title: RNA PROCESSING FACTOR2 is required for 5' end processing of nad9 and cox3 mRNAs in mitochondria of Arabidopsis thaliana.
abstract: In mitochondria of higher plants, the majority of 5' termini of mature mRNAs are generated posttranscriptionally. To gain insight into this process, we analyzed a natural 5' end polymorphism in the species Arabidopsis thaliana. This genetic approach identified the nuclear gene At1g62670, encoding a pentatricopeptide repeat protein. The functional importance of this mitochondrial restorer of fertility-like protein, designated RNA PROCESSING FACTOR2 (RPF2), is confirmed by the analysis of a respective T-DNA knockout mutant and its functional restoration by in vivo complementation. RPF2 fulfills two functions: it is required for the generation of a distinct 5' terminus of transcripts of subunit 9 of the NADH DEHYDROGENASE complex (nad9) and it determines the efficiency of 5' end formation of the mRNAs for subunit 3 of the CYTOCHROME C OXIDASE (cox3), the latter also being influenced by mitochondrial DNA sequences. Accordingly, recombinant RPF2 protein directly binds to a nad9 mRNA fragment in vitro. Two-dimensional gel electrophoresis and immunodetection analyses reveal that altered 5' processing does not influence accumulation of the nad9 and cox3 polypeptides. In accessions C24, Oystese-1, and Yosemite-0, different inactive RPF2 alleles exist, demonstrating the variability of this gene in Arabidopsis. The identification of RPF2 is a major step toward the characterization of 5' mRNA processing in mitochondria of higher plants.
authors.affiliation: Institut Molekulare Botanik, Universität Ulm, D-89069 Ulm, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Jonietz
authors.forename: Joachim
authors.initials: J
authors.lastname: Forner
authors.forename: Angela
authors.initials: A
authors.lastname: Hölzle
authors.forename: Sabine
authors.initials: S
authors.lastname: Thuss
authors.forename: Stefan
authors.initials: S
authors.lastname: Binder
mesh_terms: D000483:Alleles; D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics*; D008928:Mitochondria / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000235:genetics*; D018749:RNA, Plant / Q000235:genetics*; D016601:RNA-Binding Proteins / Q000235:genetics*
chemical_list: D029681:Arabidopsis Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; D016601:RNA-Binding Proteins; C000597734:RPF2 protein, Arabidopsis