Structure and genome of HIV

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The genome and proteins of HIV (human immunodeficiency virus) have been the subject of extensive research since the discovery of the virus in 1983. [1] [2] "In the search for the causative agent, it was initially believed that the virus was a form of the Human T-cell leukemia virus (HTLV), which was known at the time to affect the human immune system and cause certain leukemias. However, researchers at the Pasteur Institute in Paris isolated a previously unknown and genetically distinct retrovirus in patients with AIDS which was later named HIV." [3] Each virion comprises a viral envelope and associated matrix enclosing a capsid, which itself encloses two copies of the single-stranded RNA genome and several enzymes. The discovery of the virus itself occurred two years following the report of the first major cases of AIDS-associated illnesses. [4] [5]

Contents

Structure

Diagram of HIV HI-virion-structure en.svg
Diagram of HIV
Structure of the immature HIV-1 capsid in intact virus particles The structure of the immature HIV-1 capsid in intact virus particles.png
Structure of the immature HIV-1 capsid in intact virus particles
A diagram of the HIV spike protein (green), with the fusion peptide epitope highlighted in red, and a broadly neutralizing antibody (yellow) binding to the fusion peptide Protein Structure Diagram of Fusion Peptide Epitope on HIV Spike (41863579304).jpg
A diagram of the HIV spike protein (green), with the fusion peptide epitope highlighted in red, and a broadly neutralizing antibody (yellow) binding to the fusion peptide

The complete sequence of the HIV-1 genome, extracted from infectious virions, has been solved to single-nucleotide resolution. [6] The HIV genome encodes a small number of viral proteins, invariably establishing cooperative associations among HIV proteins and between HIV and host proteins, to invade host cells and hijack their internal machineries. [7] HIV is different in structure from other retroviruses. The HIV virion is ~100 nm in diameter. Its innermost region consists of a cone-shaped core that includes two copies of the (positive sense) ssRNA genome, the enzymes reverse transcriptase, integrase and protease, some minor proteins, and the major core protein. [8] The genome of human immunodeficiency virus (HIV) encodes 8 viral proteins playing essential roles during the HIV life cycle. [7]

HIV-1 is composed of two copies of noncovalently linked, unspliced, positive-sense single-stranded RNA enclosed by a conical capsid composed of the viral protein p24, typical of lentiviruses. [9] [10] The two RNAs are often identical, yet they are not independent, but form a compact dimer within the virion. [11] Several reasons as for why two copies of RNA are packaged rather than just one have been proposed, including probably a combination of these advantages: One advantage is that the two copies of RNA strands are vital in contributing to HIV-1 recombination, which occurs during reverse transcription of viral replication, thus increasing genetic diversity. [11] Another advantage is that having two copies of RNA would allow the reverse transcriptase to switch templates when encountering a break in the viral RNA, thus completing the reverse transcription without loss of genetic information. [11] Yet another reason is that the dimeric nature of the RNA genome of the virus may play a structural role in viral replication. [11] The containment of two copies of single-stranded RNA within a virion but the production of only a single DNA provirus is called pseudodiploidy. [12] The RNA component is 9749 nucleotides long [13] [14] and bears a 5’ cap (Gppp), a 3’ poly(A) tail, and many open reading frames (ORFs). [15] Viral structural proteins are encoded by long ORFs, whereas smaller ORFs encode regulators of the viral life cycle: attachment, membrane fusion, replication, and assembly. [15]

The single-strand RNA is tightly bound to p7 nucleocapsid proteins, late assembly protein p6, and enzymes essential to the development of the virion, such as reverse transcriptase and integrase. Lysine tRNA is the primer of the magnesium-dependent reverse transcriptase. [9] The nucleocapsid associates with the genomic RNA (one molecule per hexamer) and protects the RNA from digestion by nucleases. Also enclosed within the virion particle are Vif, Vpr, Nef, and viral protease.[ citation needed ] The envelope of the virion is formed by a plasma membrane of host cell origin, which is supported by a matrix composed of the viral p17 protein, ensuring the integrity of the virion particle. At the surface of the virion can be found a limited number of the envelope glycoprotein (Env) of HIV, a trimer formed by heterodimers of gp120 and gp41. Env is responsible for binding to its primary host receptor, CD4, and its co-receptor (mainly CCR5 or CXCR4), leading to viral entry into its target cell. [16]

