HIV+Genes+and+Their+Functions

__**HIV-1:**__ [|p6] [|p2] [|p1] || Proteins: Reverse Transcriptase, Protease-helps process gag and pol proteins into functioning forms, RNAse H-Breaks down the RNA genome after it is rev transcrip. into DNA (RNA not needed), and Integrase-integrates the HIV DNA into host's DNA. [] ||   ** Reverse Transcriptase **  **- p51**  ** Reverse Transcriptase and RNase H **  **- p66**  ** RNase H **  **- p15**  ** Integrase **  **- p3**1  || [] || || [] || || ]] Vif is a 23-kilodalton (1 dalton = 1 amu (From JP)) protein that is essential for viral replication. Vif inhibits the cellular protein, APOBEC3G, from entering the virion during budding from a host cell by targeting it for proteasomal degradation. Vif hijacks the cellular Cullin5 E3 ubiquitin ligase in order to target APOBEC3G for degradation. In the absence of Vif, APOBEC3G causes hypermutation of the viral genome, rendering it dead-on-arrival at the next host cell. APOBEC3G is thus a host defence to retroviral infection which HIV-1 has overcome by the acquisition of Vif. Targeting vif has been suggested as a strategy for future HIV drug therapies. || (No picture) || [] || || **__HIV-2:__**
 * **Gene:** || **Description:** || **Visual Info:** ||
 * gag || [] || [[image:http://www.bioafrica.net/proteomics/GAGmap.gif width="380" align="middle"]]
 * Matrix** - [|p17]
 * Core Antigen capsid** - [|p24]
 * Nucleocapsid** - [|p7]
 * pol || pol is the main retroviral gene. The most important protein that it codes for is reverse transcriptase which allows it to code its RNA into its host's DNA. This task is unique to retroviruses because most organisms keep their genes in DNA form. (Article 7)
 * Protease **  **- p15**
 * env || codes proteins for the entry phase of the HIV lifecycle. These proteins include gp120 and gp41 which are in the form of a polyprotein called gp160. HIV **ENV** is a polyprotein precursor (**gp160**), which is processed by cellular proteases to give a non-covalent complex of an external glycoprotein (**SU** / **gp120**) and a transmembrane glycoprotein (**TM** / **gp41**).
 * tat || [] || [[image:TAT-320x240.gif]] ||
 * rev || The rev gene allows fragments of HIV mRNA go from the nucleus to the cytoplasm without being spliced. Without this gene only regulatory genes would be produced, but with the rev gene, the mRNA that is transported now has structural proteins (gag, pol, env) and the RNA genome that make it possible for the HIV genome to spread and overwhelm the host's defense system (Wiki Rev-HIV)
 * nef || [] || [[image:NEF-320x240.gif]] ||
 * vif || [[http://www.bioafrica.net/proteomics/VIFprot.html|http://www.bioafrica.net/proteomics/VIFprot.html
 * Viral infectivity factor**, or Vif, is a protein found in HIV and other retroviruses. Its role is to disrupt the antiviral activity of the human enzyme APOBEC (See also APOBEC3G) by targeting it for ubiquitination and cellular degradation. APOBEC is a cytidine deaminase enzyme that mutates viral nucleic acids.
 * vpr || The vpr gene accelerates the production of HIV proteins. It also carries nuclear localization signals that accompany the HIV genome and signal to the cell for it to be carried into the nucleus. In addition, the vpr gene seems to be responsible in arresting the cell cycle in the G2 phase. Also an immonosuppressive.
 * vpu || [] || [[image:VPU-320x240.gif]] ||


 * **Gene:** || **Description:** ||
 * (All the genes are the same as HIV-1 except HIV-2 does not have vpu and has vpx instead) ||  ||
 * vpx || The vpr gene in HIV-1 is split into two parts in HIV-2, where vpr in HIV-2 transports the HIV genome into the nucleus and the vpx of HIV-2 arrests the cell cycle in G2 phase. ||