Tsg101, an inactive homologue of ubiquitin ligase e2, interacts specifically with human immunodeficiency virus type 2 gag polyprotein and results in increased levels of ubiquitinated gag.
The final stages of budding and release of a retroviral particle from the cell require the late (L) domain of Gag. Recently, ubiquitin and ubiquitin ligases have been implicated in the late stages of retroviral budding. In a yeast two-hybrid screen of a T-cell cDNA library to identify cellular proteins that interact with human immunodeficiency virus type 2 (HIV-2) Gag polyprotein, we identified Tsg101, an inactive homologue of ubiquitin ligase E2. Tsg101 and HIV-2 Gag interact specifically in vitro and in vivo. The interaction requires the L domain PTAPP motif in the p6 domain of HIV-2 Gag and the N-terminal Ubc-conjugation homology domain of Tsg101. Tsg101 is incorporated into HIV-2 virions. Expression of the N-terminal Ubc-conjugation homology domain of Tsg101 inhibits the release of HIV-2 virus particles. Overexpression of Tsg101 results in an increase in the level of ubiquitination of HIV-2 Gag. Our results provide evidence for recruitment of the ubiquitination machinery of the cell during late stages of the viral life cycle, mediated by the viral Gag protein.
Myers
Erin L
EL
Department of Medicine, Addenbrooke's Hospital, Cambridge CB2 2QQ, United Kingdom.
Allen
Jane F
JF
D015153:Blotting, Western; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D056827:Endosomal Sorting Complexes Required for Transport; D015683:Gene Products, gag / Q000378:metabolism; D015498:HIV-2 / Q000378:metabolism*; D006801:Humans; D008025:Ligases / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D020798:Two-Hybrid System Techniques; D025801:Ubiquitin / Q000378:metabolism*; D014771:Virion / Q000378:metabolism*; D000099177:Tsg101 Protein
D004268:DNA-Binding Proteins; D056827:Endosomal Sorting Complexes Required for Transport; D015683:Gene Products, gag; D008025:Ligases; D014157:Transcription Factors; D025801:Ubiquitin; D000099177:Tsg101 Protein