As the only proteins on the surface of the virus, the envelope glycoproteins (gp120 and gp41) are the major targets for HIV vaccine efforts. [17] Over half of the mass of the trimeric envelope spike is N-linked glycans. The density is high as the glycans shield underlying viral protein from neutralisation by antibodies. This is one of the most densely glycosylated molecules known and the density is sufficiently high to prevent the normal maturation process of glycans during biogenesis in the endoplasmic reticulum and Golgi apparatus. [18] [19] The majority of the glycans are therefore stalled as immature 'high-mannose' glycans not normally present on secreted or cell surface human glycoproteins. [20] The unusual processing and high density means that almost all broadly neutralising antibodies that have so far been identified (from a subset of patients that have been infected for many months to years) bind to or, are adapted to cope with, these envelope glycans. [21]

The molecular structure of the viral spike has now been determined by X-ray crystallography [22] and cryo-electron microscopy. [23] These advances in structural biology were made possible due to the development of stable recombinant forms of the viral spike by the introduction of an intersubunit disulphide bond and an isoleucine to proline mutation in gp41. [24] The so-called SOSIP trimers not only reproduce the antigenic properties of the native viral spike but also display the same degree of immature glycans as presented on the native virus. [25] Recombinant trimeric viral spikes are promising vaccine candidates as they display less non-neutralising epitopes than recombinant monomeric gp120 which act to suppress the immune response to target epitopes. [26]

Genome organization

Structure of the RNA genome of HIV-1 HIV-genome.png
Structure of the RNA genome of HIV-1

HIV has several major genes coding for structural proteins that are found in all retroviruses as well as several nonstructural ("accessory") genes unique to HIV. [27] The HIV genome contains nine genes that encode fifteen viral proteins. [28] These are synthesized as polyproteins which produce proteins for virion interior, called Gag, group specific antigen; the viral enzymes (Pol, polymerase) or the glycoproteins of the virion env (envelope). [29] In addition to these, HIV encodes for proteins which have certain regulatory and auxiliary functions as well. [29] HIV-1 has two important regulatory elements: Tat and Rev and few important accessory proteins such as Nef, Vpr, Vif and Vpu which are not essential for replication in certain tissues. [29] The gag gene provides the basic physical infrastructure of the virus, and pol provides the basic mechanism by which retroviruses reproduce, while the others help HIV to enter the host cell and enhance its reproduction. Though they may be altered by mutation, all of these genes except tev exist in all known variants of HIV; see Genetic variability of HIV.[ citation needed ]

HIV employs a sophisticated system of differential RNA splicing to obtain nine different gene products from a less than 10kb genome. [30] HIV has a 9.2kb unspliced genomic transcript which encodes for gag and pol precursors; a singly spliced, 4.5 kb encoding for env, Vif, Vpr and Vpu and a multiply spliced, 2 kb mRNA encoding for Tat, Rev and Nef. [30]

Proteins encoded by the HIV genome
ClassGene namePrimary protein productsProcessed protein products
Viral structural proteinsgagGag polyproteinMA, CA, SP1, NC, SP2, P6
polPol polyproteinRT, RNase H, IN, PR
envgp160gp120, gp41
Essential regulatory elementstatTat
revRev
Accessory regulatory proteinsnefNef
vprVpr
vifVif
vpuVpu

Viral structural proteins

The HIV capsid consists of roughly 200 copies of the p24 protein. The p24 structure is shown in two representations: cartoon (top) and isosurface (bottom) P24 HIV-capsid.png
The HIV capsid consists of roughly 200 copies of the p24 protein. The p24 structure is shown in two representations: cartoon (top) and isosurface (bottom)

Essential regulatory elements

Accessory regulatory proteins

RNA secondary structure

HIV pol-1 stem loop
RF01418.png
Predicted secondary structure of the HIV pol-1 stem loop
Identifiers
Symbolpol
Rfam RF01418
Other data
RNA type Cis-reg
PDB structures PDBe

