Extended nucleocapsid protein is cleaved from the Gag-Pol precursor of human immunodeficiency virus type 1.
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Chen N, Morag A, Almog N, Blumenzweig I, Dreazin O, Kotler M
Extended nucleocapsid protein is cleaved from the Gag-Pol precursor of human immunodeficiency virus type 1.
J Gen Virol. 2001 Mar;82(Pt 3):581-90.
- PubMed ID
- 11172099 [ View in PubMed]
- Abstract
Human immunodeficiency virus type 1 Gag and Gag-Pol precursors are translated from an mRNA which is indistinguishable from the full-length genomic RNA. The ratio of Gag to Gag-Pol polyproteins is approximately 20:1 and is controlled by a frameshift of the reading frame, which takes place downstream of the p7 nucleocapsid (NC) in the N terminus of the p1 peptide. The viral precursors Gag and Gag-Pol are cleaved by the virus-encoded protease (PR) into the structural proteins, and into p6(Pol), PR, reverse transcriptase and integrase. Due to the frameshift event, the cleavage site at the C terminus of NC coded in the Gag frame (ERQAN-FLGKI) changes either to ERQANFLRED or ERQANFFRED. The results presented in this report demonstrate that the NC released from the Gag-Pol precursor is 8 amino acid residues longer than the NC cleaved from the Gag polyprotein. Our results also show that truncated Gag-Pol precursors bearing cleavage site mutation at the NC/p6(Pol), and/or p6(Pol)/PR junctions, undergo autoprocessing in bacterial and eukaryotic cells, indicating that PR is active when part of the precursor.