Sox9基因在黄颡鱼卵巢发育周期的表达及对热应激的响应

The expression of Sox9 during ovarian development and heat stress in yellow catfish Pelteobagrus fulvidraco

中文关键词: Sox9  雌二醇  卵巢的年周期变化  热应激

英文关键词: Sox9  Estradiol-17β  Ovarian cycle  Heat stress

中文摘要:

      采用半定量PCR的方法，分别从时空表达、温度应激调控和血清雌二醇（Estradiol-17β，E2）水平3个方面，共同研究雌性黄颡鱼Sox9基因的功能。结果表明，Sox9a1基因在雌性黄颡鱼各组织中存在广泛的表达，而Sox9a2则在脑和卵巢中有高表达（脑>卵巢），胃中表达微弱。在卵巢年周期发育中，卵巢中Sox9a1在Ⅲ期时达到高峰，Sox9a2则在Ⅴ期时达到峰值；脑中Sox9a1和Sox9a2表达的最大值均在Ⅱ期，后随着卵巢的发育表达水平显著下降。在热应激调控试验中，卵巢中Sox9a1虽然对热应激存在响应，但并没有出现E2相一致的变化趋势，而Sox9a2的变化趋势与血浆中E2相同。虽然脑中Sox9a1和Sox9a2在卵巢年周期发育的表达变化出现下降的趋势，但在热应激条件下，脑中Sox9a1和Sox9a2在Ⅱ期与E2的变化相反，而Ⅲ期到Ⅵ期与E2的变化相一致。该实验结果表明，卵巢中Sox9a1可能不参与卵巢的年周期发育，Sox9a2则参与卵巢发育的调控和E2的合成；在脑中，我们推测热应激可能改变了Sox9与雌激素的负调控关系，但其机理需要更深入的研究。

英文摘要:

      Since the Sox9 plays a pivotal role during ovary development, the importance of two forms of Sox9 in the process of ovarian recrudescence in yellow catfish Pelteobagrus fulvidraco was analyzed. Tissue distribution pattern showed preferential expression of Sox9a2 in brain and ovary (brain>ovary), and trace amounts was detected in stomach, while the extensive expression of Sox9a1 was observed in several tissues. A semi-quantitative RT PCR was developed to measure the mRNA levels. The high transcript levels of both isoforms in ovary were found in the reproductive phase of ovarian cycle, with the highest level in stage Ⅲ for Sox9a1 and Ⅴ for Sox9a2.While the level of Sox9 in brain dropped significantly from stage Ⅱ. The phase-dependent rising of Sox9a2 and Estradiol-17β (E2) in fish exposed to higher temperature revealed the stimulatory role of heat stress. Gene expression of Sox9a1 in ovary was not consistent with E2 level in serum of fish exposed to higher temperature. Sox9 expression in brain was contrary to the level of E2 in stage Ⅱ. The expression level of Sox9a1 and Sox9a2 were closely related to level of serum E2 in stage Ⅲ-Ⅵ. Results demonstrated Sox9a2 in ovary played a crucial role in the reproductive cycle of female yellow catfish, and Sox9a1 in ovary was not involved in controlling the reproductive cycle. In addition, we infered that temperature can affect the negative regulation between Sox9 in brain and E2, while the mechanism needs further research.