The Single Nucleotide Polymorphisms, MRNA Expression And The Promoter Region Methylation Patterns Of LCORL In Qinchuan Cattle

LCORL( ligand dependent nuclear receptor corepressor-like protein) located in chromosome 6 which is closely connected with the bovine growth and carcass traits. Previous studies reported that the LCORL was significantly associated with growth and carcass traits in animals. In this experiment, from the perspective of molecular genetics, the single nucleotide polymorphisms of LCORL was detected by the method of PCR-RFLP and CRS-PCR, and screened out the SNPs which was significantly associated with growth and carcass traits in Qinchuan cattle. From the perspective of epigenetics, explored the methylation patterns of CpG islands in the promoter region of LCORL by the method of bisulfite sequencing PCR,and analyzed the relations with the expression of mRNA. For further study of LCORL gene provide molecular basis, provide a scientific basis for breeding of Qinchuan beef cattle.1. The single nucleotide polymorphisms of LCORL and its association with growth and carcass traits in Qinchuan cattleA total of 450 Qinchuan beef cattle were used to detect mutations of the LCORL by the method of PCR-RFLP and CRS-PCR. The results of this study shows: six polymorphic loci were found, there was one SNP(INT+52098A>G) in intron region, one SNP(INT+150525T>C) in the 3 ’UTR region, the other four variations(PR_-2488G>A,PR_-709C>T, PR_-471G>A, PR_-176 C>T) were located in the promoter region.Linkage disequilibrium analysis and haplotype analysis indicated that L78-Q4 was strong linkage disequilibrium, A T G C G C(16.2%) and G C G C A T(16.7%) had higher haplotype frequencies, G C A C A C(0.8%) and G T A C A T(0.7%) had lower haplotype frequencies.Correlation analysis indicated that the SNP g. INT+52098A>G was significantly associated with slaughter weight and carcass weight, the SNP g. PR_-709C>T was correlated in Qinchuan beef cattle dressing percentage. The results showed that the sequence variations of LCORLassociated with carcass traits in Qinchuancattle, the 2 SNPs can be used as candidate molecular markers for improving the performance of Qinchuan beef.2. The expression patternsof the LCORL gene in Qinchuan beef cattleReal-time fluorescent quantitative PCR results revealed that, LCORL was expressed in various tissues in adult Qinchuan cattle, the expression of spleen and intestine was the highest,and the lowest expression in muscle and heart. The expression of LCORL in adult muscle and adipose tissue was extremely significantly lower than the expressive quantity in calf muscle and adipose in Qinchuan beef cattle(P<0.01).3. The methylation patterns of CpG islands in the LCORL and its relationship with the expression of mRNAIn this study, explored the methylation status of CpG islands in the promoter region of LCORL by the method of bisulfite sequencing PCR. The results showed that the level of methylation in various tissues was relatively low, the degree of methylation was highest in liver and muscle tissue, and the degree of methylation was the lowest in spleen and kidney.The methylation level of calf muscle and adipose tissue is extremely significantly lowerthan the level of methylation in adult cattle muscle and adipose tissue(P<0.01). LCORL gene methylation and mRNA expression correlation analysis showed that the negative correlation between them.