SYMMETRICAL TRANSCRIPTION IN THE TRANSFER-RNA REGION OF THE MITOCHONDRIAL GENOME OF SACCHAROMYCES-CEREVISIAE

The occurrence of discrete transcripts originating from the non-coding strand of the yeast mitochondrial genome is described. The region und er investigation is localized in the large tRNA gene cluster between t he LSU ribosomal RNA and OXI 1 genes. The transcripts originating from the non-coding strand were detected in a wild-type strain and in a rh o- mutant. Their size range includes transcripts of about 2000 nucleot ides able to accommodate more than one ''anti-tRNA''. In some cases th eir extremities can be mapped near highly-conserved nonanucleotides th at could function as origins of transcription. The involvement of the tRNA-processing machinery in the cleavage of these transcripts is also hypothesized.