Modulation of ATR-mediated DNA damage checkpoint response by cryptochrome 1.
Mammalian cryptochromes (Crys) are essential circadian clock factors implicated in diverse clock-independent physiological functions, including DNA damage responses. Here we show that Cry1 modulates the ATR-mediated DNA damage checkpoint (DDC) response by interacting with Timeless (Tim) in a time-of-day-dependent manner. The DDC capacity in response to UV irradiation showed a circadian rhythm. Interestingly, clock-deficient Cry1 and Cry2 double knockout (Cry(DKO)) cells retained substantial DDC capacity compared with clock-proficient wild-type cells, although the Cry1-modulated oscillation of the DDC capacity was abolished in Cry(DKO) cells. We found temporal interaction of Cry1 and Tim in the nucleus. When Cry1 was expressed in the nucleus, it was critical for circadian ATR activity. We regenerated rhythmic DDC responses by ectopically expressing Cry1 in Cry(DKO) cells. In addition, we also investigated the DDC capacity in the liver of mice that were intraperitoneally injected with cisplatin at different circadian times (CT). When mice were injected at CT20, about 2-fold higher expression of phosphorylated minichromosome maintenance protein 2 (p-MCM2) was detected compared with mice injected at CT08, which consequently affected the removal rate of cisplatin-DNA adducts from genomic DNA. Taken together, our data demonstrate the intimate interaction between the circadian clock and the DDC system during genotoxic stress in clock-ticking cells.
Department of Biological Science, Dong-A University, Hadan2-dong, Saha-gu, Busan 604-714, South Korea.
Tae-Hong
TH
Kang
Sun-Hee
SH
Leem
D000818:Animals; D064007:Ataxia Telangiectasia Mutated Proteins / Q000378:metabolism; D059447:Cell Cycle Checkpoints / Q000235:genetics; D018797:Cell Cycle Proteins / Q000378:metabolism; D002478:Cells, Cultured; D057906:Circadian Clocks / Q000235:genetics; D056931:Cryptochromes / Q000378:metabolism*; D004249:DNA Damage; D004260:DNA Repair; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL
D018797:Cell Cycle Proteins; C538964:Cry1 protein, mouse; D056931:Cryptochromes; D047908:Intracellular Signaling Peptides and Proteins; C509770:Timeless protein, mouse; C576897:Atr protein, mouse; D064007:Ataxia Telangiectasia Mutated Proteins