The SLO1 PPR protein is required for RNA editing at multiple sites with similar upstream sequences in Arabidopsis mitochondria.
In Arabidopsis, RNA editing changes more than 500 cytidines to uridines in mitochondrial transcripts. The editing enzyme and co-factors involved in these processes are largely unknown. We have identified a nuclear gene SLOW GROWTH1 (SLO1) encoding an E motif-containing pentatricopeptide repeat protein that is required for RNA editing of nad4 and nad9 in Arabidopsis mitochondria. The SLO1 protein is localized to the mitochondrion, and its absence gives rise to small plants with slow growth and delayed development. A survey of approximately 500 mitochondrial RNA editing sites in Arabidopsis reveals that the editing of two sites, nad4-449 and nad9-328, is abolished in the slo1 mutants. Sequence comparison in the upstream (from -1 to -15 bp) of nad4-449 and nad9-328 editing sites shows that nine of the 15 nucleotides are identical. In addition to RNA editing, we used RNA gel blot analysis to compare the abundance and banding patterns of mitochondrial transcripts between the wild type and slo1 mutants. Of the 79 genes and open reading frames examined, steady-state levels of 56 mitochondrial transcripts are increased in the slo1 mutants. These results suggest that the SLO1 protein may indirectly regulate plant growth and development via affecting mitochondrial RNA editing and gene expression.
Sung
Tzu-Ying
TY
Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan.
Tseng
Ching-Chih
CC
Hsieh
Ming-Hsiun
MH
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics*; D020869:Gene Expression Profiling; D017343:Genes, Plant; D008928:Mitochondria / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D017393:RNA Editing; D017386:Sequence Homology, Amino Acid
D029681:Arabidopsis Proteins