The Relationship Between Bmal1 And Clock Expression And Reproduction In Hypothalamus And Testis Of Black Wire Hamster

Cricetulus barabensis is one of the major ascidians of pest mouse in farmland in northern China, which had a serious impact on people’s lives and health. Its male individuals have remarkable seasonal reproductive characteristics, two breeding seasons a year in spring and autumn, and population explosion in a short period of time caused by the fast farrowing, which could be used as an excellent animal model for the study of seasonal reproduction. In this study,the males were used as research subjects to clone circadian clock genes(Clock, Bmal1) partial gene sequences, which expression patterns were analyzed by real-time fluorescent quantitative PCR(real-time PCR) technology. The results are helpful to understand the relationship between clock gene and seasonal reproductive activity, and lay the foundation for further exploring the molecular mechanism of seasonal reproductive regulation of C. barabensis.The 1754 bp of C. barabensis Bmal1 gene cDNA were obtained by sequencing(KU645887),all of CDs region, encoding 584 amino acids; The 911 bp of C. barabensis Clock gene cDNA were obtained(KU645888), all of CDs region, encoding 303 amino acids. Both Bmal1 and Clock are members of the HLH/PAS transcription factor family, which are hydrophobic proteins,contain a number of functional sites associated with circadian rhythm and metabolic activities.Cluster analysis shows that both are conservative in evolution.From the point of view of tissue and organ expression, Bmal1 and Clock were expressed in many organs(kidney, liver, spleen, hypothalamus, epididymis, testis), and the highest expression was found in hypothalamus and testis, suggests that it may be related to the reproductive regulation. From the point of view of individual development, the expression of Bmal1 and Clock in males showed a similar law, which was highest in both hypothalamus and testis in adult stage. That shows Bmal1 and Clock play an important role on the maintenance of male adults’ physiological state. From the point of view of seasonal expression, the expression of two genes in hypothalamus and testis is not consistent. The expression of Bmal1 in hypothalamus of the males in spring and autumn was significantly higher than that in summer and winter, that is to say, which in the reproductive season was significantly higher than that in the low/non-reproductive season, but the expression of Clock in hypothalamus was significantly higher than that in summer, autumn and winter; in winter, the expression of Bmal1 in testis was significantly lower than that in the other three seasons, and there was no significant difference(P<0.05) in that in spring, summer and autumn. In summer, the expression of Clock in testis was significantly higher than that in spring, autumn and winter, and there was no significantdifference(P<0.05) between the expression of in spring, autumn and winter. The expression of Bmal1 was similar to that of GnRH, GPR54 and Dio2 in the hypothalamus, and the expression of Clock was similar to that of RFRP in the four seasons. The expression of Clock in the testis was similar to that of RFRP in the four seasons, and contrary to that of Kiss-1. Therefore, we speculate that the annual cycle signal is integrated into the reproductive axis through TSHβ/Dio2â†'RF-amide. These results suggest that Bmal1 and Clock may be an important link of the complex regulatory molecular networks of male C. barabensis.