title: Establishment and maintenance of heritable chromatin structure during earlyDrosophilaembryogenesis.
abstract: During embryogenesis, the initial chromatin state is established during a period of rapid proliferative activity. We have measured with 3-min time resolution how heritable patterns of chromatin structure are initially established and maintained during the midblastula transition (MBT). We find that regions of accessibility are established sequentially, where enhancers are opened in advance of promoters and insulators. These open states are stably maintained in highly condensed mitotic chromatin to ensure faithful inheritance of prior accessibility status across cell divisions. The temporal progression of establishment is controlled by the biological timers that control the onset of the MBT. In general, acquisition of promoter accessibility is controlled by the biological timer that measures the nucleo-cytoplasmic (N:C) ratio, whereas timing of enhancer accessibility is regulated independently of the N:C ratio. These different timing classes each associate with binding sites for two transcription factors, GAGA-factor and Zelda, previously implicated in controlling chromatin accessibility at ZGA.
authors.affiliation: Howard Hughes Medical Institute, Princeton University, Princeton, United States.
authors.forename: Shelby A
authors.initials: SA
authors.lastname: Blythe
authors.affiliation: Howard Hughes Medical Institute, Princeton University, Princeton, United States.
authors.forename: Eric F
authors.identifier: http://orcid.org/0000-0002-0727-3349
authors.initials: EF
authors.lastname: Wieschaus
mesh_terms: D000818:Animals; D001665:Binding Sites; D001683:Biological Clocks / Q000235:genetics; D002467:Cell Nucleus / Q000378:metabolism; D002843:Chromatin / Q000737:chemistry* / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D004625:Embryo, Nonmammalian; D047108:Embryonic Development / Q000235:genetics*; D004742:Enhancer Elements, Genetic; D040582:Inheritance Patterns; D038101:Insulator Elements; D009687:Nuclear Proteins; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D002843:Chromatin; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D009687:Nuclear Proteins; D014157:Transcription Factors; C063460:Trl protein, Drosophila; C512295:zld protein, Drosophila
keywords: D. melanogaster; chromatin; chromosomes; developmental biology; embryogenesis; epigenetics; genes; midblastula transition; mitosis; stem cells; zygotic genome activation