Several conserved secondary structure elements have been identified within the HIV RNA genome. The HIV viral RNA structures regulates the progression of reverse transcription. [33] The 5'UTR structure consists of series of stem-loop structures connected by small linkers. [10] These stem-loops (5' to 3') include the trans-activation region (TAR) element, the 5' polyadenylation signal [poly(A)], the PBS, the DIS, the major SD and the ψ hairpin structure located within the 5' end of the genome and the HIV Rev response element (RRE) within the env gene. [10] [34] [35] Another RNA structure that has been identified is gag stem loop 3 (GSL3), thought to be involved in viral packaging. [36] [37] RNA secondary structures have been proposed to affect the HIV life cycle by altering the function of HIV protease and reverse transcriptase, although not all elements identified have been assigned a function.[ citation needed ]

An RNA secondary structure determined by SHAPE analysis has shown to contain three stem loops and is located between the HIV protease and reverse transcriptase genes. This cis regulatory RNA has been shown to be conserved throughout the HIV family and is thought to influence the viral life cycle. [38]

V3 loop

The third variable loop or V3 loop is a part or region of the Human Immunodeficiency Virus. The V3 loop of the viron's envelope glycoprotein, gp120, allows it to infect human immune cells by binding to a cytokine receptor on the target human immune cell, such as a CCR5 cell or CXCR4 cell, depending on the strain of HIV. [39] The envelope glycoprotein (Env) gp 120/41 is essential for HIV-1 entry into cells. Env serves as a molecular target of a medicine treating individuals with HIV-1 infection, and a source of immunogen to develop AIDS vaccine. However, the structure of the functional Env trimer has remained elusive. [40]

See also

Related Research Articles

<span class="mw-page-title-main">HIV</span> Human retrovirus, cause of AIDS

The human immunodeficiency viruses (HIV) are two species of Lentivirus that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive. Without treatment, average survival time after infection with HIV is estimated to be 9 to 11 years, depending on the HIV subtype.

<span class="mw-page-title-main">Retrovirus</span> Family of viruses

A retrovirus is a type of virus that inserts a DNA copy of its RNA genome into the DNA of a host cell that it invades, thus changing the genome of that cell. After invading a host cell's cytoplasm, the virus uses its own reverse transcriptase enzyme to produce DNA from its RNA genome, the reverse of the usual pattern, thus retro (backwards). The new DNA is then incorporated into the host cell genome by an integrase enzyme, at which point the retroviral DNA is referred to as a provirus. The host cell then treats the viral DNA as part of its own genome, transcribing and translating the viral genes along with the cell's own genes, producing the proteins required to assemble new copies of the virus. Many retroviruses cause serious diseases in humans, other mammals, and birds.

<span class="mw-page-title-main">HIV vaccine development</span> In-progress vaccinations that may prevent or treat HIV infections

An HIV vaccine is a potential vaccine that could be either a preventive vaccine or a therapeutic vaccine, which means it would either protect individuals from being infected with HIV or treat HIV-infected individuals.

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

The term viral protein refers to both the products of the genome of a virus and any host proteins incorporated into the viral particle. Viral proteins are grouped according to their functions, and groups of viral proteins include structural proteins, nonstructural proteins, regulatory proteins, and accessory proteins. Viruses are non-living and do not have the means to reproduce on their own, instead depending on their host cell's machinery to do this. Thus, viruses do not code for most of the proteins required for their replication and the translation of their mRNA into viral proteins, but use proteins encoded by the host cell for this purpose.

Lentivirus is a genus of retroviruses that cause chronic and deadly diseases characterized by long incubation periods, in humans and other mammalian species. The genus includes the human immunodeficiency virus (HIV), which causes AIDS. Lentiviruses are distributed worldwide, and are known to be hosted in apes, cows, goats, horses, cats, and sheep as well as several other mammals.

<i>Gammaretrovirus</i> Genus of viruses

Gammaretrovirus is a genus in the Retroviridae family. Example species are the murine leukemia virus and the feline leukemia virus. They cause various sarcomas, leukemias and immune deficiencies in mammals, reptiles and birds.

