Human immunodeficiency virus 1 (taxid:11676)
Molecular biology
Enveloped, spherical to pleomorphic in shape, 80-100 nm in diameter. Mature capsid contains 1572 capsid proteins.
Monopartite, linear, dimeric, ssRNA(+) genome of 9,75 kb, with a 5'-cap and a 3'poly-A tail. There are two long terminal repeats (LTRs) of about 600nt long at the 5' and 3' ends. The LTRs contain the U3, R, and U5 regions. There are also a primer binding site (PBS) at the 5'end and a polypurine tract (PPT) at the 3'end.
GENE EXPRESSION
The integrated provirus utilizes the promotor elements in the 5' LTR to drive transcription. This gives rise to the unspliced full length mRNA that will serve as genomic RNA to be packaged into virions or used as a template for translation of gag and gag-(pro)pol (1 ribosomal frameshift) polyproteins. The uncompletely spliced mRNAs encode env that is cleaved into SU and TM envelope proteins, and the accessory proteins vif, vpu, and vpr. Completely spliced mRNAs encode Rev, Tat and Nef accessory proteins. Rev escorts unspliced and uncompletely spliced RNAs out of the nucleus of infected cells.
ENZYMES
- Reverse transcriptase
- RNAse H [RT]
- Polyprotein protease (Peptidase A2) [PRO]
- Retroviral Integrase [INT]
REPLICATION
NUCLEAR
Lytic replication:
- Virus attaches to host CD4 receptors through the SU glycoprotein (gp120), with subsequent interaction with a chemokine coreceptor.
- Internalization via clathrin-dependent endocytosis. TM glycoprotein (gp41) mediates dynamin-dependent fusion with the host endosomal membrane. Nucleocapsid is released into the cytoplasm, with partial uncoating.
- ssRNA(+) genome is copied into a linear dsDNA molecule by the reverse transcriptase.
- Nuclear entry of the viral dsDNA which is covalently and randomly integrated into the cell's genome by the integrase (=provirus).
- Transcription of provirus by Pol II produces viral spliced and unspliced RNAs.
- Translation of spliced viral RNAs produces tat, rev, and nef proteins.
- Rev mediates nuclear export of the uncompletely spliced RNAs.
- Translation of unspliced viral RNAs produces Env, Gag and Gag-Pol polyproteins.
- Assembly of the virion at the host cellular membrane and packaging of the viral RNA genome.
- Budding through the plasma membrane and release of the virions.
- Proteolytic processing of the precursors polyproteins by viral protease and maturation of the virions.
Latent replication : replication as a provirus integrated in the host chromosome.
Reference strains
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Epidemiology
Replication cycle
- Virus attaches to host CD4 receptors through the SU glycoprotein (gp120), with subsequent interaction with a chemokine coreceptor.
- Internalization via clathrin-dependent endocytosis. TM glycoprotein (gp41) mediates dynamin-dependent fusion with the host endosomal membrane. Nucleocapsid is released into the cytoplasm, with partial uncoating.
- ssRNA(+) genome is copied into a linear dsDNA molecule by the reverse transcriptase.
- Nuclear entry of the viral dsDNA which is covalently and randomly integrated into the cell's genome by the integrase (=provirus).
- Transcription of provirus by Pol II produces viral spliced and unspliced RNAs.
- Translation of spliced viral RNAs produces tat, rev, and nef proteins.
- Rev mediates nuclear export of the uncompletely spliced RNAs.
- Translation of unspliced viral RNAs produces Env, Gag and Gag-Pol polyproteins.
- Assembly of the virion at the host cellular membrane and packaging of the viral RNA genome.
- Budding through the plasma membrane and release of the virions.
- Proteolytic processing of the precursors polyproteins by viral protease and maturation of the virions.
Matching UniProtKB/Swiss-Prot entries
(all links/actions below point to uniprot.org website)353 entries grouped by protein
49 entries
Envelope glycoprotein gp160 (Env polyprotein)
38 entries
Gag polyprotein (Pr55Gag)
42 entries
Protein Nef (3'ORF) (Negative factor) (F-protein)
36 entries
Gag-Pol polyprotein (Pr160Gag-Pol)
41 entries
Protein Rev (ART/TRS) (Anti-repression transactivator) (Regulator of expression of viral proteins)
40 entries
Protein Tat (Transactivating regulatory protein)
39 entries
Virion infectivity factor (Vif) (SOR protein)
37 entries
Protein Vpr (R ORF protein) (Viral protein R)
31 entries