Project description:polyA RNA-seq was performed on different SMCHD1 and LRIF1 knock-out myoblast clones to assess the role of SMCHD1 and LRIF1 in transcriptioanl regulation in somatic cells
Project description:In human muscle, SMCHD1 mutations are associated with the onset of FSHD2, but the mechanism driving the disease onset remains unclear. A commonly accepted explanation is the loss of SMCHD1 binding to the D4Z4 locus activates the expression of DUX4 in FSHD2 muscle. In this study, we used human myoblasts having DUX4 non-permissive 4qB alleles as a model to study DUX4-independent functions of SMCHD1 on myoblast cell growth. Surprisingly, depletion of SMCHD1 in these cells resulted in a cell proliferation defect. Despite the absence of DUX4 target genes’ activation, these cells showed a repression of PAX7 target genes (a hallmark of FSHD) and similar changes in expression profile compared to FSHD myoblasts. Interestingly, downregulation of cell proliferation-related genes and dysregulation of fibroblasts-specific genes were observed in SMCHD1 knockdown myoblasts and FSHD2 myoblasts but not FSHD1 myoblasts. Additionally, we identified LAP2 as direct targets of SMCHD1. Depletion of LAP2 leads to cell proliferation defect similar to the effect after SMCHD1 knockdown. These data imply that DUX4 is not the only driver for the onset of FSHD, and SMCHD1 has DUX4-independent functions in muscle growth and development.
Project description:In human muscle, SMCHD1 mutations are associated with the onset of FSHD2, but the mechanism driving the disease onset remains unclear. A commonly accepted explanation is the loss of SMCHD1 binding to the D4Z4 locus activates the expression of DUX4 in FSHD2 muscle. In this study, we used human myoblasts having DUX4 non-permissive 4qB alleles as a model to study DUX4-independent functions of SMCHD1 on myoblast cell growth. Surprisingly, depletion of SMCHD1 in these cells resulted in a cell proliferation defect. Despite the absence of DUX4 target genes’ activation, these cells showed a repression of PAX7 target genes (a hallmark of FSHD) and similar changes in expression profile compared to FSHD myoblasts. Interestingly, downregulation of cell proliferation-related genes and dysregulation of fibroblasts-specific genes were observed in SMCHD1 knockdown myoblasts and FSHD2 myoblasts but not FSHD1 myoblasts. Additionally, we identified LAP2 as direct targets of SMCHD1. Depletion of LAP2 leads to cell proliferation defect similar to the effect after SMCHD1 knockdown. These data imply that DUX4 is not the only driver for the onset of FSHD, and SMCHD1 has DUX4-independent functions in muscle growth and development.
Project description:To study the role of SmcHD1 in regulating gene expression, we have stably knocked down SmcHD1 in HEK293 cells and looked at change in gene expression. shRNA3 and shRNA4 were used to target the expression of the SmcHD1 gene (Genbank Accession number NM_015295). The protein levels of SmcHD1 were knocked down in excess of 90% normal levels in 293 cells. shRNA NC5 a scrambled control shRNA and did not change SmcHD1 protein levels in 293 cells. Agilent single color 28004 was used on 9 Samples.
Project description:To study the role of SmcHD1 in regulating gene expression, we have stably knocked down SmcHD1 in HEK293 cells and looked at change in gene expression. shRNA3 and shRNA4 were used to target the expression of the SmcHD1 gene (Genbank Accession number NM_015295). The protein levels of SmcHD1 were knocked down in excess of 90% normal levels in 293 cells. shRNA NC5 a scrambled control shRNA and did not change SmcHD1 protein levels in 293 cells.
Project description:Structural Maintenance of Chromosomes Hinge Domain Containing 1 (SMCHD1) is a chromatin repressor, which is mutated in >95% of Facioscapulohumeral dystrophy (FSHD) type 2 cases. In FSHD2, SMCHD1 mutations ultimately result in the presence of the cleavage stage transcription factor DUX4 in muscle cells due to a failure in epigenetic repression of the D4Z4 macrosatellite repeat on chromosome 4q, which contains the DUX4 locus. While binding of SMCHD1 to D4Z4 and its necessity to maintain a repressive D4Z4 chromatin structure are well documented, it is unclear how SMCHD1 is recruited to D4Z4, and how it exerts its repressive properties on the chromatin. Here, we employ a quantitative proteomics approach to identify and characterize novel SMCHD1 interacting proteins, and assess their functionality in D4Z4 repression. We identify 47 robust SMCHD1 interactors, of which 19 are present in D4Z4 chromatin. We demonstrate that one of these SMCHD1 interacting proteins in D4Z4, RuvB-like 1 (RUVBL1) is indeed required for maintaining DUX4 silencing in FSHD myocytes. We also confirm the interaction of SMCHD1 with EZH inhibitory protein (EZHIP), which prevents global H3K27me3 deposition by the Polycomb repressive complex PRC2, providing novel insights into the potential function of SMCHD1 in the repression of DUX4 in the early stages of embryogenesis. The SMCHD1 interactome outlined herein can thus provide further direction into research on the potential function of SMCHD1 at genomic loci where SMCHD1 is known to act, such as D4Z4 repeats, the inactive X chromosome, autosomal gene clusters, imprinted loci and telomeres.
Project description:Immortalized myoblasts obtained from healthy and Duchenne patients where induced to fuse into multi-nucleated myotubes and Bru-seq was performed
Project description:We sought to examine whether the non-canonical SMC protein Smchd1 plays a role in chromosome conformation. We used in situ Hi-C to analyse chromosome conformation changes upon deletion of the epigenetic regulator Smchd1 in female neural stem cells. In parallel, we analysed nucleosome accessibility using ATAC-seq, gene expression using RNA-seq, chromatin marks H3K27me3 and H3K27ac and Ctcf binding using ChIP-seq. We additionally analysed Smchd1 binding genome-wide using ChIP-seq. Together, we find that deletion of Smchd1 alters chromosome conformation at Smchd1 target genes including the inactive X chromosome, Hox genes and imprinted loc. Smchd1 deletion results in gain in Ctcf binding and activation of enhancers. We propose Smchd1 functions by limiting Ctcf-mediated chromosome looping.
Project description:We sought to examine whether the non-canonical SMC protein Smchd1 plays a role in chromosome conformation. We used in situ Hi-C to analyse chromosome conformation changes upon deletion of the epigenetic regulator Smchd1 in female neural stem cells. In parallel, we analysed nucleosome accessibility using ATAC-seq, gene expression using RNA-seq, chromatin marks H3K27me3 and H3K27ac and Ctcf binding using ChIP-seq. We additionally analysed Smchd1 binding genome-wide using ChIP-seq. Together, we find that deletion of Smchd1 alters chromosome conformation at Smchd1 target genes including the inactive X chromosome, Hox genes and imprinted loci. Smchd1 deletion in differentiating ES cells results in failed Hox gene silencing. Smchd1 deletion results in gain in Ctcf binding and activation of enhancers. We propose Smchd1 functions by limiting Ctcf-mediated chromosome looping.