兴国红鲤AR基因的鉴定及MT暴露对幼鱼肝中AR和vtg表达的影响

实验克隆了兴国红鲤(Cyprinus carpio var singuonensis)雄激素受体(androgen receptor,AR)基因的全长c DNA序列和卵黄蛋白原(vitellogenin,vtg)基因的部分c DNA序列,并对雌性个体组织及甲基睾丸酮(Methyltestosterone,MT)暴露下幼鱼肝胰腺(以下简称:肝)中AR和vtg的表达进行检测。兴国红鲤AR基因c DNA全长3 229 bp,包括104 bp的5'非编码区(untranslation region,UTR)、编码846个氨基酸的2 541 bp开放阅读框(open reading frame,ORF)和485 bp 3'UTR。氨基酸序列同源性分析表明,兴国红鲤AR与其他鲤科鱼类AR的同源性较高。组织表达特征研究表明,AR在雌性个体的肝、卵巢、中肾、肌肉和端脑中有表达,其中肝中的表达量最高;vtg主要在肝、端脑和鳃中表达。兴国红鲤幼鱼在50μg/L的MT中暴露4周后,采用qRT-PCR检测了肝中AR和vtg的表达情况。在处理第1、2周,AR的表达受到一定的抑制,而在第3、4周其表达量升高,但其表达无显著性变化;而vtg的表达量在第3、4周均有极显著的升高。

Characterization of AR gene in Cyprinus carpio var singuonensis and AR and vtg expression in the liver of juveniles upon MT exposure

In the study, the full-length cDNA sequence of androgen receptor ( AR) and partial sequence of vitellogenin ( vtg) were isolated and characterized from the liver of Cyprinus carpio var singuonensis. The C. carpio var singuonensis AR cDNA was 3 229 bp in length, including 104 bp 5′-untranslated region ( UTR) , 2 541 bp open reading frame ( ORF) en-coding 846 amino acid residues, and 485 bp 3′-UTR. Predicted amino acid sequence alignment showed that C. carpio var singuonensis AR shared the highest identities with three cyprinidae species. The expression characterizations of AR and vtg in tissues of mature female fish were analyzed using qRT-PCR. AR was mainly expressed in liver, ovary, kidney, muscle and cerebrum, with the highest expression level in liver. The mRNA expression of vtg was higher in liver, cerebrum and gill. And, the expression profiles of AR and vtg in the liver of juveniles, which was exposed to Methyltestosterone ( MT, 50 μg/L) for 4 weeks, were detected by qRT-PCR. The AR expression was down-regulated in the first two weeks and was up-regulated in the 3rd and 4rd weeks, but there were no significant changes in the four weeks. However, the expression of vtg was dramatically increased in the 3rd and 4th week.