PER2基因组织表达及多态性与绵羊季节性繁殖的相关性研究

Tissue Expression and Polymorphism PER2 Gene and Their Association with Seasonal Reproduction in Sheep

为探究PER2基因在绵羊繁殖相关组织中的表达水平及其多态性与绵羊繁殖性状的关系,本实验通过实时荧光定量PCR(qPCR)检测PER2基因在季节性发情的苏尼特羊和常年发情的小尾寒羊松果体、下丘脑、垂体、卵巢、输卵管以及子宫组织中的表达情况,同时利用Sequenom MassARRAY■SNP技术检测季节性发情绵羊品种(草原型藏羊、苏尼特羊、滩羊共204只)和常年发情绵羊品种(小尾寒羊、湖羊、策勒黑羊共564只)PER2基因g.2852655T>C位点的多态性。结果表明:PER2基因在绵羊的松果体、下丘脑、垂体、卵巢、输卵管以及子宫组织中均有表达,且在季节性繁殖的苏尼特羊卵巢和子宫组织中的表达均显著高于常年发情小尾寒羊(P<0.05),而在输卵管组织中则相反(P<0.05);分型结果表明,PER2基因的g.2852655T>C位点存在3种基因型,该位点的基因型频率和等位基因频率在发情性状不同的绵羊品种之间具有显著差异。综上,PER2基因在季节性发情苏尼特羊卵巢组织中的表达量显著高于常年发情小尾寒羊,初步推测卵巢中较高水平PER2基因的表达通过抑制LHR受体的表达及孕酮的分泌,进而影响绵羊的季节性发情,且较高水平PER2基因表达可能在卵子受精和胚胎发育过程中也起到重要调控作用。

To explore the tissue expression level of period 2(PER2)gene and the association of its polymorphisms with reproduction in sheep,sqRT-PCR and qPCR were performed to investigate the expression of PER2 gene in different tissues including pineal gland,hypothalamus,pituitary,ovary,oviduct and uterus in Small Tail Han sheep and Sunite sheep,respectively.Seasonal estrous breeds(total 204 for Prairie Tibetan sheep,Tan sheep and Sunite sheep)and year-round estrous breeds(total 564 for Hu sheep,Cele black and Small Tail Han sheep)were selected,and Sequenom MassARRAY■SNP assay was applied to genotype one single nucleotide polymorphism site(SNP)of PER2 gene.Gene and genotype frequencies of this site were also analyzed in sheep with different reproductive traits.The results showed that PER2 gene expressed in all chosen tissues and the expression of PER2 in Sunite sheep was significantly higher than that in Small Tail Han sheep in ovary and uterus(P<0.05),but it was conversely expressed in oviduct(P<0.05).There were three genotypes in both year-round estrous breeds and seasonal estrous sheep breeds,and the genotype frequencies and allele frequencies of the PER2 gene g.2852655T>C locus were significantly different between year-round and seasonal estrous sheep(P<0.05).In conclusion,the expression level of PER2 gene in the ovary of Sunite sheep was significantly higher than that in the Small Tail Han sheep,and the higher expression of PER2 gene in the ovary may inhibit the expression of LH receptor and progesterone secretion,which finally affects the seasonal estrus of sheep.The higher levels of PER2 may also play an important regulatory role in egg fertilization and embryonic development in sheep.