title: Chromatin insulator bodies are nuclear structures that form in response to osmotic stress and cell death.
abstract: Chromatin insulators assist in the formation of higher-order chromatin structures by mediating long-range contacts between distant genomic sites. It has been suggested that insulators accomplish this task by forming dense nuclear foci termed insulator bodies that result from the coalescence of multiple protein-bound insulators. However, these structures remain poorly understood, particularly the mechanisms triggering body formation and their role in nuclear function. In this paper, we show that insulator proteins undergo a dramatic and dynamic spatial reorganization into insulator bodies during osmostress and cell death in a high osmolarity glycerol-p38 mitogen-activated protein kinase-independent manner, leading to a large reduction in DNA-bound insulator proteins that rapidly repopulate chromatin as the bodies disassemble upon return to isotonicity. These bodies occupy distinct nuclear territories and contain a defined structural arrangement of insulator proteins. Our findings suggest insulator bodies are novel nuclear stress foci that can be used as a proxy to monitor the chromatin-bound state of insulator proteins and provide new insights into the effects of osmostress on nuclear and genome organization.
authors.affiliation: Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA.
authors.forename: Todd
authors.initials: T
authors.lastname: Schoborg
authors.forename: Ryan
authors.initials: R
authors.lastname: Rickels
authors.forename: Josh
authors.initials: J
authors.lastname: Barrios
authors.forename: Mariano
authors.initials: M
authors.lastname: Labrador
mesh_terms: D000818:Animals; D016923:Cell Death; D002460:Cell Line; D002466:Cell Nucleolus / Q000235:genetics / Q000378:metabolism; D002467:Cell Nucleus / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D002843:Chromatin / Q000235:genetics / Q000378:metabolism*; D003470:Culture Media / Q000378:metabolism; D004330:Drosophila / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D005990:Glycerol / Q000494:pharmacology; D038101:Insulator Elements; D007814:Larva / Q000235:genetics / Q000378:metabolism; D048308:Mitogen-Activated Protein Kinase 14 / Q000378:metabolism; D009994:Osmolar Concentration; D009995:Osmosis; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological
chemical_list: D002843:Chromatin; D003470:Culture Media; D029721:Drosophila Proteins; D012965:Sodium Chloride; D048308:Mitogen-Activated Protein Kinase 14; D005990:Glycerol