Document Detail


Chromosome terminal deletion formation in Chinese hamster ovary cells.
MedLine Citation:
PMID:  7526165     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
To investigate the fate of unrejoined DNA double-strand breaks, the frequency of 60Co gamma-ray- and restriction-enzyme-induced terminal chromosome deletions, a marker of unrejoined breaks, was determined in CHO-K1 and in xrs-5 cells. The xrs-5 cell is a DNA double-strand break repair-deficient derivative of CHO-K1. Terminal deletion frequency was small in both CHO-K1 and xrs-5 cells when cells were irradiated or treated with restriction enzyme while in the G1 phase of the cell cycle. In contrast, previous studies have shown that treatment of cells in G2 leads to large deletion frequencies, especially in xrs-5 cells. Cell cycle analyses show large G2 blocks in irradiated xrs-5 cells with only partial recovery over a 24-96-h period. These results suggest that most CHO cells with unrejoined breaks are blocked in G2 and, therefore, do not contribute to chromosome mutation frequencies. The small frequencies of terminal deletions that are found in these cells may reflect either an inefficiency in the G2 checkpoint mechanism or, perhaps, a modification of broken ends that allows passage through G2.
Authors:
J L Schwartz; B A Sedita; N Laffely; D J Grdina
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Mutation research     Volume:  311     ISSN:  0027-5107     ISO Abbreviation:  Mutat. Res.     Publication Date:  1994 Nov 
Date Detail:
Created Date:  1994-11-28     Completed Date:  1994-11-28     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0400763     Medline TA:  Mutat Res     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  125-31     Citation Subset:  IM    
Affiliation:
Center for Mechanistic Biology and Biotechnology, Argonne National Laboratory, IL 60439-4833.
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MeSH Terms
Descriptor/Qualifier:
Animals
CHO Cells / radiation effects
Cell Cycle / radiation effects
Chromosome Deletion*
Cobalt Radioisotopes
Cricetinae
Cricetulus
Gamma Rays
Grant Support
ID/Acronym/Agency:
CA-37435/CA/NCI NIH HHS
Chemical
Reg. No./Substance:
0/Cobalt Radioisotopes

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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