中国大鲵生长激素受体的克隆与表达分析

摘要

The growth hormone receptor (GHR) cDNA was isolated and characterized in Chinese giant salamander (Andrias davidianus), based on a partial sequence from the transcriptome database. The full-length cDNA was 2992 bp, containing an open reading frame of 1812bpthat encoded a deduced protein of 604 amino acids with one conserved FGEFS domain and two BOX domains. System evolution analysis showed that Chinese salamander GHR had the highest similarity with the GHR proteins from amphibiansXenopus laevis, followed by sauropsida (Chrysemys picta bellii), and the lowest with mammals (Bubalus bubalis) and fish (Cynoglossus semilaevis). The expression pattern ofGHR in different tissues was evaluated. Its expression level was the highest in the liver, fol-lowed by the muscle, pituitary gland, kidney and gonads; its expression was very low in other tissues. The expression level ofGHR in the testis was higher at the early stage, and then decreased as the testes developed. However, the expression level increased as the ovary developed. Furthermore, transient treatment with 17α-Methyltestosterone (MT) and letrozole (LE) had different effects on the expression ofGHR. The expression level ofGHR in the brain and ovary was increased by MT treatment but decreased by LE treatment. Our results indicated that GHR may play an important role in gonadal development, and was affected differently by MT and LE treatment.%利用中国大鲵(Andrias davidianus)性腺转录组测序获得的生长激素受体(GHR)基因部分序列,克隆获得基因全长2992 bp,开放阅读框1812 bp,编码604个氨基酸,该蛋白具有高度保守的FGEFS基序与BOX框。系统进化分析结果显示,中国大鲵GHR氨基酸序列与两栖类非洲爪蟾(Xenopus laevis)同源性最高,蜥形纲锦龟(Chrysemys picta bellii)次之,哺乳类水牛(Bubalus bubalis)和鱼类半滑舌鳎(Cynoglossus semilaevis))最低。实时定量PCR结果表明, GHR基因在肝中表达最高,肌肉、垂体、肾、性腺中的表达量次之,其他各组织表达量较低。在精巢发育早期GHR表达较高,随后表达量逐渐降低,在卵巢中表达量随时间增长而增加；17α-甲基睾丸酮(MT)与芳香化酶抑制剂来曲唑(LE)短暂处理后GHR基因在脑与卵巢中表达量发生变化, MT处理后,脑与卵巢中GHR表达量增加, LE处理后脑与卵巢中表达量降低。研究表明, GHR基因在大鲵性腺发育中可能发挥作用,且MT与LE可能通过不同的途径调节GHR基因的表达。