鸽GnIH和GnRH基因克隆及其在不同繁殖阶段下丘脑中的表达

为研究促性腺激素抑制激素（gonadotropin-inhibitory hormone,GnIH）和促性腺激素释放激素（gonadotropin-releasing hormone,GnRH）基因在鸽繁殖不同阶段下丘脑组织中的表达变化,探讨GnIH和GnRH基因与鸽繁殖调控之间的关系,本研究以鸽cDNA为模板扩增GnIH和GnRH基因CDS区序列并进行克隆测序,采用实时荧光定量PCR技术检测了产蛋前、产蛋后及哺乳期鸽下丘脑组织中GnIH和GnRH基因mRNA表达水平。序列分析结果表明,鸽GnIH基因CDS区全长522 bp,已提交GenBank,登录号：MG589638,编码173个氨基酸,与已知其他鸟类GnIH同源性达85%以上;鸽GnRH基因CDS区全长276 bp,已提交GenBank,登录号：MG589639,编码91个氨基酸,与已知其他鸟类GnRH同源性达80%以上。鸽GnIH前体包含1个GnIH和2个GnIH相关肽（GnIH-RP-1、GnIH-RP-2）,具有典型的"LPXRF"基序;GnRH前体包含1个信号肽、1个GnRH和1个GnRH相关肽（GAP）。实时荧光定量PCR结果表明,产蛋前鸽下丘脑中GnIH基因表达量最高,且极显著高于产蛋后和哺育期（P<0.01）;产蛋后鸽下丘脑中GnRH基因表达量最高,且极显著高于产蛋前和哺育期（P<0.01）;产蛋前鸽下丘脑中GnIH基因表达量极显著高于GnRH基因（P<0.01）,而产蛋后和哺育期鸽下丘脑中GnRH基因表达量极显著或显著高于GnIH基因（P<0.01;P<0.05）。结果表明,GnIH和GnRH基因的表达与母鸽不同繁殖阶段的转变有关,为进一步研究鸽繁殖分子机制奠定基础。

Cloning and Expression of GnIH and GnRH Genes in Hypothalamus of Pigeons at Different Breeding Stages

In order to clarify the expression levels of gonadotropin-inhibitory hormone (GnIH) and gonadotropin-releasing hormone (GnRH) genes in hypothalamus of pigeons at different reproductive stages,and explore the relationship between GnIH and GnRH genes and reproductive performance,the CDS sequence of GnIH and GnRH genes were amplified,cloned and analyzed,and the expression level of GnIH and GnRH genes was detected in hypothalamus of pigeons in pre-laying,post-laying and feeding periods,respectively.Sequence analysis results showed that 522 bp of pigeon GnIH gene complete CDS (GenBank accession No.:MG589638) was obtained which encoded 173 amino acids,and 276 bp of pigeon GnRH gene complete CDS (GenBank accession No.:MG589639) was obtained which encoded 91 amino acids.The homology between GnIH and GnRH genes of pigeon and those of other birds were more than 85% and 80%,respectively.GnIH precursor included a GnIH peptide and two GnIH-related peptides (GnIH-RP-1,GnIH-RP-2) which had the typical C-terminal "LPXRF-amide" sequence.GnRH precursor included a signal peptide,a GnRH peptide and a GnRH-associated peptide (GAP).Real-time PCR results indicated that the expression level of GnIH gene in hypothalamus of pigeons in pre-laying period was extremely significantly higher than that in post-laying and feeding periods (P<0.01).The expression level of GnRH gene in hypothalamus of pigeons in post-laying period was extremely significantly higher than that in pre-laying and feeding periods (P<0.01).The expression level of GnIH gene in hypothalamus of pigeons in pre-laying period was extremely significantly higher than GnRH gene (P<0.01).The expression levels of GnRH gene in hypothalamus of pigeons in post-laying and feeding periods were extremely significantly and significantly higher than GnIH gene (P<0.01;P<0.05).The results revealed that the expression of GnIH and GnRH genes was related to the transformation of female pigeons in different breeding stages,which laid a foundation for discussing the molecular mechanism of pigeon production.