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:X chromosome inactivation involves multiple levels of chromatin modification, established progressively and in a stepwise manner during early development. The chromosomal protein Smchd1 has recently been shown to play an important role in DNA methylation of CpG islands (CGIs), a late step in the X inactivation pathway required for long-term stability of gene silencing. Here we show that inactive X chromosome (Xi) CGI methylation can occur via either Smchd1 dependent or independent pathways. Smchd1 dependent CGI methylation, the primary pathway, is acquired gradually over an extended period, whereas Smchd1 independent CGI methylation occurs rapidly after the onset of X inactivation. The de novo methyltransferase Dnmt3b is required for methylation of both classes of CGI, whereas Dnmt3a and Dnmt3L are dispensable. Xi CGIs methylated by these distinct pathways differ in respect to their sequence characteristics and immediate chromosomal environment. We discuss the implications of these results for understanding CGI methylation during development. Examination of CpG methylated DNA from wild type and smchd1 null male and female somatic cells and female ES cells differentiated for either 7 or 10 days. Duplicate samples of each type were generated.
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 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 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 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 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 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 loc. Smchd1 deletion results in gain in Ctcf binding and activation of enhancers. We propose Smchd1 functions by limiting Ctcf-mediated chromosome looping.