<span class="mw-page-title-main">Envelope glycoprotein GP120</span> Glycoprotein exposed on the surface of the HIV virus

Envelope glycoprotein GP120 is a glycoprotein exposed on the surface of the HIV envelope. It was discovered by Professors Tun-Hou Lee and Myron "Max" Essex of the Harvard School of Public Health in 1984. The 120 in its name comes from its molecular weight of 120 kDa. Gp120 is essential for virus entry into cells as it plays a vital role in attachment to specific cell surface receptors. These receptors are DC-SIGN, Heparan Sulfate Proteoglycan and a specific interaction with the CD4 receptor, particularly on helper T-cells. Binding to CD4 induces the start of a cascade of conformational changes in gp120 and gp41 that lead to the fusion of the viral membrane with the host cell membrane. Binding to CD4 is mainly electrostatic although there are van der Waals interactions and hydrogen bonds.

The murine leukemia viruses are retroviruses named for their ability to cause cancer in murine (mouse) hosts. Some MLVs may infect other vertebrates. MLVs include both exogenous and endogenous viruses. Replicating MLVs have a positive sense, single-stranded RNA (ssRNA) genome that replicates through a DNA intermediate via the process of reverse transcription.

<span class="mw-page-title-main">APOBEC3G</span> Protein and coding gene in humans

APOBEC3G is a human enzyme encoded by the APOBEC3G gene that belongs to the APOBEC superfamily of proteins. This family of proteins has been suggested to play an important role in innate anti-viral immunity. APOBEC3G belongs to the family of cytidine deaminases that catalyze the deamination of cytidine to uridine in the single stranded DNA substrate. The C-terminal domain of A3G renders catalytic activity, several NMR and crystal structures explain the substrate specificity and catalytic activity.

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.

Group-specific antigen, or gag, is the polyprotein that contains the core structural proteins of an Ortervirus. It was named as such because scientists used to believe it was antigenic. Now it is known that it makes up the inner shell, not the envelope exposed outside. It makes up all the structural units of viral conformation and provides supportive framework for mature virion.

Env is a viral gene that encodes the protein forming the viral envelope. The expression of the env gene enables retroviruses to target and attach to specific cell types, and to infiltrate the target cell membrane.

Visna-maedi virus from the genus Lentivirus and subfamily Orthoretrovirinae, is a retrovirus that causes encephalitis and chronic pneumonitis in sheep. It is known as visna when found in the brain, and maedi when infecting the lungs. Lifelong, persistent infections in sheep occur in the lungs, lymph nodes, spleen, joints, central nervous system, and mammary glands; The condition is sometimes known as ovine progressive pneumonia (OPP), particularly in the United States, or Montana sheep disease. White blood cells of the monocyte/macrophage lineage are the main target of the virus.

<span class="mw-page-title-main">Retroviral psi packaging element</span>

The retroviral psi packaging element, also known as the Ψ RNA packaging signal, is a cis-acting RNA element identified in the genomes of the retroviruses Human immunodeficiency virus (HIV) and Simian immunodeficiency virus (SIV). It is involved in regulating the essential process of packaging the retroviral RNA genome into the viral capsid during replication. The final virion contains a dimer of two identical unspliced copies of the viral genome.

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

Vpu is an accessory protein that in HIV is encoded by the vpu gene. Vpu stands for "Viral Protein U". The Vpu protein acts in the degradation of CD4 in the endoplasmic reticulum and in the enhancement of virion release from the plasma membrane of infected cells. Vpu induces the degradation of the CD4 viral receptor and therefore participates in the general downregulation of CD4 expression during the course of HIV infection. Vpu-mediated CD4 degradation is thought to prevent CD4-Env binding in the endoplasmic reticulum to facilitate proper Env assembly into virions. It is found in the membranes of infected cells, but not the virus particles themselves.

<span class="mw-page-title-main">Rev (HIV)</span> HIV-1 regulating protein

Rev is a transactivating protein that is essential to the regulation of HIV-1 protein expression. A nuclear localization signal is encoded in the rev gene, which allows the Rev protein to be localized to the nucleus, where it is involved in the export of unspliced and incompletely spliced mRNAs. In the absence of Rev, mRNAs of the HIV-1 late (structural) genes are retained in the nucleus, preventing their translation.

