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Dynamics of H3 and H2B octamer variants

Date

2020

Authors

McVay, Abigail Lea, author
Hansen, Jeffrey C., advisor
Quackenbush, Sandra, committee member
DeLuca, Jennifer, committee member

Journal Title

Journal ISSN

Volume Title

Abstract

Introductions of alterations within a nucleosome can lead to drastic changes to the accessibility and stability of genetic material during various phases of the cell cycle. To understand these changes, three octamer mutants were recombined, reconstituted with a high affinity tandem repeat sequence, and tested using a combination of in vitro experimental methods. All Tailless, H2BTL and an H2BTL & H3TL nucleosomal array mutants were sedimented, digested, re-associated, and visualized in order to determine the role of histone tails and their influence on chromatin condensate structure. The All Tailless octamer mutant expressed an inability to form complex molecular structures, suggesting that histone tails are necessary to further the process of chromatin condensate association and subsequent folding. The H2BTL mutant expressed high levels of concentration and an increased level of association compared to the other mutants. This lead to the assumption that the exclusion of only one histone tail lead to a greater ability to associate compared to mutants lacking two or more tails. The H2BTL & H3TL mutant had a possibility of two distinct populations within solution, suggesting that the exclusion of at least two tails led to a loosely compacted and easily accessible chromatin condensate structure. In summary, this data suggests that as histone tails are excluded from octamer mutants, the chromatin condensates expresses a decreased ability to form higher degrees of compaction. Exclusion of histone tails from octamer mutants also resulted in a more accessible 601-12 tandem repeat sequence susceptible to various changes.

Description

2020 Spring.
Includes bibliographical references.

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Subject

condensates
magnesium
mutant
FPLC
analytical ultracentrifugation
Micrococcal Nuclease

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