title: Tissue-specific regulation of chromatin insulator function.
abstract: Chromatin insulators organize the genome into distinct transcriptional domains and contribute to cell type-specific chromatin organization. However, factors regulating tissue-specific insulator function have not yet been discovered. Here we identify the RNA recognition motif-containing protein Shep as a direct interactor of two individual components of the gypsy insulator complex in Drosophila. Mutation of shep improves gypsy-dependent enhancer blocking, indicating a role as a negative regulator of insulator activity. Unlike ubiquitously expressed core gypsy insulator proteins, Shep is highly expressed in the central nervous system (CNS) with lower expression in other tissues. We developed a novel, quantitative tissue-specific barrier assay to demonstrate that Shep functions as a negative regulator of insulator activity in the CNS but not in muscle tissue. Additionally, mutation of shep alters insulator complex nuclear localization in the CNS but has no effect in other tissues. Consistent with negative regulatory activity, ChIP-seq analysis of Shep in a CNS-derived cell line indicates substantial genome-wide colocalization with a single gypsy insulator component but limited overlap with intact insulator complexes. Taken together, these data reveal a novel, tissue-specific mode of regulation of a chromatin insulator.
authors.affiliation: Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Leah H
authors.initials: LH
authors.lastname: Matzat
authors.forename: Ryan K
authors.initials: RK
authors.lastname: Dale
authors.forename: Nellie
authors.initials: N
authors.lastname: Moshkovich
authors.forename: Elissa P
authors.initials: EP
authors.lastname: Lei
mesh_terms: D000818:Animals; D002490:Central Nervous System / Q000378:metabolism; D002843:Chromatin / Q000235:genetics* / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism; D016678:Genome; D038101:Insulator Elements / Q000235:genetics*; D009132:Muscles / Q000378:metabolism; D009154:Mutation; D059372:Nucleotide Motifs / Q000235:genetics; D009928:Organ Specificity; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D002843:Chromatin; D029721:Drosophila Proteins; D012097:Repressor Proteins; C083738:su(Hw) protein, Drosophila