title: Sequence and organization of a 7.2 kb region of wheat mitochondrial DNA containing the large subunit (26S) rRNA gene.
abstract: We report the sequence of a 7.2 kilobase pair DNA fragment containing a copy of the wheat mitochondrial gene (rrn26) that encodes the mitochondrial large-subunit ribosomal RNA (26S rRNA). The mature 26S rRNA was determined by direct RNA sequencing to be 3467 nucleotides long, and to share a 5'-terminal pentanucleotide (5'-AUCAU), thought to be important in post-transcriptional processing, with the wheat mitochondrial small-subunit (18S) rRNA. Two other prominent features of the sequence were noted. First, upstream of rrn26 are located two tandem copies of a 70 base pair element containing a putative mitochondrial promoter motif (TCGTATAAAAA). Second, downstream of rrn26 is a sequence element that, if transcribed, would produce an RNA with a secondary structure resembling that of tRNAs but differing sufficiently from the latter structure to preclude any transcript from functioning normally in translation. These upstream and downstream sequence elements may play a role in the expression of rrn26 in wheat mitochondria.
authors.affiliation: Department of Biochemistry, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: D F
authors.initials: DF
authors.lastname: Spencer
authors.forename: M N
authors.initials: MN
authors.lastname: Schnare
authors.forename: M B
authors.initials: MB
authors.lastname: Coulthart
authors.forename: M W
authors.initials: MW
authors.lastname: Gray
mesh_terms: D001483:Base Sequence; D004272:DNA, Mitochondrial / Q000235:genetics*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012335:RNA, Ribosomal / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D014908:Triticum / Q000235:genetics*
chemical_list: D004272:DNA, Mitochondrial; D012335:RNA, Ribosomal; C065096:RNA, ribosomal, 26S