DNMT1基因在牛胎盘及组织中的印记特征分析OA

To investigate the allelic expression and DNA methylation status of the DNA methyltransferase 1(DNMT1)gene in bovine placenta and other tissues,and to reveal the imprinting pattern of the DNMT1 gene in various bovine tissues,whole genome sequencing(WGS)was performed on genomic DNA from three placentas(1-3)and their parental samples to screen the single nucleotide polymorphism(SNP);Transcriptome sequencing(RNA-seq)was to analyze the allelic expression pattern of DNMT1 gene and whole genome bisulfite sequencing(WGBS)was conducted to detect the DNA methylation status of DNMT1 locus.The results were as follows:1)A total of 12 valid SNP loci were identified in the exons of the DNMT1 gene,with 0,12 and 12 loci detected in the three placentas,respectively.DNMT1 exhibited maternal allelic expression in placenta 2,while biallelic expression was observed in placenta 3.2)SNP-based direct sequencing of RT-PCR products was applied to analyze another 17 placental samples,with the SNP rs211542364 used to distinguish parental alleles.Among the 17 placental tissues,10 were identified as heterozygous placentas,of which two displayed maternal allelic expression and the others showed biallelic expression,which verified the above conclusion.3)Using the same SNP locus,the DNMT1 gene was found to exhibit biallelic expression in 6 tissues(heart,liver,spleen,lung,kidney and brain)from 7 adult cattle.4)Analysis of WGBS data revealed that among the four CpG islands at the DNMT1 gene locus,CpG:89 was hypomethylated,while the other three CpG islands(CpG:18,CpG:18 and CpG:33)showed hypermethylation,and no differentially methylated regions(DMRs)were detected.5)Bisulfite sequencing further confirmed that CpG:89,located in the promoter and exon 1 regions of the DNMT1 gene,was hypomethylated in both placentas with maternal expression and biallelic expression.These findings suggest that DNA methylation modification at the DNMT1 gene locus can not regulate the polymorphic imprinted expression of the DNMT1 gene in bovine placenta.In summary,DNMT1 acts as a polymorphic imprinted gene in bovine placenta,but is expressed biallelically in other bovine tissues.Its imprinted expression is not controlled by DNA methylation.This study provides a reference for further exploring the function and imprinting regulatory mechanism of DNMT1 gene.