title: Polarization microscopy of extended chromatin fibers.
abstract: Analysis of the formation of extended chromatin fibers (ECFs) in response to the action of gravity following lysis by hypertonic and detergent solutions is a useful technical procedure relevant for studies of the positioning of particular DNA signals on chromatin filaments. Additionally, if toluidine blue molecules are allowed to bind electrostatically to available DNA phosphates on ECFs, the birefringence brightness generated in these filaments, as observed by polarization microscopy, facilitates the description of the frequency of ECF formation and extension of the chromatin filaments generated. Thus, different patterns of DNA-nuclear matrix protein associations related to varying transcriptional activities and chromatin organization in isolated cells can be assessed. A technique for producing ECFs in different isolated cell types under variable physiological and/or pathological conditions is detailed in this chapter.
authors.affiliation: Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas, SP, Brazil.
authors.forename: Maria Luiza S
authors.initials: ML
authors.lastname: Mello
authors.forename: Benedicto de Campos
authors.initials: Bde C
authors.lastname: Vidal
mesh_terms: D000818:Animals; D001718:Birefringence; D002843:Chromatin / Q000378:metabolism*; D022781:Hepatocytes / Q000166:cytology; D051379:Mice; D008859:Microscopy, Polarization / Q000379:methods*; D013194:Staining and Labeling
chemical_list: D002843:Chromatin