Chromatin Structure of Schizosaccharomyces Pombe: From the Lowest to the Highest Orders of Folding

I have used new methods for chromatin isolation, together with conventional methods for measuring the nucleosome repeat length, to determine the repeat length of Schizosaccharomyces pombe chromatin. I obtained a result of 156 $\pm$ 2 bp. Equivalent results are obtained using a psoralen crosslinking method for measuring the repeat length in viable spheroplasts. That result, together with other control experiments, rules out many possible artifacts. The measured value of 156 $\pm$ 2 bp is smaller than the length of DNA found in the chromatosome. Thus, the chromatosome cannot be the fundamental unit of chromatin structure in all eukaryotes. The cross-linker model of chromatin higher-order structure is incompatible with a nucleosome repeat length of 156 bp, and thus cannot apply to all eukaryotes. The solenoid model of higher order structure is compatible with this repeat length only if the solenoid is right-handed. I note two other properties of this chromatin. (1) Early in digestion, the DNA length of mononucleosomes from S. pombe and A. nidulans exceeds the nucleosome repeat length. (2) Many methods for isolating chromatin from S. pombe yield an apparent nucleosome repeat length of $\sim$140 bp; this result is found to be an artifactual consequence of nucleosome sliding.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Biochemistry

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Godde, James Scott

Contributors dc:contributor

• Widom, Jonathan

• Biology, Molecular
• Biology, Cell
• Chemistry, Biochemistry

Identifier

(UMI)AAI9314872

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/72354