• DNA Methyltransferase 3B Expression is Regulated by microRNA-222 in Intestinal Epithelial Cells

      Wu, Jing; Vucenik, Ivana; Wang, Jian-Ying (2015)
      DNA methyltransferases (DNMTs) regulate distinct cellular functions by regulating gene transcription, genome stability, chromatin compaction and genome defense, but the exact mechanisms that control DNMTs levels remain largely unknown. Posttranscriptional processes are major mechanisms by which mammalian cells control gene expression, particularly in altering mRNA turnover and translation. microRNAs (miRNAs) are able to directly bind to the cis-elements located at the 3'-untranslated regions (3′-UTRs) of target mRNAs leading to changes in mRNA stability and translation, through which regulate gene expression. In the present study we reported that DNMT3B mRNA is a novel target of microRNA-222 (miR-222) and that miR-222 represses DNMT3B expression post-transcriptionally in human intestinal epithelial cells (IECs). Overexpression of miR-222 resulted in no significantly change in the levels of DNMT3B mRNA, but reduced new synthesis of DNMT3B dramatically. Overexpression of miR-222 also repressed the growth of intestinal epithelial cells, which arrested in G1 phase. These findings indicate that miR-222 represses translation of DNMT3B mRNA, in turn affecting intestinal epithelial homoeostasis by affecting intestinal epithelial cell proliferation.