006/viro.1999.9825 . PMID   10497112.
  37. ↑ Selinka HC, Giroglou T, Sapp M (August 2002). "Analysis of the infectious entry pathway of human papillomavirus type 33 pseudovirions". Virology. 299 (2): 279–287. doi: 10.1006/viro.2001.1493 . PMID   12202231.
  38. ↑ Day PM, Lowy DR, Schiller JT (March 2003). "Papillomaviruses infect cells via a clathrin-dependent pathway". Virology. 307 (1): 1–11. doi: 10.1016/S0042-6822(02)00143-5 . PMID   12667809.
  39. 1 2 Kämper N, Day PM, Nowak T, Selinka HC, Florin L, Bolscher J, Hilbig L, Schiller JT, Sapp M (January 2006). "A membrane-destabilizing peptide in capsid protein L2 is required for egress of papillomavirus genomes from endosomes". Journal of Virology. 80 (2): 759–68. doi:10.1128/JVI.80.2.759-768.2006. PMC   1346844 . PMID   16378978.
  40. 1 2 Day PM, Baker CC, Lowy DR, Schiller JT (September 2004). "Establishment of papillomavirus infection is enhanced by promyelocytic leukemia protein (PML) expression". Proceedings of the National Academy of Sciences of the United States of America. 101 (39): 14252–7. Bibcode:2004PNAS..10114252D. doi: 10.1073/pnas.0404229101 . PMC   521143 . PMID   15383670.
  41. ↑ Zhang, Pengwei; Monteiro Da Silva, Gabriel; Deatherage, Catherine; Burd, Christopher; Dimaio, Daniel (2018). "Cell-Penetrating Peptide Mediates Intracellular Membrane Passage of Human Papillomavirus L2 Protein to Trigger Retrograde Trafficking". Cell. 174 (6): 1465–1476.e13. doi:10.1016/j.cell.2018.07.031. PMC   6128760 . PMID   30122350.
  42. 1 2 Alison A. McBride (18 March 2017). "Mechanisms and strategies of papillomavirus replication". Biological Chemistry . 398 (8): 919–927. doi:10.1515/HSZ-2017-0113. ISSN   1431-6730. PMID   28315855. Wikidata   Q39186071.
  43. ↑ Do HT, Koriyama C, Khan NA, Higashi M, Kato T, Le NT, Matsushita S, Kanekura T, Akiba S (January 2013). "The etiologic role of human papillomavirus in penile cancers: a study in Vietnam". British Journal of Cancer. 108 (1): 229–33. doi:10.1038/bjc.2012.583. PMC   3553541 . PMID   23299525.
  44. ↑ Gogilashvili K, Shonia N, Burkadze G (December 2012). "The role of human papillomavirus in oral squamous cell carcinoma (review)". Georgian Medical News (213): 32–6. PMID   23293230.
  45. ↑ Preti M, Rotondo JC, Holzinger D, Micheletti L, Gallio N, McKay-Chopin S, Carreira C, Privitera SS, Watanabe R, Ridder R, Pawlita M, Benedetto C, Tommasino M, Gheit T (2020). "Role of Human Papillomavirus Infection in the Etiology of Vulvar Cancer in Italian Women". Infect Agents Cancer. 20: 20. doi: 10.1186/s13027-020-00286-8 . PMC   7110671 . PMID   32266002.
  46. ↑ Tolstov Y, Hadaschik B, Pahernik S, Hohenfellner M, Duensing S (January 2014). "Human papillomaviruses in urological malignancies: a critical assessment". Urologic Oncology. 32 (1): 46.e19–27. doi:10.1016/j.urolonc.2013.06.012. PMID   24140249.
  47. ↑ "PDB101: Molecule of the Month: Human Papillomavirus and Vaccines". RCSB: PDB-101. Retrieved 2018-05-14.
  48. ↑ Guan J, Bywaters SM, Brendle SA, Ashley RE, Makhov AM, Conway JF, Christensen ND, Hafenstein S (6 December 2017). "High-Resolution Structure Analysis of Antibody V5 Conformational Epitope on Human Papillomavirus 16". Viruses. 9 (12): 374. doi: 10.3390/v9120374 . PMC   5744149 . PMID   29211035.
