DNA topoisomerase II as primary cellular target for salvicine in Saccharomyces cerevisiae

AIM: To identify whether DNA topoisomerase II (Topo II) is the primary cell ular target of salvicine in Saccharomyces cerevisiae (S cerevisiae) and the action mode of salvicine. METHODS: The catalytic activity of Topo II was d etermined by Topo II mediated supercoiled pBR322 relaxation. The effects of salvicine on the growth of four strains of S cerevisiae were assessed by c lone forming assay. RESULTS: Salvicine inhibited Topo II mediated supercoil ed pBR322 relaxation in cell-free system. Cytotoxicities of salvicine to pa rent (JN394) and TOPI deleted (JN394top1(-)) yeast cells were at the same l evel, suggesting Topo I might not be the cellular target of salvicine. Salv icine displayed high activity against JN394t2-1 cells at 25 degreesC, while no growth inhibition was observed at 30 degreesC in the concentration rang e of interest. Furthermore, JN394t2-5 cells which expressed top2-5 mutant a llele were highly resistant to salvicine and etoposide (VP16). CONCLUSION: Topo II was the primary cellular target of salvicine in vivo and salvicine killed yeast cells mainly by trapping the DNA-Topo II cleavage complex. Sal vicine and might share some similar action locus on Topo II.