Bovine immunodeficiency virus (BIV) is a retrovirus belonging to the genus Lentivirus. It is similar to the human immunodeficiency virus (HIV) and infects cattle. The cells primarily infected are lymphocytes and monocytes/macrophages.

Mason-Pfizer monkey virus (M-PMV), formerly Simian retrovirus (SRV), is a species of retroviruses that usually infect and cause a fatal immune deficiency in Asian macaques. The ssRNA virus appears sporadically in mammary carcinoma of captive macaques at breeding facilities which expected as the natural host, but the prevalence of this virus in feral macaques remains unknown. M-PMV was transmitted naturally by virus-containing body fluids, via biting, scratching, grooming, and fighting. Cross contaminated instruments or equipment (fomite) can also spread this virus among animals.

Vpx is a virion-associated protein encoded by human immunodeficiency virus type 2 HIV-2 and most simian immunodeficiency virus (SIV) strains, but that is absent from HIV-1. It is similar in structure to the protein Vpr that is carried by SIV and HIV-2 as well as HIV-1. Vpx is one of five accessory proteins carried by lentiviruses that enhances viral replication by inhibiting host antiviral factors.

Rio Negro virus is an alphavirus that was first isolated in Argentina in 1980. The virus was first called Ag80-663 but was renamed to Rio Negro virus in 2005. It is a former member of the Venezuelan equine encephalitis complex (VEEC), which are a group of alphaviruses in the Americas that have the potential to emerge and cause disease. Río Negro virus was recently reclassified as a distinct species. Closely related viruses include Mucambo virus and Everglades virus.

