title: Processing followed by complete editing of an altered mitochondrial atp6 RNA restores fertility of cytoplasmic male sterile rice.
abstract: Two atp6 genes were found in the mitochondrial genome of cytoplasmic male sterile (CMS) rice carrying the [cms-bo] cytoplasm. One (N-atp6) was identical to the normal cytoplasmic gene, while the second (B-atp6) was identified as a candidate CMS gene by Southern analysis of the mitochondrial genome of CMS cybrid rice. The coding sequence of B-atp6 was identical to the normal N-atp6 gene but its 3'-flanking sequence was different starting at 49 bases downstream from the stop codon. Northern analysis showed that B-atp6 is transcribed into a 2.0 kb RNA in the absence of the Rf-1 gene, whereas two discontinuous RNAs, of approximately 1.5 and 0.45 kb, were detected in the presence of the Rf-1 gene. Determination of the 3' and 5' ends of these RNAs suggested that the two discontinuous RNAs were generated from the 2.0 kb RNA by RNA processing at sites within the B-atp6-specific sequences by the action of the Rf-1 gene. Sequence analysis of cDNA clones derived from the N-atp6 RNA and the processed and unprocessed RNAs of B-atp6 indicated that the processed B-atp6 RNAs were edited as efficiently as the N-atp6, whereas unedited and partially edited RNAs were detected among unprocessed RNAs. RNA processing by Rf-1 thus influences the sequential post-transcriptional editing of the B-atp6 RNAs. Because the unprocessed RNAs of B-atp6 are possibly translated into altered polypeptides, our results suggest that interaction of RNA processing and editing plays a role in controlling CMS expression and the restoration of fertility in rice.
authors.affiliation: Plantech Research Institute, Yokohama, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Iwabuchi
authors.forename: J
authors.initials: J
authors.lastname: Kyozuka
authors.forename: K
authors.initials: K
authors.lastname: Shimamoto
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D015870:Gene Expression; D017343:Genes, Plant; D007246:Infertility / Q000235:genetics; D008928:Mitochondria / Q000502:physiology*; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D012275:Oryza / Q000235:genetics*; D006180:Proton-Translocating ATPases / Q000235:genetics*; D012313:RNA / Q000235:genetics / Q000378:metabolism*; D017393:RNA Editing; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000235:genetics; D015183:Restriction Mapping; D016415:Sequence Alignment
chemical_list: D009838:Oligodeoxyribonucleotides; D012333:RNA, Messenger; D012313:RNA; D006180:Proton-Translocating ATPases