scholarly journals A Polycomb group protein complex with sequence-specific DNA-binding and selective methyl-lysine-binding activities

2006 ◽  
Vol 20 (9) ◽  
pp. 1110-1122 ◽  
Author(s):  
T. Klymenko
Keyword(s):  
Dna Binding ◽  
Protein Complex ◽  
Polycomb Group ◽  
Polycomb Group Protein ◽  
Group Protein

The DNA-binding polycomb group protein pleiohomeotic mediates silencing of a Drosophila homeotic gene

Development ◽  
1999 ◽  
Vol 126 (17) ◽  
pp. 3905-3913 ◽  
Author(s):  
C. Fritsch ◽  
J.L. Brown ◽  
J.A. Kassis ◽  
J. Muller
Keyword(s):  
Dna Binding ◽  
Binding Sites ◽  
Point Mutations ◽  
Polycomb Group ◽  
Homeotic Gene ◽  
Homeotic Genes ◽  
Polycomb Group Protein ◽  
Cis Acting ◽  
Group Protein

Polycomb group (PcG) proteins repress homeotic genes in cells where these genes must remain inactive during development. This repression requires cis-acting silencers, also called PcG response elements. Currently, these silencers are ill-defined sequences and it is not known how PcG proteins associate with DNA. Here, we show that the Drosophila PcG protein Pleiohomeotic binds to specific sites in a silencer of the homeotic gene Ultrabithorax. In an Ultrabithorax reporter gene, point mutations in these Pleiohomeotic binding sites abolish PcG repression in vivo. Hence, DNA-bound Pleiohomeotic protein may function in the recruitment of other non-DNA-binding PcG proteins to homeotic gene silencers.

scholarly journals pipsqueak Encodes a Factor Essential for Sequence-Specific Targeting of a Polycomb Group Protein Complex

2002 ◽  
Vol 22 (17) ◽  
pp. 6261-6271 ◽  
Author(s):  
Der-Hwa Huang ◽  
Yuh-Long Chang ◽  
Chih-Chao Yang ◽  
I-Ching Pan ◽  
Balas King
Keyword(s):  
Protein Complex ◽  
Specific Binding ◽  
Binding Activity ◽  
Polycomb Group ◽  
Homeotic Genes ◽  
Polycomb Group Protein ◽  
Gaga Factor ◽  
Dna Binding Activity ◽  
Group Protein ◽  
Functional Relevance

ABSTRACT The Polycomb (Pc) group (Pc-G) of repressors is essential for transcriptional silencing of homeotic genes that determine the axial development of metazoan animals. It is generally believed that the multimeric complexes formed by these proteins nucleate certain chromatin structures to silence promoter activity upon binding to Pc-G response elements (PRE). Little is known, however, about the molecular mechanism involved in sequence-specific binding of these complexes. Here, we show that an immunoaffinity-purified Pc protein complex contains a DNA binding activity specific to the (GA) n motif in a PRE from the bithoraxoid region. We found that this activity can be attributed primarily to the large protein isoform encoded by pipsqueak (psq) instead of to the well-characterized GAGA factor. The functional relevance of psq to the silencing mechanism is strongly supported by its synergistic interactions with a subset of Pc-G that cause misexpression of homeotic genes.

scholarly journals A Bridging Model for Persistence of a Polycomb Group Protein Complex through DNA Replication In Vitro

2012 ◽  
Vol 46 (6) ◽  
pp. 784-796 ◽  
Author(s):  
Stanley M. Lo ◽  
Nicole E. Follmer ◽  
Bettina M. Lengsfeld ◽  
Egbert V. Madamba ◽  
Samuel Seong ◽  
...  
Keyword(s):  
Dna Replication ◽  
Protein Complex ◽  
Polycomb Group ◽  
Polycomb Group Protein ◽  
Bridging Model ◽  
Group Protein

scholarly journals RING1 is associated with the polycomb group protein complex and acts as a transcriptional repressor.

