Comparative requirements for the restriction of retrovirus infection by TRIM5α and TRIMCyp

The restriction factors, TRIM5 alpha in most primates and TRIMCyp in owl monkeys, block infection of various retroviruses soon after virus entry into the host cell. Rhesus monkey TRIN15 alpha (TRIM5 alpha(rh)) inhibits human immunodeficiency virus (HIV-1) and feline immunodeficiency virus (FIV) more potently than human TRIM5a (TRIM5 alpha(hu)). TRIMCyp restricts infection of HIV-1, simian immunodeficiency virus of African green monkeys (SIVagm) and FIV. Early after infection, TRIMCyp, like TRIM5 alpha(rh) and TRIM5 alpha(hu), decreased the amount of particulate viral capsid in the cytosol of infected cells. The requirements for the TRIMCyp and TRIN15a domains in restricting different retroviruses were investigated. Potent restriction of FIV by TRIMCyp occurred in the complete absence of RING and B-box 2 domains; by contrast, efficient FIV restriction by TRIM5 alpha(rh) required these domains. Variable region 1 of the TRIM5 alpha(rh) B30.2 domain contributed to the potency of HIV-1, FIV and equine infectious anemia vir-us restriction. Thus, although differences exist in the requirements of TRIMCyp and TRIM5 alpha for RING/B-box 2 domains, both restriction factors exhibit mechanistic similarities. (c) 2007 Elsevier Inc. All rights reserved.