title: The composition and organization of Drosophila heterochromatin are heterogeneous and dynamic.
abstract: Heterochromatin is enriched for specific epigenetic factors including Heterochromatin Protein 1a (HP1a), and is essential for many organismal functions. To elucidate heterochromatin organization and regulation, we purified Drosophila melanogaster HP1a interactors, and performed a genome-wide RNAi screen to identify genes that impact HP1a levels or localization. The majority of the over four hundred putative HP1a interactors and regulators identified were previously unknown. We found that 13 of 16 tested candidates (83%) are required for gene silencing, providing a substantial increase in the number of identified components that impact heterochromatin properties. Surprisingly, image analysis revealed that although some HP1a interactors and regulators are broadly distributed within the heterochromatin domain, most localize to discrete subdomains that display dynamic localization patterns during the cell cycle. We conclude that heterochromatin composition and architecture is more spatially complex and dynamic than previously suggested, and propose that a network of subdomains regulates diverse heterochromatin functions.
authors: Division of Biological Systems and Engineering, Lawrence Berkeley National Laboratory, Berkeley, United States.
authors: Joel M
authors: JM
authors: Swenson
authors: Division of Biological Systems and Engineering, Lawrence Berkeley National Laboratory, Berkeley, United States.
authors: Serafin U
authors: 0000-0002-4094-4220
authors: SU
authors: Colmenares
authors: Division of Biological Systems and Engineering, Lawrence Berkeley National Laboratory, Berkeley, United States.|Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.
authors: Amy R
authors: AR
authors: Strom
authors: Division of Biological Systems and Engineering, Lawrence Berkeley National Laboratory, Berkeley, United States.
authors: Sylvain V
authors: SV
authors: Costes
authors: Division of Biological Systems and Engineering, Lawrence Berkeley National Laboratory, Berkeley, United States.|Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.
authors: Gary H
authors: 0000-0003-1534-0385
authors: GH
authors: Karpen
mesh_terms: D000818:Animals; D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone / Q000032:analysis*; D004331:Drosophila melanogaster / Q000235:genetics* / Q000502:physiology*; D005786:Gene Expression Regulation; D006570:Heterochromatin / Q000737:chemistry*; D062211:Spatio-Temporal Analysis
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D006570:Heterochromatin; D000090266:Chromobox Protein Homolog 5
keywords: D. melanogaster; cell biology; chromosomes; genes; genome-wide RNAi screen; heterochromatin; nuclear organization; position effect variegation