Figure 5.
MutLα promotes pri-miR-422a processing. (A, B) In-vitro reconstitution of miRNA processing. Reconstitution of miRNA processing was performed in reactions containing pri-miR-422a, Drosha and DGCR8 in the presence or absence of MutLα, as indicated. Three independent experiments were performed. Data were quantified, presented as mean ± SD, and plotted in (B). (C, D) Stimulation of Drosha/DGCR8-mediated processing of pre-miR-30a and pre-miR-16-1 by MutLα, respectively. (E, F) MutLα stimulates the processing of miR-422a and miR-16-1 in vivo, respectively. HCT116 cells with or without MLH1 expression were transfected with plasmids carrying the indicated pri-miRNAs, and RNAs were isolated 48 h after transfection and analyzed for conversion of the exogenous pri-miRNAs to their corresponding pre- and mature miRNAs using northern blotting analysis as described 49. U6 snRNA was used as a loading control. M, a 23-oligonucleotide size marker; Lα, MutLα Vctr, vector alone.