scholarly journals BEN-solo factors partition active chromatin to ensure proper gene activation in Drosophila

2019 ◽  
Author(s):  
Malin Ueberschär ◽  
Huazhen Wang ◽  
Chun Zhang ◽  
Shu Kondo ◽  
Tsutomu Aoki ◽  
...  
Keyword(s):  
Transcriptional Repression ◽  
Gene Activation ◽  
Adapter Protein ◽  
Active Chromatin ◽  
Symmetric Configuration ◽  
Insulator Function ◽  
Developmental Patterning ◽  
Insulator Proteins ◽  
Repressor Activity

AbstractThe Drosophila genome encodes three BEN-solo proteins including Insensitive (Insv), Elba1 and Elba2 that possess activities in both transcriptional repression and chromatin insulation. These proteins all have a DNA binding BEN domain. A fourth protein Elba3 bridges Elba1 and Elba2 to form a heterotrimeric complex ELBA. Here we report comprehensive investigation on the in vivo functions of these proteins in Drosophila embryos. We generate ChIP-seq data of all these factors from all cognate and non-cognate mutants to assess common and distinct binding locations of Insv and ELBA, and genetic interdependencies. Notably, while most Elba1 and Elba2 binding requires the full ELBA complex, the adapter protein Elba3 can associate with chromatin and repress gene expression independently of Elba1 and Elba2. We also employ high-resolution ChIP-nexus mapping to show that Insv binds to DNA in a symmetric configuration while the ELBA complex binds asymmetrically in vivo. We observe that motifs of known insulator proteins are enriched in ELBA and Insv ChIP peaks and demonstrate that ELBA collaborates with other insulator factors to regulate developmental patterning in embryos. To differentiate the insulator function of ELBA and Insv from their repressor activity, we determined real-time transcription change in mutant embryos using precision nuclear run-on sequencing. ELBA factor mutants dampen expression differences between pairs of ELBA-bound neighboring genes. Finally, transgenic reporters confirm insulation activity of ELBA- and Insv-bound sites. Altogether, these findings define ELBA and Insv as general insulator proteins in Drosophila and demonstrate the functional importance of insulators in partitioning transcription units.

scholarly journals BEN-solo factors partition active chromatin to ensure proper gene activation in Drosophila

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Malin Ueberschär ◽  
Huazhen Wang ◽  
Chun Zhang ◽  
Shu Kondo ◽  
Tsutomu Aoki ◽  
...  
Keyword(s):  
Binding Sites ◽  
Transcriptional Repression ◽  
Gene Activation ◽  
Adjacent Gene ◽  
Functional Importance ◽  
Active Chromatin ◽  
Comprehensive Investigation ◽  
Developmental Patterning ◽  
Insulator Proteins ◽  
Bound Sequence

AbstractThe Drosophila genome encodes three BEN-solo proteins including Insensitive (Insv), Elba1 and Elba2 that possess activities in transcriptional repression and chromatin insulation. A fourth protein—Elba3—bridges Elba1 and Elba2 to form an ELBA complex. Here, we report comprehensive investigation of these proteins in Drosophila embryos. We assess common and distinct binding sites for Insv and ELBA and their genetic interdependencies. While Elba1 and Elba2 binding generally requires the ELBA complex, Elba3 can associate with chromatin independently of Elba1 and Elba2. We further demonstrate that ELBA collaborates with other insulators to regulate developmental patterning. Finally, we find that adjacent gene pairs separated by an ELBA bound sequence become less differentially expressed in ELBA mutants. Transgenic reporters confirm the insulating activity of ELBA- and Insv-bound sites. These findings define ELBA and Insv as general insulator proteins in Drosophila and demonstrate the functional importance of insulators to partition transcription units.

scholarly journals MafG Sumoylation Is Required for Active Transcriptional Repression

2006 ◽  
Vol 26 (12) ◽  
pp. 4652-4663 ◽  
Author(s):  
Hozumi Motohashi ◽  
Fumiki Katsuoka ◽  
Chika Miyoshi ◽  
Yasuhiro Uchimura ◽  
Hisato Saitoh ◽  
...  
Keyword(s):  
Binding Site ◽  
Histone Deacetylase ◽  
Transcriptional Repression ◽  
Cultured Cells ◽  
Physiological Role ◽  
Histone Deacetylase Inhibition ◽  
Dna Binding Site ◽  
Repressor Complex ◽  
Repressor Activity

