Direct mutagenesis of Ha-ras-1 oncogenes by N-nitroso-N-methylurea during initiation of mammary carcinogenesis in rats

Helmut Zarbl, Saraswati Sukumar, Anne V. Arthur, Dionisio Martin-Zanca, Mariano Barbacid

Research output: Contribution to journalArticle


Induction of mammary carcinomas in rats by a single exposure to a carcinogen during sexual development often involves malignant activation of the Ha-ras-1 locus. Each of the Ha-ras-1 oncogenes present in tumours induced by N-nitroso-N-methylurea, but not in those induced by 7,12-dimethylbenz(a) anthracene, became activated by the same G → A transition, the type of mutation induced by N-nitroso-N-methylurea. These results are consistent with the notion that Ha-ras-1 oncogenes are directly activated by the carcinogen during initiation of neoplasia.

Original languageEnglish (US)
Pages (from-to)382-385
Number of pages4
Issue number6018
Publication statusPublished - 1985
Externally publishedYes


ASJC Scopus subject areas

  • General

Cite this