Document Detail

Differential role of repair proteins, BRCA1/NBS1 and Ku70/DNA-PKcs, in radiation-induced centrosome overduplication.
MedLine Citation:
PMID:  20825415     Owner:  NLM     Status:  MEDLINE    
Centrosomes are important cytoplasmic organelles involved in chromosome segregation, defects in which can result in aneuploidy, and contribute to tumorigenesis. It is known that DNA damage causes the supernumerary centrosomes by a mechanism in which centrosomes continue to duplicate during cell cycle arrest at checkpoints. We show here that ionizing radiation induces the overduplication of centrosomes in a dose-dependent manner, and that the level of overduplication is pronounced in BRCA1- and NBS1-deficient cells, even though their checkpoint control is abrogated. Conversely, marginal increases in overduplication were observed in Ku70- and DNA-PKcs-deficient cells, which are intact in checkpoint control. The frequency of radiation-induced overduplication of centrosomes might be associated with DNA repair, as it was decreased with reduced cell killing after protracted exposures to radiation. As a result, when the frequency of radiation-induced centrosome overduplication was plotted against radiation-induced cell killing, similar curves were seen for both protracted and acute exposures in wild-type cells, Ku70-deficient, and DNA-PKcs-deficient cells, indicating a common mechanism for centrosome overduplication. However, the absence of either BRCA1 or NBS1 enhanced radiation-induced overduplication frequencies by 2-4-fold on the basis of the same cell killing. These results suggest that radiation-induced centrosome overduplication is regulated by at least two mechanisms: a checkpoint-dependent pathway involved in wild-type cells, Ku70-deficient and DNA-PKcs-deficient cells; and a checkpoint-independent pathway as observed in BRCA1-deficient and NBS1-deficient cells.
Mikio Shimada; Junya Kobayashi; Ryoichi Hirayama; Kenshi Komatsu
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Cancer science     Volume:  101     ISSN:  1349-7006     ISO Abbreviation:  Cancer Sci.     Publication Date:  2010 Dec 
Date Detail:
Created Date:  2010-11-16     Completed Date:  2010-12-15     Revised Date:  2012-06-25    
Medline Journal Info:
Nlm Unique ID:  101168776     Medline TA:  Cancer Sci     Country:  England    
Other Details:
Languages:  eng     Pagination:  2531-7     Citation Subset:  IM    
Copyright Information:
© 2010 Japanese Cancer Association.
Radiation Biology Center, Kyoto University, Kyoto, Japan.
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MeSH Terms
Antigens, Nuclear / metabolism*
BRCA1 Protein / metabolism*
Cell Cycle Proteins / metabolism*
Cell Division / radiation effects*
Cell Line
Centrosome / radiation effects*
DNA Damage / radiation effects
DNA Repair / radiation effects
DNA-Activated Protein Kinase / metabolism*
DNA-Binding Proteins / metabolism*
Dose-Response Relationship, Radiation
Mice, Knockout
Nuclear Proteins / metabolism*
Radiation, Ionizing
Reg. No./Substance:
0/Antigens, Nuclear; 0/BRCA1 Protein; 0/Cell Cycle Proteins; 0/DNA-Binding Proteins; 0/Ku autoantigen; 0/Nijmegen breakage syndrome 1 protein, mouse; 0/Nuclear Proteins; EC Protein Kinase; EC protein, mouse

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