山羊促甲状腺素β亚基基因(TSHB) cDNA克隆 与组织表达研究

促甲状腺素β亚基基因(TSHB)主要表达于动物垂体腺,其表达受到光照周期调控并且与动物季节性繁殖活动密切相关.本实验以济宁青山羊和辽宁绒山羊为研究对象,运用RT-PCR方法克隆获得山羊TSHB基因部分cDNA序列(GenBank No.:JQ937288),并使用RT-PCR与荧光定量PCR技术检测TSHB基因在济宁青山羊与辽宁绒山羊下丘脑-垂体-卵巢繁殖轴及其他组织的表达分布情况.结果表明,山羊TSHB基因编码区417bp,编码含有138个氨基酸的蛋白质;各哺乳动物间TSHB基因高度保守,山羊与绵羊、牛TSHB基因同源性最高,达99％;另外,两品种山羊TSHB基因均在垂体中高表达,在济宁青山羊下丘脑、卵巢及海马等组织低度表达,而在辽宁绒山羊下丘脑低度表达,两品种其他组织均没有表达.非繁殖季节济宁青山羊垂体TSHB基因表达水平是辽宁绒山羊的1.6倍(P=0.061),其对季节性繁殖的调控功能值得进一步研究.本研究首次对山羊TSHB基因cDNA序列进行了克隆和表达分析,研究结果对山羊繁殖调控具有重要意义.

cDNA cloning and tissue expression of thyroid stimulating hormone beta chain gene (TSHB) in goats

Thyroid stimulating hormone beta chain (TSHB) is mainly expressed in pituitary, which is regulated intensely by photoperiod and closely related to seasonal reproduction in animals. To study the expression profile and function of goat TSHB gene, a cDNA fragment was cloned and its expression was detected in 22 tissues of goat by using RT-PCR method. TSHB gene expression in hypothalamus-pituitary-ovary?axis and other four tissues was analyzed by qPCR. The results showed that whole coding region of goat TSHB gene was 417 bp in length, encoding a protein of 138 amino acid residues, which has high homology (99%) with both sheep and cattle. Moreover, TSHB gene is highly conservative in mammals. The results also indicated that goat TSHB gene was expressed abundantly in pituitaries of both Jining Grey goats and Liaoning Cashmere goats. Compared with Liaoning Cashmere goat, its expression in pituitary of Jining Grey goat was 1.6-fold over-expressed. Additionally, there were very low expression levels in hypothalamus (for both breeds), ovary and hippocampus for Jining Grey goat, and no expression in other tested tissues. In the present study, cDNA clone of goat TSHB gene was obtained and its expression was initially detected in goats. The results will be helpful for further researches on gene function of goat TSHB.