Characterization of a yeast mitochondrial promoter by deletion mutagenesis.

We have generated collections of mutants of the promoter for the small rRNA gene from the mitochondria of yeast deleted from either the 3' or 5' end. Plasmids containing the partially deleted promoter were assayed for their ability to direct correct transcriptional initiation in a homologous in vitro system. We find that the region required for high-efficiency promoter function lies between positions -10 and +2. Our methods detected no effect of flanking sequences on the strength of this promoter.