高邮鸭与金定鸭GnRHR2基因组织表达差异分析

Differential Analysis of Tissue Expression of GnRHR2 mRNA in Gaoyou and Jinding Duck Breeds

克隆鸭GnRHR基因序列,并研究其对产蛋性能的调节作用。采用RT-PCR技术从鸭生殖轴组织总RNA中克隆GnRHR基因cDNA序列,并利用Real-time PCR技术分析GnRHR基因在不同产蛋期高邮鸭和金定鸭生殖轴组织中的表达。序列分析结果表明克隆序列长度约500 bp,属II型GnRHR基因序列,与家鸡cGnRHR2序列的同源性为96%。金定鸭群体的开产日龄较高邮鸭群体早30 d,72周龄产蛋数比高邮鸭多83个。从产蛋早期至高峰期,GnRHR2基因在高邮鸭和金定鸭下丘脑、垂体中的表达量呈上调趋势,且高邮鸭的表达量显著高于金定鸭(P<0.05,P<0.01);而在卵巢中的表达量呈下调趋势,金定鸭卵巢组织中的表达量显著高于高邮鸭(P<0.01)。产蛋期前卵巢中GnRHR2基因的暂时性高表达可能有助于性成熟的启动,提早开产日龄;产蛋早期后下丘脑、垂体中GnRHR2基因的持续上调表达对产蛋高峰期的维持具有重要作用。

The objective of this study was to clone the sequence of Duck GnRHR gene and knowledge of its function in reproduction.RT-PCR method was used to clone GnRHR cDNA from duck reproductive tissues,and its expression levels during early laying days and laying fastigium period between Gaoyou and Jinding duck breeds were tested by Real-time PCR.Sequencing and homology analysis showed the cloned duck GnRHR cDNA was about 500bp in length,and it belonged to the avian type II GnRHR isoforms.It was 96% identical to the cGnRHR2 sequence reported in domestic chicken.Compared to Gaoyou duck,the first laying age of Jinding duck predated 30 days,the production exceed 83 eggs.Real-time PCR results indicated expression levels of GnRHR2 increased in pituitary and hypothalamus,but decreased in ovary from early laying days to laying fastigium period.A pronounced breed difference existed,with higher expression levels（P0.05,P0.01） in Gaoyou duck pituitary and hypothalamus.In contrast,higher expression levels（P0.01）occurred in Jinding duck.It suggested that the short-lived higher expression of ovary GnRHR2 gene before early laying days was necessary for the onset of sexual maturation,and the upregulation in pituitary and hypothalamus after early laying days could aid to keep laying fastigium.