Rhesus monkey TRIM5α has distinct HIV-1 restriction activity among different mammalian cell lines.

Rhesus monkey TRIM5α (TRIM5α(rh)), a member of the tripartite motif (TRIM) family, was identified as the main restriction factor responsible for resistance of old world monkey cells to HIV-1 infection. However, the precise mechanism of HIV-1 infection inhibition by TRIM5α remains elusive and appears to be related to some cellular cofactors. Here we reported that TRIM5α(rh) can significantly reduce the infection efficiency of VSV-G pseudotyped HIV-1/MA-YFP virus in human epithelial carcinoma (HeLa) cells, moderately reduce in porcine kidney (PK-15) cells and have no effect on the pseudotyped virus infection in Madin-Darby canine kidney (MDCK) cells. Furthermore, we found that the different HIV-1 restriction activities have no relation with the intracellular localization of TRIM5α(rh). These results indicate that the cellular environment is very important for the efficient anti-HIV-1 activity of TRIM5α(rh). We speculate that some unknown factors required for HIV-1 infection inhibition activity are adequately expressed in HeLa cells, inadequately expressed in PK-15 cells and absent in MDCK cells.