Department of Morphology, Surgery and Experimental Medicine; University of Ferrara; Ferrara, Italy.
Epigenetics. 2013 Sep;8(9):990-7. doi: 10.4161/epi.25798. Epub 2013 Jul 24.
Aberrant methylation at the H19 paternal imprinted gene has been identified in different cohorts of infertile males. The causes of H19 methylation errors are poorly understood. In this study, we investigated the methylation status of the H19 gene in semen DNA samples from infertile males affected by MTHFR gene promoter hypermethylation. DNA from normal and abnormal semen samples harbouring MTHFR gene promoter hypermethylated, hmMTHFR-nor and hmMTHFR-abn, and without MTHFR methylation, MTHFR-nor and MTHFR-abn, were investigated for methylation status in the H19 locus using bisulfite-treated DNA PCR, followed by cloning and sequencing. The prevalence of H19 hypomethylated clones was 20% in hmMTHFR-nor and 0% in MTHFR-nor semen samples (p<0.05), and 28% in hmMTHFR-abn compared with 16% in MTHFR-abn semen samples (p>0.05). These results underscore the association between H19 methylation defects and hypermethylation of the MTHFR gene promoter in normal semen samples and suggest that aberrant methylation at H19 may occur in the normal sperm of infertile males affected by MTHFR gene dysfunction. These findings provide new insights into the mechanisms causing abnormal methylation in imprinted genes and, in turn, male infertility.
在不同的不育男性队列中已经发现了 H19 父系印迹基因的异常甲基化。H19 甲基化错误的原因尚不清楚。在这项研究中，我们研究了 MTHFR 基因启动子高甲基化影响的不育男性精液 DNA 样本中 H19 基因的甲基化状态。使用亚硫酸氢盐处理的 DNA PCR 、克隆和测序，研究了正常和异常精液样本中含有 MTHFR 基因启动子高甲基化的 hmMTHFR-nor 和 hmMTHFR-abn 以及没有 MTHFR 甲基化的 MTHFR-nor 和 MTHFR-abn 中 H19 基因座的甲基化状态。hmMTHFR-nor 精液样本中 H19 低甲基化克隆的发生率为 20%，而 MTHFR-nor 精液样本中为 0%（p<0.05），hmMTHFR-abn 与 MTHFR-abn 精液样本相比为 28%（p>0.05）。这些结果强调了 H19 甲基化缺陷与正常精液样本中 MTHFR 基因启动子高甲基化之间的关联，并表明 MTHFR 基因功能障碍影响的不育男性正常精子中可能发生 H19 异常甲基化。这些发现为导致印迹基因异常甲基化的机制提供了新的见解，并进而为男性不育提供了新的见解。
