Selective Response of Ty1 Transposition Test to Carcinogens

M. PESHEVA1, O. KRASTANOVA1, R. STAMENOVA2, P. VENKOV2 and Tsv. TSVETKOV2
1Sofia University, Faculty of Biology, BG - 1421 Sofia, Bulgaria
2 Institute of Cryobiology and Food Technologies, BG - 1407 Sofia, Bulgaria

Abstract

PESHEVA, M., O. KRASTANOVA, R. STAMENOVA, P. VENKOV and Tsv. TSVETKOV, 2008. Selective response of Ty1 transposition test to carcinogens. Bulg. J. Agric. Sci., 14: 1-15

The Ty1 assay is a short-term test for detection of carcinogens based on induction the transposition of a gene-engineered Ty1 retrotransposon in Saccharomyces cerevisiae cells. Previously, we have shown that Ty1 transposition is induced to positive values of the Ty1 test by a number of laboratory carcinogens, including such that are undetectable by Salmonella, DEL or other short-term tests. Here, we provide evidence that the Ty1 test responds positively in concentration and kinetics experiments to the carcinogens 3-aminotriazole, formaldehyde, urethane, benz(a)pyrene, benz(a)anthracene, to the carcionogenic heavy metals arsenic, hexavalent chromium and to the carcinogenic free bile acids chenodeoxycholic and taurodeoxycholic acids. However, the Ty1 test gives negative values with the non-carcinogenic mutagens 5-bromuracil, benzo(e)pyrene, benz(b)anthracene and anthracene, with the heavy metals cadmium and threevalent chromium and the non-carcinogenic conjugated bile acids lythocholic and taurodeoxycholic acids. Results obtained by using the S. cerevisiae D7 test and the studied compounds make the involvement of enhanced gene conversion in the Ty1 test response not likely, and strongly suggest that the positive answer to treatment with carcinogens is due to enchanced Ty1 transposition. It is concluded that the Ty1 test shows a selective positive response to carcinogens and gives negative values with the studied non-carcinogenic mutagens.

Key words: Ty1 transposition, short-term test, carcinogens

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