miR-200b mediates post-transcriptional repression of ZFHX1B.

MicroRNAs have important functions during animal development and homeostasis through post-transcriptional regulation of their cognate mRNA targets. ZFHX1B is a transcriptional repressor involved in the TGFbeta signaling pathway and in processes of epithelial to mesenchymal transition via regulation of E-cadherin. We show that Zfhx1b and miR-200b are regionally coexpressed in the adult mouse brain and that miR-200b represses the expression of Zfhx1b via multiple sequence elements present in the 3'-untranslated region. Overexpression of miR-200b leads to repression of endogenous ZFHX1B, and inhibition of miR-200b relieves the repression of ZFHX1B. In accordance with these findings, miR-200b regulates the activity of the E-cadherin promoter.