DNA
microarray analysis reveals new aspects in diazaborine action and resistance.
Brigitte Pertschy,
Claudia Mikula, Helmut Bergler, Gregor Högenauer
IMBM, Karl-Franzens-University Graz, Universitätsplatz 2, Graz, 8010, Austria
(brigitte.pertschy@uni-graz.at)
Diazaborine is a heterocyclic boron containing compound which inhibits growth of Saccharomyces cerevisiae. Although it could be shown that allelic forms of several genes lead to resistance to diazaborine, the molecular targets of diazaborine have not been discovered yet. In order to gain a better insight into the action of diazaborine in yeast and to elucidate the mechanisms underlying diazaborine resistance, we performed a microarray time course study. Wild type yeast cells were grown in the presence of the inhibitor for 3 to 60 minutes and alterations in the transcription profiles were monitored. In addition, diazaborine resistant strains were analyzed and compared to the wild type strain. Interestingly, a few genes were already induced or repressed after 3 minutes of incubation with diazaborine. The number of genes induced and repressed was growing with time. In order to prevent signals from genes which are induced indirectly by protein factors synthesized in response to the drug, cycloheximide was added in combination with diazaborine in one experiment. Whereas early induced genes did not depend on protein synthesis, the induction of later responding genes often could be blocked by inhibition of translation. Diazaborine resistant mutants showed partly different reactions to diazaborine than the wild type strain, shedding light on the metabolic reactions taking place in yeast cells upon diazaborine incubation.