Drosophila MSL complex globally acetylates H4 Lys16 on the male X chromosome for dosage compensation
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ABSTRACT:
ORGANISM(S): Drosophila melanogaster
PROVIDER: GSE14884 | GEO | 2009/06/10
SECONDARY ACCESSION(S): PRJNA111947
REPOSITORIES: GEO
Similar Datasets
Project description:Drosophila MSL complex binds the single male X chromosome to upregulate gene expression to equal that from the two female X chromosomes. However, it has been puzzling that ~25% of transcribed genes on the X do not stably recruit MSL complex. Here, we find that almost all active genes on the X are associated with robust H4 Lys16 acetylation (H4K16ac), the histone modification catalyzed by MSL complex. The distribution of H4K16ac is much broader than that of MSL complex, and our results favor the idea that chromosome-wide H4K16ac reflects transient association of MSL complex, occurring through spreading or chromosomal looping. Our results parallel those of localized Polycomb repressive complex and its more broadly distributed H3K27me3 chromatin mark, suggesting a common principle for the establishment of active and silenced chromatin domains For ChIP-on-chip experiments in larvae, 1000 third instar larvae were collected and chromatin was prepared as described previously. Five IPs were performed for each of the two biological replicates. For SL2 cells and male larvae, one ChIP-on-chip experiment was performed using anti-H4K16ac from Serotec (AHP417) (1-2 ul/IP). However, this antibody was discontinued, and an additional experiment for each was performed using anti-H4K16ac from Upstate/Millipore (07-329) (3 ul/IP). Both replicates for Kc cells and female larvae were also performed using anti-H4K16ac from Upstate/Millipore. Replicate experiments were highly reproducible.
2009-06-10 | E-GEOD-14884 | biostudies-arrayexpress
Project description:Confinement of the X chromosome into a territory for dosage compensation (DC) is a prime example of subnuclear compartmentalization for transcription regulation at the megabase scale. In D. melanogaster, two sex-specific non-coding (nc) RNAs roX1 and roX2 are transcribed from the X chromosome. They associate with the Male-specific lethal (MSL) complex, which by acetylating histone H4 lysine 16 (H4K16ac) confers approximately 2-fold upregulated expression of male X-linked genes. Current models explain X-over-autosome specificity based on the MSL2 subunit recognizing cis-regulatory DNA high-affinity sites (HAS). However, HAS motifs are also found on autosomes, indicating that additional factors have evolved to confer stable association of the MSL complex with the X. Here, we show that the low-complexity C-terminal domain (CTD) of MSL2 renders its recruitment to the X chromosome sensitive to roX ncRNAs. roX-MSL2-CTD form a stably condensated state, and functional analyses in Drosophila and mammalian cells reveal the critical importance of their interplay for DC in vivo. Replacing the CTD of mammalian MSL2 with that from Drosophila and expressing roX in cis is sufficient to nucleate ectopic DC in mammalian cells. Thus, the condensating nature of roX-MSL2CTD is the primary determinant for specific compartmentalization of the X in Drosophila.
2020-08-07 | GSE129795 | GEO
Project description:The Drosophila MSL complex mediates dosage compensation by increasing transcription of the single X chromosome in males approximately two-fold. This is accomplished through recognition of the X chromosome and subsequent acetylation of histone H4K16 on X-linked genes. Initial binding to the X is thought to occur at a subset of sites. However, the consensus sequence motif of entry sites (M-bM-^@M-^\MSL recognition elementM-bM-^@M-^] or MRE) is only slightly enriched on the X (~2 fold), and only a fraction of them is utilized by the MSL complex. Here we ask whether chromatin context could distinguish between utilized and non-utilized copies of the motif, by comparing their relative enrichment for histone modifications and chromosomal proteins mapped in the NHGRI modENCODE project. Through a comparative analysis of the chromatin features in male S2 cells, which contain MSL complex, and female Kc cells, which lack the complex, we find that the presence of active chromatin modifications, together with an elevated local GC content in surrounding sequence, has strong predictive value for functional MSL entry sites, independent of MSL binding. We tested these sites for function in Kc cells by RNAi knockdown of Sxl, resulting in induction of MSL complex. We show that ectopic MSL expression in Kc cells leads to H4K16 acetylation around these sites, and a relative increase in X chromosome transcription. Collectively, our results support a model in which a pre-existing active chromatin environment, coincident with H3K36me3, contributes to MSL entry site selection. The consequences of MSL targeting of the male X chromosome include increase in nucleosome lability, enrichment for H4K16 acetylation and JIL-1 kinase, and depletion of linker histone H1 on active X-linked genes. Our finding serves as a model to understand how chromatin and local sequence features are involved in the selection of functional protein binding sites in the genome. The key Drosophila female sex determinant protein, SXL, represses dosage compensation by inhibiting MSL2 translation. Loss of SXL results in the expression, stabilization, and targetting of the MSL complex in female cells. Therefore, depletion of SXL by RNA interference (RNAi) in female Kc cells will lead to a MSL2-dependent increase in transcription from the female X chromosomes, consistent with the induction of dosage compensation. In this experiment, we generated ChIP-chip profiles of H4K16 acetylation (H4K16ac) in Kc cells of control (GFP) and Sxl RNAi. For ChIP, we used Upstate (now Millipore) anti-H4K16ac antibody, catalog # 07-329, lot #JBC1355376.