References

  1. Barré-Sinoussi F, Chermann JC, Rey F, Nugeyre MT, Chamaret S, Gruest J, Dauguet C, Axler-Blin C, Vézinet-Brun F, Rouzioux C, Rozenbaum W, Montagnier L (May 1983). "Isolation of a T-lymphotropic retrovirus from a patient at risk for acquired immune deficiency syndrome (AIDS)". Science. 220 (4599): 868–71. Bibcode:1983Sci...220..868B. doi:10.1126/science.6189183. PMID   6189183. S2CID   390173.
  2. Gallo RC, Sarin PS, Gelmann EP, Robert-Guroff M, Richardson E, Kalyanaraman VS, Mann D, Sidhu GD, Stahl RE, Zolla-Pazner S, Leibowitch J, Popovic M (May 1983). "Isolation of human T-cell leukemia virus in acquired immune deficiency syndrome (AIDS)". Science. 220 (4599): 865–7. Bibcode:1983Sci...220..865G. doi:10.1126/science.6601823. PMID   6601823.
  3. Churi C, Ross MW (2015). "Hiv/Aids" . In Whelehan P, Bolin A (eds.). The international encyclopedia of human sexuality. Wiley. ISBN   9781405190060. OCLC   949701914.
  4. Centers for Disease Control (June 1981). "Pneumocystis pneumonia--Los Angeles". MMWR. Morbidity and Mortality Weekly Report. 30 (21): 250–2. PMID   6265753.
  5. Centers for Disease Control (CDC) (July 1981). "Kaposi's sarcoma and Pneumocystis pneumonia among homosexual men--New York City and California" (PDF). MMWR. Morbidity and Mortality Weekly Report. 30 (25): 305–8. PMID   6789108. Archived from the original on October 22, 2012. Retrieved September 15, 2017.{{cite journal}}: CS1 maint: unfit URL (link)
  6. Watts JM, Dang KK, Gorelick RJ, Leonard CW, Bess JW, Swanstrom R, Burch CL, Weeks KM (August 2009). "Architecture and secondary structure of an entire HIV-1 RNA genome". Nature. 460 (7256): 711–6. Bibcode:2009Natur.460..711W. doi:10.1038/nature08237. PMC   2724670 . PMID   19661910.
  7. 1 2 Li G, De Clercq E (September 2016). "HIV Genome-Wide Protein Associations: a Review of 30 Years of Research". Microbiology and Molecular Biology Reviews. 80 (3): 679–731. doi:10.1128/MMBR.00065-15. PMC   4981665 . PMID   27357278.
  8. Singleton P, Sainsbury D, eds. (2006). "Hiv" . Dictionary of microbiology & molecular biology (3rd ed.). Hoboken, NJ: Wiley. ISBN   9780470035450. OCLC   71223221.
  9. 1 2 3 4 5 6 7 Montagnier L (1999). "Human Immunodeficiency Viruses (Retroviridae)". Encyclopedia of Virology (2nd ed.). pp. 763–774.
  10. 1 2 3 Lu K, Heng X, Summers MF (July 2011). "Structural determinants and mechanism of HIV-1 genome packaging". Journal of Molecular Biology. 410 (4): 609–33. doi:10.1016/j.jmb.2011.04.029. PMC   3139105 . PMID   21762803.
  11. 1 2 3 4 Moore, Michael D.; Hu, Wei Shau (2009). "HIV-1 RNA dimerization: It takes two to tango". AIDS reviews. 11 (2): 91–102. ISSN   1139-6121. PMC   3056336 . PMID   19529749.
  12. Hwang CK, Svarovskaia ES, Pathak VK (October 2001). "Dynamic copy choice: steady state between murine leukemia virus polymerase and polymerase-dependent RNase H activity determines frequency of in vivo template switching". Proceedings of the National Academy of Sciences of the United States of America. 98 (21): 12209–14. Bibcode:2001PNAS...9812209H. doi: 10.1073/pnas.221289898 . PMC   59793 . PMID   11593039.
  13. Wain-Hobson S, Sonigo P, Danos O, Cole S, Alizon M (January 1985). "Nucleotide sequence of the AIDS virus, LAV". Cell. 40 (1): 9–17. doi:10.1016/0092-8674(85)90303-4. PMID   2981635. S2CID   33055050.
  14. Ratner L, Haseltine W, Patarca R, Livak KJ, Starcich B, Josephs SF, Doran ER, Rafalski JA, Whitehorn EA, Baumeister K (1985). "Complete nucleotide sequence of the AIDS virus, HTLV-III". Nature. 313 (6000): 277–84. Bibcode:1985Natur.313..277R. doi:10.1038/313277a0. PMID   2578615. S2CID   4316242.
  15. 1 2 Castelli JC, Levy A (2002). "HIV (Human Immunodeficiency Virus)". Encyclopedia of Cancer. Vol. 2 (2nd ed.). pp. 407–415.
