Project description:The Drosophila insulator-binding proteins (IBPs) dCTCF/Beaf32 mark the physical borders of chromosomal domains involving co-factors that participate in long-range interactions. Chromosomal borders are further enriched in specific histone modifications yet the implication of histone modifiers and nucleosome dynamics remains largely unknown in such context. Here, we show that IBP depletion impairs nucleosome dynamics over genes flanked by their binding sites. Biochemical purification identifies a key histone methyltransferase of H3K36, NSD/dMes-4, as a novel co-factor of IBPs involved in chromatin accessibility, which specifically co-regulates hundreds of genes flanked by Beaf32/dCTCF. dMes-4 presets chromatin before the recruitment of transcriptional activators including DREF that triggers Set2/Hypb-mediated H3K36me3, RNA splicing and nucleosome positioning. Our results unveil a model for how IBPs regulate gene expression and nucleosome dynamics through NSD/dMes-4, which may contribute to regulate H3K27me3 spreading. Together, our data suggest a division of labor for how IBPs may dynamically regulate chromatin organization depending on distinct co-factors. mRNA profiles of Beaf32-depleted or Wild-Type control Drosophila S2 cells by RNASeq (Illumina)
Project description:The Drosophila insulator-binding proteins (IBPs) dCTCF/Beaf32 mark the physical borders of chromosomal domains involving co-factors that participate in long-range interactions. Chromosomal borders are further enriched in specific histone modifications yet the implication of histone modifiers and nucleosome dynamics remains largely unknown in such context. Here, we show that IBP depletion impairs nucleosome dynamics over genes flanked by their binding sites. Biochemical purification identifies a key histone methyltransferase of H3K36, NSD/dMes-4, as a novel co-factor of IBPs involved in chromatin accessibility, which specifically co-regulates hundreds of genes flanked by Beaf32/dCTCF. dMes-4 presets chromatin before the recruitment of transcriptional activators including DREF that triggers Set2/Hypb-mediated H3K36me3, RNA splicing and nucleosome positioning. Our results unveil a model for how IBPs regulate gene expression and nucleosome dynamics through NSD/dMes-4, which may contribute to regulate H3K27me3 spreading. Together, our data suggest a division of labor for how IBPs may dynamically regulate chromatin organization depending on distinct co-factors. Nucleosome profiles of Beaf32-depleted or Wild-Type control Drosophila S2 cells by MNase-Seq (Illumina/TruSeq) for total/bulk nucleosomes or following immunoprecipitation with anti-H3K27me3 antibodies
Project description:The Drosophila insulator-binding proteins (IBPs) dCTCF/Beaf32 mark the physical borders of chromosomal domains involving co-factors that participate in long-range interactions. Chromosomal borders are further enriched in specific histone modifications yet the implication of histone modifiers and nucleosome dynamics remains largely unknown in such context. Here, we show that IBP depletion impairs nucleosome dynamics over genes flanked by their binding sites. Biochemical purification identifies a key histone methyltransferase of H3K36, NSD/dMes-4, as a novel co-factor of IBPs involved in chromatin accessibility, which specifically co-regulates hundreds of genes flanked by Beaf32/dCTCF. dMes-4 presets chromatin before the recruitment of transcriptional activators including DREF that triggers Set2/Hypb-mediated H3K36me3, RNA splicing and nucleosome positioning. Our results unveil a model for how IBPs regulate gene expression and nucleosome dynamics through NSD/dMes-4, which may contribute to regulate H3K27me3 spreading. Together, our data suggest a division of labor for how IBPs may dynamically regulate chromatin organization depending on distinct co-factors. ChIP-Seq profiles of H3K36 methylation and RNA Pol II in Drosophila S2 cell line (wild-type) cells
Project description:The Drosophila insulator-binding proteins (IBPs) dCTCF/Beaf32 mark the physical borders of chromosomal domains involving co-factors that participate in long-range interactions. Chromosomal borders are further enriched in specific histone modifications yet the implication of histone modifiers and nucleosome dynamics remains largely unknown in such context. Here, we show that IBP depletion impairs nucleosome dynamics over genes flanked by their binding sites. Biochemical purification identifies a key histone methyltransferase of H3K36, NSD/dMes-4, as a novel co-factor of IBPs involved in chromatin accessibility, which specifically co-regulates hundreds of genes flanked by Beaf32/dCTCF. dMes-4 presets chromatin before the recruitment of transcriptional activators including DREF that triggers Set2/Hypb-mediated H3K36me3, RNA splicing and nucleosome positioning. Our results unveil a model for how IBPs regulate gene expression and nucleosome dynamics through NSD/dMes-4, which may contribute to regulate H3K27me3 spreading. Together, our data suggest a division of labor for how IBPs may dynamically regulate chromatin organization depending on distinct co-factors.
