Fig. 6.—

Implicated restriction factors. Of 67TRIM genes, several members have been implicated as restriction factors, either positively or negatively impacting viral fitness. In many of these cases, direct interactions with viral proteins has not been detected (top) (reviewed in Ozato et al. 2008; Kawai and Akira 2011). Seven of these genes have evolved under positive selection in primates—two that were previously published, TRIM5 and TRIM22 (Sawyer et al. 2007; Sawyer et al. 2005), in addition to TRIM25 (Gack et al. 2009), TRIM21 (Mallery et al. 2010), TRIM15, TRIM31, and TRIM38 (Uchil et al. 2008) (Overlap). We believe these restriction factors likely act via a direct interaction interface to recognize or evade viral proteins. In addition, we found ten TRIM genes to be rapidly evolving that represent novel restriction factor candidates which may also act via direct host–virus interactions (bottom).