2012-03-19 | E-GEOD-34857 | biostudies-arrayexpress
Project description:Confinement of the X chromosome into a territory for dosage compensation (DC) is a prime example of subnuclear compartmentalization for transcription regulation at the megabase scale. In D. melanogaster, two sex-specific non-coding (nc) RNAs roX1 and roX2 are transcribed from the X chromosome. They associate with the Male-specific lethal (MSL) complex, which by acetylating histone H4 lysine 16 (H4K16ac) confers approximately 2-fold upregulated expression of male X-linked genes. Current models explain X-over-autosome specificity based on the MSL2 subunit recognizing cis-regulatory DNA high-affinity sites (HAS). However, HAS motifs are also found on autosomes, indicating that additional factors have evolved to confer stable association of the MSL complex with the X. Here, we show that the low-complexity C-terminal domain (CTD) of MSL2 renders its recruitment to the X chromosome sensitive to roX ncRNAs. roX-MSL2-CTD form a stably condensated state, and functional analyses in Drosophila and mammalian cells reveal the critical importance of their interplay for DC in vivo. Replacing the CTD of mammalian MSL2 with that from Drosophila and expressing roX in cis is sufficient to nucleate ectopic DC in mammalian cells. Thus, the condensating nature of roX-MSL2CTD is the primary determinant for specific compartmentalization of the X in Drosophila.
2020-08-07 | GSE129796 | GEO
Project description:Long non-coding RNAs are involved in dosage compensation both in mammals and in Drosophila by inducing changes in the X-chromosome chromatin structure. In Drosophila melanogaster, roX1 and roX2 are long non-coding RNAs that together with proteins form the male-specific lethal (MSL) complex, which coats the entire male X-chromosome and mediates dosage compensation by increased transcriptional output. It has been shown that in polytene chromosomes, in absence of both roX1 and roX2, the MSL-complex is decreased on the male X-chromosome and found relocated to the chromocenter, and the 4th chromosome. Here we address the role of roX RNAs in MSL-complex targeting and in the evolution of dosage compensation in Drosophila. We performed ChIP-seq experiments and show that MSL-complex recruitment to high affinity sites (HAS) on the X-chromosome is independent on roX and that the HAS sequence motif is conserved in D. simulans. Additionally, a complete and enzymatically active MSL-complex is recruited to six specific genes on the 4th chromosome. Interestingly, our sequence analysis shows that in the absence of roX RNAs, the MSL-complex has affinity to regions enriched in Hoppel transposable elements and to repeats in general. We hypothesize that roX mutants reveal an ancient targeting of the MSL-complex and propose that the role of roX RNAs is to restrict MSL-complex from binding to heterochromatin.
2014-11-07 | GSE58768 | GEO
Project description:X-chromosome dosage compensation in Drosophila requires the male-specific lethal (MSL) complex, which up-regulates gene expression from the single male X chromosome. Here, we define X-chromosome-specific MSL binding at high resolution in two male cell lines and in late-stage embryos. We find that the MSL complex is highly enriched over most expressed genes, with binding biased toward the 3' end of transcription units. The binding patterns are largely similar in the distinct cell types, with ~600 genes clearly bound in all three cases. Genes identified as clearly bound in one cell type and not in another indicate that attraction of MSL complex correlates with expression state. Thus, sequence alone is not sufficient to explain MSL targeting. We propose that the MSL complex recognizes most X-linked genes, but only in the context of chromatin factors or modifications indicative of active transcription. Distinguishing expressed genes from the bulk of the genome is likely to be an important function common to many chromatin organizing and modifying activities. Keywords: ChIP-chip
2007-08-01 | GSE8575 | GEO
Project description:MSL (Male-specific lethal) complex increases transcription on the single X chromosome of Drosophila males in order to equalize expression of X-linked genes between males (XY) and females (XX). The increase in transcript levels correlates with MSL- dependent acetylation of histone H4 at K16 within the bodies of active genes, but identification of the transcriptional step affected has not been possible. In this study, we use global run-on sequencing (GRO-seq) to examine the specific effect of MSL complex on RNA Polymerase II (RNAP II) on a genome-wide level. Results indicate that MSL complex enhances transcription by facilitating the progression of RNAP II across the bodies of active X-linked genes. Improving transcriptional output downstream of typical gene-specific control may explain how dosage compensation can be imposed on the diverse set of genes along an entire chromosome. Global Run-On Sequencing (GRO-Seq) reads, i.e., RNA-Seq of nascent RNA transcripts, from D. Melanogaster SL2 cells. Two biological replicates were analyzed.
