title: Polycomb, epigenomes, and control of cell identity.
abstract: In development, cell identity is maintained by epigenetic functions that prevent changes in cell type-specific transcription programs. Recent insights into gene silencing mechanisms by Polycomb group (PcG) and trithorax group (trxG) proteins reveal that the memory system involves a concerted process of chromatin modification, blocking of RNA polymerase II, and synthesis of noncoding RNA. Remarkably, cell memory is regulated by a balance between repressors and activators that maintains both transcription status and at the same time the possibility of switching to a different state.
authors.affiliation: Dulbecco Telethon Institute, Institute of Genetics & Biophysics CNR, Via Pietro Castellino 111, 80131, Naples, Italy. orlando@iigb.na.cnr.it
authors.forename: Valerio
authors.initials: V
authors.lastname: Orlando
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D019070:Cell Lineage / Q000235:genetics*; D002467:Cell Nucleus / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D004268:DNA-Binding Proteins / Q000235:genetics; D029721:Drosophila Proteins; D005057:Eukaryotic Cells / Q000166:cytology / Q000378:metabolism*; D020868:Gene Silencing / Q000502:physiology*; D018392:Genomic Imprinting / Q000235:genetics*; D006801:Humans; D063146:Polycomb-Group Proteins; D012097:Repressor Proteins / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D063146:Polycomb-Group Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; C063460:Trl protein, Drosophila