牛RASGRF1基因的组织印记表达与分析OA北大核心CSTPCD

Genomic imprinting is a mammalian epigenetic phenomenon in which genes show parental-specific monoallelic expression.Imprinted genes play an important role in embryonic development and placental nutrition transport.The Ras protein specific guanine nucleotide releasing factor 1(RASGRF1)gene encodes 140 kD RAS specific guanine nucleotide releasing factor,and it is related to the growth and development traits of animals in infancy.Rasgrf1 gene is a paternal imprinted gene in mice(Mus musculus),but its imprinting status in cattle(Bos taurus)has not been studied.In order to study the imprinting status and regulatory mechanism of RASGRF1 gene in cattle,the expression of RASGRF1 gene in bovine 6 tissues(heart,liver,spleen,lung,kidney,brain)and placenta was analyzed by quantitative RT-PCR,and then the allele expression of RASGRF1 gene in bovine tissue and placenta was analyzed by direct sequencing of RT-PCR products based on SNP.Finally,the methylation status of the promoter region of RASGRF1 gene was studied by sulfite direct sequencing.The results showed that RASGRF1 gene showed tissue-specific expression in cattle,its transcript was not detected in heart and liver.RASGRF1 gene is monoallelically expressed in spleen,lung,kidney and brain,and paternally expressed in bovine placenta.There was no differential methylation region(DMRs)was found in the promoter and exon 1 region of bovine RASGRF1 gene.Hypomethylation was shown in heart,liver,spleen,lung,kidney,brain,placenta and sperm.These results indicated that DNA methylation in this region was not involved in the regulation of imprinting expression of RASGRF1 gene,the imprinting of bovine RASGRF1 gene might be regulated by other epigenetic modifications.This study provides a reference for the further study of the function and imprinting regulation mechanism of bovine RASGRF1gene.