Expression Regulation Of Cx43 Genes In Carp Muscle

Cyprinus carpio is one of the most widely cultured freshwater fish species in the world. Carp has the following characteristics:the strong adaptability, the quick growth speed, easy breeding, high feed conversion efficiency and so on. The meat of Carp is tasty and has a high nutritional value, and thus the demand for breeding high quality carps has been increasedConnexin43(Cx43) is one of the homologous proteins of the connexin family, is also the most widely expression connexin. During the early embryonic development, Cx43 can widely expressed in muscle fibers, the contraction of muscle fibers is facilitated by low-resistance electrical coupling via gap junctions composed primarily of connexin43 (Cx43). In addition, Cx43 is necessary in the process of transmission of signaling molecules and metabolites. In mammals, as well as in zebrafish, frogs and chickens, Cx43 is downregulated during late embryogenesis and early post-natal life. Conservation of the Cx43 expression pattern suggests the existence of a conservation of mechanism. Studies have shown that Cx43 was common target genes of miR-1 and miR-206, and Cx43 is very important during the skeletal myoblast fusion.To study the roles of the Cx43 during the early development of carp, we have detected the expression of Cx43 gene in different periods of carp embryos by whole mount in situ hybridization, MyoD is the positive control and found that Cx43 was expressed around the eye, head and heart, while the neural system and paraxial cells, and the express stretches to the tail end of thel2h embryo; Cx43 was mainly expressed in the nervous system, paraxial cell, and the expression is obvious in all of somite;In the 48h embryo, except for the head, the expression of axial and paraxial cells were quantity decreased and hardly observed Cx43 expression in somites. RT-PCR results also show that the expression of Cx43 is highest in 24h carp embryos. All of the results have shown that Cx43 gene begins to express and work during the early embryo development and then declines with the incubation.In addition, bioinformatics software show that:Cx43 mRNA contains two binding sites for miR-206/miR-1 in its 3’-UTR region in zebrafish, compared with the carp genome, the 3’-UTR of carp and zebrafish wre mostly matched.The ’seed’ sequence, corresponding to the most important region for miRNA-land miRNA-206, the previous bases seven of seed sequence was completely. In order to further test our prediction, the construction of dual luciferase reporter vector were performed as described to explored the role for miRNA-1 and miR-206 in the regulation of Cx43 in NIH-3T3 cells. Luciferase assays showed that miR-206 downregulate Cx43 expression.The results of our study suggest that miR-206 can also targeted to the Cx43 3’-UTR region in the carp muscle tissue.