2 options
Centromeric chromatin: Structure, function and epigenetic inheritance.
- Format:
- Book
- Thesis/Dissertation
- Author/Creator:
- Panchenko, Tatyana.
- Language:
- English
- Subjects (All):
- Biochemistry.
- Cytology.
- Molecular biology.
- 0307.
- 0379.
- 0487.
- Penn dissertations--Cell and Molecular Biology.
- Cell and Molecular Biology--Penn dissertations.
- Local Subjects:
- Penn dissertations--Cell and Molecular Biology.
- Cell and Molecular Biology--Penn dissertations.
- 0307.
- 0379.
- 0487.
- Physical Description:
- 202 pages
- Contained In:
- Dissertation Abstracts International 74-10B(E).
- System Details:
- Mode of access: World Wide Web.
- text file
- Summary:
- The centromere is the chromosomal locus that determines the site of kinetochore formation and spindle attachment during mitosis and is therefore critical for proper chromosome segregation and cell viability. Centromere protein A (CENP-A) is a histone H3 variant that epigenetically specifies centromere location independently of DNA sequence. Therefore, there must exist unique features of the CENP-A protein, the CENP-A containing nucleosome or the higher order chromatin structure specified by the presence of CENP-A that allows the cells to distinguish the centromere from the rest of the chromatin. We utilize a set of complimentary in-vitro and in-vivo approaches in order to gain insight into the structure and specification of centromeric chromatin. First, by using a recombinant nucleosome array system we find that CENP-A arrays are composed of octameric nucleosomes that assemble in a stepwise mechanism, recapitulating conventional array assembly with canonical histones. CENP-A-containing arrays are globally condensed relative to arrays with the canonical histones and importantly the DNA termini within each nucleosome are loosely connected to CENP-A as detected by measuring both, the DNA as well we the protein components of the nucleosome array. Next, we extend our analysis of CENP-A containing chromatin by analyzing functional human centromeres using genomics tools. We find that, very consistently with our in-vitro observations, the predominant form of the CENP-A particle at human centromeres is an octameric nucleosome, CENP-A nucleosomes are very highly phased and CENP-A nucleosomes exhibit similar DNA unwrapping behavior as octameric CENP-A nucleosomes reconstituted with recombinant components. Lastly, we define the natural chromatin environment of CENP-A containing nucleosomes found at functional centromeres by determining their post translational modification status. By setting up a large scale purification system and coupling it with high resolution mass spectrometry we find that the CENP-A N-terminal tail is both trimethylated at its Glycine 1 position after constitutive initiating Methionine removal and doubly phosphorylated at Serine 16 and Serine 18 positions. We also find that the phosphorylation at the N-terminal tail plays a role in mediating the condensation status of centromeric chromatin. Taken together, these findings greatly extend our understanding of the unique properties of centromeric chromatin.
- Notes:
- Thesis (Ph.D. in Cell and Molecular Biology) -- University of Pennsylvania, 2013.
- Source: Dissertation Abstracts International, Volume: 74-10(E), Section: B.
- Adviser: Ben E. Black.
- Local Notes:
- School code: 0175.
- ISBN:
- 9781303175725
- Access Restriction:
- Restricted for use by site license.
The Penn Libraries is committed to describing library materials using current, accurate, and responsible language. If you discover outdated or inaccurate language, please fill out this feedback form to report it and suggest alternative language.