RNA synthesis and control of cell division in the yeast S. cerevisiae

Cells of the yeast Saccharomyces cerevisiae rapidly accumulated in the G1 phase of the cell cycle when exposed to the chelating agents o-phenanthroline (OP) or 8-hydroxyquinoline (HQ). Zinc salts fully reversed the growth-inhibitory effect of both OP and HQ. Cells treated with these chelating agents showed limited RNA accumulation and little RNA degradation. Rates of RNA synthesis were drastically reduced by low concentrations of these compounds. Whereas rates of protein synthesis were essentially unaffected. Rates of synthesis of mRNA and tRNA were less affected than were rates of synthesis of high molecular weight RNA. Processing of ribosomal precursor RNA was altered. these results suggest that the primary effect of OP and HQ is on rRNA synthesis. RNA metabolism must therefore have a key role in the regulation of the cell cycle.