title: Dual functionality ofcis-regulatory elements as developmental enhancers and Polycomb response elements.
abstract: Developmental gene expression is tightly regulated through enhancer elements, which initiate dynamic spatio-temporal expression, and Polycomb response elements (PREs), which maintain stable gene silencing. These twocis-regulatory functions are thought to operate through distinct dedicated elements. By examining the occupancy of theDrosophilapleiohomeotic repressive complex (PhoRC) during embryogenesis, we revealed extensive co-occupancy at developmental enhancers. Using an established in vivo assay for PRE activity, we demonstrated that a subset of characterized developmental enhancers can function as PREs, silencing transcription in a Polycomb-dependent manner. Conversely, some classicDrosophilaPREs can function as developmental enhancers in vivo, activating spatio-temporal expression. This study therefore uncovers elements with dual function: activating transcription in some cells (enhancers) while stably maintaining transcriptional silencing in others (PREs). Given that enhancers initiate spatio-temporal gene expression, reuse of the same elements by the Polycomb group (PcG) system may help fine-tune gene expression and ensure the timely maintenance of cell identities.
authors.affiliation: Genome Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg D69117, Germany.
authors.forename: Jelena
authors.initials: J
authors.lastname: Erceg
authors.affiliation: Genome Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg D69117, Germany.
authors.forename: Tibor
authors.initials: T
authors.lastname: Pakozdi
authors.affiliation: Genome Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg D69117, Germany.
authors.forename: Raquel
authors.initials: R
authors.lastname: Marco-Ferreres
authors.affiliation: Genome Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg D69117, Germany.
authors.forename: Yad
authors.initials: Y
authors.lastname: Ghavi-Helm
authors.affiliation: Genome Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg D69117, Germany.
authors.forename: Charles
authors.initials: C
authors.lastname: Girardot
authors.affiliation: Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland.
authors.forename: Adrian P
authors.initials: AP
authors.lastname: Bracken
authors.affiliation: Genome Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg D69117, Germany.
authors.forename: Eileen E M
authors.identifier: 0000-0002-9544-8339
authors.initials: EE
authors.lastname: Furlong
mesh_terms: D000818:Animals; D004330:Drosophila / Q000196:embryology / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins / Q000378:metabolism*; D047108:Embryonic Development / Q000235:genetics; D004742:Enhancer Elements, Genetic; D018507:Gene Expression Regulation, Developmental; D063146:Polycomb-Group Proteins / Q000378:metabolism*; D020218:Response Elements
chemical_list: D029721:Drosophila Proteins; D063146:Polycomb-Group Proteins
keywords: Polycomb response elements (PREs); developmental enhancers; embryonic development; pleiohomeotic repressive complex (PhoRC); silencing; spatio–temporal expression; transcriptional repression