Truncation of TRIM5 in the <i>Feliformia</i> explains the absence of retroviral restriction in cells of the domestic cat

Abstract

TRIM5[alpha] mediates a potent retroviral restriction phenotype in diverse mammalian species. Here, we identify a TRIM5 transcript in cat cells with a truncated B30.2 capsid binding domain and ablated restrictive function which, remarkably, is conserved across the &lt;i&gt;Feliformia&lt;/i&gt;. Cat TRIM5 displayed no restriction activity, but ectopic expression conferred a dominant negative effect against human TRIM5[alpha]. Our findings explain the absence of retroviral restriction in cat cells and suggest that disruption of the TRIM5 locus has arisen independently at least twice in the &lt;i&gt;Carnivora&lt;/i&gt;, with implications concerning the evolution of the host and pathogen in this taxon