Similar Datasets
Project description:Chromatin insulators are DNA-protein complexes localized throughout the genome capable of establishing independent transcriptional domains. It was previously reported that the Drosophila su(Hw) mRNA physically associates with the gypsy chromatin insulator protein complex within the nucleus and may serve a noncoding function to affect insulator activity. However, how this mRNA is recruited to the gypsy complex is not known. Here, we utilized RNA-affinity pulldown coupled with mass spectrometry to identify a novel RNA-binding protein, Isha (CG4266), that associates with su(Hw) mRNA in vitro and in vivo. Isha harbors a conserved RNA recognition motif and RNA Polymerase II C-terminal domain-interacting domain (CID). We found that Isha physically interacts with total and elongating Polymerase II and associates with chromatin at the 5' end of genes in an RNA-dependent manner. Furthermore, ChIP-seq analysis reveals Isha overlaps particularly with the core gypsy insulator component CP190 on chromatin. Depletion of Isha reduces enhancer-blocking and barrier activities of the gypsy insulator and disrupts the nuclear localization of insulator bodies. Our results reveal a novel factor Isha that promotes gypsy insulator activity that may act as a nuclear RNA-binding protein adapter for su(Hw) noncoding mRNA.
| S-EPMC9434307 | biostudies-literature
Project description:Chromatin insulators are DNA-protein complexes localized throughout the genome capable of establishing independent transcriptional domains. It was previously reported that the Drosophila su(Hw) mRNA physically associates with the gypsy chromatin insulator protein complex within the nucleus and may serve a noncoding function to affect insulator activity. However, how this mRNA is recruited to the gypsy complex is not known. Here we utilized RNA-affinity pull down coupled with mass spectrometry to identify a novel RNA-binding protein, Isha, that associates with su(Hw) mRNA in vitro and in vivo. Isha harbors a conserved RNA recognition motif (RRM) and RNA Polymerase II CTD-interacting domain (CID). We found that Isha physically interacts with total and elongating RNA Pol II and associates with chromatin at the 5’ end of genes in an RNA-dependent manner. Furthermore, ChIP-seq analysis reveals Isha overlaps particularly with gypsy factor CP190 on chromatin. Depletion of Isha reduces enhancer-blocking and barrier activities of the gypsy insulator and disrupts the nuclear localization of insulator bodies. Our results reveal a novel factor that promotes gypsy insulator activity that may act as a nuclear RNA-binding protein adapter for su(Hw) noncoding mRNA.
2022-05-26 | GSE200994 | GEO
Project description:Chromatin insulators are DNA-protein complexes localized throughout the genome capable of establishing independent transcriptional domains. It was previously reported that the Drosophila su(Hw) mRNA physically associates with the gypsy chromatin insulator protein complex within the nucleus and may serve a noncoding function to affect insulator activity. However, how this mRNA is recruited to the gypsy complex is not known. Here we utilized RNA-affinity pull down coupled with mass spectrometry to identify a novel RNA-binding protein, Isha, that associates with su(Hw) mRNA in vitro and in vivo. Isha harbors a conserved RNA recognition motif (RRM) and RNA Polymerase II CTD-interacting domain (CID). We found that Isha physically interacts with total and elongating RNA Pol II and associates with chromatin at the 5’ end of genes in an RNA-dependent manner. Furthermore, ChIP-seq analysis reveals Isha overlaps particularly with gypsy factor CP190 on chromatin. Depletion of Isha reduces enhancer-blocking and barrier activities of the gypsy insulator and disrupts the nuclear localization of insulator bodies. Our results reveal a novel factor that promotes gypsy insulator activity that may act as a nuclear RNA-binding protein adapter for su(Hw) noncoding mRNA.
