The Drosophila Grp/Chk1 DNA damage checkpoint controls entry into anaphase.
It is well established that DNA damage induces checkpoint-mediated interphase arrest in higher eukaryotes, but recent studies demonstrate that DNA damage delays entry into anaphase as well. Damaged DNA in syncytial and gastrulating Drosophila embryos delays the metaphase/anaphase transition . In human cultured cells, DNA damage also induces a delay in mitosis . However, the mechanism by which DNA damage delays the anaphase onset is controversial. Some studies implicate a DNA damage checkpoint , whereas other studies invoke a spindle checkpoint . To resolve this issue, we compared the effects of random DNA breaks induced by X-irradiation to site-specific I-CreI endonuclease-induced chromosome breaks on cell-cycle progression in wild-type and checkpoint-defective Drosophila neuroblasts. We found that both the BubR1 spindle checkpoint pathway and the Grp/Chk1 DNA damage checkpoint pathway are involved in delaying the metaphase/anaphase transition after extensive X-irradiation-induced DNA damage, whereas Grp/Chk1, but not BubR1, is required to delay anaphase onset in the presence of I-CreI-induced double-strand breaks. On the basis of these results, we propose that DNA damage in nonkinetochore regions produces a Grp/Chk1 DNA-damage-checkpoint-mediated delay in the metaphase/anaphase transition.
Royou
Anne
A
Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064 USA.
Macias
Hector
H
Sullivan
William
W
D000705:Anaphase / Q000502:physiology*; D000818:Animals; D001921:Brain / Q000502:physiology; D018797:Cell Cycle Proteins; D000071877:Checkpoint Kinase 1; D004249:DNA Damage / Q000502:physiology*; D004252:DNA Mutational Analysis; D004262:DNA Restriction Enzymes; D004330:Drosophila / Q000235:genetics / Q000254:growth & development*; D029721:Drosophila Proteins; D007814:Larva / Q000502:physiology; D008677:Metaphase / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000502:physiology; D011494:Protein Kinases / Q000235:genetics / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases; D014965:X-Rays
D018797:Cell Cycle Proteins; D029721:Drosophila Proteins; D011494:Protein Kinases; C584277:BUB1 protein, human; C090464:Bub1 spindle checkpoint protein; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; D017346:Protein Serine-Threonine Kinases; C000605877:grp protein, Drosophila; D004262:DNA Restriction Enzymes; C048901:endodeoxyribonuclease CreI