Antiviral proteins are proteins that are induced by human or animal cells to interfere with viral replication. These proteins are isolated to inhibit the virus from replicating in a host's cells and stop it from spreading to other cells.[ citation needed ] The Pokeweed antiviral protein and the Zinc-Finger antiviral protein are two major antiviral proteins that have undergone several tests for viruses, including HIV and influenza.[ citation needed ]
Pokeweed antiviral protein is a ribosome inactivating protein that provides pokeweed plants protection against both viral and fungal infections. [1] It also protects other types of plants that have genetically engineered to express RAP that do not normally do so. [1] Recombinant pokeweed antiviral protein has also been proposed as a treatment of human diseases such as AIDS and cancer. [2] [3]
ZAP (Zinc finger Antiviral Protein) is encoded by the ZC3HAV1 gene in humans [4] whose expression is induced by interferon and helps fight a number of viral infections including influenza. [5]
Ribonuclease L or RNase L (for latent), ais an interferon (IFN)-induced ribonuclease which, upon activation, destroys all RNA within the cell (both cellular and viral) as well as inhibiting mRNA export. [6] [7] RNase L is an enzyme that in humans is encoded by the RNASEL gene in humans.
Interferon-induced transmembrane protein 3 (IFITM3) inhibits the replication of number of enveloped RNA viruses including influenza A, HIV and the Ebola and Dengue viruses. [8] Consequently pharmacological induction of IFITM3 potentially could be used to treat a number of viral infections. [5]
Protein kinase R is interferon stimulated and activated either by double-stranded RNA (occurring as an intermediate in RNA viruses replication) or by other proteins. It is able to phosphorylate the eukaryotic translation initiation factor eIF2α thus inhibiting further cellular mRNA translation. [9]
Interferons are a group of signaling proteins made and released by host cells in response to the presence of several viruses. In a typical scenario, a virus-infected cell will release interferons causing nearby cells to heighten their anti-viral defenses.
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 (backward). 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.
Antiviral drugs are a class of medication used for treating viral infections. Most antivirals target specific viruses, while a broad-spectrum antiviral is effective against a wide range of viruses. Antiviral drugs are a class of antimicrobials, a larger group which also includes antibiotic, antifungal and antiparasitic drugs, or antiviral drugs based on monoclonal antibodies. Most antivirals are considered relatively harmless to the host, and therefore can be used to treat infections. They should be distinguished from virucides, which are not medication but deactivate or destroy virus particles, either inside or outside the body. Natural virucides are produced by some plants such as eucalyptus and Australian tea trees.
Ribonuclease H is a family of non-sequence-specific endonuclease enzymes that catalyze the cleavage of RNA in an RNA/DNA substrate via a hydrolytic mechanism. Members of the RNase H family can be found in nearly all organisms, from bacteria to archaea to eukaryotes.
Dicer, also known as endoribonuclease Dicer or helicase with RNase motif, is an enzyme that in humans is encoded by the DICER1 gene. Being part of the RNase III family, Dicer cleaves double-stranded RNA (dsRNA) and pre-microRNA (pre-miRNA) into short double-stranded RNA fragments called small interfering RNA and microRNA, respectively. These fragments are approximately 20–25 base pairs long with a two-base overhang on the 3′-end. Dicer facilitates the activation of the RNA-induced silencing complex (RISC), which is essential for RNA interference. RISC has a catalytic component Argonaute, which is an endonuclease capable of degrading messenger RNA (mRNA).
The hepatitis C virus (HCV) is a small, enveloped, positive-sense single-stranded RNA virus of the family Flaviviridae. The hepatitis C virus is the cause of hepatitis C and some cancers such as liver cancer and lymphomas in humans.
Viral pathogenesis is the study of the process and mechanisms by which viruses cause diseases in their target hosts, often at the cellular or molecular level. It is a specialized field of study in virology.
Ribonuclease L or RNase L, known sometimes as ribonuclease 4 or 2'-5' oligoadenylate synthetase-dependent ribonuclease, is an interferon (IFN)-induced ribonuclease which, upon activation, destroys all RNA within the cell as well as inhibiting mRNA export. RNase L is an enzyme that in humans is encoded by the RNASEL gene.
Human Herpes Virus (HHV) Infected Cell Polypeptide 0 (ICP0) is a protein, encoded by the DNA of herpes viruses. It is produced by herpes viruses during the earliest stage of infection, when the virus has recently entered the host cell; this stage is known as the immediate-early or α ("alpha") phase of viral gene expression. During these early stages of infection, ICP0 protein is synthesized and transported to the nucleus of the infected host cell. Here, ICP0 promotes transcription from viral genes, disrupts structures in the nucleus known as nuclear dots or promyelocytic leukemia (PML) nuclear bodies, and alters the expression of host and viral genes in combination with a neuron specific protein. At later stages of cellular infection, ICP0 relocates to the cell cytoplasm to be incorporated into new virion particles.
