Extended nucleocapsid protein is cleaved from the Gag-Pol precursor of human immunodeficiency virus type 1.
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.
Chen
Nissim
N
Experimental Pathology Unit1 and Clinical Virology Unit2, The Hebrew University, Hadassah Medical School, PO Box 12272, Jerusalem 91120, Israel.
Morag
Abraham
A
Experimental Pathology Unit1 and Clinical Virology Unit2, The Hebrew University, Hadassah Medical School, PO Box 12272, Jerusalem 91120, Israel.
Almog
Nava
N
Experimental Pathology Unit1 and Clinical Virology Unit2, The Hebrew University, Hadassah Medical School, PO Box 12272, Jerusalem 91120, Israel.
Blumenzweig
Immanuel
I
Experimental Pathology Unit1 and Clinical Virology Unit2, The Hebrew University, Hadassah Medical School, PO Box 12272, Jerusalem 91120, Israel.
Dreazin
Orna
O
National Public Health Laboratories, Ministry of Health, Israel3.
Kotler
Moshe
M
Experimental Pathology Unit1 and Clinical Virology Unit2, The Hebrew University, Hadassah Medical School, PO Box 12272, Jerusalem 91120, Israel.
D000818:Animals; D001665:Binding Sites; D019556:COS Cells; D002460:Cell Line; D002522:Chlorocebus aethiops; D004789:Enzyme Activation; D015683:Gene Products, gag / Q000235:genetics / Q000378:metabolism*; D016333:HIV Protease / Q000235:genetics / Q000378:metabolism*; D015497:HIV-1 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D019251:Nucleocapsid / Q000235:genetics / Q000378:metabolism*; D011498:Protein Precursors / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D014407:Tumor Cells, Cultured; D054301:gag Gene Products, Human Immunodeficiency Virus
D015683:Gene Products, gag; D011498:Protein Precursors; D011993:Recombinant Fusion Proteins; D054301:gag Gene Products, Human Immunodeficiency Virus; C083002:p6 gag protein, Human immunodeficiency virus 1; D016333:HIV Protease