绵羊CCNG1基因克隆及表达分析

Molecular cloning and tissue expression of the CCNG1 gene in sheep

细胞周期蛋白cyclin G1(CCNG1)是一个重要的细胞周期调控因子,参与哺乳动物颗粒细胞增殖、卵母细胞成熟等繁殖生物学过程,但其在绵羊中鲜有报道。为了研究CCNG1基因对绵羊发情调控以及季节性繁殖的影响,文章对绵羊CCNG1基因进行了克隆和组织表达谱分析,利用Real-time PCR对该基因在多浪羊(常年发情)与中国美利奴羊(季节性繁殖)发情周期不同阶段性腺轴组织的表达变化进行了实时检测。获得了绵羊CCNG1基因部分c DNA序列,其中编码区全长885 bp,编码294个氨基酸。CCNG1蛋白结构经预测存在多个磷酸化位点和蛋白激酶C磷酸化位点。CCNG1基因在所检测绵羊各组织中均有表达,但在卵巢与肾脏中为高丰度表达;CCNG1在不同绵羊品种发情周期不同阶段性腺轴组织的表达变化规律基本一致,卵巢、子宫、松果体、垂体均是在发情期达到峰值。但是在发情期和发情后期卵巢CCNG1的表达量存在显著的品种间差异(P<0.01)。研究结果表明,CCNG1可能通过参与卵泡的生长发育继而达到对绵羊发情和季节性繁殖的调控。

The CCNG1 gene encodes cyclin G1, which is an important cell cycle regulator and has been reported to be involved in reproductive biological processes, such as oocyte maturation and granule cell proliferation in mammals. But the study of CCNG1 in sheep has been rarely reported. To examine the effects of CCNG1 on estrous control and seasonal breeding in sheep, we first cloned and characterized the expression level of the sheep CCNG1 gene. Then by Real-time PCR, we detect-ed and analyzed the expressions of CCNG1 gene at mRNA levels in the hypothalamus-pituitary-ovary （HPO） axis in different stages of an estrous cycle in Duo Lang sheep （non-seasonal breeding） and Merino sheep （seasonal breeding）. The results showed that the open reading frame of the sheep CCNG1 gene is 885 bp in length and encodes 294 amino acids. Bioinformatic analysis indicated that the secondary structure of the sheep CCNG1 protein contained multiple phosphorylation sites and some Protein Kinase C phosphorylation sites. CCNG1 mRNA was identified in all tissues tested, with the levels in ovary and kidney＆amp;nbsp;higher than others. The expression profiles of CCNG1 in the HPO axis in different stages of an estrous cycle were similar in different sheep breeds：the expression levels of CCNG1 in the ovary, uterus, pineal gland and pituitary gland all peaked in the estrus phase. But there were significant differences for expression change extent of CCNG1 in ovaries in the oestrus and metes-trus phase between different sheep breeds. The results suggested that CCNG1 probably participated in the regulation of es-trous behavior and seasonal reproduction through controling the growth and development of follicles in sheep.