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            "Radiation-mediated proteolysis of CDT1 by CUL4-ROC1 and CSN complexes constitutes a new checkpoint."
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            Higa LA, Mihaylov IS, Banks DP, Zheng J, Zhang H
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  Published Nov. 1, 2003
  
    in Nat Cell Biol
    
      volume 5
    
  
  .
   
   
Pubmed ID:
  14578910
 
 
  Abstract:
   
  
    
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	Genomic integrity is maintained by checkpoints that guard against undesired replication after DNA damage. Here, we show that CDT1, a licensing factor of the pre-replication complex (preRC), is rapidly proteolysed after UV- or gamma-irradiation. The preRC assembles on replication origins at the end of mitosis and during G1 to license DNA for replication in S phase. Once the origin recognition complex (ORC) binds to origins, CDC6 and CDT1 associate with ORC and promote loading of the MCM2-7 proteins onto chromatin, generating the preRC. We show that radiation-mediated CDT1 proteolysis is independent of ATM and CHK2 and can occur in G1-phase cells. Loss of the COP9-signalosome (CSN) or CUL4-ROC1 complexes completely suppresses CDT1 proteolysis. CDT1 is specifically polyubiquitinated by CUL4 complexes and the interaction between CDT1 and CUL4 is regulated in part by gamma-irradiation. Our study reveals an evolutionarily conserved and uncharacterized G1 checkpoint that induces CDT1 proteolysis by the CUL4-ROC1 ubiquitin E3 ligase and CSN complexes in response to DNA damage.
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This publication refers to following REPAIRtoire entries:
 
 
 
 
Last modification of this entry: Oct. 6, 2010
 
 
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