Finally, we identified the nucleotide targets of MTHI1. RESULTS Lack of MTHI1 Leads to the Reduced Accumulation and Translation of mRNA We recovered a photosynthetic mutant, kindly provided by Rachel Teneligliptin Dent, generated by insertional mutagenesis with a paromomycin resistance cassette (Dent et al., 2005), originally called CAL014.01.38. whose product is required for the Maturation/stability and Translation of the and mRNAs, and the mutation was renamed and genes in mutants. In this study, we characterized the MTHI1 OPR protein, a protein that is critical for the biogenesis of the chloroplast ATP synthase CFo. We showed that this protein controls the accumulation and translation of mRNA, encoding a subunit of the selective proton channel, and enhances the translation of mRNA, which encodes the other subunit of the channel. Finally, we identified the nucleotide targets of MTHI1. RESULTS Lack of MTHI1 Leads to the Reduced Accumulation and Translation of mRNA We recovered a photosynthetic mutant, kindly provided by Rachel Dent, generated by insertional mutagenesis with a paromomycin resistance cassette (Dent et al., 2005), originally called CAL014.01.38. This mutant shows the same phenotype as Teneligliptin mRNA, hence AtpH synthesis (Physique 1C) and accumulation of all subunits of the ATP synthase complex (Physique 1B). In addition, it shows a strongly reduced synthesis of AtpI in 14C pulse-labeling experiments (Physique 1C). Therefore, we renamed this mutant Mutants. (A) Schematic representation of the (top) and (bottom) transcription models. CDSs are shown as thick rectangles, while 5 UTRs are depicted as thin rectangles. Bent arrows represent promoters. The major transcripts detected in (C) with probes specific to or are indicated. (0) represents a precursor transcript that cannot be observed in the wild type because it is usually efficiently processed but can be detected in mutants. Total cell extracts of wild type (WT; a dilution series is usually shown) and the two mutant strains were probed with antibodies against the proteins indicated around the left. The accumulation of all ATP synthase subunits was dramatically reduced in the two mutant strains, while that of cytochrome (cyt. complex, PSI, and PSII, respectively) was unaffected. The red asterisk points to a cross-reaction of the antibody, preserved in the mutant strains, against the subunit of mitochondrial ATP synthase. (C) (Top) Accumulation of the and transcripts in the same strains, assessed by RNA gel blots. The transcript is usually provided as a loading control. (Bottom) Rate of translation of ATP synthase subunits in the same strains, assessed by 5 pulse-labeling experiment in the presence of 14C acetate (5 Ci mL?1) and cycloheximide, an inhibitor of cytosolic translation (10 g mL?1). The positions of the AtpI and AtpH subunits are indicated. WT, wild type. (D) Quantification of transcripts amount (se) in wild-type (WT) and mutant strains estimated from RNA gel blots similar to the representative blot shown in (C). (Left) Relative accumulation (rel accum.) of the four transcript. (Right) Relative Teneligliptin abundance of each transcript, and Teneligliptin the sum of them, compared with that of the same band in the wild type (set to 100, symbolized by a gray dashed line) in the two Mouse monoclonal to CDH2 mutants (dark gray, = 4). The reduced synthesis of AtpI prompted us to monitor the accumulation of its transcript in mutants. The gene belongs to a polycistronic transcription unit that comprises a gene encoding the PSII D2 protein ((apoprotein of complex Chlorophyll-Protein I), (PSI subunit), and ribosomal protein Rps12 (transcripts, including the tetra-,.