Linked Life Data

15474419

Source:http://linkedlifedata.com/resource/pubmed/id/15474419

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
2004-10-11
pubmed:abstractText
The 3,N(4)-ethenocytosine (epsilon C) residue might have biological role in vivo since it is recognized and efficiently excised in vitro by the E. coli mismatch-specific uracil-DNA glycosylase (MUG) and the human thymine-DNA glycosylase (hTDG). In the present work we have generated mug defective mutant of E. coli by insertion of a kanamycin cassette to assess the role of MUG in vivo. We show that human TDG complements the enzymatic activity of MUG when expressed in a mug mutant. The epsilon C-DNA glycosylase defective strain did not exhibit spontaneous mutator phenotype and did not show unusual sensitivity to any of the following DNA damaging treatments: methylmethanesulfonate, N-methyl-N'-nitro-N-nitrosoguanidine, ultraviolet light, H(2)O(2), paraquat. However, plasmid DNA damaged by 2-chloroacetaldehyde treatment in vitro was inactivated at a greater rate in a mug mutant than in wild-type host, suggesting that MUG is required for the in vivo processing of the ethenobases. In addition, 2-chloroacetaldehyde treatment induces preferentially G.C --> C.G and A.T --> T.A transversions in mug mutant. Comparison of the mutation frequencies induced by the site-specifically incorporated epsilon C residue in E. coli wild-type versus mug indicates that MUG repairs more than 80% of epsilon C residues in vivo. Furthermore, the results show that nucleotide excision repair and recombination are not involved in the processing of epsilon C in E. coli. Based on the mutagenesis data we suggest that epsilon C may be less toxic and less mutagenic than expected. The increased spontaneous mutation rate for G.C --> A.T transition in the ung mug double mutant as compared to the single ung mutant suggest that MUG may be a back-up repair enzyme to the classic uracil-DNA glycosylase.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
1568-7864
pubmed:author
pubmed:issnType
Print
pubmed:day
2
pubmed:volume
3
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1579-90
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Role of mismatch-specific uracil-DNA glycosylase in repair of 3,N4-ethenocytosine in vivo.
pubmed:affiliation
Groupe Réparation de l'AND, CNRS UMR 8113, LBPA-ENS Cachan, Institut Gustave Roussy, 39 rue Camille Desmoulins, 94805 Villejuif Cedex, France.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't