ABSTRACT: RNAseq : MCF-7 cells were transfected with siRNA targeting both DDX5 and DDX17 RNA helicases, and total RNA were extracted as described previously (Dardenne Cell Rep 2014).
Project description:We aimed at analysing the effect of RNA helicases DDX5 and DDX17 and of the transcription factor REST on gene expression in the human SH-SY5Y neuroblastoma cell line (European Collection of Cell Cultures, ECACC), which was cultured as recommended by the supplier.
Project description: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 M-bM-^@M-^\master orchestratorsM-bM-^@M-^] of differentiation, that dynamically orchestrate several layers of gene expression. 6 samples of MCF7 cells exposed to different treatments were analyzed: 3 x siCTRLM-BM- ; 3 x si(DDX5-17) AND 6 samples of MCF10 cells exposed to different treatments were analyzed: 3 x siCTRLM-BM- ; 3 x si(DDX5-17)
Project description:This project includes ChIP of total RNA pol II in human SH-SY5Y neuroblastoma cells following the joint depletion of RNA helicases DDX5 and DDX17 to determine the genome-wide effect of DDX5/DDX17 on RNA Pol II distribution.
Project description: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.
Project description:DEAD-box RNA helicases DDX5 and DDX17 regulate gene expression at different levels such as transcription and splicing, but the underlying mechanisms are not fully understood. A calibrated ChIP-seq analysis of total RNA Polymerase II was carried out in DDX5/DDX17-depleted SH-SY5Y cells to analyse the contribution of DDX5/DDX17 to RNAPII distribution. Univ Lyon, ENS de Lyon, CNRS UMR 5239, INSERM U1293, Laboratory of Biology and Modelling of the Cell, 46 Allée d'Italie, F-69007, Lyon, France. Corresponding author: cyril.bourgeois@inserm.fr
Project description:DEAD-box RNA helicases DDX5 and DDX17 regulate gene expression at different levels such as transcription and splicing, but the underlying mechanisms are not fully understood. A transcriptome analysis of DDX5/DDX17-depleted human cells confirmed was carried out to further characterize the widespread deregulation of alternative splicing. This study also revealed a deregulation of 3’ end processing leading to transcriptional read-through. Univ Lyon, ENS de Lyon, CNRS UMR 5239, INSERM U1293, Laboratory of Biology and Modelling of the Cell, 46 Allée d'Italie, F-69007, Lyon, France. Corresponding author: cyril.bourgeois@inserm.fr
Project description:The fate of NSCs is strictly controlled by dynamic programs related to time. This process requires an interconnection between intrinsic and extrinsic factors to modulate the gene expression programs and precisely control the action of various downstream signaling. Several studies have been identified the uncovered functions of DDX5 and DDX17 involved in multiple aspects of gene regulatory networks and some of those have been suggested their potential roles regarding neural differentiation. In this study, we sought to distinguish the mode of action of DDX5 and DDX17 underlying the neurogenesis between two distinct cell stages including pluripotent and neural stem cell pools. We employ the ability of RNA interference to investigate the functional involvement of these two RNA helicases during embryonic and adult neurogenesis.
Project description:Background & Aims: Transcription termination fine tunes gene expression and contributes to specify the function of RNAs in eukaryotic cells. Transcription termination of hepatitis B virus (HBV) is subjected to the recognition of the canonical polyadenylation signal (cPAS) common to all viral transcripts. The regulation of the usage of this cPAS and its impact on viral gene expression and replication is currently unknown. Approach & Results: To unravel the regulation of HBV transcript termination, we used a 3’ RACE-PCR assay together with single molecule sequencing both in in vitro infected hepatocytes and in chronically infected patients. The detection of a previously unidentified transcriptional readthrough indicated that the cPAS was not systematically recognized during HBV replication in vitro and in vivo. After gene expression downregulation, followed by RNA and chromatin immunoprecipitation experiments, we showed the role of the RNA helicases DDX5 and DDX17 in promoting viral transcriptional readthrough, which was, furthermore, associated to HBV RNA destabilization. Moreover, downregulation of DDX5 and DDX17 allowed the precise termination of HBV transcripts at cPAS, which was associated with increased viral replication. Conclusions: Our findings identify DDX5 and DDX17 as crucial determinants for HBV transcriptional fidelity and as host restriction factors for HBV replication.
Project description:Neural cell fate specification is a highly regulated process in which stem cells sequentially possess the transcriptional profile changed and give raise to particular cell lineages such as neuron and glial cells. The NTERA2 cell line is one of the well-characterized hEC cells that can be used as a model system for identifying the regulatory network during human pluripotent stem cells differentiated toward the neural lineage. It has been demonstrated that DDX5 and DDX17, as transcriptional co-regulator, can play a role in various cellular mechanisms depending on their interaction with the different types of transcription factors. Here, we performed ChIP-seq for DDX5 and DDX17 to identify their preferential binding targets during stage transition from pluripotent to neural cell lineage.
Project description:The DEAD-box ATP-dependent RNA helicases DDX5 and DDX17 play a role in many aspects of cellular RNA biology, including metabolism, translation, splicing, transcription regulation, ribosome biogenesis, mRNA nuclear export, and miRNA processing. Moreover, both RNA helicases were found to either promote or inhibit viral replication upon several RNA virus infections. Here we show that DDX5 depletion by siRNA or CRISPR/Cas9 has a negative impact on Sindbis virus (SINV) infection at the viral protein, RNA and infectious particle level. Moreover, we demonstrate that DDX5 which is predominately nuclear in uninfected conditions, re-localizes to the cytoplasm upon infection where it interacts with the viral RNA and with the SINV capsid protein. Furthermore, proteomic analysis of DDX5 interactome in mock and SINV infected HCT116 cells confirmed its interaction with DDX17 and identified PNPT1 as a new DDX5 partner. Of note, while PNPT1 localization remains mostly unchanged in mock and infected cells, DDX17 re-localizes to the cytoplasm with DDX5 upon SINV infection and interacts with SINV capsid protein. Finally, depletion of DDX17 further reduces SINV infection in a DDX5-depleted background suggesting a cumulative proviral effect of DDX5 and 17 proteins on SINV.