RNA helicases DDX5 and DDX17 dynamically orchestrate transcription, microRNA and splicing programs in cell differentiation

RNA helicases DDX5 and DDX17 are members of a large family of highly conserved proteins involved in gene expression regulation, although their in vivo targets and activities in biological processes like cell differentiation, that requires reprogramming of gene expression programs at multiple levels, are not well characterized. In this report, we uncovered a new mechanism by which DDX5 and DDX17 cooperate with hnRNP H/F splicing factors to define epithelial- and myoblast-specific splicing subprograms. We next observed that downregulation of DDX5 and DDX17 protein expression during epithelial to mesenchymal transdifferentiation and during myogenesis contributes to switching splicing programs during these processes. Remarkably, this downregulation is mediated by the production of microRNAs induced upon differentiation in a DDX5/DDX17-dependent manner. Since DDX5 and DDX17 also function as coregulators of master transcriptional regulators of differentiation, we propose to name these proteins “master orchestrators” of differentiation, that dynamically orchestrate several layers of gene expression. 6 samples of MCF7 cells exposed to different treatments were analyzed: 3 x siCTRL ; 3 x si(DDX5-17) AND 6 samples of MCF10 cells exposed to different treatments were analyzed: 3 x siCTRL ; 3 x si(DDX5-17)