Publication Date:
2004-10-23
Description:
In mammalian cells, repair of DNA double-strand breaks (DSBs) by nonhomologous end-joining (NHEJ) is critical for genome stability. Although the end-bridging and ligation steps of NHEJ have been reconstituted in vitro, little is known about the end-processing reactions that occur before ligation. Recently, functionally homologous end-bridging and ligation activities have been identified in prokarya. Consistent with its homology to polymerases and nucleases, we demonstrate that DNA ligase D from Mycobacterium tuberculosis (Mt-Lig) possesses a unique variety of nucleotidyl transferase activities, including gap-filling polymerase, terminal transferase, and primase, and is also a 3' to 5' exonuclease. These enzyme activities allow the Mt-Ku and Mt-Lig proteins to join incompatible DSB ends in vitro, as well as to reconstitute NHEJ in vivo in yeast. These results demonstrate that prokaryotic Ku and ligase form a bona fide NHEJ system that encodes all the recognition, processing, and ligation activities required for DSB repair.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Della, Marina -- Palmbos, Phillip L -- Tseng, Hui-Min -- Tonkin, Louise M -- Daley, James M -- Topper, Leana M -- Pitcher, Robert S -- Tomkinson, Alan E -- Wilson, Thomas E -- Doherty, Aidan J -- R01 CA102563/CA/NCI NIH HHS/ -- R01 CA102563-01A1/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 2004 Oct 22;306(5696):683-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Cambridge Institute for Medical Research, University of Cambridge, Department of Haematology, Hills Road, Cambridge CB2 2XY, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15499016" target="_blank"〉PubMed〈/a〉
Keywords:
Bacterial Proteins/chemistry/genetics/*metabolism
;
DNA/*metabolism
;
DNA Damage
;
DNA Ligases/chemistry/genetics/*metabolism
;
DNA Nucleotidyltransferases/chemistry/metabolism
;
DNA Primase/chemistry/metabolism
;
*DNA Repair
;
DNA-Directed DNA Polymerase/chemistry/metabolism
;
Exonucleases/chemistry/metabolism
;
Mutation
;
Mycobacterium tuberculosis/genetics/*metabolism
;
Polymerase Chain Reaction
;
Protein Structure, Tertiary
;
Recombination, Genetic
;
Saccharomyces cerevisiae/genetics
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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