GSBS Dissertations and Theses

Approval Date

4-30-2008

Document Type

Doctoral Dissertation

Department

Graduate School of Biomedical Sciences

Subjects

DNA Damage; Mitosis; Mitotic Spindle Apparatus; Drosophila melanogaster; Cell Cycle Proteins; Drosophila Proteins; Academic Dissertations

Abstract

DNA damage induces mitotic exit delays through a process that requires the spindle assembly checkpoint (SAC), which blocks the metaphase to anaphase transition in the presence of unaligned chromosomes. Using time-lapse confocal microscopy in syncytial Drosophila embryos, we show that DNA damage leads to arrest during prometaphase and anaphase. In addition, functional GFP fusions to the SAC components MAD2 and Mps1, and the SAC target Cdc20 relocalize to kinetochore through anaphase arrest, and a null mad2mutation blocks damage induced prometaphase and anaphase arrest. We also show that the DNA damage signaling kinase Chk2 is required for damage induced metaphase and anaphase arrest, and that a functional GFP-Chk2 fusion localizes to kinetochores and centrosomes through mitosis. In addition, in the absence of Chk2, we find that DNA damage sufficient to fragment centromere DNA does not delay mitotic exit. We conclude that DNA damage signaling through Chk2 triggers Mad2-dependent delays in mitotic progression, both before or after the metaphase-anaphase transition.

Rights and Permissions

Copyright is held by the author, with all rights reserved.

Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.