Related Experiment Videos
Repeating oligonucleosomal units. A new element of chromatin structure
Nucleic Acids Research
|February 11, 1980
Summary
Researchers identified a fundamental chromatin unit, the "clisone," composed of 12 histone H1 molecules. This discovery reveals that chromatin is organized into repeating 12-nucleosome structures, impacting our understanding of supranucleosomal organization.
Area of Science:
- Molecular Biology
- Chromatin Biology
- Biochemistry
Background:
- Understanding supranucleosomal chromatin structure is crucial for deciphering gene regulation and genome organization.
- Histone H1 plays a key role in higher-order chromatin folding, but its precise structural contribution remains debated.
Purpose of the Study:
- To investigate the molecular organization of histone H1 within chromatin.
- To determine the fundamental repeating units of supranucleosomal chromatin structure.
Main Methods:
- Crosslinking of histone H1 polymers in isolated nuclei and extended chromatin using bifunctional reagents (methyl-4-mercaptobutyrimidate and dimethyl suberimidate dihydrochloride).
- Purification and molecular weight distribution analysis of histone H1 homopolymers.
- Characterization of elementary structures within histone H1 polymers.
Main Results:
- Obtained milligram quantities of purified histone H1 homopolymers.
- Identified an elementary structure, termed 'clisone,' composed of 12 histone H1 molecules.
- Demonstrated that H1 homopolymers from both nuclei and chromatin are integer multiples of the clisone unit.
- Found evidence for repeating 12-nucleosome units in chromatin chains.
Conclusions:
- Chromatin is organized into repeating oligonucleosomal units, each containing 12 nucleosomes.
- The 'clisone' represents a fundamental building block of supranucleosomal chromatin structure.
- Linearized nucleosomal chains preserve information about higher-order chromatin organization, suggesting a conserved structural principle.