Mitochondrial transcription and processing of transcripts during release from glucose repression in 'resting cells' of Saccharomyces cerevisiae.

Mitochondrial transcription and processing of transcripts have been investigated at different stages of release from glucose repression in resting cells of Saccharomyces cerevisiae. Transcripts were identified by hybridization with nick-translated or terminally labelled gene-specific probes. This allowed the determination of the steady-state levels of individual transcripts in the mitochondrial RNA population. Results showed different gene-specific patterns of response to respiratory induction: no increase in the level of transcripts (oxi2); a rapid increase in the steady-state levels of all transcripts (cob); a very strong increase in the processing of the high-molecular-mass precursors (oxi3 and oli2); an increase in the level of stable circular transcripts (oxi3). As a whole the results indicate specific and differentiated effects of release from glucose repression on the expression of the different mitochondrial genes and demonstrate the importance of processing events in mitochondrial regulation.