Linked Life Data

16288010

Source:http://linkedlifedata.com/resource/pubmed/id/16288010

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
22
pubmed:dateCreated
2005-11-18
pubmed:abstractText
Combined cytogenetic and biochemical approaches were used to investigate the contributions of the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs) in the maintenance of genomic stability in nonirradiated and irradiated primary mouse embryo fibroblasts (MEF). We show that telomere dysfunction contributes only marginally to genomic instability associated with DNA-PKcs deficiency in the absence of radiation. Following exposure to ionizing radiation, DNA-PKcs-/- MEFs are radiosensitized mainly as a result of the associated DNA double-strand break (DSB) repair defect. This defect manifests as an increase in the fraction of DSB rejoining with slow kinetics although nearly complete rejoining is achieved within 48 hours. Fifty-four hours after ionizing radiation, DNA-PKcs-/- cells present with a high number of simple and complex chromosome rearrangements as well as with unrepaired chromosome breaks. Overall, induction of chromosome aberrations is 6-fold higher in DNA-PKcs-/- MEFs than in their wild-type counterparts. Spectral karyotyping-fluorescence in situ hybridization technology distinguishes between rearrangements formed by prereplicative and postreplicative DSB rejoining and identifies sister chromatid fusion as a significant source of genomic instability and radiation sensitivity in DNA-PKcs-/- MEFs. Because DNA-PKcs-/- MEFs show a strong G1 checkpoint response after ionizing radiation, we propose that the delayed rejoining of DNA DSBs in DNA-PKcs-/- MEFs prolongs the mean life of broken chromosome ends and increases the probability of incorrect joining. The preponderance of sister chromatid fusion as a product of incorrect joining points to a possible defect in S-phase arrest and emphasizes proximity in these misrepair events.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0008-5472
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
65
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
10223-32
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Postreplicative joining of DNA double-strand breaks causes genomic instability in DNA-PKcs-deficient mouse embryonic fibroblasts.
pubmed:affiliation
Department of Cell Biology, Physiology, and Immunology, Institute of Biotechnology and Biomedicine, Universitat Autònoma de Barcelona, Bellaterra, Spain.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't