2022-05-26 | GSE200993 | GEO
Project description:Isha is a su(Hw) mRNA-binding protein required for insulator function
| PRJNA827823 | ENA
Project description:Insulators are DNA elements that divide chromosomes into independent transcriptional domains. The Drosophila genome contains hundreds of binding sites for the Suppressor of Hairy-wing [Su(Hw)] insulator protein, corresponding to locations of the retroviral gypsy insulator and non-gypsy binding regions (BRs). The first non-gypsy BR identified, 1A-2, resides in cytological region 1A. Using a quantitative transgene system, we show that 1A-2 is a composite insulator containing enhancer blocking and facilitator elements. We discovered that 1A-2 separates the yellow (y) gene from a previously unannotated, non-coding RNA gene, named yar for y-achaete (ac) intergenic RNA. The role of 1A-2 was elucidated using homologous recombination to excise these sequences from the natural location, representing the first deletion of any Su(Hw) BR in the genome. Loss of 1A-2 reduced yar RNA accumulation, without affecting mRNA levels from the neighboring y and ac genes. These data indicate that within the 1A region, 1A-2 acts an activator of yar transcription. Taken together, these studies reveal that the properties of 1A-2 are context-dependent, as this element has both insulator and enhancer activities. These findings imply that the function of non-gypsy Su(Hw) BRs depends on the genomic environment, predicting that Su(Hw) BRs represent a diverse collection of genomic regulatory elements.
| S-EPMC2493044 | biostudies-literature
Project description:Isha is a su(Hw) mRNA-binding protein required for insulator function [RIP-seq]
| PRJNA827828 | ENA
Project description:Isha is a su(Hw) mRNA-binding protein required for insulator function [ChIP-seq]
| PRJNA827830 | ENA
Project description:This SuperSeries is composed of the SubSeries listed below.
2011-02-12 | GSE20313 | GEO
Project description:Specific interactions of the genome with the nuclear lamina (NL) are thought to assist chromosome folding inside the nucleus and to contribute to the regulation of gene expression. High-resolution mapping has recently identified hundreds of large, sharply defined lamina-associated domains (LADs) in the human genome, and suggested that the insulator protein CTCF may help to demarcate these domains. Here, we report the detailed structure of LADs in Drosophila cells, and investigate the putative roles of five insulator proteins in LAD organization. We found that the Drosophila genome is also organized in discrete LADs, which are about five times smaller than human LADs but contain on average a similar number of genes. Systematic comparison to new and published insulator binding maps shows that only SU(HW) binds preferentially at LAD borders and at specific positions inside LADs, while GAF, CTCF, BEAF-32 and DWG are mostly absent from these regions. By knockdown and overexpression studies we demonstrate that SU(HW) weakens genome - NL interactions through a local antagonistic effect, but we did not obtain evidence that it is essential for border formation. Our results provide insights into the evolution of LAD organization and identify SU(HW) as a fine-tuner of genome - NL interactions.
| S-EPMC2991331 | biostudies-literature
Project description:Despite increasing data on the properties of replication origins, molecular mechanisms underlying origin recognition complex (ORC) positioning in the genome are still poorly understood. The Su(Hw) protein accounts for the activity of best-studied Drosophila insulators. Here, we show that Su(Hw) recruits the histone acetyltransferase complex SAGA and chromatin remodeler Brahma to Su(Hw)-dependent insulators, which gives rise to regions with low nucleosome density and creates conditions for ORC binding. Depletion in Su(Hw) leads to a dramatic drop in the levels of SAGA, Brahma and ORC subunits and a significant increase in nucleosome density on Su(Hw)-dependent insulators, whereas artificial Su(Hw) recruitment itself is sufficient for subsequent SAGA, Brahma and ORC binding. In contrast to the majority of replication origins that associate with promoters of active genes, Su(Hw)-binding sites constitute a small proportion (6%) of ORC-binding sites that are localized preferentially in transcriptionally inactive chromatin regions termed BLACK and BLUE chromatin. We suggest that the key determinants of ORC positioning in the genome are DNA-binding proteins that constitute different DNA regulatory elements, including insulators, promoters and enhancers. Su(Hw) is the first example of such a protein.
| S-EPMC3675495 | biostudies-literature