The Neurospora mitochondrial genome: the region coding for the polycistronic cytochrome oxidase subunit I transcript is preceded by a transfer RNA gene.

We have sequenced a 682 bp fragment of Neurospora crassa mitochondrial DNA to complete the sequence between the gene for cytochrome b and the unassigned reading frame, URF U. The sequence contains a gene for a cysteine tRNA. The 5' end of the 6 kb polycistronic transcript of cytochrome c oxidase subunit 1 is immediately downstream from this tRNA. This shows that also in fungal mitochondria tRNAs can be used as processing signals, whereas palindromic sequences containing double Pst I sites, also present in this region, are not used for processing.