Karpinska, Barbara; Karpinski, Stanislaw ; Hallgren, Jan-erik

THE CHLB GENE ENCODING A SUBUNIT OF LIGHT-INDEPENDENT PROTOCHLOROPHYLLIDE REDUCTASE IS EDITED IN CHLOROPLASTS OF CONIFERS

ChlB is one of three chloroplast genes shown so far to be required for light-independent chlorophyll synthesis. It occurs in some algae, lower plants, and gymnosperms, but not in angiosperms. We have demonstrated, for the first time in conifer chloroplasts, the presence of two internal C to U editing sites in this transcript. In the chlB transcript of Pinus sylvestris, the editing of the second position in a CCG codon leads to an amino-acid substitution from proline to leucine. Editing of a nearby CGG codon, resulting in an arginine to tryptophan substitution, has also been observed. The nucleotide sequence of this region has been compared with other species of gymnosperms. Out of seven species analysed, editing at both sites has only been detected in spruce, while in Larix only the editing which results. in the Arg to Trp substitution was found. In other cases, both leucine and tryptophan are encoded by cpDNA, suggesting that conservation of these amino acids, through encoding by DNA or by editing of the RNA, is critical for the protein function. Transcripts are partially edited at the CGG codon and the relative abundance of cDNA molecules with the edited C is species-specific. The possible involvement of RNA editing in the regulation of gene expression in different organs of pine seedlings is discussed.

Pubmed ID: 9108142

Keywords: Larix chinensisPLarix chinensisILarix chinensisNLarix chinensisULarix chinensisSLarix chinensis, Larix chinensisELarix chinensisSLarix chinensisTLarix chinensis, Larix chinensisSLarix chinensisPLarix chinensisRLarix chinensisULarix chinensisCLarix chinensisELarix chinensis, Larix chinensisNLarix chinensisULarix chinensisCLarix chinensisLLarix chinensisELarix chinensisOLarix chinensisTLarix chinensisILarix chinensisDLarix chinensisELarix chinensis, Larix chinensisDLarix chinensisNLarix chinensisALarix chinensis, Larix chinensisLLarix chinensisALarix chinensisRLarix chinensisILarix chinensisXLarix chinensis, Larix chinensisRLarix chinensisNLarix chinensisALarix chinensis, Larix chinensisCLarix chinensisOLarix chinensisNLarix chinensisILarix chinensisFLarix chinensisELarix chinensisRLarix chinensis, Larix chinensisPLarix chinensisILarix chinensisNLarix chinensisULarix chinensisSLarix chinensis Larix chinensisSLarix chinensisYLarix chinensisLLarix chinensisVLarix chinensisELarix chinensisSLarix chinensisTLarix chinensisRLarix chinensisILarix chinensisSLarix chinensis, Larix chinensisCLarix chinensisDLarix chinensisNLarix chinensisALarix chinensis, Larix chinensisGLarix chinensisELarix chinensisNLarix chinensisELarix chinensis Larix chinensisELarix chinensisXLarix chinensisPLarix chinensisRLarix chinensisELarix chinensisSLarix chinensisSLarix chinensisILarix chinensisOLarix chinensisNLarix chinensis, Larix chinensisPLarix chinensisILarix chinensisNLarix chinensisELarix chinensis

Supplemental Data:
→ Nucleotide Data (14)
→ Protein Data (7)
→ Sequence Data (84)

Current Genetics, 1997; Vol 31(4) : 343 - 347