COMPLETE ABSENCE OF MITOCHONDRIAL-DNA IN THE PETITE-NEGATIVE YEAST SCHIZOSACCHAROMYCES-POMBE LEADS TO RESISTANCE TOWARDS THE ALKALOID LYCORINE

The petite-positive yeast Saccharomyces cerevisiae can be efficiently and completely converted to respiratory-deficient cytoplasmic petite m utants by intercalating drugs. Rho(0) petites from Schizosaccharomyces pombe could only be obtained in strains carrying a nuclear mutation. In this paper we report the efficient isolation of rho(0) mutants in a Sch. pombe strain containing a mitochondrial mutator mutation. We als o show that the alkaloid lycorine is able to differentiate between cel ls containing defective mitochondrial DNA (mit(-)) and those lacking m itochondrial DNA completely (rho(0)). Rho(0) cells are resistant to th e alkaloid whereas mit(-) and wild-type cells show the same sensitivit y.