Linked Life Data

8921978

Source:http://linkedlifedata.com/resource/pubmed/id/8921978

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1996-12-18
pubmed:abstractText
Salmonella typhimurium, compared to Escherichia coli, is deficient in an inducible glycosylase activity harbouring only constitutive glycosylase functions. 3-Methyladenine-DNA glycosylase I encoded by the E. coli tag gene is a constitutively expressed repair enzyme that primarily removes N3-methyladenine but also N3-methylguanine from DNA by glycosylic cleavage in the first step of the base excision repair. In order to investigate in vivo effect of the overexpressed glycosylase I activity on survival capacity and mutation induction in S. typhimurium, and thereby elucidate the significance of both 3-methylpurines in cellular sensitivity to methylating agents (e.g., DMS), we transformed four his- S. typhimurium strains with the plasmid pCY5 carrying the E. coli tag gene under the control of the lac promoter. Although the 3-methyladenine-DNA glycosylase activity in cells carrying pCY5 was only 10-fold higher on exposure to IPTG compared to the TA1535 control strain carrying pUC8, the overexpression of the Tag protein completely suppressed deficiency in an inducible glycosylase activity, rendering cells resistance to toxic effects of DMS. The suppression was not influenced by the nucleotide excision repair pathway since there was no difference in recovered survival among NER-proficient and NER-deficient strains. The yield of mutation induction in the reversion assay was decreased to the level of spontaneous (his-->his+) revertant colonies showing that in the overall population in overexpressed conditions in vivo 3-methyl-guanine, in addition to 3-methyladenine, must have been removed from DNA by the E. coli Tag protein and therefore accounts for the second most important cytotoxic lesion.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/3-methyladenine, http://linkedlifedata.com/resource/pubmed/chemical/3-methyladenine-DNA glycosylase, http://linkedlifedata.com/resource/pubmed/chemical/3-methylguanine, http://linkedlifedata.com/resource/pubmed/chemical/Adenine, http://linkedlifedata.com/resource/pubmed/chemical/DNA Glycosylases, http://linkedlifedata.com/resource/pubmed/chemical/Guanine, http://linkedlifedata.com/resource/pubmed/chemical/Isopropyl Thiogalactoside, http://linkedlifedata.com/resource/pubmed/chemical/Mutagens, http://linkedlifedata.com/resource/pubmed/chemical/N-Glycosyl Hydrolases, http://linkedlifedata.com/resource/pubmed/chemical/Nitrosourea Compounds, http://linkedlifedata.com/resource/pubmed/chemical/Sulfuric Acid Esters, http://linkedlifedata.com/resource/pubmed/chemical/dimethyl sulfate
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0027-5107
pubmed:author
pubmed:issnType
Print
pubmed:day
28
pubmed:volume
358
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
81-7
pubmed:dateRevised
2004-11-17
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Effect of overexpression of E. coli 3-methyladenine-DNA glycosylase I (Tag) on survival and mutation induction in Salmonella typhimurium.
pubmed:affiliation
University of Zagreb, Faculty of Food Technology and Biotechnology, Laboratory of Biology and Microbial Genetics, Croatia.
pubmed:publicationType
Journal Article