miR-23a/27a/24基因簇g.65307469G>A突变对大白猪产仔数和启动子活性的影响.

[Objectives]The paper aimed to study the relationship between the polymorphisms of variants in miR-23a/27a/24 gene cluster promoter and litter size traits and its potential mechanism in Large White sow, and to provide a new potential genetic marker for molecular breeding of reproductive traits in sow. [Methods]The pooled sequencing was used to screen for variants in the promoter region of porcine miR-23a/27a/24 gene cluster, and the direct sequencing was used to detect genotype variants in a Large White sows population(n=345). The association between the polymorphisms and litter size traits was analyzed by a linear model. Different allelic promoter vectors were constructed and transfected into porcine ovarian granulosa cells(GC), and the effect of the variants on promoter activity was analyzed by luciferase activity assay. Bioinformatic methods were used to predict the potential binding of differential transcription factors in different allelic promoter, and the effect of differential transcription factors on the activity of different allelic promoters was verified by luciferase activity assay. [Results]A novel G/A variant, named g.65307469G>A, was identified at -648 nt(Chr. 2, 65 307 469 nt)in the promoter region of porcine miR-23a/27a/24 gene cluster. Three genotypes(GG, GA and AA)were observed in the Large White sow population, of which GG was the dominant genotype(89.57%)and the G allele was the dominant allele(94.64%). The association analysis revealed that the total number of piglets born(TNB)of sows with GA genotype was 0.56 higher than that of sows with GG genotype per litter(P<0.05). Luciferase activity assay showed that the activity of promoter region with G allele was significantly higher than that of promoter region with the A allele(P<0.05). A potentially binding site for transcription factor thanatos-associated protein 1(THAP1)was found in the promoter regions with the G allele, but not A allele, and a porcine THAP1 overexpression vector was successfully constructed. The results of the co-transformation experiment revealed that the THAP1 had no significant effect on the activity of the promoter regions with the G or A alleles(P>0.05). [Conclusions]The miR-23a/27a/24 gene cluster was a candidate gene cluster for litter size traits in Large White sow. The g.65307469G>A mutation affected the promoter activity of miR-23a/27a/24 gene cluster, but was not related to the transcription factor THAP1. [ABSTRACT FROM AUTHOR]