PcG complexes and chromatin silencing.
Silencing complexes in yeast and in the fly have many similarities. This repressive complex is assembled by a chain of recruitment; its extent and stability depend on the concentration of components and affect an extended chromatin region, probably through interactions with nucleosomes. Recent results show that assembly of the complex is antagonized by transcriptional activity in the region but is favored by interactions with other complexes nearby or in other regions that associate in the same nuclear environment. How such a complex interferes with transcriptional activity is not entirely clear but current evidence suggests that they compete with the chromatin structure required for the binding of activators.
Pirrotta
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Department of Zoology, University of Geneva, 30 quai Ernest Ansermet, CH1211, Geneva, Switzerland. pirrotta@sc2a.unige.ch
D000818:Animals; D002843:Chromatin; D004330:Drosophila; D029721:Drosophila Proteins; D019476:Insect Proteins / Q000378:metabolism*; D063150:Polycomb Repressive Complex 1; D012045:Regulatory Sequences, Nucleic Acid; D012097:Repressor Proteins / Q000378:metabolism; D015003:Yeasts
D002843:Chromatin; D029721:Drosophila Proteins; D019476:Insect Proteins; C066770:Pc protein, Drosophila; D012097:Repressor Proteins; D063150:Polycomb Repressive Complex 1