Journal Article

Contribution of ogt-encoded alkyltransferase to resistance to chloroethylnitrosoureas in nucleotide excision repair-deficient <i>Escherichia coli</i>

Nieves Abril, Francisco Ferrezuelo, Maria-Jose Prieto-Alamo, Joseph A. Rafferty, Geoffrey P. Margison and Carmen Pueyo

in Carcinogenesis

Volume 17, issue 8, pages 1609-1614
Published in print August 1996 | ISSN: 0143-3334
e-ISSN: 1460-2180 | DOI: http://dx.doi.org/10.1093/carcin/17.8.1609
Contribution of ogt-encoded alkyltransferase to resistance to chloroethylnitrosoureas in nucleotide excision repair-deficient Escherichia coli

More Like This

Show all results sharing this subject:

  • Clinical Cytogenetics and Molecular Genetics

GO

Show Summary Details

Preview

We investigated the relative contribution of the two Escherichia coli DNA alkyltransferases (ATases) to the increased sensitivity of ATase-deficient bacteria to the mutagenic and lethal effects of chloroethylnitrosoureas (CNU). The ogt-encoded protein was the principal determinant in resistance to the mutagenic effects of CNU in E.coli. Thus, only when the ogt gene was inactivated was sensitivity to mutagenesis greatly increased; the contribution of inactivation of the ada gene was relatively minor. Furthermore, induction of the adaptive response provided essentially no protection against CNU mutagenesis in either an ogt+ or ogt background. Finally, overexpression of the ogt gene into ogt ada double mutants provided the greatest protection against CNU; introduction of the full-length or truncated ada gene was protective, but to a much lesser extent. Mammalian ATases were not as protective against mutation induction by CNU as Ogt, even though they were apparently expressed at higher level. In order of effectiveness the ATases ranked Ogt > human > truncated Ada= Ada > rat. This order was not observed in the protection against killing by 1-(2-chloroethyl)-3-cyclohexy1–1-nitrosourea, where truncated Ada = human > Ogt > rat = Ada. Higher mutation frequency and toxicity were observed in uvr mutants, suggesting that one or more of the potentially mutagenic and/or toxic lesions are also substrates for the excision repair proteins.

Journal Article.  0 words. 

Subjects: Clinical Cytogenetics and Molecular Genetics

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.