CtIP-dependent DNA resection is required for DNA damage checkpoint maintenance but not initiation

TY - JOUR

T1 - CtIP-dependent DNA resection is required for DNA damage checkpoint maintenance but not initiation

AU - Kousholt, Arne Nedergaard

AU - Fugger, Kasper

AU - Hoffmann, Saskia

AU - Larsen, Brian D

AU - Menzel, Tobias

AU - Sartori, Alessandro A

AU - Sørensen, Claus Storgaard

PY - 2012/6/25

Y1 - 2012/6/25

N2 - To prevent accumulation of mutations, cells respond to DNA lesions by blocking cell cycle progression and initiating DNA repair. Homology-directed repair of DNA breaks requires CtIP-dependent resection of the DNA ends, which is thought to play a key role in activation of ATR (ataxia telangiectasia mutated and Rad3 related) and CHK1 kinases to induce the cell cycle checkpoint. In this paper, we show that CHK1 was rapidly and robustly activated before detectable end resection. Moreover, we show that the key resection factor CtIP was dispensable for initial ATR-CHK1 activation after DNA damage by camptothecin and ionizing radiation. In contrast, we find that DNA end resection was critically required for sustained ATR-CHK1 checkpoint signaling and for maintaining both the intra-S- and G2-phase checkpoints. Consequently, resection-deficient cells entered mitosis with persistent DNA damage. In conclusion, we have uncovered a temporal program of checkpoint activation, where CtIP-dependent DNA end resection is required for sustained checkpoint signaling.

AB - To prevent accumulation of mutations, cells respond to DNA lesions by blocking cell cycle progression and initiating DNA repair. Homology-directed repair of DNA breaks requires CtIP-dependent resection of the DNA ends, which is thought to play a key role in activation of ATR (ataxia telangiectasia mutated and Rad3 related) and CHK1 kinases to induce the cell cycle checkpoint. In this paper, we show that CHK1 was rapidly and robustly activated before detectable end resection. Moreover, we show that the key resection factor CtIP was dispensable for initial ATR-CHK1 activation after DNA damage by camptothecin and ionizing radiation. In contrast, we find that DNA end resection was critically required for sustained ATR-CHK1 checkpoint signaling and for maintaining both the intra-S- and G2-phase checkpoints. Consequently, resection-deficient cells entered mitosis with persistent DNA damage. In conclusion, we have uncovered a temporal program of checkpoint activation, where CtIP-dependent DNA end resection is required for sustained checkpoint signaling.

KW - Carrier Proteins

KW - Cell Cycle Checkpoints

KW - Cell Line, Tumor

KW - DNA

KW - DNA Damage

KW - Humans

KW - Nuclear Proteins

KW - Protein Kinases

KW - Protein-Serine-Threonine Kinases

KW - Signal Transduction

U2 - 10.1083/jcb.201111065

DO - 10.1083/jcb.201111065

M3 - Journal article

C2 - 22733999

SN - 0021-9525

VL - 197

SP - 869

EP - 876

JO - Journal of Cell Biology

JF - Journal of Cell Biology

IS - 7

ER -