ABSTRACT A straightforward mechanism for eliciting transcriptional repression would be to simply block the DNA binding site for activators. Such passive repression is often mediated by transcription factors that lack an intrinsic repressor activity. MafG is a bidirectional regulator of transcription, a repressor in its homodimeric state but an activator when heterodimerized with p45. Here, we report that MafG is conjugated to SUMO-2/3 in vivo. To clarify the possible physiological role(s) for sumoylation in regulating MafG activity, we evaluated mutant and wild-type MafG in transgenic mice and cultured cells. Whereas sumoylation-deficient MafG activated p45-dependent transcription normally and did not affect heterodimer activity, repression by the sumoylation-deficient MafG mutant was severely compromised in vivo. Furthermore, the SUMO-dependent repression activity of MafG was sensitive to histone deacetylase inhibition. Thus, repression by MafG is not achieved through simple passive repression by competing for the activator binding site but requires sumoylation, which then mediates transcriptional repression through recruitment of a repressor complex containing histone deacetylase activity.

scholarly journals Set2 Is a Nucleosomal Histone H3-Selective Methyltransferase That Mediates Transcriptional Repression

2002 ◽  
Vol 22 (5) ◽  
pp. 1298-1306 ◽  
Author(s):  
Brian D. Strahl ◽  
Patrick A. Grant ◽  
Scott D. Briggs ◽  
Zu-Wen Sun ◽  
James R. Bone ◽  
...  
Keyword(s):  
Transcriptional Repression ◽  
Gene Activation ◽  
Limited Information ◽  
Set Domain ◽  
Biochemical Purification ◽  
Heterologous Promoter ◽  
Nucleosomal Histone

ABSTRACT Recent studies of histone methylation have yielded fundamental new insights pertaining to the role of this modification in gene activation as well as in gene silencing. While a number of methylation sites are known to occur on histones, only limited information exists regarding the relevant enzymes that mediate these methylation events. We thus sought to identify native histone methyltransferase (HMT) activities from Saccharomyces cerevisiae. Here, we describe the biochemical purification and characterization of Set2, a novel HMT that is site-specific for lysine 36 (Lys36) of the H3 tail. Using an antiserum directed against Lys36 methylation in H3, we show that Set2, via its SET domain, is responsible for methylation at this site in vivo. Tethering of Set2 to a heterologous promoter reveals that Set2 represses transcription, and part of this repression is mediated through the HMT activity of the SET domain. These results suggest that Set2 and methylation at H3 Lys36 play a role in the repression of gene transcription.

scholarly journals KDM2B is a histone H3K79 demethylase and induces transcriptional repression via SIRT1-mediated chromatin silencing

2017 ◽  
Author(s):  
Joo-Young Kang ◽  
Ji-Young Kim ◽  
Kee-Beom Kim ◽  
Jin Woo Park ◽  
Hana Cho ◽  
...  
Keyword(s):  
Transcriptional Repression ◽  
Histone H3 ◽  
Active Chromatin ◽  
Knockdown Cell ◽  
Genome Wide Analysis ◽  
Genome Wide ◽  
Demethylase Activity ◽  
H4k16 Acetylation ◽  
H3k79 Methylation

AbstractThe methylation of histone H3 lysine 79 (H3K79) is an active chromatin marker and is prominant in actively transcribed regions of the genome. However, demethylase of H3K79 remains unknown despite intensive research. Here, we show that KDM2B (also known as FBXL10), a member of the Jumonji C family of proteins and known for its histone H3K36 demethylase activity, is a di- and tri-methyl H3K79 demethylase. We demonstrate that KDM2B induces transcriptional repression of HOXA7 and MEIS1 via occupancy of promoters and demethylation of H3K79. Furthermore, genome-wide analysis suggests that H3K79 methylation levels increase when KDM2B is depleted, indicating that KDM2B functions as an H3K79 demethylase in vivo. Finally, stable KDM2B-knockdown cell lines exhibit displacement of NAD+-dependent deacetylase SIRT1 from chromatin, with concomitant increases in H3K79 methylation and H4K16 acetylation. Our findings identify KDM2B as an H3K79 demethylase and link its function to transcriptional repression via SIRT1-mediated chromatin silencing.

