Nucleic Acids Research, Vol 27, Issue 16 3348-3354, Copyright © 1999 by Oxford University Press
G Coffey, U Lakshmipathy and C Campbell
Mammalian mitochondrial protein extracts possess DNA end-binding (DEB)
activity. Protein binding to a 394 bp double-stranded DNA molecule was
measured using an electrophoretic mobility shift assay. Mitochondrial DEB
activity was highly specific for linear DNA. Inclusion of a vast excess of
non-radioactive circular DNA did not disrupt binding to radioactive f394.
In contrast, binding was abolished by the inclusion of linear competitor
DNA. In mammals, nuclear DEB activity is due to Ku, a hetero-dimer composed
of the Ku70 and Ku86 proteins. To determine whether mitochondrial DEB
activity was also due to Ku, protein extracts were prepared from the
Chinese hamster XR-V15B cell line, which lacks this protein. As
anticipated, nuclear extracts prepared from these cells lacked DEB
activity. In contrast, mitochondrial extracts prepared from these cells had
wild-type levels of DEB activity, demonstrating that this latter activity
is not a consequence of nuclear contamination. Although the nuclear and
mitochondrial DEB activities are independent of each other, they are
nevertheless closely related, since mitochondrial DEB activity was
'supershifted' by both anti-Ku70 and anti-Ku86 antisera. The nuclear DEB
protein Ku plays an essential role in nuclear DNA double-strand break
repair. The DEB activity described herein may therefore play a similar role
in mitochondrial DNA repair.
ARTICLES
Mammalian mitochondrial extracts possess DNA end-binding activity
Department of Pharmacology, University of Minnesota Medical School, 3- 249 Millard Hall, 435 Delaware Street SE, Minneapolis, MN 55455, USA.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  J. P. Duxin, B. Dao, P. Martinsson, N. Rajala, L. Guittat, J. L. Campbell, J. N. Spelbrink, and S. A. Stewart Human Dna2 Is a Nuclear and Mitochondrial DNA Maintenance Protein Mol. Cell. Biol., August 1, 2009; 29(15): 4274 - 4282. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 U. Lakshmipathy and C. Campbell Antisense-mediated decrease in DNA ligase III expression results in reduced mitochondrial DNA integrity Nucleic Acids Res., February 1, 2001; 29(3): 668 - 676. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Coffey and C. Campbell An alternate form of Ku80 is required for DNA end-binding activity in mammalian mitochondria Nucleic Acids Res., October 1, 2000; 28(19): 3793 - 3800. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. Lundberg, M. Mavinakere, and C. Campbell Deficient DNA End Joining Activity in Extracts from Fanconi Anemia Fibroblasts J. Biol. Chem., March 16, 2001; 276(12): 9543 - 9549. [Abstract] [Full Text] [PDF]
|
|