The primate TRIMCyp fusion genes and mechanism of restricting retroviruses replication

TRIM5-cyclophilin A (TRIMCyp) fusion gene is an unusual TRIM5 locus. At present, this fusion phenomenon has been found in the representative species which contain owl monkey ( Aotus trivirgatus ) of Aotus genus that belongs to New World monkeys and Old World monkeys such as Northern pig-tailed macaque ( M. leonina ), Sunda pig-tailed macaque( M. nemestrina ), Crab-eating macaque ( M. fascicularis ), Indian rhesus macaque ( M. mulatta ) and Assam macaque ( M. assamensis ), etc. But the fusion mode and transcription splicing pattern of TRIMCyp fusion gene are different between New World and Old World monkeys. The TRIMCyp fusion gene of New World monkeys is formed by inserting a CypA pseudogene cDNA sequence into the region between exon 7 and exon 8 of the TRIM5 locus through retrotransposition. However the TRIMCyp fusion gene of Old World monkeys results from the retrotransposition of a CypA pseudogene cDNA into 3' terminal or 3'-UTR of TRIM5 gene. The distributions, genotypes, expression and restricting activities against different retroviruses of TRIMCyp were different across species of primates. Moreover, most of the researches focused on the TRIMCyp fusion gene of owl monkey and pig-tailed macaque and found that they may play very important roles in restricting HIV-1 replication and determine the susceptibility to HIV-1 infection. It was reported that the TRIMCyp protein of owl monkey could inhibit HIV-1 infection in a similar way as TRIM5α, but TRIMCyp protein of pig-tailed monkey loss the restricting activity to HIV-1 infection. Here we reviewed the distributions, genotypes and restriction mechanism for inhibiting retroviruses replication of TRIMCyp fusion gene in primates