scholarly journals INSM1 functions as a transcriptional repressor of the neuroD/β2 gene through the recruitment of cyclin D1 and histone deacetylases

2006 ◽  
Vol 397 (1) ◽  
pp. 169-177 ◽  
Author(s):  
Wei-Dong Liu ◽  
Hong-Wei Wang ◽  
Michelle Muguira ◽  
Mary B. Breslin ◽  
Michael S. Lan
Keyword(s):  
Cyclin D1 ◽  
Chromatin Immunoprecipitation ◽  
Transcriptional Repression ◽  
Histone Deacetylases ◽  
Mammalian Cells ◽  
Transcriptional Repressor ◽  
Chromatin Immunoprecipitation Assay ◽  
Immunoprecipitation Assay ◽  
Repressor Activity

INSM1/IA-1 (insulinoma-associated 1) is a developmentally regulated zinc-finger transcription factor, exclusively expressed in the foetal pancreas and nervous system, and in tumours of neuroendocrine origin. We have identified an INSM1 binding site in the neuroD/β2 promoter and demonstrated transcriptional repressor activity of INSM1 by transient transfection assay. A chromatin immunoprecipitation assay confirmed that in vivo INSM1 is situated on the promoter region of the neuroD/β2 gene. In an attempt to elucidate the molecular mechanism of transcriptional repression by the INSM1 gene, cyclin D1 was identified as an interacting protein by using a 45-day-old human foetal brain cDNA library and a yeast two-hybrid screen. The physical association between INSM1 and cyclin D1 was confirmed by in vitro and in vivo pull-down assay. Cyclin D1 co-operates with INSM1 and suppresses neuroD/β2 promoter activity. Co-immunoprecipitation of INSM1, cyclin D1 and HDACs (histone deacetylases) in mammalian cells revealed that INSM1 interacts with HDAC-1 and -3 and that this interaction is mediated through cyclin D1. Overexpression of cyclin D1 and HDAC-3 significantly enhanced the transcriptional repression activity of INSM1 on the neuroD/β2 promoter. A further chromatin immunoprecipitation assay confirmed that HDAC-3 occupies this same region of the neuroD/β2 promoter, by forming a transcription complex with INSM1. Thus we conclude that INSM1 recruits cyclin D1 and HDACs, which confer transcriptional repressor activity.

scholarly journals Acetylation of Nuclear Hormone Receptor-Interacting Protein RIP140 Regulates Binding of the Transcriptional Corepressor CtBP

2001 ◽  
Vol 21 (18) ◽  
pp. 6181-6188 ◽  
Author(s):  
Ngan Vo ◽  
Clark Fjeld ◽  
Richard H. Goodman
Keyword(s):  
Hormone Receptor ◽  
Transcriptional Repression ◽  
Gene Activation ◽  
Nuclear Hormone Receptor ◽  
Binding Motif ◽  
Interacting Protein ◽  
Amino Terminal ◽  
Development And Differentiation

ABSTRACT CtBP (carboxyl-terminal binding protein) participates in regulating cellular development and differentiation by associating with a diverse array of transcriptional repressors. Most of these interactions occur through a consensus CtBP-binding motif, PXDLS, in the repressor proteins. We previously showed that the CtBP-binding motif in E1A is flanked by a Lys residue and suggested that acetylation of this residue by the p300/CBP-associated factor P/CAF disrupts the CtBP interaction. In this study, we show that the interaction between CtBP and the nuclear hormone receptor corepressor RIP140 is regulated similarly, in this case by p300/CBP itself. CtBP was shown to interact with RIP140 in vitro and in vivo through a sequence, PIDLSCK, in the amino-terminal third of the RIP140 protein. Acetylation of the Lys residue in this motif, demonstrated in vivo by using an acetylated RIP140-specific antibody, dramatically reduced CtBP binding. Mutation of the Lys residue to Gln resulted in a decrease in CtBP binding in vivo and a loss of transcriptional repression. We suggest that p300/CBP-mediated acetylation disrupts the RIP140-CtBP complex and derepresses nuclear hormone receptor-regulated genes. Disruption of repressor-CtBP interactions by acetylation may be a general mode of gene activation.