2010-12-22 | E-GEOD-25321 | biostudies-arrayexpress
Project description:The Drosophila MSL complex mediates dosage compensation by increasing transcription of the single X chromosome in males approximately two-fold. This is accomplished through recognition of the X chromosome and subsequent acetylation of histone H4K16 on X-linked genes. Initial binding to the X is thought to occur at a subset of sites. However, the consensus sequence motif of entry sites (“MSL recognition element” or MRE) is only slightly enriched on the X (~2 fold), and only a fraction of them is utilized by the MSL complex. Here we ask whether chromatin context could distinguish between utilized and non-utilized copies of the motif, by comparing their relative enrichment for histone modifications and chromosomal proteins mapped in the NHGRI modENCODE project. Through a comparative analysis of the chromatin features in male S2 cells, which contain MSL complex, and female Kc cells, which lack the complex, we find that the presence of active chromatin modifications, together with an elevated local GC content in surrounding sequence, has strong predictive value for functional MSL entry sites, independent of MSL binding. We tested these sites for function in Kc cells by RNAi knockdown of Sxl, resulting in induction of MSL complex. We show that ectopic MSL expression in Kc cells leads to H4K16 acetylation around these sites, and a relative increase in X chromosome transcription. Collectively, our results support a model in which a pre-existing active chromatin environment, coincident with H3K36me3, contributes to MSL entry site selection. The consequences of MSL targeting of the male X chromosome include increase in nucleosome lability, enrichment for H4K16 acetylation and JIL-1 kinase, and depletion of linker histone H1 on active X-linked genes. Our finding serves as a model to understand how chromatin and local sequence features are involved in the selection of functional protein binding sites in the genome.
2012-03-19 | GSE34858 | GEO
Project description:The Drosophila MSL complex mediates dosage compensation by increasing transcription of the single X chromosome in males approximately two-fold. This is accomplished through recognition of the X chromosome and subsequent acetylation of histone H4K16 on X-linked genes. Initial binding to the X is thought to occur at a subset of sites. However, the consensus sequence motif of entry sites (“MSL recognition element” or MRE) is only slightly enriched on the X (~2 fold), and only a fraction of them is utilized by the MSL complex. Here we ask whether chromatin context could distinguish between utilized and non-utilized copies of the motif, by comparing their relative enrichment for histone modifications and chromosomal proteins mapped in the NHGRI modENCODE project. Through a comparative analysis of the chromatin features in male S2 cells, which contain MSL complex, and female Kc cells, which lack the complex, we find that the presence of active chromatin modifications, together with an elevated local GC content in surrounding sequence, has strong predictive value for functional MSL entry sites, independent of MSL binding. We tested these sites for function in Kc cells by RNAi knockdown of Sxl, resulting in induction of MSL complex. We show that ectopic MSL expression in Kc cells leads to H4K16 acetylation around these sites, and a relative increase in X chromosome transcription. Collectively, our results support a model in which a pre-existing active chromatin environment, coincident with H3K36me3, contributes to MSL entry site selection. The consequences of MSL targeting of the male X chromosome include increase in nucleosome lability, enrichment for H4K16 acetylation and JIL-1 kinase, and depletion of linker histone H1 on active X-linked genes. Our finding serves as a model to understand how chromatin and local sequence features are involved in the selection of functional protein binding sites in the genome. The key Drosophila female sex determinant protein, SXL, represses dosage compensation by inhibiting MSL2 translation. Loss of SXL results in the expression, stabilization, and targetting of the MSL complex in female cells. Therefore, depletion of SXL by RNA interference (RNAi) in female Kc cells will lead to a MSL2-dependent increase in transcription from the female X chromosomes, consistent with the induction of dosage compensation. In this experiment, we generated gene expression profiles of Kc cells of control (GFP), Sxl RNAi and Sxl-Msl2 RNAi experiments.
2012-03-19 | E-GEOD-34858 | biostudies-arrayexpress
Project description:MSL (Male-specific lethal) complex increases transcription on the single X chromosome of Drosophila males in order to equalize expression of X-linked genes between males (XY) and females (XX). The increase in transcript levels correlates with MSL- dependent acetylation of histone H4 at K16 within the bodies of active genes, but identification of the transcriptional step affected has not been possible. In this study, we use global run-on sequencing (GRO-seq) to examine the specific effect of MSL complex on RNA Polymerase II (RNAP II) on a genome-wide level. Results indicate that MSL complex enhances transcription by facilitating the progression of RNAP II across the bodies of active X-linked genes. Improving transcriptional output downstream of typical gene-specific control may explain how dosage compensation can be imposed on the diverse set of genes along an entire chromosome.
2010-12-22 | GSE25321 | GEO