scholarly journals Combgap contributes to recruitment of Polycomb group proteins in Drosophila

2016 ◽  
Vol 113 (14) ◽  
pp. 3826-3831 ◽  
Author(s):  
Payal Ray ◽  
Sandip De ◽  
Apratim Mitra ◽  
Karel Bezstarosti ◽  
Jeroen A. A. Demmers ◽  
...  
Keyword(s):  
Dna Binding ◽  
Binding Sites ◽  
Binding Proteins ◽  
Dna Binding Proteins ◽  
Polycomb Group ◽  
Developmentally Regulated ◽  
Polycomb Response Elements ◽  
Protein Recruitment ◽  
Polycomb Repressive Complex 1 ◽  
Transcriptional State

Polycomb group (PcG) proteins are responsible for maintaining the silenced transcriptional state of many developmentally regulated genes. PcG proteins are organized into multiprotein complexes that are recruited to DNA via cis-acting elements known as “Polycomb response elements” (PREs). In Drosophila, PREs consist of binding sites for many different DNA-binding proteins, some known and others unknown. Identification of these DNA-binding proteins is crucial to understanding the mechanism of PcG recruitment to PREs. We report here the identification of Combgap (Cg), a sequence-specific DNA-binding protein that is involved in recruitment of PcG proteins. Cg can bind directly to PREs via GTGT motifs and colocalizes with the PcG proteins Pleiohomeotic (Pho) and Polyhomeotic (Ph) at the majority of PREs in the genome. In addition, Cg colocalizes with Ph at a number of targets independent of Pho. Loss of Cg leads to decreased recruitment of Ph at only a subset of sites; some of these sites are binding sites for other Polycomb repressive complex 1 (PRC1) components, others are not. Our data suggest that Cg can recruit Ph in the absence of PRC1 and illustrate the diversity and redundancy of PcG protein recruitment mechanisms.

scholarly journals Genome wide screens in yeast to identify potential binding sites and target genes of DNA-binding proteins

2007 ◽  
Vol 36 (1) ◽  
pp. e8-e8 ◽  
Author(s):  
Jue Zeng ◽  
Jizhou Yan ◽  
Ting Wang ◽  
Deborah Mosbrook-Davis ◽  
Kyle T. Dolan ◽  
...  
Keyword(s):  
Dna Binding ◽  
Binding Sites ◽  
Binding Proteins ◽  
Target Genes ◽  
Dna Binding Proteins ◽  
Genome Wide ◽  
Potential Binding

scholarly journals Differential Contributions of DNA-Binding Proteins to Polycomb Response Element Activity at the Drosophila giant Gene

Genetics ◽  
2020 ◽  
Vol 214 (3) ◽  
pp. 623-634
Author(s):  
Elnaz Ghotbi ◽  
Kristina Lackey ◽  
Vicki Wong ◽  
Katie T. Thompson ◽  
Evan G. Caston ◽  
...  
Keyword(s):  
Dna Binding ◽  
Dna Sequences ◽  
Transcriptional Repression ◽  
Binding Proteins ◽  
Target Genes ◽  
Dna Binding Proteins ◽  
Polycomb Group ◽  
Link Type ◽  
Element Activity

Polycomb-group (PcG) proteins are evolutionarily conserved epigenetic regulators whose primary function is to maintain the transcriptional repression of target genes. Recruitment of Drosophila melanogaster PcG proteins to target genes requires the presence of one or more Polycomb Response Elements (PREs). The functions or necessity for more than one PRE at a gene are not clear and individual PREs at some loci may have distinct regulatory roles. Various combinations of sequence-specific DNA-binding proteins are present at a given PRE, but only Pleiohomeotic (Pho) is present at all strong PREs. The giant (gt) locus has two PREs, a proximal PRE1 and a distal PRE2. During early embryonic development, Pho binds to PRE1 ∼30-min prior to stable binding to PRE2. This observation indicated a possible dependence of PRE2 on PRE1 for PcG recruitment; however, we find here that PRE2 recruits PcG proteins and maintains transcriptional repression independently of Pho binding to PRE1. Pho-like (Phol) is partially redundant with Pho during larval development and binds to the same DNA sequences in vitro. Although binding of Pho to PRE1 is dependent on the presence of consensus Pho-Phol-binding sites, Phol binding is less so and appears to play a minimal role in recruiting other PcG proteins to gt. Another PRE-binding protein, Sp1/Kruppel-like factor, is dependent on the presence of Pho for PRE1 binding. Further, we show that, in addition to silencing gene expression, PcG proteins dampen transcription of an active gene.

scholarly journals Genetic and epigenetic control of the spatial organization of the genome

