Study On Differences Of FSHR Gene Structure And Expression In Sheep With Different Fecundity

The prolificacy of sheep is one of the assurances of production level and economic benefits insheep industry. Improvement of sheep prolificacy can significantly heighten production efficiency.. Inthis study, we analyzed the correlation between polymorphism of FSHR gene and fecundity.Futhermore, the expression pattern and promotor structure of FSHR gene was studied using highprolificacy sheep breed (Small Tail Han Sheep) and low prolificacy sheep breed (Tan Sheep) as acontrol. The aim of this study is to find the differences of FSHR gene function and expression betweensheep breeds with different fecundity.（1）Screening SNP sites at all exons of FSHR gene by PCR-RFLP and analyzing relationshipbetween genetic variations of FSHR gene and high prolificacy of sheep. The results as following:Three mutations (T1235C (S1) AG2357-2358C (S2) and A149G (S3),) were detected in exon1and exon10respectively, which did not lead to the change of amino acids. At the S2and S3loci,significant differences of genotype distribution were found between Small Tail Han sheep and Tansheep (P<0.01). The results of haplotype analysis indicated that H2, H7and H1, H7were preponderanthaplotype in high prolificacy sheep breed and low prolificacy sheep breed, respectively. Significantdifference between litter size and genotypes was found only at S2site in Small Tail Han sheep. Thereare differences between H5/H7, H7/H7and another diplotypes.(2) Studying expression pattern of FSHR gene during different stages of estrous cycle in5tissuesof Small Tail Han sheep and Tan sheep by RT-qPCR. The results as following:Between two breeds, different expression was found in oviduct during every stage of estrous cycle(P<0.05), at the same time, expression differences were found in hypothalamus during period of estrus(P<0.05) and in pituitary during period of proestrus (P<0.05). For Small Tail Han sheep, expressiondifferences existed in pituitary during every stage of estrous cycle (P<0.05); For Tan sheep, expressiondifferences existed in hypothalamus and oviduct during every stage of estrous cycle (P<0.05). Therewere expression differences in oviduct during every stage of estrous cycle (P<0.05), in hypothalamusand ovary during period of proestrus (P<0.05) and in pituitary during period of estrus (P<0.05). Nodifference was found in uterus (P>0.05).(3) Cloning the5’ upstream sequences of FSHR gene for Small Tail Han sheep and Tan sheep.and evaluating different functions and structures of promoter using bioinformatics analysis. The resultsas following:The5’ upstream sequences in length2582bp were obtained from two breeds, which included thefirst exon and promoter of FSHR gene. The results of bioinformatics analysis shown which is highlypossible that the promoters of FSHR gene for Small Tail Han sheep and Tan sheep were in region of2045-2295bp and2038-2288bp. The TATA box was found in these regions in both breeds.INF.1transcriptional binding site was only found in Small Tail Han sheep and CpG island was not foundin both breeds.