[The maturation steps of human immunodeficiency virus and the role of proteolysis].

HIV-1 virions are as immature noninfectious particles lacking a central core. Shortly after budding, virions temporally mature and acquire cores and infectious activity. The cause of maturation remains poorly studied. We have revealed that the virions produced early after infection following 24-36 hours, never mature and remain noninfectious, and only virions produced 48-72 hours after infection mature. The mature virions contain 3 times more genomic viral RNA than "early" virus. The "early" virions contain the same proteolytically cleaved Gag proteins as mature virions in contrast to the accepted version. The virus protease inhibitor Indinavir sulfate (IS) fully blocks infectivity when added early after infection. The early proteolysis of Gag precursor in the infected cells and inclusion into the virions of cellularly cleaved matrix protein (cMA) are shown in the IS-treated cells. cMA is associated with genomic viral RNA.