  49. ↑ Meyers C, Frattini MG, Hudson JB, Laimins LA (August 1992). "Biosynthesis of human papillomavirus from a continuous cell line upon epithelial differentiation". Science. 257 (5072): 971–3. Bibcode:1992Sci...257..971M. doi:10.1126/science.1323879. PMID   1323879.
  50. ↑ McLaughlin-Drubin ME, Christensen ND, Meyers C (May 2004). "Propagation, infection, and neutralization of authentic HPV16 virus". Virology. 322 (2): 213–9. doi: 10.1016/j.virol.2004.02.011 . PMID   15110519.
  51. ↑ Goodsell, D.S (2018). "Human Papillomavirus and Vaccines". RCSB Protein Data Bank. doi:10.2210/rcsb_pdb/mom_2018_5.
  52. 1 2 3 Zheng ZM, Baker CC (September 2006). "Papillomavirus genome structure, expression, and post-transcriptional regulation". Frontiers in Bioscience. 11: 2286–302. doi:10.2741/1971. PMC   1472295 . PMID   16720315.
  53. 1 2 Tang S, Tao M, McCoy JP, Zheng ZM (May 2006). "The E7 oncoprotein is translated from spliced E6*I transcripts in high-risk human papillomavirus type 16- or type 18-positive cervical cancer cell lines via translation reinitiation". Journal of Virology. 80 (9): 4249–63. doi:10.1128/JVI.80.9.4249-4263.2006. PMC   1472016 . PMID   16611884.
  54. ↑ Wang X, Meyers C, Wang HK, Chow LT, Zheng ZM (August 2011). "Construction of a full transcription map of human papillomavirus type 18 during productive viral infection". Journal of Virology. 85 (16): 8080–92. doi:10.1128/JVI.00670-11. PMC   3147953 . PMID   21680515.
  55. ↑ Jia R, Liu X, Tao M, Kruhlak M, Guo M, Meyers C, Baker CC, Zheng ZM (January 2009). "Control of the papillomavirus early-to-late switch by differentially expressed SRp20". Journal of Virology. 83 (1): 167–80. doi:10.1128/JVI.01719-08. PMC   2612334 . PMID   18945760.
  56. ↑ McBride AA, McPhillips MG, Oliveira JG (December 2004). "Brd4: tethering, segregation and beyond". Trends in Microbiology. 12 (12): 527–9. doi:10.1016/j.tim.2004.10.002. PMID   15539109.
  57. ↑ Doorbar J, Campbell D, Grand RJ, Gallimore PH (February 1986). "Identification of the human papilloma virus-1a E4 gene products". The EMBO Journal. 5 (2): 355–62. doi:10.1002/j.1460-2075.1986.tb04219.x. PMC   1166739 . PMID   3011404.
  58. ↑ Bravo IG, Alonso A (December 2004). "Mucosal human papillomaviruses encode four different E5 proteins whose chemistry and phylogeny correlate with malignant or benign growth". Journal of Virology. 78 (24): 13613–26. doi:10.1128/JVI.78.24.13613-13626.2004. PMC   533923 . PMID   15564472.
  59. ↑ "PDB 2I0I".
  60. 1 2 3 Gupta S, Takhar PP, Degenkolbe R, Koh CH, Zimmermann H, Yang CM, Guan Sim K, Hsu SI, Bernard HU (December 2003). "The human papillomavirus type 11 and 16 E6 proteins modulate the cell-cycle regulator and transcription cofactor TRIP-Br1". Virology. 317 (1): 155–64. doi: 10.1016/j.virol.2003.08.008 . PMID   14675634.
  61. 1 2 3 Glaunsinger BA, Lee SS, Thomas M, Banks L, Javier R (November 2000). "Interactions of the PDZ-protein MAGI-1 with adenovirus E4-ORF1 and high-risk papillomavirus E6 oncoproteins". Oncogene. 19 (46): 5270–80. doi:10.1038/sj.onc.1203906. PMC   3072458 . PMID   11077444.
  62. ↑ "iHOP information Hyperlinked over Proteins UBE3A". Archived from the original on 2007-09-27. Retrieved 2007-05-01.
