RHON1 is a novel ribonucleic acid-binding protein that supports RNase E function in the Arabidopsis chloroplast.
The Arabidopsis endonuclease RNase E (RNE) is localized in the chloroplast and is involved in processing of plastid ribonucleic acids (RNAs). By expression of a tandem affinity purification-tagged version of the plastid RNE in the Arabidopsis rne mutant background in combination with mass spectrometry, we identified the novel vascular plant-specific and co-regulated interaction partner of RNE, designated RHON1. RHON1 is essential for photoautotrophic growth and together with RNE forms a distinct ∼800 kDa complex. Additionally, RHON1 is part of various smaller RNA-containing complexes. RIP-chip and other association studies revealed that a helix-extended-helix-structured Rho-N motif at the C-terminus of RHON1 binds to and supports processing of specific plastid RNAs. In all respects, such as plastid RNA precursor accumulation, protein pattern, increased number and decreased size of chloroplasts and defective chloroplast development, the phenotype of rhon1 knockout mutants resembles that of rne lines. This strongly suggests that RHON1 supports RNE functions presumably by conferring sequence specificity to the endonuclease.
Department Biology 1, Biocenter of the Ludwig-Maximilians-University Munich, Chair of Plant Molecular Biology, Planegg-Martinsried D-82152, Germany.
Rhea
R
Stoppel
Nikolay
N
Manavski
Aleks
A
Schein
Gadi
G
Schuster
Marlene
M
Teubner
Christian
C
Schmitz-Linneweber
Jörg
J
Meurer
D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002736:Chloroplasts / Q000201:enzymology* / Q000235:genetics; D019281:Dimerization; D004722:Endoribonucleases / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010641:Phenotype; D010788:Photosynthesis; D017434:Protein Structure, Tertiary; D012323:RNA Processing, Post-Transcriptional; D018747:RNA, Chloroplast / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000378:metabolism; D012338:RNA, Ribosomal, 23S / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment
D029681:Arabidopsis Proteins; C576818:RHON1 protein, Arabidopsis; D018747:RNA, Chloroplast; D012333:RNA, Messenger; D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S; D016601:RNA-Binding Proteins; D004722:Endoribonucleases; C529496:RNase E, Arabidopsis