Identification of residues within the L2 region of rhesus TRIM5α that are required for retroviral restriction and cytoplasmic body localization

The intracellular restriction factor TRIM5α, inhibits infection by numerous retroviruses in a species-specific manner. The best characterized example of this restriction is the TRIM5α protein from rhesus macaques (rhTRIM5α), which potently inhibits HIV-1 infection. TRIM5α localizes to cytoplasmic assemblies of protein referred to as cytoplasmic bodies, though the role that these bodies play in retroviral restriction is unclear. We employed a series of truncation mutants to identify a discrete region, located within the Linker2 region connecting the coiled-coil and B30.2/PRYSPRY domains of TRIM5α, which is required for cytoplasmic body localization. Deletion of this region in the context of full-length rhTRIM5α abrogates cytoplasmic body localization. Alanine mutagenesis of the residues in this region identifies two stretches of amino acids that are required for both cytoplasmic body localization and retroviral restriction. This work suggests that the determinants that mediate TRIM5α localization to cytoplasmic bodies play a requisite role in retroviral restriction.