Effects Of The Promoter Mutation On Transcription Levels Of THRSP Gene And Its Target Genes In Pigs

THRSP gene is regarded as a transcription factor for regulation and activation of thyroid hormone receptor,and regulates the enzymes expression in fat synthesis pathway to affect the lipid metabolism in specific organization.The hybridization pigs,Duroc x(Yorkshire x Landrace),were selected and divided into 3 groups,A,D and F.The promoter genotypes of all pigs were determined based on the SNPs in THRSP gene promoter region.Each group maintained the same promoter genotypes,respectively.The effects of different promoter genotype on candidate target genes were analyzed in fat synthesis pathways.The expression levels of THRSP and its candidate target genes in pig liver were detected and investigated by RNA-seq and Q-PCR.The results showed that:(1)5 mutation sites were located upstream of the CDS,A-95 T,G-98 A,A-376 G,T-400 C and C-459 T,in the promoter region of THRSP gene,in which the promoter genotypes of A,D and F group were CCTTGGGGAA,CCCCAAAATT and CCTCGAGAAT,respectively.(2)The expression level of THRSP gene in group A was significantly higher than that in group D and F,and F higher than that in group D(P<0.05)by means of qPCR.The expression of the heterozygote group F was middle level between A and D.(3)The different expressions of THRSP candidate target genes between different groups were significant,in which the expressions of group A in Malic enzyme 1(ME1),ATP citrate-lyase(ACL),Fatty acid synthase(FASN)and Phosphoenolpyruvate carboxykinase(PEPCK)were higher than that of D and F(P<0.05),and the expressions between D and F were no-significant.(4)RNA-Seq results showed the effects of THRSP expression levels on the transcription of Malic enzyme 3(ME3)and FASN were significant(P <0.05),in which the high level group(A)of THRSP significantly upregulated ME3 and FASN,but the transcription levels of PEPCK1,PEPCK2 and ACL failed to cause significant impact among 3 groups(p>0.05).