Role of RNA in facilitating Gag/Gag-Pol interaction.
We have examined the influence of RNA upon the interaction of Gag-Pol with Gag during human immunodeficiency virus type 1 (HIV-1) assembly. COS7 cells were transfected with protease-negative HIV-1 proviral DNA, and Gag/Gag-Pol complexes were detected by coimmunoprecipitation with anti-integrase. In COS7 cells, Gag/Gag-Pol is found almost entirely in pelletable, membrane-bound complexes. Exposure of cells to 1% Triton X-100 releases Gag/Gag-Pol from bulk membrane, but the complexes remain pelletable. The role of RNA in facilitating the interaction between Gag and Gag-Pol was examined in these bulk membrane-free, pelletable complexes. The specific presence of viral genomic RNA is not required to maintain the Gag/Gag-Pol interaction, but some type of RNA is, since exposure to RNase destabilized the Gag/Gag-Pol complex. When present only in Gag, the nucleocapsid mutation R7R10K11S, which inhibits Gag binding to RNA, inhibits the formation of both Gag and Gag/Gag-Pol complexes. When present only in Gag-Pol, this mutation has no effect upon complex formation. This result indicates that Gag-Pol may not interact directly with RNA but rather requires RNA-facilitated Gag multimerization for its interaction with Gag.
Khorchid
Ahmad
A
Lady Davis Institute for Medical Research and McGill AIDS Center Jewish General Hospital, McGill University, Montreal, Quebec, Canada H3T 1E2.
Halwani
Rabih
R
Wainberg
Mark A
MA
Kleiman
Lawrence
L
D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D004279:DNA, Viral / Q000235:genetics / Q000378:metabolism; D015685:Fusion Proteins, gag-pol / Q000378:metabolism*; D015683:Gene Products, gag / Q000378:metabolism*; D015497:HIV-1 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D011533:Proviruses; D012367:RNA, Viral / Q000378:metabolism*; D014162:Transfection; D019065:Virus Assembly
D004279:DNA, Viral; D015685:Fusion Proteins, gag-pol; D015683:Gene Products, gag; D012367:RNA, Viral