scholarly journals Intergenic transcription through a Polycomb group response element counteracts silencing

2005 ◽  
Vol 19 (6) ◽  
pp. 697-708 ◽  
Author(s):  
S. Schmitt
Keyword(s):  
Polycomb Group ◽  
Response Element ◽  
Group Response

scholarly journals Site-Specific Recognition of a 70-Base-Pair Element Containing d(GA)n Repeats Mediatesbithoraxoid Polycomb Group Response Element-Dependent Silencing

2001 ◽  
Vol 21 (14) ◽  
pp. 4528-4543 ◽  
Author(s):  
Jacob W. Hodgson ◽  
Bob Argiropoulos ◽  
Hugh W. Brock
Keyword(s):  
Dna Binding ◽  
Binding Activity ◽  
Polycomb Group ◽  
Gaga Factor ◽  
Mobility Shift ◽  
Response Element ◽  
Site Specific ◽  
Specific Recognition ◽  
Group Response ◽  
Flanking Regions

ABSTRACT Polycomb group proteins act through Polycomb group response elements (PREs) to maintain silencing at homeotic loci. The minimal 1.5-kb bithoraxoid (bxd) PRE contains a region required for pairing-sensitive repression and flanking regions required for maintenance of embryonic silencing. Little is known about the identity of specific sequences necessary for function of the flanking regions. Using gel mobility shift analysis, we identify DNA binding activities that interact specifically with a multipartite 70-bp fragment (MHS-70) downstream of the pairing-sensitive sequence. Deletion of MHS-70 in the context of a 5.1-kb bxd Polycomb group response element derepresses maintenance of silencing in embryos. A partially purified binding activity requires multiple, nonoverlapping d(GA)3repeats for MHS-70 binding in vitro. Mutation of d(GA)3repeats within MHS-70 in the context of the 5.1-kb bxd PRE destabilizes maintenance of silencing in a subset of cells in vivo but gives weaker derepression than deletion of MHS-70. These results suggest that d(GA)3 repeats are important for silencing but that other sequences within MHS-70 also contribute to silencing. Antibody supershift assays and Western analyses show that distinct isoforms of Polyhomeotic and two proteins that recognize d(GA)3 repeats, the TRL/GAGA factor and Pipsqueak (Psq), are present in the MHS-70 binding activity. Mutations inTrl and psq enhance homeotic phenotypes ofph, indicating that TRL/GAGA factor and Psq are enhancers of Polycomb which have sequence-specific DNA binding activity. These studies demonstrate that site-specific recognition of thebxd PRE by d(GA) n repeat binding activities mediates PcG-dependent silencing.

scholarly journals Modulation of the Activity of a Polycomb-Group Response Element in Drosophila by a Mutation in the Transcriptional Activator Woc

2011 ◽  
Vol 1 (6) ◽  
pp. 471-478 ◽  
Author(s):  
Amanda Noyes ◽  
Catherine Stefaniuk ◽  
Yuzhong Cheng ◽  
James A. Kennison ◽  
Judith A. Kassis
Keyword(s):  
Transcriptional Activator ◽  
Polycomb Group ◽  
Response Element ◽  
Group Response

Polycomb Group Repression Is Blocked by the Drosophila suppressor of Hairy-wing [su(Hw)] Insulator

Genetics ◽  
1998 ◽  
Vol 148 (1) ◽  
pp. 331-339
Author(s):  
Daniel R Mallin ◽  
Jane S Myung ◽  
J Scott Patton ◽  
Pamela K Geyer
Keyword(s):  
Reporter Genes ◽  
Polycomb Group ◽  
Polycomb Group Proteins ◽  
Binding Region ◽  
Position Effects ◽  
Response Element ◽  
Polycomb Group Genes ◽  
Chromosomal Position ◽  
Group Response

Abstract The suppressor of Hairy-wing [SU(HW)] binding region disrupts communication between a large number of enhancers and promoters and protects transgenes from chromosomal position effects. These properties classify the SU(HW) binding region as an insulator. While enhancers are blocked in a general manner, protection from repressors appears to be more variable. In these studies, we address whether repression resulting from the Polycomb group genes can be blocked by the SU(HW) binding region. The effects of this binding region on repression established by an Ultrabithorax Polycomb group Response Element were examined. A transposon carrying two reporter genes, the yellow and white genes, was used so that repression and insulation could be assayed simultaneously. We demonstrate that the SU(HW) binding region is effective at preventing Polycomb group repression. These studies suggest that one role of the su(Hw) protein may be to restrict the range of action of repressors, such as the Polycomb group proteins, throughout the euchromatic regions of the genome.

scholarly journals The role of Polycomb-group response elements in regulation of engrailed transcription in Drosophila

Development ◽  
2008 ◽  
Vol 135 (4) ◽  
pp. 669-676 ◽  
Author(s):  
S. K. DeVido ◽  
D. Kwon ◽  
J. L. Brown ◽  
J. A. Kassis
Keyword(s):  
Polycomb Group ◽  
Response Elements ◽  
Group Response

scholarly journals Structure and function of an ectopic Polycomb chromatin domain

