ISSN:
1617-4623
Keywords:
Flowering plants
;
Mitochondria
;
RNA editing
;
nad3-rps12 locus
;
Co-transcription
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The organization of the genesnad3 andrps12 has been investigated in the mitochondrial genome of two dicotyledonous plants —Helianthus andMagnolia — and one monocotyledonous plant (Allium). These plants all contain a completerps12 gene downstream of thenad3 gene. This arrangement is thus highly conserved within angiosperms. The two genes are co-transcribed and the transcript is modified at several positions by RNA editing of the C to U-type, thus confirming that both genes encode functional proteins. Some 26, 35 and 27 editing events have been identified in the PCR-derivednad3-rps12 cDNA population from sunflower,Magnolia and onion, respectively. Editing of thenad3-rps12 transcript is thus more extensive inMagnolia than in the other angiosperms so far investigated and radically changes the genomically encoded polypeptide sequence. A novel species-specific codon modification was observed inMagnolia. Several homologous sites show differences in editing pattern among plant species. A C-to-U alteration is also found in the non-coding region separating thenad3 andrps12 genes in sunflower. The PCR-derived cDNA populations from thenad3-rps12 loci analysed were found to be differently edited. In addition the plant species show marked variations in the completeness of RNA editing, with only theMagnolia nad3 mRNA being edited fully.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02172523
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