Uhrf1对肠上皮发育的影响

作为一种常见的表观遗传修饰类型,DNA甲基化对哺乳动物发育起着重要作用。Uhrf1作为重要的表观遗传调控因子,在DNA合成过程中可结合半甲基化的DNA同时招募DNA甲基转移酶1参与DNA甲基化的维持,保证遗传信息在细胞分裂前后的稳定传递。目前关于Uhrf1介导的DNA甲基化是否影响肠上皮发育过程尚不清楚。为探索Uhrf1在肠上皮发育中的作用,本研究成功构建了肠上皮特异性敲除Uhrf1的小鼠模型,利用HE染色对肠上皮组织形态学观察发现,与正常小鼠相比,敲除Uhrf1的小鼠肠上皮发育异常,主要表现为绒毛变短,数量减少,隐窝萎缩;通过表型分析发现,在小鼠肠上皮中特异性敲除Uhrf1后,细胞增殖明显受到抑制、凋亡细胞增加、细胞分化异常,同时肠干细胞相关基因表达降低。进一步对可能的分子机制进行初步探索发现Uhrf1缺失后DNA甲基化水平大幅下降,诱发DNA损伤。本研究结果表明Uhrf1介导的DNA甲基化对肠上皮的正常发育成熟具有重要作用,有望丰富Uhrf1介导的DNA甲基化在体内的生物学功能,并为进一步明确Uhrf1介导的表观遗传调控机制提供实验依据。

Effect of Uhrf1 on intestinal development

As a best-characterized epigenetic modification,DNA methylation plays an important role in mammalian development.Uhrf1 is a critical epigenetic regulator that can bind to hemimethylated DNA and recruit DNA methyltransferase 1 to maintain DNA methylation.So far,the role of Uhrf1-mediated DNA methylation in intestinal development is still unknown.In order to investigate the impact of Uhrf1 deletion in intestinal development,we have successfully constructed the epithelial-specific Uhrf1 knockout mouse model.After Uhrf1 ablation,we found the mutant mice exhibited abnormal epithlial structure with less and shorter villi and shrinked crypts compared with wild type mice via hematoxylin-eosin staining.Further analysis showed that Uhrf1 deletion in the intestinal epithelium significantly decreased the cell proliferation and induced cell apoptosis.In addition,Uhrf1 deletion inhibited the normal epithelial differentiation and the expression of intestinal stem cell marker genes.Preliminary mechanism study revealed that loss of Uhrf1 caused global DNA hypomethylation which induced DNA damage in crypt cells.Taken together,our data suggested that DNA methylation mediated by Uhrf1 is vital for the normal intestinal development.Our results enriched the in vivo role of Uhrf1 and laid the foundation for further epigenetic regulatory mechanism exploration.