title: Binding of histones to Xenopus laevis ribosomal genes with different levels of expression.
abstract: The association of ribosomal RNA genes with histones as a function of their expression has been studied in Xenopus laevis erythrocytes, where the genes are silent, and tadpoles at stage 40, where these genes are actively transcribed. Isolated nuclei were either treated with formaldehyde or irradiated with an ultraviolet laser to cross-link proteins to DNA. The covalently linked protein-DNA complexes were purified by centrifugation through CsCl and immunoprecipitated with antibodies against H1, H2A and H4. DNA from the precipitated complexes was analysed for the presence of ribosomal DNA sequences by hybridization to specific probes. The actively transcribed ribosomal genes from X. laevis embryos are associated with H1, H2A and H4 as are the non-transcribed genes in the erythrocytes.
authors.affiliation: Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia.
authors.forename: S I
authors.initials: SI
authors.lastname: Dimitrov
authors.forename: H N
authors.initials: HN
authors.lastname: Tateossyan
authors.lastname: Stefanovsky VYu
authors.forename: V R
authors.initials: VR
authors.lastname: Russanova
authors.forename: L
authors.initials: L
authors.lastname: Karagyozov
authors.forename: I G
authors.initials: IG
authors.lastname: Pashev
mesh_terms: D000818:Animals; D004247:DNA / Q000235:genetics; D015342:DNA Probes; D004275:DNA, Ribosomal / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004912:Erythrocytes / Q000378:metabolism / Q000528:radiation effects; D005260:Female; D015870:Gene Expression; D006657:Histones / Q000235:genetics* / Q000378:metabolism; D015151:Immunoblotting; D009693:Nucleic Acid Hybridization / Q000235:genetics; D014982:Xenopus laevis / Q000235:genetics*
chemical_list: D015342:DNA Probes; D004275:DNA, Ribosomal; D004268:DNA-Binding Proteins; D006657:Histones; D004247:DNA