Expression of a nuclear-encoded psbH gene complements the plastidic RNA processing defect in the PSII mutant hcf107 in Arabidopsis thaliana.

摘要: Summary The helical-repeat RNA-binding protein HCF107 is required for processing, stabilization and translation of plastid-encoded psbH mRNA. The gene encodes a small, hydrophilic subunit the PSII complex part plastidic psbB–psbT–psbH–petB–petD transcription unit. In Arabidopsis hcf107 mutants, only trace amounts proteins can be detected. Beside drastically reduced synthesis PsbH, CP47 was also in these although corresponding psbB transcripts accumulate to wild type levels. This situation raises question, whether reduction direct consequence mutation, based on targeting mRNA, or secondary affect due absent PsbH. To clarify this issue we introduced chimeric construct comprising sequence encoding chloroplast transit peptide into hcf107-2 background. We found that nucleus-localized able complement mutant defect resulting photoautotrophic plants. D1 accumulated barely half level. Further experiments showed cytosolically synthesized PsbH imported chloroplasts assembled complexes. Using approach, tetratricopeptide repeat responsible expression not CP47. addition data suggest necessity one-helix membrane spanning accumulation higher