The structure and maintenance of centromeric chromatin
Abstract/Contents
- Abstract
- When a human cell divides, it pulls its chromosomes into regions that will become new cells. The pull is applied to a single region on each chromosome called the centromere. Centromeres are defined by high concentrations of nucleosomes containing the protein CENP-A instead of the canonical histone H3. CENP-A nucleosomes directly recruit proteins that bridge between the nucleosomes and the forces that pull chromosomes apart. These proteins also affect CENP-A chromatin itself. This thesis examines the role of two proteins that directly interact with CENP-A nucleosomes, CENP-C and CENP-N, in centromere maintenance and structure. It was found that CENP-A nucleosomes have little to no dissociation from centromeric regions. We hypothesized that this lack of dissociation is caused by increased nucleosome stability due to binding to CENP-C and CENP-N. To test this, we generated cell lines where we could induce the degradation of the endogenous proteins. Using these cells, we employed several orthogonal methods to show that CENP-C and CENP-N do not affect CENP-A nucleosome stability at the centromere. Next, we explored the role of these proteins on centromeric chromatin structure. Not much is known about CENP-A chromatin structure due to technical limitations. To overcome this, we instead looked for activities that alter CENP-A chromatin structure. We developed a novel activity-based assay that detects CENP-A nucleosome clustering. Using this assay, we discovered that CENP-C can cluster CENP-A nucleosomes from different strands of DNA. We showed that this activity is specific and depends on CENP-C's ability to bind CENP-A nucleosomes. We identified the minimal domain necessary for the clustering which will serve as the basis for further studies. Lastly, we examined the role of these proteins in disease. We looked at CENP-N mutations associated with familial idiopathic pulmonary fibrosis. We found that one mutation, E46Q, lowered the levels of CENP-T at the centromere. Since CENP-T functions in kinetochore formation, we hypothesize that this leads to impaired kinetochore function and more chromosome segregation errors. Consistent with this, we found that this mutation sensitized the cells to PDMP, a drug that selectively kills aneuploid cells.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2018; ©2018 |
| Publication date | 2018; 2018 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Cao, Shengya |
|---|---|
| Degree supervisor | Straight, Aaron, 1966- |
| Thesis advisor | Straight, Aaron, 1966- |
| Thesis advisor | Ferrell, James Ellsworth |
| Thesis advisor | Herschlag, Daniel |
| Degree committee member | Ferrell, James Ellsworth |
| Degree committee member | Herschlag, Daniel |
| Associated with | Stanford University, Department of Biochemistry. |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Shengya Cao. |
|---|---|
| Note | Submitted to the Department of Biochemistry. |
| Thesis | Thesis Ph.D. Stanford University 2018. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2018 by Shengya Cao
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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