Rapeseed mitochondrial ccb206, a gene involved in cytochrome c biogenesis, is co-transcribed with the nad3 and rps12 genes: organization, transcription, and RNA editing of the nad3/rps12/ccb206 locus.
We describe here the structure and expression of the nad3/rps12/ccb206 locus in the mitochondrial genomes of rapeseed (Brassica napus L.) and related species. In the rapeseed mitochondrial genome there are three tandemly located open reading frames for subunit 3 of NADH dehydrogenase (nad3), the S12 subunit protein of the mitochondrial ribosome (rps12), and a homologue of one subunit of the ABC-heme transporter (ccb206). The gene organization of the nad3/rps12/ccb206 locus found in rapeseed mitochondria is not conserved in Arabidopsis thaliana mitochondria, where the ccb206 and nad3/rps12 loci are separated from each other. We show here that the rapeseed gene-organization pattern is also present in other Brassica species, but not in radish, a species very closely related to Brassica. Northern hybridization and RT-PCR analyses indicate that these three mitochondrial genes are possibly co-transcribed. Ten, seven, and 39 C-to-U RNA editing events occur in the rapeseed nad3, rps12, and ccb206 transcripts, respectively. Finally we show that codon position 21 of nad3 is edited in a highly species-specific manner among related Brassica species, including rapeseed and radish.
Itani
K
K
Laboratory of Plant Genecology, Hokkaido National Agricultural Experiment Station, 1, Hitsuji-ga-oka, Toyohira-ku, Sapporo 062-8555, Japan.
Handa
H
H
D018528:ATP-Binding Cassette Transporters / Q000235:genetics*; D000595:Amino Acid Sequence; D001483:Base Sequence; D001937:Brassica / Q000235:genetics*; D003001:Cloning, Molecular; D003574:Cytochrome c Group / Q000096:biosynthesis*; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D017343:Genes, Plant / Q000235:genetics; D008928:Mitochondria / Q000235:genetics*; D024101:Mitochondrial Proteins; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics*; D017393:RNA Editing / Q000235:genetics*; D017422:Sequence Analysis, DNA; D014158:Transcription, Genetic / Q000235:genetics
D018528:ATP-Binding Cassette Transporters; C116480:Ccb206 protein, Brassica napus; D003574:Cytochrome c Group; D024101:Mitochondrial Proteins; D010940:Plant Proteins; C103919:Rps12 protein, plant