Abstract:The innate immune system is the main defense against viral infections in teleost fish. As an important part of the innate immune system, the TRIM protein family participates in the regulation of the immune network during virus infection. Among such proteins, TRIM25 has been reported to play an important role in the immune response of many types of fish. In this study, 16 copies of the trim25 gene in common carp (Cyprinus carpio) were compared with those of other species by phylogenetic and syntenic analyses. Functional domain structures for 16 copies of the TRIM25 protein were predicted, and the expression and cis-regulatory network in tissues for each gene copy were compared. Sequence alignment and phylogenetic analysis showed that the TRIM25 protein structure of C. carpio was highly similar to that of Sinocyclocheilus grahami and Danio rerio, but distinct from that of other species beyond Cyprinidae. The results of gene synteny indicated that the upstream and downstream genes of trim25 were relatively conserved in the evolution of different species. Structural analysis of TRIM25 showed that six of the sixteen copies in C. carpio had complete functional domains; five of these copies were highly expressed in liver and brain tissue. In the expression quantitative trait loci (eQTL) regulatory network for trim25, 5 and 17 SNPs were determined to regulate trim25 expression in liver and brain tissue, respectively. In this study, the sequence differences of multiple copies of trim25 in common carp were compared, and the evolutionary relationship and synteny of trim25 were identified. The diversity of the structure and tissue expression of trim25 genes in the common carp were revealed, and the SNP sites that may regulate trim25 gene expression were identified, providing a reference for future research on trim25 related regulation and disease resistance in the C. carpio.
