Deposition of newly synthesized histones: new histones H2A and H2B do not deposit in the same nucleosome with new Histones H3 and H4
The authors have developed procedures to study histone-histone interactions during the deposition of histones in replicating cells. Cells are labeled for 60 min with dense amino acids, and subsequently, the histones within the nucleosomes are cross-linked into an octameric complex with formaldehyde. These complexes are sedimented to equilibrium in density gradients and octamer and dioctamer complexes separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. With reversal of the cross-link, the distribution of the individual density-labeled histones in the octamer is determined. Newly synthesized H3 and H4 deposits as a tetramer and are associated with old H2A and H2B. Newly synthesized H2A and H2B deposit as a dimer associated with old H2A, H2B, H3, and H4. The significance of these results with respect to the dynamics of histone interactions in the nucleus is discussed. Control experiments are presented to test for artifactual formation of these complexes during preparative procedures. In addition, reconstitution experiments were performed to demonstrate that the composition of these octameric complexes can be determined from their distribution of density gradients.
- Research Organization:
- Medical College of Wisconsin, Milwaukee
- OSTI ID:
- 5514782
- Journal Information:
- Biochemistry; (United States), Vol. 26:8
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
HISTONES
BIOSYNTHESIS
CROSS-LINKING
LABELLED COMPOUNDS
AMINO ACIDS
ANIMAL CELLS
CARBON 13
DEUTERIUM COMPOUNDS
ELECTROPHORESIS
NITROGEN 15
NUCLEOSOMES
TRITIUM COMPOUNDS
CARBON ISOTOPES
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
CHROMATIN
EVEN-ODD NUCLEI
HYDROGEN COMPOUNDS
ISOTOPES
LIGHT NUCLEI
NITROGEN ISOTOPES
NUCLEI
NUCLEOPROTEINS
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
POLYMERIZATION
PROTEINS
STABLE ISOTOPES
SYNTHESIS
550201* - Biochemistry- Tracer Techniques