Gag-Pol polyprotein, MoMLV (Pr180gag-pol)

Some retroviruses, including HIV-1, regulate the relative amounts of gag and pol gene products by a translational frameshift mechanism. Immunoblotting of cell lysates indicated that a protein of approximately 160 kDa, the expected translation product of the fused gag-pol gene, was the dominant species detected with HIV-specific antiserum during the first several hours of infection with this recombinant virus. Large numbers of budding, immature, and mature retrovirus-like particles were visualized by electron microscopy when the wild-type gag-pol gene was expressed, whereas no particles were detected in cells that expressed the fused gag-pol gene.During budding, it recruits, in a PPXY-dependent or independent manner, Nedd4-like ubiquitin ligases that conjugate ubiquitin molecules to Gag-Pol, or to Gag-Pol binding host factors. Interaction with HECT ubiquitin ligases probably links the viral protein to the host ESCRT pathway and facilitates release.