1997 ◽  
Vol 17 (7) ◽  
pp. 4105-4113 ◽  
Author(s):  
D P Satijn ◽  
M J Gunster ◽  
J van der Vlag ◽  
K M Hamer ◽  
W Schul ◽  
...  
Keyword(s):  
Protein Complex ◽  
Transcriptional Repressor ◽  
Ring Finger ◽  
Polycomb Group ◽  
Gene Activity ◽  
Polycomb Group Protein ◽  
Human Osteosarcoma Cells ◽  
Group Protein ◽  
Nuclear Domains ◽  
Zinc Binding Domain

The Polycomb (Pc) protein is a component of a multimeric, chromatin-associated Polycomb group (PcG) protein complex, which is involved in stable repression of gene activity. The identities of components of the PcG protein complex are largely unknown. In a two-hybrid screen with a vertebrate Pc homolog as a target, we identify the human RING1 protein as interacting with Pc. RING1 is a protein that contains the RING finger motif, a specific zinc-binding domain, which is found in many regulatory proteins. So far, the function of the RING1 protein has remained enigmatic. Here, we show that RING1 coimmunoprecipitates with a human Pc homolog, the vertebrate PcG protein BMI1, and HPH1, a human homolog of the PcG protein Polyhomeotic (Ph). Also, RING1 colocalizes with these vertebrate PcG proteins in nuclear domains of SW480 human colorectal adenocarcinoma and Saos-2 human osteosarcoma cells. Finally, we show that RING1, like Pc, is able to repress gene activity when targeted to a reporter gene. Our findings indicate that RING1 is associated with the human PcG protein complex and that RING1, like PcG proteins, can act as a transcriptional repressor.

scholarly journals The polycomb group protein complex of Drosophila melanogaster has different compositions at different target genes.

1997 ◽  
Vol 17 (12) ◽  
pp. 6773-6783 ◽  
Author(s):  
H Strutt ◽  
R Paro
Keyword(s):  
Protein Complex ◽  
Target Genes ◽  
Regulatory Elements ◽  
Polycomb Group ◽  
Regulatory Sequences ◽  
Polycomb Group Protein ◽  
Polycomb Group Genes ◽  
Sex Combs ◽  
Group Protein

In Drosophila the Polycomb group genes are required for the long-term maintenance of the repressed state of many developmental regulatory genes. Their gene products are thought to function in a common multimeric complex that associates with Polycomb group response elements (PREs) in target genes and regulates higher-order chromatin structure. We show that the chromodomain of Polycomb is necessary for protein-protein interactions within a Polycomb-Polyhomeotic complex. In addition, Posterior Sex Combs protein coimmunoprecipitates Polycomb and Polyhomeotic, indicating that they are members of a common multimeric protein complex. Immunoprecipitation experiments using in vivo cross-linked chromatin indicate that these three Polycomb group proteins are associated with identical regulatory elements of the selector gene engrailed in tissue culture cells. Polycomb, Polyhomeotic, and Posterior Sex Combs are, however, differentially distributed on regulatory sequences of the engrailed-related gene invected. This suggests that there may be multiple different Polycomb group protein complexes which function at different target sites. Furthermore, Polyhomeotic and Posterior Sex Combs are also associated with expressed genes. Polyhomeotic and Posterior Sex Combs may participate in a more general transcriptional mechanism that causes modulated gene repression, whereas the inclusion of Polycomb protein in the complex at PREs leads to stable silencing.

scholarly journals The DNA-binding Polycomb-group protein Pleiohomeotic maintains both active and repressed transcriptional states through a single site

Development ◽  
2008 ◽  
Vol 135 (24) ◽  
pp. 4131-4139 ◽  
Author(s):  
M. Fujioka ◽  
G. L. Yusibova ◽  
J. Zhou ◽  
J. B. Jaynes
Keyword(s):  
Dna Binding ◽  
Polycomb Group ◽  
Single Site ◽  
Polycomb Group Protein ◽  
Group Protein

Polycomb group protein complex involved in plant vernalization

2011 ◽  
Vol 33 (3) ◽  
pp. 207-212
Author(s):  
Yan-Rong AN ◽  
Jian-Bin XU ◽  
Hai-Long AN
Keyword(s):  
Protein Complex ◽  
Polycomb Group ◽  
Polycomb Group Protein ◽  
Group Protein
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