2019 ◽  
Vol 5 (1) ◽  
pp. eaau9739 ◽  
Author(s):  
Sandip De ◽  
Yuzhong Cheng ◽  
Ming-an Sun ◽  
Natalie D. Gehred ◽  
Judith A. Kassis
Keyword(s):  
Domain Structure ◽  
Regulatory Elements ◽  
Structure And Function ◽  
Polycomb Group ◽  
Chromatin Domain ◽  
Repressive Mark ◽  
Group Response ◽  
Dna Elements ◽  
And Function

Polycomb group proteins (PcGs) drive target gene repression and form large chromatin domains. InDrosophila, DNA elements known as Polycomb group response elements (PREs) recruit PcGs to the DNA. We have shown that, within theinvected-engrailed(inv-en) Polycomb domain, strong, constitutive PREs are dispensable for Polycomb domain structure and function. We suggest that the endogenous chromosomal location imparts stability to this Polycomb domain. To test this possibility, a 79-kbentransgene was inserted into other chromosomal locations. This transgene is functional and forms a Polycomb domain. The spreading of the H3K27me3 repressive mark, characteristic of PcG domains, varies depending on the chromatin context of the transgene. Unlike at the endogenous locus, deletion of the strong, constitutive PREs from the transgene leads to both loss- and gain-of function phenotypes, demonstrating the important role of these regulatory elements. Our data show that chromatin context plays an important role in Polycomb domain structure and function.

scholarly journals Transcription through Intergenic Chromosomal Memory Elements of the Drosophila Bithorax Complex Correlates with an Epigenetic Switch

2002 ◽  
Vol 22 (22) ◽  
pp. 8026-8034 ◽  
Author(s):  
Gerhard Rank ◽  
Matthias Prestel ◽  
Renato Paro
Keyword(s):  
Memory Function ◽  
Polycomb Group ◽  
Published Data ◽  
Homeotic Genes ◽  
Bithorax Complex ◽  
Memory Element ◽  
Cellular Memory ◽  
Response Elements ◽  
Group Response ◽  
Differential Expression Pattern

ABSTRACT The proteins of the trithorax and Polycomb groups maintain the differential expression pattern of homeotic genes established by the early embryonic patterning system during development. These proteins generate stable and heritable chromatin structures by acting via particular chromosomal memory elements. We established a transgenic assay system showing that the Polycomb group response elements bxd and Mcp confer epigenetic inheritance throughout development. With previously published data for the Fab7 cellular memory module, we confirmed the cellular memory function of Polycomb group response elements. In Drosophila melanogaster, several of these memory elements are located in the large intergenic regulatory regions of the homeotic bithorax complex. Using a transgene assay, we showed that transcription through a memory element correlated with the relief of silencing imposed by the Polycomb group proteins and established an epigenetically heritable active chromatin mode. A memory element remodeled by the process of transcription was able to maintain active expression of a reporter gene throughout development. Thus, transcription appears to reset and change epigenetic marks at chromosomal memory elements regulated by the Polycomb and trithorax proteins. Interestingly, in the bithorax complex of D. melanogaster, the segment-specific expression of noncoding intergenic transcripts during embryogenesis seems to fulfill this switching role for memory elements regulating the homeotic genes.

scholarly journals The iab-7 Polycomb Response Element Maps to a Nucleosome-Free Region of Chromatin and Requires Both GAGA and Pleiohomeotic for Silencing Activity

2001 ◽  
Vol 21 (4) ◽  
pp. 1311-1318 ◽  
Author(s):  
Rakesh K. Mishra ◽  
Jozsef Mihaly ◽  
Stéphane Barges ◽  
Annick Spierer ◽  
François Karch ◽  
...  
Keyword(s):  
Binding Sites ◽  
Polycomb Group ◽  
Polycomb Group Protein ◽  
Gaga Factor ◽  
Response Element ◽  
Polycomb Response Element ◽  
Free Region ◽  
Group Protein

ABSTRACT In the work reported here we have undertaken a functional dissection of a Polycomb response element (PRE) from the iab-7 cis-regulatory domain of the Drosophila melanogasterbithorax complex (BX-C). Previous studies mapped the iab-7PRE to an 860-bp fragment located just distal to the Fab-7boundary. Located within this fragment is an ∼230-bp chromatin-specific nuclease-hypersensitive region called HS3. We have shown that HS3 is capable of functioning as a Polycomb-dependent silencer in vivo, inducing pairing-dependent silencing of amini-white reporter. The HS3 sequence contains consensus binding sites for the GAGA factor, a protein implicated in the formation of nucleosome-free regions of chromatin, and Pleiohomeotic (Pho), a Polycomb group protein that is related to the mammalian transcription factor YY1. We show that GAGA and Pho interact with these sequences in vitro and that the consensus binding sites for the two proteins are critical for the silencing activity of theiab-7 PRE in vivo.

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