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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2011-2-25
pubmed:abstractText
Thermus thermophilus is an extremely thermophilic eubacterium that grows optimally at 70-75°C. It does not have a gene encoding O(6)-alkylguanine-DNA alkyltransferase (AGT) for the repair of O(6)-methylguanine (O(6)-meG), but it has a homologous gene atl encoding alkyltransferase-like (ATL) proteins in which the cysteine residue in the active site of the PCHR motif conserved in AGT is replaced by alanine (i.e. lack of methyltransferase activity). To investigate the role of ATL protein in the repair of O(6)-meG, we isolated atl deletion mutants and measured specific G:C?A:T transition mutations induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) by a His(+) reversion system at the hisD3110 locus. MNNG caused an increased mutation frequency in the atl-deficient mutant but a significantly higher frequency increase in a uvrA mutant, which is deficient in nucleotide excision repair (NER), indicating that both ATL protein and NER played an important role in preventing G:C?A:T transitions. We observed no difference in MNNG sensitivity between the uvrA atl double mutant and the parent uvrA strain. Our results support a recently proposed repair model in which ATL protein acts as a sensor of O(6)-meG damage and recruits UvrA protein to repair the lesion via an NER system. In addition, the finding that the uvrA atl strain mutated with greater frequency than the single atl strain suggests that O(6)-meG is repaired by NER in the absence of ATL protein. We also discuss the possible association of a transcription-repair coupling factor in a transcription-coupled repair pathway and of MutS protein in a mismatch repair pathway with ATL/NER-mediated repair of O(6)-meG.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
1464-3804
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
26
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
303-8
pubmed:meshHeading
pubmed:year
2011
pubmed:articleTitle
Role of alkyltransferase-like (ATL) protein in repair of methylated DNA lesions in Thermus thermophilus.
pubmed:affiliation
Department of Environmental Genomics, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't