A DYW‐protein knockout in Physcomitrella affects two closely spaced mitochondrial editing sites and causes a severe developmental phenotype. (10th September 2013)

• Record Type: Journal Article
• Authors: Schallenberg‐Rüdinger, Mareike; Kindgren, Peter; Zehrmann, Anja; Small, Ian; Knoop, Volker
• Is Part Of: Plant journal. Volume 76:Number 3(2013:Nov.)
• Page Start: 420
• Page End: 432
• Publication Date: 2013-09-10
• Subjects: Plant molecular biology -- Periodicals; Plant cells and tissues -- Periodicals; Botany -- Periodicals; 580
• DOI: 10.1111/tpj.12304
• Languages: English
• ISSNs: 0960-7412

Abstract

<abstract abstract-type="main" id="tpj12304-abs-0001"> <title>Summary</title> <p>RNA‐binding pentatricopeptide repeat (PPR) proteins carrying a carboxy‐terminal DYW domain similar to cytidine deaminases have been characterized as site‐specific factors for C‐to‐U RNA editing in plant organelles. Here we report that knockout of DYW‐PPR_65 in <italic>Physcomitrella patens</italic> causes a severe developmental phenotype in the moss and specifically affects two editing sites located 18 nucleotides apart on the mitochondrial <italic>ccmFC </italic>mRNA. Intriguingly, PPR_71, another DYW‐type PPR, had been identified previously as an editing factor specifically affecting only the downstream editing site, ccmFCeU122SF. The now characterized PPR_65 binds specifically only to the upstream target site, ccmFCeU103PS, in full agreement with a recent RNA‐recognition code for PPR arrays. The functional interference between the two editing events may be caused by a combination of three factors: (i) the destabilization of an RNA secondary structure interfering with PPR_71 binding by prior binding of PPR_65; (ii) the resulting upstream C–U conversion; or (iii) a direct interaction between the two DYW proteins. Indeed, we find the <italic>Physcomitrella </italic>DYW‐PPRs to interact in yeast‐two‐hybrid assays. The moss DYW‐PPRs also interact yet more strongly with MORF (Multiple Organellar RNA editing Factor)/RIP (RNA editing factor interacting proteins) proteins of <italic>Arabidopsis</italic> known to be general editing factors in flowering plants, although MORF homologues are entirely absent in the moss. Finally, we demonstrate binding of <italic>Physcomitrella </italic>DYW‐PPR_98, for which no KO lines could be raised, to its predicted target sequence upstream of editing site atp9eU92SL. Together with the functional characterization of DYW‐PPR_65, this completes the assignment of RNA editing factors to all editing sites in the <italic>Physcomitrella</italic> mitochondrial transcriptome.</p> </abstract>