Comparison of the Levels of the 21S Mitochondrial rRNA in Derepressed and Glucose-Repressed Saccharomyces cerevisiae

A cDNA preparation, synthesized by using Saccharomyces cerevisiae mitochondrial RNA as template and oligodeoxythymidylic acid as primer, was found to specifically hybridize to the mitochondrial 21S rRNA by the following criteria: (i) it hybridizes only to the 21S RNA species in mitochondrial RNA and not to RNA from a [rho0] mutant, and (ii) it hybridizes to fragments in restriction digests of mitochondrial DNA that contain the 21S rRNA gene but not to nuclear DNA. This cDNA was used as a probe to demonstrate that a 2.6-fold decrease in the cellular level of the mitochondrial large rRNA is associated with glucose repression of mitochondrial function in S. cerevisiae. A corresponding decrease in the level of mitochondrial DNA was not observed.