The polypeptide composition of HIV-I virus-like particles produced by CV-I cells during mono- and coinfection with recombinant vaccinia virus (rVV) strains containing the whole p55) and carboxyterminal truncated (p48) gag genes and gag-pol sequence is studied. In monoinfection both the gag-strains actively produced virus-like particles consisting of non-processed p55Gag and p48Gag polyprotein without p6 domain. In case of a coinfection of the cells with one of these strains and the rVV producing p160Gag-Pol polyprotein the virus-like particles consisted of p24 protein and a negligible amount of non-processed Gag precursors. The share of p24 protein increased in proportion to the duration of coinfection and decreased with a reduction of multiplicity of infection with rVV carrying p160Gag-Pol. Hence, the absence of p6 domain does not influence the processing of Gag proteins during virus-like particles assembly and budding. In contrast to the natural systems of HIV-I development, in the rVV expression system the p6Gag domain virtually does not contribute to reactions between Gag and Gag-Pol precursors and to the particles' morphogenesis.

*Fusion Proteins, gag-pol/METABOLISM *Gene Products, gag/METABOLISM *HIV-1/METABOLISM *Protein Precursors/METABOLISM *Vaccinia Virus/GENETICS *Virion/METABOLISM

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