Expression of CMS-unique and flanking mitochondrial DNA sequences in Phaseolus vulgaris L.
The expression of mitochondrial DNA sequences unique to a cytoplasmically male-sterile (CMS) line of Phaseolus vulgaris was investigated. RNA-blot hybridizations with strand-specific probes demonstrated CMS-unique transcripts (7.0, 6.8, 4.7, 3.3 and 2.8 kb) to be in the sense orientation with respect to the longest open reading frames within the CMS-unique region. Hybridizations revealed co-transcription of CMS-unique and upstream, atpA-coding sequences to generate the 6.8-kb RNA. However, hybridizations with CMS-unique and flanking DNA probes accounted for only 4.9 kb of the longest and most abundant (7.0 kb) CMS-unique transcript, providing indirect evidence for the involvement of a splicing process in the generation of this transcript. Sedimentation experiments demonstrated the association of 7.0- and 6.8-kb CMS-unique transcripts with polyribosomes in seedlings and floral buds of a CMS line and a line restored to fertility by the nuclear gene Fr2. However, steady-state levels of the 7.0- and 6.8-kb transcripts were decreased in the restored line relative to the CMS line.
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Horticultural Sciences Department, University of Florida, Gainesville 32611.
D004272:DNA, Mitochondrial / Q000235:genetics*; D005111:Extrachromosomal Inheritance; D007887:Fabaceae / Q000235:genetics*; D005298:Fertility / Q000235:genetics; D005786:Gene Expression Regulation; D017343:Genes, Plant; D009693:Nucleic Acid Hybridization; D016366:Open Reading Frames; D010935:Plant Diseases / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics; D010946:Plants, Medicinal; D006180:Proton-Translocating ATPases / Q000235:genetics; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
D004272:DNA, Mitochondrial; D010940:Plant Proteins; D012333:RNA, Messenger; D006180:Proton-Translocating ATPases