Project description:The Drosophila insulator-binding proteins (IBPs) dCTCF/Beaf32 mark the physical borders of chromosomal domains involving co-factors that participate in long-range interactions. Chromosomal borders are further enriched in specific histone modifications yet the implication of histone modifiers and nucleosome dynamics remains largely unknown in such context. Here, we show that IBP depletion impairs nucleosome dynamics over genes flanked by their binding sites. Biochemical purification identifies a key histone methyltransferase of H3K36, NSD/dMes-4, as a novel co-factor of IBPs involved in chromatin accessibility, which specifically co-regulates hundreds of genes flanked by Beaf32/dCTCF. dMes-4 presets chromatin before the recruitment of transcriptional activators including DREF that triggers Set2/Hypb-mediated H3K36me3, RNA splicing and nucleosome positioning. Our results unveil a model for how IBPs regulate gene expression and nucleosome dynamics through NSD/dMes-4, which may contribute to regulate H3K27me3 spreading. Together, our data suggest a division of labor for how IBPs may dynamically regulate chromatin organization depending on distinct co-factors.
Project description:The Drosophila insulator-binding proteins (IBPs) dCTCF/Beaf32 mark the physical borders of chromosomal domains involving co-factors that participate in long-range interactions. Chromosomal borders are further enriched in specific histone modifications yet the implication of histone modifiers and nucleosome dynamics remains largely unknown in such context. Here, we show that IBP depletion impairs nucleosome dynamics over genes flanked by their binding sites. Biochemical purification identifies a key histone methyltransferase of H3K36, NSD/dMes-4, as a novel co-factor of IBPs involved in chromatin accessibility, which specifically co-regulates hundreds of genes flanked by Beaf32/dCTCF. dMes-4 presets chromatin before the recruitment of transcriptional activators including DREF that triggers Set2/Hypb-mediated H3K36me3, RNA splicing and nucleosome positioning. Our results unveil a model for how IBPs regulate gene expression and nucleosome dynamics through NSD/dMes-4, which may contribute to regulate H3K27me3 spreading. Together, our data suggest a division of labor for how IBPs may dynamically regulate chromatin organization depending on distinct co-factors.
Project description:Transcription of genes residing within constitutive heterochromatin is paradoxical to the tenets of epigenetic code. Regulatory mechanisms of Drosophila melanogaster heterochromatic gene transcription remain largely unknown. We investigated the contribution of pericentromeric genome organization and heterochromatic factors in orchestrating heterochromatic gene expression. Using 5C-seq, we characterized the pericentromeric TADs in Drosophila melanogaster. Het TAD borders are enriched in nuclear matrix attachment regions while the intra-TAD interactions are mediated by various insulator binding proteins. Heterochromatic genes of similar expression levels cluster into Het TADs, indicating transcriptional co-regulation. HP1a or Su(var)3-9 RNAi results in perturbation of global pericentromeric TAD organization but the expression of the heterochromatic genes is minimally affected. A subset of active heterochromatic genes has been shown to have combination of HP1a/H3K9me3 with H3K36me3 at their exons. Consequently, knock-down of dMES-4 (H3K36 methyl transferase) downregulates expression of the heterochromatic genes. Furthermore, dADD1, present near the TSS of the active heterochromatic genes, is likely to regulate the heterochromatic gene expression in the presence of HP1a or H3K9me3 marks. Therefore, our findings provide mechanistic insights into the interplay of chromatin interactions and the combination of heterochromatic factors (HP1a, H3K9me3, dMES-4 and dADD1) in regulating heterochromatic gene expression.
Project description:Transcription of genes residing within constitutive heterochromatin is paradoxical to the tenets of epigenetic code. Regulatory mechanisms of Drosophila melanogaster heterochromatic gene transcription remain largely unknown. We investigated the contribution of pericentromeric genome organization and heterochromatic factors in orchestrating heterochromatic gene expression. Using 5C-seq, we characterized the pericentromeric TADs in Drosophila melanogaster. Het TAD borders are enriched in nuclear matrix attachment regions while the intra-TAD interactions are mediated by various insulator binding proteins. Heterochromatic genes of similar expression levels cluster into Het TADs, indicating transcriptional co-regulation. HP1a or Su(var)3-9 RNAi results in perturbation of global pericentromeric TAD organization but the expression of the heterochromatic genes is minimally affected. A subset of active heterochromatic genes has been shown to have combination of HP1a/H3K9me3 with H3K36me3 at their exons. Consequently, knock-down of dMES-4 (H3K36 methyl transferase) downregulates expression of the heterochromatic genes. Furthermore, dADD1, present near the TSS of the active heterochromatic genes, is likely to regulate the heterochromatic gene expression in the presence of HP1a or H3K9me3 marks. Therefore, our findings provide mechanistic insights into the interplay of chromatin interactions and the combination of heterochromatic factors (HP1a, H3K9me3, dMES-4 and dADD1) in regulating heterochromatic gene expression.