title: A nuclear-encoded chloroplast-targeted S1 RNA-binding domain protein affects chloroplast rRNA processing and is crucial for the normal growth of Arabidopsis thaliana.
abstract: Despite the fact that a variety of nuclear-encoded RNA-binding proteins (RBPs) are targeted to the chloroplast and play essential roles during post-transcriptional RNA metabolism in the chloroplast, the physiological roles of the majority of chloroplast-targeted RBPs remain elusive. Here, we investigated the functional role of a nuclear-encoded S1 domain-containing RBP, designated SDP, in the growth and development of Arabidopsis thaliana. Confocal analysis of the SDP-green fluorescent protein revealed that SDP was localized to the chloroplast. The loss-of-function sdp mutant displayed retarded seed germination and pale-green phenotypes, and grew smaller than the wild-type plants. Chlorophyll a content and photosynthetic activity of the sdp mutant were much lower than those of wild-type plants, and the structures of the chloroplast and the prolamellar body were abnormal in the sdp mutant. The processing of rRNAs in the chloroplast was defective in the sdp mutant, and SDP was able to bind chloroplast 23S, 16S, 5S and 4.5S rRNAs. Notably, SDP possesses RNA chaperone activity. Transcript levels of the nuclear genes involved in chlorophyll biosynthesis were altered in the sdp mutant. Collectively, these results suggest that chloroplast-targeted SDP harboring RNA chaperone activity affects rRNA processing, chloroplast biogenesis and photosynthetic activity, which is crucial for normal growth of Arabidopsis.
authors.affiliation: Department of Plant Biotechnology, Chonnam National University, Gwangju, 500-757, Korea.
authors.forename: Ji Hoon
authors.initials: JH
authors.lastname: Han
authors.affiliation: Department of Plant Biotechnology, Chonnam National University, Gwangju, 500-757, Korea.
authors.forename: Kwanuk
authors.initials: K
authors.lastname: Lee
authors.affiliation: Department of Wood Science and Landscape Architecture, College of Agriculture and Life Sciences, Chonnam National University, Gwangju, 500-757, Korea.
authors.forename: Kwang Ho
authors.initials: KH
authors.lastname: Lee
authors.affiliation: School of Life Sciences and Biotechnology, Kyungpook National University, Daegu, 702-701, Korea.
authors.forename: Sunyo
authors.initials: S
authors.lastname: Jung
authors.affiliation: Department of Systems Biology, Yonsei University, Seoul, 120-749, Korea.
authors.forename: Young
authors.initials: Y
authors.lastname: Jeon
authors.affiliation: Department of Systems Biology, Yonsei University, Seoul, 120-749, Korea.
authors.forename: Hyun-Sook
authors.initials: HS
authors.lastname: Pai
authors.affiliation: Department of Plant Biotechnology, Chonnam National University, Gwangju, 500-757, Korea.
authors.forename: Hunseung
authors.initials: H
authors.lastname: Kang
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D060365:Chloroplast Proteins / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D010788:Photosynthesis; D012323:RNA Processing, Post-Transcriptional; D012335:RNA, Ribosomal / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D060365:Chloroplast Proteins; D009687:Nuclear Proteins; D012335:RNA, Ribosomal; D016601:RNA-Binding Proteins
keywords: Arabidopsis thaliana; RNA chaperone; S1 RNA-binding domain protein; chloroplast; rRNA processing