Abstract

Several factors direct the placement of specific nucleosomes, which in turn have the ability to regulate DNA accessibility. These factors include, but are not limited to, nucleotide sequence preference, nucleotide modifications, the type of histones present within the nucleosome, and the presence of additional transcription factor or chromatin remodelers. A combination of these and other factors are responsible for tightly controlled efficient transcription within the eukaryotic cell. In order to contribute to the understanding of these complicated processes, three separate hypothesis-driven investigations were carried out. First, we looked into nucleosome positioning and phasing within closely related cells lines. Second, we examined domain level nucleosome occupancy on various portions of the chromosome. Finally, we generated a novel method that significantly reduces data loss in in vitro nucleosome reconstitution experiments caused by nucleosome fragment-end bias. All three of our investigations yielded separate results. First, by examining positions and phasing patterns within similar cell types we find common patterns and minor differences within similar cell types. The presence of minor differences in nucleosome positions may cause unique expression patterns. Secondly, we found that decreased domain level nucleosome occupancy at the chromosome arms is not caused by the presence of a class of nucleosomes, termed fragile nucleosomes. Finally, we found that when our nucleosome recovery method is applied conservatively to our dataset, it is possible to recover 80% of the lost nucleosome reconstitution data.

Degree

College and Department

Life Sciences; Microbiology and Molecular Biology

Rights

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