Identification , molecular characterization , and analysis of the expression pattern of genes of SoxF subgroup in the Yellow River Carp , Cyprinus carpio

Sox7, Sox17, and Sox18 are members of the SoxF (Sry-related high-mobility group box) family of transcription factors. SoxF factors regulate endothelial cell fate, as well as development and differentiation of blood cells and lymphatic vessels. There is little information about the functions of these genes in fish. We obtained the full-length cDNA sequence of SoxF genes including Sox7, Sox17, and Sox18 in Cyprinus carpio. Sox7 and Sox18 had two copies. The construction of a phylogenetic tree showed that these genes were homologous to genes in other species. Chromosome synteny analysis indicated that the gene order of Sox7 and Sox18 was highly conserved in fish. However, great change of genomic sequences around Sox17 had happened. Numerous putative transcription factor binding sites were identified in the 5′ flanking regions of SoxF genes, which might be involved in the regulation of the nervous system, in vascular epidermal differentiation, and in embryonic development. The expression levels of SoxF genes were highest in gastrula, and abundantly expressed in the adult brain. We investigated the expression levels of SoxF genes in five specific parts of the brain. The expression levels of Sox7 and Sox18 were highest in the mesencephalon, while the expression level of Sox17 was highest in the epencephalon. The expression patterns of SoxF genes indicated a potential function of these genes in neurogenesis and in vascular development in carp. These results provide new information for further studies on the potential functions of SoxF genes in carp.