  63. ↑ "Biochemistry, Nottingham University – 3.0 Enzymes of the Ubiquitin Pathway". Archived from the original on 2007-05-06. Retrieved 2007-05-01.
  64. ↑ Kelley ML, Keiger KE, Lee CJ, Huibregtse JM (March 2005). "The global transcriptional effects of the human papillomavirus E6 protein in cervical carcinoma cell lines are mediated by the E6AP ubiquitin ligase". Journal of Virology. 79 (6): 3737–47. doi:10.1128/JVI.79.6.3737-3747.2005. PMC   1075713 . PMID   15731267.
  65. 1 2 Kiyono T, Hiraiwa A, Fujita M, Hayashi Y, Akiyama T, Ishibashi M (October 1997). "Binding of high-risk human papillomavirus E6 oncoproteins to the human homologue of the Drosophila discs large tumor suppressor protein". Proceedings of the National Academy of Sciences of the United States of America. 94 (21): 11612–6. Bibcode:1997PNAS...9411612K. doi: 10.1073/pnas.94.21.11612 . PMC   23554 . PMID   9326658.
  66. ↑ Nishimura A, Nakahara T, Ueno T, Sasaki K, Yoshida S, Kyo S, Howley PM, Sakai H (April 2006). "Requirement of E7 oncoprotein for viability of HeLa cells". Microbes and Infection. 8 (4): 984–93. doi:10.1016/j.micinf.2005.10.015. PMID   16500131.
  67. ↑ Jackson ME, Pennie WD, McCaffery RE, Smith KT, Grindlay GJ, Campo MS (1991). "The B subgroup bovine papillomaviruses lack an identifiable E6 open reading frame". Molecular Carcinogenesis. 4 (5): 382–7. doi:10.1002/mc.2940040510. PMID   1654923. S2CID   22514962.
  68. ↑ Carter JJ, Wipf GC, Madeleine MM, Schwartz SM, Koutsky LA, Galloway DA (May 2006). "Identification of human papillomavirus type 16 L1 surface loops required for neutralization by human sera". Journal of Virology. 80 (10): 4664–72. doi:10.1128/JVI.80.10.4664-4672.2006. PMC   1472072 . PMID   16641259.
  69. ↑ Campos SK, Ozbun MA (2009). Papavasiliou N (ed.). "Two highly conserved cysteine residues in HPV16 L2 form an intramolecular disulfide bond and are critical for infectivity in human keratinocytes". PLOS ONE. 4 (2): e4463. Bibcode:2009PLoSO...4.4463C. doi: 10.1371/journal.pone.0004463 . PMC   2636891 . PMID   19214230.
  70. ↑ Richards RM, Lowy DR, Schiller JT, Day PM (January 2006). "Cleavage of the papillomavirus minor capsid protein, L2, at a furin consensus site is necessary for infection". Proceedings of the National Academy of Sciences of the United States of America. 103 (5): 1522–7. Bibcode:2006PNAS..103.1522R. doi: 10.1073/pnas.0508815103 . PMC   1360554 . PMID   16432208.
  71. ↑ Yang R, Yutzy WH, Viscidi RP, Roden RB (April 2003). "Interaction of L2 with beta-actin directs intracellular transport of papillomavirus and infection". The Journal of Biological Chemistry. 278 (14): 12546–53. doi: 10.1074/jbc.M208691200 . PMID   12560332.
  72. ↑ Bossis I, Roden RB, Gambhira R, Yang R, Tagaya M, Howley PM, Meneses PI (June 2005). "Interaction of tSNARE syntaxin 18 with the papillomavirus minor capsid protein mediates infection". Journal of Virology. 79 (11): 6723–31. doi:10.1128/JVI.79.11.6723-6731.2005. PMC   1112158 . PMID   15890910.
  73. ↑ Pastrana DV, Gambhira R, Buck CB, Pang YY, Thompson CD, Culp TD, Christensen ND, Lowy DR, Schiller JT, Roden RB (July 2005). "Cross-neutralization of cutaneous and mucosal Papillomavirus types with anti-sera to the amino terminus of L2". Virology. 337 (2): 365–72. doi: 10.1016/j.virol.2005.04.011 . PMID   15885736.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.