Altered nucleosomes of active nucleolar chromatin contain accessible histone H3 in its hyperacetylated forms
Chromatin of the organism Physarum polycephalum contains a class of conformationally altered nucleosomes previously localized to the transcribing regions of ribosomal genes in nucleoli. When nuclei are treated with 2-iodo(2-tritium)acetate, the histone H3 sulfhydryl group of the altered nucleosomes is derivatized while that of folded nucleosomes is not, and the labeled histones can then be identified by autoradiography of gels that separate H3 isoforms. The H3 derivatized is predominantly of tri- and tetraacetylated forms. In contrast, total free histone reacted with iodoacetate shows no preferential labeling of isoforms. Selective reaction of acetylated H3 is prevalent in both nucleolar and non-nucleolar chromatin. The results link specific patterns of H3 acetylation to changes in nucleosome conformation that occur during transcription.
- Research Organization:
- Mount Sinai School of Medicine, New York, NY
- OSTI ID:
- 6332660
- Journal Information:
- J. Biol. Chem.; (United States), Vol. 15
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CHROMATIN
CHEMICAL COMPOSITION
GENES
TRANSCRIPTION
HISTONES
ACETYLATION
ACETATES
AUTORADIOGRAPHY
CELL NUCLEI
ELECTROPHORESIS
FUNGI
NUCLEOSOMES
PHYSARUM
TRITIUM COMPOUNDS
ACYLATION
CARBOXYLIC ACID SALTS
CELL CONSTITUENTS
CHEMICAL REACTIONS
LABELLED COMPOUNDS
NUCLEOPROTEINS
ORGANIC COMPOUNDS
PLANTS
PROTEINS
550201* - Biochemistry- Tracer Techniques