中国大鲵Cyp51基因特征与性腺表达分析

采用RT-PCR法从大鲵( Andrias davidianus )性腺中分离获得 Cyp51 基因全长cDNA 1 975 bp, 5′端非编码区135 bp, 3′端非编码区331 bp,开放阅读框( ORF)1 509 bp,编码503氨基酸。生物信息学分析显示, Cyp51 基因编码蛋白的二级结构含有50.20%的α-螺旋,9.96%的延伸链,3.59%的β-转角,36.25%的无规则卷曲。系统进化树显示,大鲵与两栖类中的热带爪蟾和非洲爪蟾同源性最高,与其它物种也有较高的同源性。qRT-PCR分析结果显示, Cyp51 基因在卵巢、肝、肾等组织表达水平显著性高于其它各组织;性腺发育不同时期表达结果显示, Cyp51 基因在1-5Y卵巢中表达显著性高于精巢,在6Y时无显著性差异;在雌性与伪雌性性腺中表达水平显著高于雄性及伪雄性性腺。结果表明 Cyp51 基因对大鲵的性腺分化,尤其是卵巢发育有着重要作用。

Genetic characterization and gonad expression analysis of Cyp51 in Andrias davidianus

Full length of the Cyp51 cDNA sequence was isolated employing RT-PCR technology with total of 1 975 bp containing 5′UTR 135 bp noncoding region, 3′UTR 331 bp noncoding region and open reading frame ( ORF) 1 509 bp encoding 503aa. Bioinformatics analysis displayed that CYP51 protein secondary structure included 50.20%α-helix, 9.96% extension chain, 3.59% beta-turn and 36.25% random coil. The phylogenetic tree showed that Andrias davidianus had the highest homology with Xenopus laevis and X. tropicalis in amphibians and extensive homology with other species. The expression of Cyp51 exhibited significantly high expression level, which was observed in the ovary, liver and kidney. The low expressions were observed in other tissues. The expression pattern in developing gonad showed that Cyp51 had a significant higher level in ovary than that in testis during 1-5Y, however, there was no significant difference in 6Y. Additionally, Cyp51 expression level was significantly higher in ovary of normal or sex reversal female individuals than that in testis of normal or sex reversal male individuals. The current results indicated that Cyp51 plays a vital role in gonadal differentiation in Chinese giant salamander, especially in ovary development.