MITOCHONDRIAL-DNA SEQUENCE-ANALYSIS OF THE CYTOCHROME-OXIDASE SUBUNIT-II GENE FROM PODOSPORA-ANSERINA - A GROUP-IA INTRON WITH A PUTATIVE ALTERNATIVE SPLICE SITE

A 5 kb region of the 95 kb mitochondrial genome of Podospora anserina race s has been mapped and sequenced (1 kb = 103 base-pairs). This DNA region is continuous with the sequence for the ND4L and ND5 gene complex in the accompanying paper. We show that this sequence contains the gene for cytochrome oxidase subunit II (COII). This gene is 4 kb in length and is interrupted by a subgroup IB intron (1267 base-pairs (bp) in length) and a subgroup IA intron (1992 bp in length). This group IA intron has a long open reading frame (ORF; 472 amino acid residues) discontinuous with the upstream exon sequence. A putative alternative splice site is present, which brings the ORF into phase with the 5′ exon sequence. The 5′- and 3′-flanking regions of the COII gene contain G + C-rich palindromic sequences that resemble similar sequences flanking many Neurospora crassa mitochondrial genes. © 1990.