Genomic imprinting is an epigenetic regulation in mammals in which a small subset of genes is monoallelically expressed dependent on their parental origin. A large imprinted domain, SGCE/PEG10 locus, is located on human chromosome 7q21s and mouse proximal chromosome 6. However, genomic imprinting of bovine SGCE/PEG10 cluster has not been systematically studied. In this study, we investigated allele expression of 14 genes of the SGCE/PEG10 locus in bovine somatic tissues and term placenta using a single nucleotide polymorphism (SNP)-based sequencing method. In addition to SGCE and PEG10, two conserved paternally expressed genes in human and mice, five other genes (TFPI2, GNG11, ASB4, PON1, and PON3) were paternally expressed. Three genes, BET1, COL1A2, and CASD1, exhibited tissue-specific monoallelic expression. CALCR showed monoallelic expression in tissues but biallelic expression in the placenta. Three genes, GNGT1, PPP1R9A, and PON2, showed biallelic expression in cattle. Five differentially methylated regions (DMRs) were found to be associated with the allelic expression of TFPI2, COL1A2, SGCE/PEG10, PON3, and ASB4 genes, respectively. The SGCE/PEG10 DMR is a maternally hypermethylated germline DMR, but TFPI2, COL1A2, PON3, and ASB4 DMRs are secondary DMRs. In summary, we identified five novel bovine imprinted genes (GNG11, BET1, COL1A2, CASD1, and PON1) and four secondary DMRs at the SGCE/PEG10 locus.

中文翻译：

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牛 SGCE/PEG10 基因座的等位基因表达和 DNA 甲基化情况

基因组印记是哺乳动物的一种表观遗传调控，其中一小部分基因根据其亲代起源单等位基因表达。一个大的印记结构域SGCE/PEG10位点位于人类染色体7q21s和小鼠近端染色体6上。然而，牛SGCE/PEG10簇的基因组印记尚未得到系统研究。在本研究中，我们使用基于单核苷酸多态性（SNP）的测序方法研究了牛体细胞组织和足月胎盘中SGCE/PEG10位点的14个基因的等位基因表达。除了SGCE和PEG10这两个在人和小鼠中保守的父系表达基因之外，另外五个基因（TFPI2、GNG11、ASB4、PON1和PON3）也被父系表达。BET1、COL1A2和CASD1三个基因表现出组织特异性单等位基因表达。CALCR在组织中显示单等位基因表达，但在胎盘中显示双等位基因表达。三个基因GNGT1、PPP1R9A和PON2在牛中显示出双等位基因表达。发现五个差异甲基化区域 (DMR) 分别与TFPI2、COL1A2、SGCE/PEG10、PON3和ASB4基因的等位基因表达相关。 SGCE /PEG10 DMR 是母系高甲基化种系 DMR，但TFPI2、COL1A2、PON3和ASB4 DMR 是次要 DMR。总之，我们在SGCE/PEG10基因座上鉴定了 5 个新的牛印记基因（ GNG11、BET1、COL1A2、CASD1和PON1）和 4 个二级 DMR 。