title: Poised RNA polymerase II changes over developmental time and prepares genes for future expression.
abstract: Poised RNA polymerase II (Pol II) is predominantly found at developmental control genes and is thought to allow their rapid and synchronous induction in response to extracellular signals. How the recruitment of poised RNA Pol II is regulated during development is not known. By isolating muscle tissue from Drosophila embryos at five stages of differentiation, we show that the recruitment of poised Pol II occurs at many genes de novo and this makes them permissive for future gene expression. A comparison with other tissues shows that these changes are stage specific and not tissue specific. In contrast, Polycomb group repression is tissue specific, and in combination with Pol II (the balanced state) marks genes with highly dynamic expression. This suggests that poised Pol II is temporally regulated and is held in check in a tissue-specific fashion. We compare our data with findings in mammalian embryonic stem cells and discuss a framework for predicting developmental programs on the basis of the chromatin state.
authors.affiliation: Stowers Institute for Medical Research, Kansas City, MO 64110, USA.
authors.forename: Bjoern
authors.initials: B
authors.lastname: Gaertner
authors.forename: Jeff
authors.initials: J
authors.lastname: Johnston
authors.forename: Kai
authors.initials: K
authors.lastname: Chen
authors.forename: Nina
authors.initials: N
authors.lastname: Wallaschek
authors.forename: Ariel
authors.initials: A
authors.lastname: Paulson
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Garruss
authors.forename: Karin
authors.initials: K
authors.lastname: Gaudenz
authors.forename: Bony
authors.initials: B
authors.lastname: De Kumar
authors.forename: Robb
authors.initials: R
authors.lastname: Krumlauf
authors.forename: Julia
authors.initials: J
authors.lastname: Zeitlinger
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D002843:Chromatin / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D006801:Humans; D051379:Mice; D008822:Mice, Transgenic; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism; D009132:Muscles / Q000166:cytology / Q000378:metabolism*; D009928:Organ Specificity / Q000502:physiology; D063146:Polycomb-Group Proteins / Q000235:genetics / Q000378:metabolism; D012319:RNA Polymerase II / Q000235:genetics / Q000378:metabolism*
chemical_list: D002843:Chromatin; D029721:Drosophila Proteins; D009124:Muscle Proteins; D063146:Polycomb-Group Proteins; D012319:RNA Polymerase II