Arabidopsis Mitochondrial Transcription Termination Factor mTERF2 Promotes Splicing of Group IIB Introns

Members of the mitochondrial transcription termination factor (mTERF) family regulate gene expression in chloroplasts and/or mitochondria at different steps. Here, we investigated the molecular function of chloroplast-localized mTERF2 in Arabidopsis thaliana. Loss-of-function mterf2 mutants are embryo lethal. Thus, artificial microRNA-mediated mterf2 knockdown plants were generated. In amiR-mterf2 mutants, plant development is perturbed and chlorophyll content reduced. A defect in photosynthesis is accompanied by reduced levels of photosystem subunits, although corresponding messenger RNA levels are unaffected. RNA immunoprecipitation followed by RNA sequencing (RIP-Seq) experiments combined with whole-genome RNA-Seq, RNA gel-blot and quantitative RT-PCR analyses revealed the requirement of mTERF2 for splicing of the group IIB introns of ycf3 (intron 1) and rps12. Overall design: Examination of differential gene expression in the Arabdidopsis thaliana artificial micro RNA generated mterf2 knock-down mutant compared to wild type in three replicates