In Vivo Analyses of the Roles of Essential Omp85-Related Proteins in the Chloroplast Outer Envelope Membrane

摘要: Two different, essential Omp85 (Outer membrane protein, 85 kD)-related proteins exist in the outer envelope of Arabidopsis (Arabidopsis thaliana) chloroplasts: Toc75 (Translocon at chloroplasts, 75 kD), encoded by atTOC75-III; and OEP80 Envelope Protein, 80 AtOEP80/atTOC75-V. The atToc75-III protein is closely related to originally identified pea (Pisum sativum) it forms a preprotein translocation channel during chloroplast import; AtOEP80 considerably more divergent from Toc75, its role unknown. As knockout mutations for atTOC75-III are embryo lethal, we employed dexamethasone-inducible RNA interference strategy (using pOpOff2 vector) conduct vivo studies on roles these two older, postembryonic plants. We conducted comparative plants silenced (atToc75-III↓) or (AtOEP80↓), as well additional stable, missense allele (toc75-III-3/modifier altered response gravity1), our results indicated that both important biogenesis stages development. Moreover, photosynthetic nonphotosynthetic development, albeit different degrees: atToc75-III↓ phenotypes were severe than those AtOEP80↓. Qualitative similarity between AtOEP80↓ may be linked deficiencies other TOC Detailed analysis plants, electron microscopy, immunoblotting, quantitative proteomics, import assays, defective relation plastids preproteins, confirming earlier hypothesis functions promiscuously substrate-specific pathways.