The role of centromere protein-E in chromosome segregation.

Format:

Book

Thesis/Dissertation

Author/Creator:

Schaar, Bruce Terence.

Contributor:

Yen, Timothy J., advisor.

University of Pennsylvania.

Language:

English

Subjects (All):

Cytology.

0379.

Penn dissertations--Cell biology.

Cell biology--Penn dissertations.

Penn dissertations--Molecular biology.

Molecular biology--Penn dissertations.

Local Subjects:

Penn dissertations--Cell biology.

Cell biology--Penn dissertations.

Penn dissertations--Molecular biology.

Molecular biology--Penn dissertations.

0379.

Physical Description:

129 pages

Contained In:

Dissertation Abstracts International 58-03B.

System Details:

Mode of access: World Wide Web.

text file

Summary:

The faithful segregation of the newly replicated genome relies on the interactions between the eukaryotic cell's dynamic microtubule polymer system, and DNA itself during mitosis. The principle liaison between the chromosome and microtubules of the mitotic spindle is a structure called the kinetochore. This macromolecular complex is based upon the centromeric heterochromatin, and can be seen by electron microscopy as an electron-dense disc that overlies the primary constriction of the chromosome. Little is known about kinetochore constituents or how they navigate the replicated genome via its microtubule connections to ensure that each daughter cell has one copy of each chromosome. This study focuses on a kinetochore component called Centromere Protein-E (CENP-E), a member of the kinesin microtubule motor protein superfamily. CENP-E's motor activity was tested by creating a recombinant fusion protein, and assaying its motility in vitro. CENP-E was determined to be a minus-end directed microtubule motor, establishing a new subfamily of kinesin related proteins. The role of CENP-E in vivo was addressed by using antibody microinjection to prevent its assembly onto kinetochores at mitosis. Chromosomes that lack CENP-E cannot convert from being mono-oriented to a single spindle pole to attaining a second microtubule attachment, which is essential for segregation of the two sister chromatids to the daughter cells. Taken together with the in vitro data of CENP-E's minus end directed motor activity, a model emerges in which CENP-E is a poleward motor at the kinetochore to capture a microtubule from the opposite spindle pole when the chromosome becomes mono-oriented. The tension applied to the captured microtubule stabilizes it and allows the chromosome to congress to the metaphase plate via its new connection. Other kinetochore components that could bind CENP-E to the kinetochore were sought using the yeast two-hybrid screen. This screen identified CENP-E, another kinetochore protein that assembles onto centromeres prior to CENP-E, as a molecular "hitch" to harness CENP-E's motor activity.

Notes:

Thesis (Ph.D. in Cell Biology and Molecular Biology) -- University of Pennsylvania, 1997.

Source: Dissertation Abstracts International, Volume: 58-03, Section: B, page: 1065.

Supervisor: Timothy J. Yen.

Local Notes:

School code: 0175.

ISBN:

9780591362978

Access Restriction:

Restricted for use by site license.