生肌调节因子是肌肉形成的关键控制因素.通过RTPCR方法克隆得到鳜鱼主要生肌调节因子MyoD序列.鳜鱼MyoD基因cDNA长度为813 bp,编码270个氨基酸,推导的氨基酸序列含有1个bHLH结构.经与其他动物MyoD氨基酸序列比对发现不同动物MyoD的bHLH结构域保守性高.通过合成地高辛标记的反义RNA探针对鳜鱼不同发育阶段的胚胎进行整体胚胎原位杂交,结果发现:MyoD最早在肌节早期被检测到信号.伴随着鳜鱼体节从头部往后发育,MyoD也从头部往尾部表达.在体节期,MyoD在中后部表达.尾芽期MyoD的表达量达到最大值.然而,尾芽期过后,头部MyoD的表达量急剧减少,但尾部仍然有强烈的信号.在血流期仍然能在鳜鱼尾部检测到MyoD的微弱信号.到孵出期在鳜鱼鱼眼的后方和胸部腹侧检测到MyoD的强信号,而身体其他地方检测不到信号.仔鱼期没有检测到MyoD表达的信号.
Myogenic regulatoryfactors (MRFs) plays a key role in controlling myogenesis. The cDNA of MyoD in Siniperca chuatsi was cloned using RTPCR. The sequence length of MyoD is 813 bp and encoding 270 amino acids. The MyoD includes a bHLH structures, which showed high conservation with other animals. The application of Dig labeled RNA probe on the detection of MyoD expression at different embryonic developmental stages by wholemount in situ hybridization. The results showed that MyoD expression was first detected in early myomere stage. As somite formed from rostral to caudal, the MyoD expressed from rostral to caudal. The most rich expression stage was the caudal bud stage. After the caudal bud stage, the expression of the gene decreased rapidly, especially in the anterior somites where somatic cells were differentiated, but the posterior somites still showed a strong expression in the caudal somites. Blood circulation stage showed a weak expression. After hatching about 12 hours, there was a strong expression in the back of the eyes and the chest of the fish. At larval stage, no expressional signal was detected.