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Rearrangements of the nucleosome structure in chromatin by poly(ADP-ribose)
L Thibeault1, M Hengartner, J Lagueux
1Laboratory of Molecular Endocrinology, CHUL Research Center, Sainte-Foy, Canada.
Biochimica Et Biophysica Acta
|June 24, 1992
Summary
Poly(ADP-ribose) interacts with nucleosomes, altering histone accessibility and suggesting modulated nucleosome structure. This interaction does not appear to cause complete histone removal from DNA.
Area of Science:
- Biochemistry
- Molecular Biology
- Epigenetics
Background:
- Nucleosomes are the fundamental units of DNA packaging in eukaryotes.
- Poly(ADP-ribose) (PAR) is a post-translational modification involved in various cellular processes.
- The precise impact of PAR on nucleosome structure remains incompletely understood.
Purpose of the Study:
- To investigate the effect of poly(ADP-ribose) on nucleosomal structure.
- To determine if PAR binding alters histone accessibility within nucleosomes.
Main Methods:
- Incubation of polynucleosomes with in vitro synthesized poly(ADP-ribose) chains.
- Enzyme-Linked Immunosorbent Assay (ELISA) using antibodies against core histones (H2A, H2B, H3, H4), histone H1, and specific histone peptides.
- Assessment of antibody binding to evaluate epitope accessibility.
Main Results:
- Poly(ADP-ribose) polymers bind to nucleosomes.
- PAR binding alters the accessibility of histone epitopes, with binding varying based on PAR concentration.
- Antibody recognition of core histones and histone H1 persists, indicating histones are not fully displaced.
Conclusions:
- Poly(ADP-ribose) modulates nucleosome structure by altering histone accessibility.
- PAR does not appear to cause complete dissociation of histones from nucleosomal DNA.