Ty1 transposition induced by carcinogens in Saccharomyces cerevisiae yeast depends on mitochondrial function.

The transposition of the Ty mobile genetic element of Saccharomyces cerevisiae is induced by carcinogens. While the molecular background of spontaneous Ty1 transposition is well understood, the detailed mechanism of carcinogen induced Ty1 transposition is not clear. We found that mitochondrial functions participate in the Ty induced transposition induced by carcinogens. Contrary to the parental rho+ cells rho− mutants (spontaneous or induced by ethidium bromide) do not increase the rate of Ty1 transposition upon treatment with carcinogens. Preliminary results strongly suggest that the absence of oxidative phosphorylation in rho− mutants is the reason for the inhibited Ty transposition. The lack of carcinogen induced Ty1 transposition in rho− cells is not specific for a particular carcinogen and represents a general feature of different carcinogenic substances inducing rho−. It is concluded that carcinogen induced Ty1 transposition depends on the functional state of mitochondria and cannot take place in cells with compromised mitochondrial function (rho−).