Project description:Recent work from others and us revealed interactions between the Sin3/HDAC complex, the H3K4me3 demethylase KDM5A, GATAD1 and EMSY. Here, we characterize the EMSY/KDM5A/SIN3B complex in detail by quantitative interaction proteomics and ChIP-sequencing. We identify a novel substoichiometric interactor of the complex, ZNF131, which recruits EMSY to a large number of active, H3K4me3 marked promoters. Interestingly, using an EMSY knock-out line and subsequent rescue experiments, we show that EMSY is in most cases positively correlated with transcriptional activity of its target genes and stimulates cell proliferation. Finally, by immunohistochemical staining of primary breast tissue microarrays we find that EMSY/KDM5A/SIN3B complex subunits are frequently overexpressed in primary breast cancer cases in a correlative manner. Taken together, these data open venues for exploring the possibility that sporadic breast cancer patients with EMSY amplification might benefit from epigenetic combination therapy targeting both the KDM5A demethylase and histone deacetylases.
Project description:Histone H3K4 methylation has been linked to transcriptional activation. JARID1A (also known as RBP2 or KDM5A), a member of the JARID1 protein family, is an H3K4 demethylase, previously implicated in the regulation of transcription and differentiation. Here we show that JARID1A is physically and functionally associated with two histone deacetylase complexes. Immunoaffinity purification of JARID1A confirmed a previously described association with the SIN3B-containing HDAC complex, and revealed an association with the nucleosome remodeling and deacetylase (NuRD) complex. Sucrose density gradient and sequential immunoprecipitation analyses further confirmed the stable association of JARID1A with these two HDAC complexes. JARID1A depletion led to changes in the expression of hundreds of genes, two-thirds of which were also controlled by CHD4, the NuRD catalytic subunit. Gene ontology analysis confirmed that the genes commonly regulated by both JARID1A and CHD4 were categorized as developmentally regulated genes. ChIP analyses suggested that CHD4 controls chromatin association with JARID1A and modulates H3K4 levels at the promoter and coding regions of target genes. We further demonstrated that the C. elegans homologues of JARID1 and CHD4 function in the same pathway during vulva development. Taken together, these results suggest that JARID1A and the NuRD complex cooperatively function to control developmentally regulated genes. Genome-wide transcriptomic analysis of HeLa cells transfected with JARID1A complex component siRNA
Project description:Sin3A and Sin3B bind to distinct and overlapping target sites. Sin3 proteins bind to distinct sites in cycling myoblasts whereas there is a converge of Sin3A and Sin3B proteins to sites in differentiated myotubes. We identified a subset of Sin3 target genes involved in muscle differentiation and physiology and showed that conditional ablation of Sin3 proteins in vivo in mouse results in sarcomere defects Examination of Sin3A and Sin3B binding during myogenesis
Project description:Histone H3K4 methylation has been linked to transcriptional activation. JARID1A (also known as RBP2 or KDM5A), a member of the JARID1 protein family, is an H3K4 demethylase, previously implicated in the regulation of transcription and differentiation. Here we show that JARID1A is physically and functionally associated with two histone deacetylase complexes. Immunoaffinity purification of JARID1A confirmed a previously described association with the SIN3B-containing HDAC complex, and revealed an association with the nucleosome remodeling and deacetylase (NuRD) complex. Sucrose density gradient and sequential immunoprecipitation analyses further confirmed the stable association of JARID1A with these two HDAC complexes. JARID1A depletion led to changes in the expression of hundreds of genes, two-thirds of which were also controlled by CHD4, the NuRD catalytic subunit. Gene ontology analysis confirmed that the genes commonly regulated by both JARID1A and CHD4 were categorized as developmentally regulated genes. ChIP analyses suggested that CHD4 controls chromatin association with JARID1A and modulates H3K4 levels at the promoter and coding regions of target genes. We further demonstrated that the C. elegans homologues of JARID1 and CHD4 function in the same pathway during vulva development. Taken together, these results suggest that JARID1A and the NuRD complex cooperatively function to control developmentally regulated genes.
Project description:We have sequenced miRNA libraries from human embryonic, neural and foetal mesenchymal stem cells. We report that the majority of miRNA genes encode mature isomers that vary in size by one or more bases at the 3’ and/or 5’ end of the miRNA. Northern blotting for individual miRNAs showed that the proportions of isomiRs expressed by a single miRNA gene often differ between cell and tissue types. IsomiRs were readily co-immunoprecipitated with Argonaute proteins in vivo and were active in luciferase assays, indicating that they are functional. Bioinformatics analysis predicts substantial differences in targeting between miRNAs with minor 5’ differences and in support of this we report that a 5’ isomiR-9-1 gained the ability to inhibit the expression of DNMT3B and NCAM2 but lost the ability to inhibit CDH1 in vitro. This result was confirmed by the use of isomiR-specific sponges. Our analysis of the miRGator database indicates that a small percentage of human miRNA genes express isomiRs as the dominant transcript in certain cell types and analysis of miRBase shows that 5’ isomiRs have replaced canonical miRNAs many times during evolution. This strongly indicates that isomiRs are of functional importance and have contributed to the evolution of miRNA genes