Murine respirovirus, formerly Sendai virus (SeV) and previously also known as murine parainfluenza virus type 1 or hemagglutinating virus of Japan (HVJ), is an enveloped, 150-200 nm–diameter, negative sense, single-stranded RNA virus of the family Paramyxoviridae. It typically infects rodents and it is not pathogenic for humans or domestic animals.
RIG-I is a cytosolic pattern recognition receptor (PRR) that can mediate induction of a type-I interferon (IFN1) response. RIG-I is an essential molecule in the innate immune system for recognizing cells that have been infected with a virus. These viruses can include West Nile virus, Japanese Encephalitis virus, influenza A, Sendai virus, flavivirus, and coronaviruses.
Interferon alpha-2 is a protein that in humans is encoded by the IFNA2 gene.
MDA5 is a RIG-I-like receptor dsRNA helicase enzyme that is encoded by the IFIH1 gene in humans. MDA5 is part of the RIG-I-like receptor (RLR) family, which also includes RIG-I and LGP2, and functions as a pattern recognition receptor capable of detecting viruses. It is generally believed that MDA5 recognizes double stranded RNA (dsRNA) over 2000nts in length, however it has been shown that whilst MDA5 can detect and bind to cytoplasmic dsRNA, it is also activated by a high molecular weight RNA complex composed of ssRNA and dsRNA. For many viruses, effective MDA5-mediated antiviral responses are dependent on functionally active LGP2. The signaling cascades in MDA5 is initiated via CARD domain. Some observations made in cancer cells show that MDA5 also interacts with cellular RNA is able to induce an autoinflammatory response.
Interferon-induced transmembrane protein 1 is a protein that in humans is encoded by the IFITM1 gene. IFITM1 has also recently been designated CD225. This protein has several additional names: fragilis, IFI17 [interferon-induced protein 17], 9-27 [Interferon-inducible protein 9-27] and Leu13.
Adolfo García-Sastre,(born in Burgos, 10 October 1964) is a Spanish professor of Medicine and Microbiology and co-director of the Global Health & Emerging Pathogens Institute at the Icahn School of Medicine at Mount Sinai in New York City. His research into the biology of influenza viruses has been at the forefront of medical advances in epidemiology.
RIG-I-like receptors are a type of intracellular pattern recognition receptor involved in the recognition of viruses by the innate immune system. RIG-I is the best characterized receptor within the RIG-I like receptor (RLR) family. Together with MDA5 and LGP2, this family of cytoplasmic pattern recognition receptors (PRRs) are sentinels for intracellular viral RNA that is a product of viral infection. The RLR receptors provide frontline defence against viral infections in most tissues.
Radical S-adenosyl methionine domain-containing protein 2 is a protein that in humans is encoded by the RSAD2 gene. RSAD2 is a multifunctional protein in viral processes that is an interferon stimulated gene. It has been reported that viperin could be induced by either IFN-dependent or IFN-independent pathways and certain viruses may use viperin to increase their infectivity.
An interferon-stimulated gene (ISG) is a gene that can be expressed in response to stimulation by interferon. Interferons bind to receptors on the surface of a cell, initiating protein signaling pathways within the cell. This interaction leads to the expression of a subset of genes involved in the innate immune system response. ISGs are commonly expressed in response to viral infection, but also during bacterial infection and in the presence of parasites. It's currently estimated that 10% of the human genome is regulated by interferons (IFNs). Interferon stimulated genes can act as an initial response to pathogen invasion, slowing down viral replication and increasing expression of immune signaling complexes. There are three known types of interferon. With approximately 450 genes highly expressed in response to interferon type I. Type I interferon consists of INF-α, INF-β, INF-ω and is expressed in response to viral infection. ISGs induced by type I interferon are associated with viral replication suppression and increase expression of immune signaling proteins. Type II interferon consists only of INF-γ and is associated with controlling intracellular pathogens and tumor suppressor genes. Type III interferon consists of INF-λ and is associated with viral immune response and is key in anti-fungal neutrophil response.
Interferon-induced transmembrane protein 2 is a protein that in humans is encoded by the IFITM2 gene. IFITM1 is a member of the IFITM family which is encoded by IFITM genes.
HSV epigenetics is the epigenetic modification of herpes simplex virus (HSV) genetic code.