Graduate School of Biomedical Sciences
DNA Damage; Mitosis; Mitotic Spindle Apparatus; Drosophila melanogaster; Cell Cycle Proteins; Drosophila Proteins; Academic Dissertations
Life Sciences | Medicine and Health Sciences
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.
Kwak, Seongae, "Mitotic Response to DNA Damage in Early Drosophila Embroyos: a Dissertation" (2008). University of Massachusetts Medical School. GSBS Dissertations and Theses. Paper 371.