Differentiation arrest and stromal cell-independent growth of murine erythroleukemia cells are associated with elevated expression of ets-related genes but not with mutation of p53

1993 ◽  
Vol 13 (9) ◽  
pp. 5582-5592
Author(s):  
R J Nibbs ◽  
K Itoh ◽  
W Ostertag ◽  
P R Harrison
Keyword(s):  
Stromal Cells ◽  
Stromal Cell ◽  
Gene Activation ◽  
Leukemic Cells ◽  
Term Survival ◽  
Elevated Expression ◽  
D Cells ◽  
Murine Erythroleukemia

The ELM erythroleukemia is novel in that long-term survival of leukemic cells in culture (ELM-D cells) is dependent on contact with a bone marrow-derived stromal feeder cell layer. However, a number of stroma-independent (ELM-I) mutants that vary in their ability to differentiate in vitro in response to erythropoietin and interleukin-3 have been derived. We have attempted to define the genetic changes responsible for these different phenotypes. At the p53 locus in the primary leukemic cells, one copy of the gene has been lost whereas the other contains an 18-bp depletion, implicating its mutation as an early step in the development of the leukemia. Changes in ets gene expression have also been found. The Fli-1 gene region is rearranged in the primary tumor because of the insertion of a retrovirus inserted upstream of one Fli-1 allele, but this does not result in Fli-1 gene activation in any of the ELM-D or ELM-I cell lines except one. It seems significant that this line is the only one to have lost the ability to differentiate in response to erythropoietin. In addition, up-regulation of erg is associated with stromal cell-independent growth, since all ELM-I mutants have moderate levels of erg mRNA, whereas only low or undetectable levels are found in primary leukemic cells in vivo or in ELM-D cells in vitro. This up-regulation of erg mRNA seems to be important for stromal cell-independent growth, since ELM-D cells show elevated expression of the erg gene after separation from stromal cells. This seems to be made permanent in ELM-I mutants, since they do not down-regulate erg mRNA when grown in contact with stromal cells. We therefore propose that ets family members regulate both the survival and differentiation of erythroid cells.

Novel pathway for thyroid hormone receptor action through interaction with jun and fos oncogene activities

1991 ◽  
Vol 11 (12) ◽  
pp. 6016-6025
Author(s):  
X K Zhang ◽  
K N Wills ◽  
M Husmann ◽  
T Hermann ◽  
M Pfahl
Keyword(s):  
Signal Transduction ◽  
Dna Binding ◽  
Thyroid Hormone Receptor ◽  
Gene Activation ◽  
Signal Transduction Pathway ◽  
Large Family ◽  
Transduction Pathway ◽  
Regulatory Pathway

Many essential biological pathways, including cell growth, development, and metabolism, are regulated by thyroid hormones (THs). TH action is mediated by intracellular receptors that belong to a large family of ligand-dependent transcription factors, including the steroid hormone and retinoic acid receptors. So far it has been assumed that TH receptors (TRs) regulate gene transcription only through the classical protein-DNA interaction mechanism. Here we provide evidence for a regulatory pathway that allows cross-talk between TRs and the signal transduction pathway used by many growth factors, oncogenes, and tumor promoters. In transient transfection studies, we observed that the oncogenes c-jun and c-fos inhibit TR activities, while TRs inhibit induction of the c-fos promoter and repress AP-1 site-dependent gene activation. A truncated TR that lacks only 17 amino acids from the carboxy terminus can no longer antagonize AP-1 activity. The cross-regulation between TRs and the signal transduction pathway appears to be based on the ability of TRs to inhibit DNA binding of the transcription factor AP-1 in the presence of THs. The constituents of AP-1, c-Jun, and c-Fos, vice versa, can inhibit TR-induced gene activation in vivo, and c-Jun inhibits TR DNA binding in vitro. This novel regulatory pathway is likely to play a major role in growth control and differentiation by THs.

Sign in / Sign up

Export Citation Format

Share Document