Split gene for mitochondrial 24S ribosomal RNA of Neurospora crassa

Abstract

The 60 kb circular mitochondrial genome of N. crassa has previously been shown to contain a single transcription unit for 17S and 24S rRNA mapping within the largest Eco RI fragment E1 (19.6 kb). This fragment was isolated from uncloned mitochondrial DNA and further analyzed by cleavage with restriction endonucleases Hind II, Hind III, Bam HI, Pvu II and BgI I, and by electron microscopy of rRNA/DNA hybrids. The resulting map shows a 2.3 kb intervening sequence interrupting the gene for 24S rRNA. The main part (2.7 kb) of this gene is separated from the 17S rRNA gene by a 5 kb segment which contains several transfer RNA genes. This segment is much longer than the putative 1 kb spacer sequence within the 32S precursor molecule for both rRNAs, suggesting a second splicing event in that region.