Identification of a region in the Pr55gag-polyprotein essential for HIV-1 particle formation.

The pr55gag polyprotein of HIV-1 plays a critical role in the formation of immature virus particles in the cell and during the budding process. We investigated the influence of amino acid substitutions in the p24CA- region of the gag polyprotein on the viral assembly process. Deletion of the amino acids 341-352 in the carboxy terminal part of the p24CA resulted in a loss of the capacity of the gag polyprotein to form virus-like particles when expressed in eucaryotic cells by recombinant vaccinia virus. In further experiments it turned out that the amino acids 341-346 and 350-352 are important for the ability of the pr55gag to form virus-like particles. Because these stretches are conserved among HIV-1, HIV-2, SIV, and FIV, we conclude that these amino acids form a domain highly important for the assembly of these lentiviruses.