RRC ID 1759
Author Asakura Y, Barkan A.
Title Arabidopsis orthologs of maize chloroplast splicing factors promote splicing of orthologous and species-specific group II introns.
Journal Plant Physiol.
Abstract Chloroplast genomes in plants and green algae contain numerous group II introns, large ribozymes that splice via the same chemical steps as spliceosome-mediated splicing in the nucleus. Most chloroplast group II introns are degenerate, requiring interaction with nucleus-encoded proteins to splice in vivo. Genetic approaches in maize (Zea mays) and Chlamydomonas reinhardtii have elucidated distinct sets of proteins that assemble with chloroplast group II introns and facilitate splicing. Little information is available, however, concerning these processes in Arabidopsis (Arabidopsis thaliana). To determine whether the paucity of data concerning chloroplast splicing factors in Arabidopsis reflects a fundamental difference between protein-facilitated group II splicing in monocot and dicot plants, we examined the mutant phenotypes associated with T-DNA insertions in Arabidopsis genes encoding orthologs of the maize chloroplast splicing factors CRS1, CAF1, and CAF2 (AtCRS1, AtCAF1, and AtCAF2). We show that the splicing functions and intron specificities of these proteins are largely conserved between maize and Arabidopsis, indicating that these proteins were recruited to promote the splicing of plastid group II introns prior to the divergence of monocot and dicot plants. We show further that AtCAF1 promotes the splicing of two group II introns, rpoC1 and clpP-intron 1, that are found in Arabidopsis but not in maize; AtCAF1 is the first splicing factor described for these introns. Finally, we show that a strong AtCAF2 allele conditions an embryo-lethal phenotype, adding to the body of data suggesting that cell viability is more sensitive to the loss of plastid translation in Arabidopsis than in maize.
Volume 142(4)
Pages 1656-63
Published 2006-12
DOI 10.1104/pp.106.088096
PII pp.106.088096
PMID 17071648
PMC PMC1676066
MeSH Arabidopsis / anatomy & histology Arabidopsis / genetics* Arabidopsis / metabolism Arabidopsis Proteins / genetics Arabidopsis Proteins / metabolism Arabidopsis Proteins / physiology* Chloroplasts / genetics* Chloroplasts / metabolism Genome, Plant Introns* Mutagenesis, Insertional Phenotype Plant Proteins / genetics Plant Proteins / metabolism Plant Proteins / physiology RNA Splicing* RNA Splicing Factors RNA, Messenger / metabolism Seedlings / anatomy & histology Seedlings / genetics Seedlings / metabolism Species Specificity Zea mays / genetics Zea mays / metabolism
IF 6.305
Times Cited 69