HIVbio: HIV Bioinformatics
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HIV Life Cycles
HIV Imp Enzymes
Drugs : HAART
Therapeutics and Vaccines
The HIVbio is the home page of various informations that are provided here for Human Immunodefeciency Virus (HIV) life cycle and Infection. HIV is a lentivirus having two copies single strand RNA (ssRNA) as its genetic material.The Virus mainly infects the cells of immune system e.g T-helper, Macrophase, dendritic cells. Since these cells are important for proper working of body's defense system, reults into development of Acquired Immuno Defeciency Syndrome (AIDS).The HIV has mainly six steps in its life cycle
1. Binding and Fusion 1 2 3 4 5 6 7
2. Reverse Transcription 1
3. Integration 1 2 3 4
HIV begins its life cycle when it binds to a CD4 receptor and one of two co-receptors on the surface of a CD4+ T- lymphocyte. The virus then fuses with the host cell. After fusion, the virus releases RNA, its genetic material, into the host cell.
An HIV enzyme called reverse transcriptase converts the single- stranded HIV RNA to double-stranded HIV DNA.
The newly formed HIV DNA enters the host cell's nucleus, where an HIV enzyme called integrase "hides" the HIV DNA within the host cell's own DNA. The integrated HIV DNA is called provirus. The provirus may remain inactive for several years, producing few or no new copies of HIV.
When the host cell receives a signal to become active, the provirus uses a host enzyme called RNA polymerase to create copies of the HIV genomic material, as well as shorter strands of RNA called messenger RNA (mRNA). The mRNA is used as a blueprint to make long chains of HIV proteins.
An HIV enzyme called protease cuts the long chains of HIV proteins into smaller individual proteins. As the smaller HIV proteins come together with copies of HIV's RNA genetic material, a new virus particle is assembled.
The newly assembled virus pushes out ("buds") from the host cell. During budding, the new virus steals part of the cell's outer envelope. This envelope, which acts as a covering, is studded with protein/sugar combinations called HIV glycoproteins. These HIV glycoproteins are necessary for the virus to bind CD4 and co- receptors. The new copies of HIV can now move on to infect other cells.