  16. Checkly MA, Freed EO (22 July 2011). "HIV-1 envelope glycoprotein biosynthesis, trafficking, and incorporation". Journal of Molecular Biology. 410 (4): 582–608. doi:10.1016/j.jmb.2011.04.042. PMC   3139147 . PMID   21762802.
  17. National Institute of Health (June 17, 1998). "Crystal structure of key HIV protein reveals new prevention, treatment targets" (Press release). Archived from the original on February 19, 2006. Retrieved September 14, 2006.
  18. Behrens AJ, Vasiljevic S, Pritchard LK, Harvey DJ, Andev RS, Krumm SA, Struwe WB, Cupo A, Kumar A, Zitzmann N, Seabright GE, Kramer HB, Spencer DI, Royle L, Lee JH, Klasse PJ, Burton DR, Wilson IA, Ward AB, Sanders RW, Moore JP, Doores KJ, Crispin M (March 2016). "Composition and Antigenic Effects of Individual Glycan Sites of a Trimeric HIV-1 Envelope Glycoprotein". Cell Reports. 14 (11): 2695–706. doi:10.1016/j.celrep.2016.02.058. PMC   4805854 . PMID   26972002.
  19. Pritchard LK, Spencer DI, Royle L, Bonomelli C, Seabright GE, Behrens AJ, Kulp DW, Menis S, Krumm SA, Dunlop DC, Crispin DJ, Bowden TA, Scanlan CN, Ward AB, Schief WR, Doores KJ, Crispin M (June 2015). "Glycan clustering stabilizes the mannose patch of HIV-1 and preserves vulnerability to broadly neutralizing antibodies". Nature Communications. 6: 7479. Bibcode:2015NatCo...6.7479P. doi:10.1038/ncomms8479. PMC   4500839 . PMID   26105115.
  20. Pritchard LK, Harvey DJ, Bonomelli C, Crispin M, Doores KJ (September 2015). "Cell- and Protein-Directed Glycosylation of Native Cleaved HIV-1 Envelope". Journal of Virology. 89 (17): 8932–44. doi:10.1128/JVI.01190-15. PMC   4524065 . PMID   26085151.
  21. Crispin M, Doores KJ (April 2015). "Targeting host-derived glycans on enveloped viruses for antibody-based vaccine design". Current Opinion in Virology. Viral pathogenesis • Preventive and therapeutic vaccines. 11: 63–9. doi:10.1016/j.coviro.2015.02.002. PMC   4827424 . PMID   25747313.
  22. Julien JP, Cupo A, Sok D, Stanfield RL, Lyumkis D, Deller MC, Klasse PJ, Burton DR, Sanders RW, Moore JP, Ward AB, Wilson IA (December 2013). "Crystal structure of a soluble cleaved HIV-1 envelope trimer". Science. 342 (6165): 1477–83. Bibcode:2013Sci...342.1477J. doi:10.1126/science.1245625. PMC   3886632 . PMID   24179159.
  23. Lyumkis D, Julien JP, de Val N, Cupo A, Potter CS, Klasse PJ, Burton DR, Sanders RW, Moore JP, Carragher B, Wilson IA, Ward AB (December 2013). "Cryo-EM structure of a fully glycosylated soluble cleaved HIV-1 envelope trimer". Science. 342 (6165): 1484–90. Bibcode:2013Sci...342.1484L. doi:10.1126/science.1245627. PMC   3954647 . PMID   24179160.
  24. Sanders RW, Derking R, Cupo A, Julien JP, Yasmeen A, de Val N, Kim HJ, Blattner C, de la Peña AT, Korzun J, Golabek M, de Los Reyes K, Ketas TJ, van Gils MJ, King CR, Wilson IA, Ward AB, Klasse PJ, Moore JP (September 2013). "A next-generation cleaved, soluble HIV-1 Env trimer, BG505 SOSIP.664 gp140, expresses multiple epitopes for broadly neutralizing but not non-neutralizing antibodies". PLOS Pathogens. 9 (9): e1003618. doi: 10.1371/journal.ppat.1003618 . PMC   3777863 . PMID   24068931.
  25. Pritchard LK, Vasiljevic S, Ozorowski G, Seabright GE, Cupo A, Ringe R, Kim HJ, Sanders RW, Doores KJ, Burton DR, Wilson IA, Ward AB, Moore JP, Crispin M (June 2015). "Structural Constraints Determine the Glycosylation of HIV-1 Envelope Trimers". Cell Reports. 11 (10): 1604–13. doi:10.1016/j.celrep.2015.05.017. PMC   4555872 . PMID   26051934.
  26. de Taeye SW, Ozorowski G, Torrents de la Peña A, Guttman M, Julien JP, van den Kerkhof TL, Burger JA, Pritchard LK, Pugach P, Yasmeen A, Crampton J, Hu J, Bontjer I, Torres JL, Arendt H, DeStefano J, Koff WC, Schuitemaker H, Eggink D, Berkhout B, Dean H, LaBranche C, Crotty S, Crispin M, Montefiori DC, Klasse PJ, Lee KK, Moore JP, Wilson IA, Ward AB, Sanders RW (December 2015). "Immunogenicity of Stabilized HIV-1 Envelope Trimers with Reduced Exposure of Non-neutralizing Epitopes". Cell. 163 (7): 1702–15. doi:10.1016/j.cell.2015.11.056. PMC   4732737 . PMID   26687358.