2017 ◽  
Vol 28 (3) ◽  
pp. 364-369 ◽  
Author(s):  
Jason Brickner
Keyword(s):  
Gene Expression ◽  
Dna Binding ◽  
Chromatin Structure ◽  
Binding Sites ◽  
Spatial Organization ◽  
Binding Proteins ◽  
Dna Binding Proteins ◽  
Adaptive Function ◽  
Nuclear Structures ◽  
Eukaryotic Genomes

Eukaryotic genomes are spatially organized within the nucleus by chromosome folding, interchromosomal contacts, and interaction with nuclear structures. This spatial organization is observed in diverse organisms and both reflects and contributes to gene expression and differentiation. This leads to the notion that the arrangement of the genome within the nucleus has been shaped and conserved through evolutionary processes and likely plays an adaptive function. Both DNA-binding proteins and changes in chromatin structure influence the positioning of genes and larger domains within the nucleus. This suggests that the spatial organization of the genome can be genetically encoded by binding sites for DNA-binding proteins and can also involve changes in chromatin structure, potentially through nongenetic mechanisms. Here I briefly discuss the results that support these ideas and their implications for how genomes encode spatial organization.

DISPOM: A DISCRIMINATIVE DE-NOVO MOTIF DISCOVERY TOOL BASED ON THE JSTACS LIBRARY

2013 ◽  
Vol 11 (01) ◽  
pp. 1340006 ◽  
Author(s):  
JAN GRAU ◽  
JENS KEILWAGEN ◽  
ANDRÉ GOHR ◽  
IVAN A. PAPONOV ◽  
STEFAN POSCH ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Binding ◽  
Binding Sites ◽  
Motif Discovery ◽  
Binding Proteins ◽  
Target Genes ◽  
De Novo ◽  
Specific Binding ◽  
Dna Binding Proteins ◽  
De Novo Motif Discovery

DNA-binding proteins are a main component of gene regulation as they activate or repress gene expression by binding to specific binding sites in target regions of genomic DNA. However, de-novo discovery of these binding sites in target regions obtained by wet-lab experiments is a challenging problem in computational biology, which has not yet been solved satisfactorily. Here, we present a detailed description and analysis of the de-novo motif discovery tool Dispom, which has been developed for finding binding sites of DNA-binding proteins that are differentially abundant in a set of target regions compared to a set of control regions. Two additional features of Dispom are its capability of modeling positional preferences of binding sites and adjusting the length of the motif in the learning process. Dispom yields an increased prediction accuracy compared to existing tools for de-novo motif discovery, suggesting that the combination of searching for differentially abundant motifs, inferring their positional distributions, and adjusting the motif lengths is beneficial for de-novo motif discovery. When applying Dispom to promoters of auxin-responsive genes and those of ABI3 target genes from Arabidopsis thaliana, we identify relevant binding motifs with pronounced positional distributions. These results suggest that learning motifs, their positional distributions, and their lengths by a discriminative learning principle may aid motif discovery from ChIP-chip and gene expression data. We make Dispom freely available as part of Jstacs, an open-source Java library that is tailored to statistical sequence analysis. To facilitate extensions of Dispom, we describe its implementation using Jstacs in this manuscript. In addition, we provide a stand-alone application of Dispom at http://www.jstacs.de/index.php/Dispom for instant use.

scholarly journals Variable Requirements for DNA-Binding Proteins at Polycomb-Dependent Repressive Regions in Human HOX Clusters

2013 ◽  
Vol 33 (16) ◽  
pp. 3274-3285 ◽  
Author(s):  
Caroline J. Woo ◽  
Peter V. Kharchenko ◽  
Laurence Daheron ◽  
Peter J. Park ◽  
Robert E. Kingston
Keyword(s):  
Dna Binding ◽  
Cell Fate ◽  
Binding Proteins ◽  
Regulatory Elements ◽  
Dna Binding Proteins ◽  
Polycomb Group ◽  
Content Type ◽  
Evolutionarily Conserved ◽  
Hoxd Cluster ◽  
Hox Clusters

Polycomb group (PcG)-mediated repression is an evolutionarily conserved process critical for cell fate determination and maintenance of gene expression during embryonic development. However, the mechanisms underlying PcG recruitment in mammals remain unclear since few regulatory sites have been identified. We report two novel prospective PcG-dependent regulatory elements within the human HOXB and HOXC clusters and compare their repressive activities to a previously identified element in the HOXD cluster. These regions recruited the PcG proteins BMI1 and SUZ12 to a reporter construct in mesenchymal stem cells and conferred repression that was dependent upon PcG expression. Furthermore, we examined the potential of two DNA-binding proteins, JARID2 and YY1, to regulate PcG activity at these three elements. JARID2 has differential requirements, whereas YY1 appears to be required for repressive activity at all 3 sites. We conclude that distinct elements of the mammalian HOX clusters can recruit components of the PcG complexes and confer repression, similar to what has been seen inDrosophila. These elements, however, have diverse requirements for binding factors, which, combined with previous data on other loci, speaks to the complexity of PcG targeting in mammals.

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