EMB2794, a mitochondrial PPR protein required for splicing of nad2 intron 2 in Arabidopsis thaliana

CAINZOS MAXIMILIANO; BRENNICKE AXEL; ZABALETA, EDUARDO; CORDOBA JUAN PABLO; OSTERSETZER OREN; MARCHETTI, FERNANDA; TAKENAKA M; PAGNUSSAT, GABRIELA C

Buenos Aires

Congreso; Latin American Society for Developmental Biology Meeting 2019, LASBD; 2019

LASBD

The Arabidopsis genome encodes 458 genes containing the pentatricopeptide repeat (PPR) motif. The PPR proteins are classified into two groups, termed as P and PLS classes. Typically, the PLS-class proteins are mainly involved in the RNA editing of mitochondrial and chloroplast transcripts, whereas most of the analyzed P-class proteins have been assigned to other RNA-processing events as splicing, trimming and stability. Many embryo-lethal mutants in Arabidopsis are related to disruption of different PPR genes, but only a few have been characterized in detail. We study EMB2794 gene, which encodes a P-class PPR protein. Null mutations in this gene result in embryo lethal phenotype, and we show that it is due to altered splicing of nad2 transcripts in Arabidopsis mitochondria. Biochemical analyses further indicate that recombinant EMB2794 binds to both nad2 immature transcripts, which is most likely important to the trans-splicing of these particular pre-RNA transcripts. Homozygous lines show embryo-defective phenotype and can be partially rescued by the addition of sucrose to the growth medium. The rescued homozygous plants contain only traces of complex I, which lack NADH-dehydrogenase activity.