  27. 1 2 3 Mushahwar IK (2007). "Human Immunodeficiency Viruses: Molecular Virology, pathogenesis, diagnosis and treatment". Perspectives in Medical Virology. 13: 75–87. doi:10.1016/S0168-7069(06)13005-0. ISBN   9780444520739.
  28. Li G, Piampongsant S, Faria NR, Voet A, Pineda-Peña AC, Khouri R, Lemey P, Vandamme AM, Theys K (February 2015). "An integrated map of HIV genome-wide variation from a population perspective". Retrovirology. 12 (1): 18. doi: 10.1186/s12977-015-0148-6 . PMC   4358901 . PMID   25808207.
  29. 1 2 3 4 5 6 7 8 9 10 11 12 13 Votteler J, Schubert U (2008). "Human Immunodeficiency Viruses: Molecular Biology". Encyclopedia of Virology (3rd ed.). pp. 517–525.
  30. 1 2 Feinberg Mark B, Greene Warner C (1992). "Molecular Insights into human immunodeficiency virus type1 pathogenesis". Current Opinion in Immunology. 4 (4): 466–474. doi:10.1016/s0952-7915(06)80041-5. PMID   1356348.
  31. 1 2 King Steven R (1994). "HIV: Virology and Mechanisms of disease". Annals of Emergency Medicine. 24 (3): 443–449. doi:10.1016/s0196-0644(94)70181-4. PMID   7915889.
  32. Benko DM, Schwartz S, Pavlakis GN, Felber BK (June 1990). "A novel human immunodeficiency virus type 1 protein, tev, shares sequences with tat, env, and rev proteins". Journal of Virology. 64 (6): 2505–18. doi:10.1128/JVI.64.6.2505-2518.1990. PMC   249426 . PMID   2186172.
  33. Krupkin M, Jackson LN, Ha B, Puglisi EV (Dec 2020). "Advances in understanding the initiation of HIV-1 reverse transcription". Curr Opin Struct Biol. 65: 175–183. doi:10.1016/j.sbi.2020.07.005. PMC   9973426 . PMID   32916568. S2CID   221636459.
  34. Berkhout B (January 1992). "Structural features in TAR RNA of human and simian immunodeficiency viruses: a phylogenetic analysis". Nucleic Acids Research. 20 (1): 27–31. doi:10.1093/nar/20.1.27. PMC   310321 . PMID   1738599.
  35. Paillart JC, Skripkin E, Ehresmann B, Ehresmann C, Marquet R (February 2002). "In vitro evidence for a long range pseudoknot in the 5'-untranslated and matrix coding regions of HIV-1 genomic RNA". The Journal of Biological Chemistry. 277 (8): 5995–6004. doi: 10.1074/jbc.M108972200 . PMID   11744696.
  36. Damgaard CK, Andersen ES, Knudsen B, Gorodkin J, Kjems J (February 2004). "RNA interactions in the 5' region of the HIV-1 genome". Journal of Molecular Biology. 336 (2): 369–79. doi:10.1016/j.jmb.2003.12.010. PMID   14757051.
  37. Rong L, Russell RS, Hu J, Laughrea M, Wainberg MA, Liang C (September 2003). "Deletion of stem-loop 3 is compensated by second-site mutations within the Gag protein of human immunodeficiency virus type 1". Virology. 314 (1): 221–8. doi:10.1016/S0042-6822(03)00405-7. PMID   14517075.
  38. Wang Q, Barr I, Guo F, Lee C (December 2008). "Evidence of a novel RNA secondary structure in the coding region of HIV-1 pol gene". RNA. 14 (12): 2478–88. doi:10.1261/rna.1252608. PMC   2590956 . PMID   18974280.
  39. "The interactions of the gp120 V3 loop of different HIV-1 strains with the potent anti-HIV human monoclonal antibody 447-52D". Weizmann Institute of Science: Department of Structural Biology. Archived from the original on 2007-07-18. Retrieved 2017-04-18.
  40. Takeda S, Takizawa M, Miyauchi K, Urano E, Fujino M, Murakami T, Murakami T, Komano J (June 2016). "Conformational properties of the third variable loop of HIV-1AD8 envelope glycoprotein in the liganded conditions". Biochemical and Biophysical Research Communications. 475 (1): 113–8. doi:10.1016/j.bbrc.2016.05.051. PMID   27178216.