Molecular characterization and expression of the related-male gene sox30 in the common carp Cyprinus carpio

The Sox (SRY-related HMG-box) family of transcription factors is involved in the regulation of embryonic development and determination of cell fate. Sox proteins serve as transcriptional regulators that are complexed with other proteins. For this study, we initially cloned and characterized the full-length cDNAs, DNA sequences, and 5′-flanking regions of the common carp Cyprinus carpio Sox30. The sequence analysis suggested that Ccsox30 carried a distinct HMG-box of the Sox family within Cyprinus carpio. Phylogenetic and gene structure analysis revealed that sox30 was homologous to mammalian Sox30, whereas chromosome synteny analysis demonstrated that the position of Cyprinus carpio Sox30 in the genome was different from that of other vertebrates. This might have been due to the split of the Sox30 flanking gene by several genes not yet found near the Ccsox30 in evolution, or because the genome sequencing data was not annotated. The results of Real Tim Quantitative-PCR (RT-qPCR) revealed that Sox30 expression was high in the testes, and the expression was traced in other tissues by researching the tissue distribution of C. carpio and ontogeny of Ccsox30 expression in the gonads. This expression pattern suggested that Ccsox30 may be involved in spermatogonial differentiation and spermatogenesis.