title: Formation of a Polycomb-Domain in the Absence of Strong Polycomb Response Elements.
abstract: Polycomb group response elements (PREs) in Drosophila are DNA-elements that recruit Polycomb proteins (PcG) to chromatin and regulate gene expression. PREs are easily recognizable in the Drosophila genome as strong peaks of PcG-protein binding over discrete DNA fragments; many small but statistically significant PcG peaks are also observed in PcG domains. Surprisingly, in vivo deletion of the four characterized strong PREs from the PcG regulated invected-engrailed (inv-en) gene complex did not disrupt the formation of the H3K27me3 domain and did not affect inv-en expression in embryos or larvae suggesting the presence of redundant PcG recruitment mechanism. Further, the 3D-structure of the inv-en domain was only minimally altered by the deletion of the strong PREs. A reporter construct containing a 7.5kb en fragment that contains three weak peaks but no large PcG peaks forms an H3K27me3 domain and is PcG-regulated. Our data suggests a model for the recruitment of PcG-complexes to Drosophila genes via interactions with multiple, weak PREs spread throughout an H3K27me3 domain.
authors.affiliation: Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Sandip
authors.initials: S
authors.lastname: De
authors.affiliation: Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Apratim
authors.initials: A
authors.lastname: Mitra
authors.affiliation: Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Yuzhong
authors.initials: Y
authors.lastname: Cheng
authors.affiliation: Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Karl
authors.initials: K
authors.lastname: Pfeifer
authors.affiliation: Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Judith A
authors.initials: JA
authors.lastname: Kassis
mesh_terms: D000818:Animals; D002843:Chromatin / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics*; D004331:Drosophila melanogaster / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D049750:Genome, Insect; D056466:Histone Demethylases / Q000235:genetics; D060227:Imaginal Discs / Q000254:growth & development / Q000378:metabolism; D007814:Larva / Q000235:genetics / Q000254:growth & development; D063146:Polycomb-Group Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D011485:Protein Binding / Q000235:genetics; D000072417:Protein Domains / Q000235:genetics; D020218:Response Elements / Q000235:genetics*
chemical_list: D002843:Chromatin; D004268:DNA-Binding Proteins; D063146:Polycomb-Group Proteins; D056466:Histone Demethylases