REDUCED INFECTIVITY OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 PRODUCED IN THE PRESENCE OF A TRUNCATED GAG PROTEIN CONTAINING P7 GAG AND P6 GAG

The C-terminal portion of human immunodeficiency virus type 1 p55gag p rotein, p15gag, contains two functional proteins; p6gag which is requi red for incorporation of Vpr into the virion, and p7gag which binds to viral RNA and is necessary for packaging of genomic RNA into virions. p7gag protein overexpressed in trans may compete with wild type p55ga g for binding to genomic viral RNA, thereby inhibiting incorporation o f RNA into the virions. To investigate if overexpression of the C-term inal portion of p55gag could interfere with generation of infectious v irus, a plasmid producing a protein consisting of p2gag, p7gag and p6g ag, termed p15gag, was generated and cotransfected with an infectious proviral human immunodeficiency virus type 1 clone. Cells overexpress ing p15gag in trans produced approximately 40 fold less infectious vi rus than cells lacking exogenous p15gag. These results demonstrated t hat expression of the C-terminal portion of p55gag efficiently reduced virus infectivity.