Tyra N McCray, Mohammad F Azim, Tessa M Burch-Smith
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引用次数: 0
Abstract
In plants, cytidine-to-uridine (C-to-U) editing is a crucial step in processing mitochondria- and chloroplast-encoded transcripts. This editing requires nuclear-encoded proteins including members of the pentatricopeptide (PPR) family, especially PLS-type proteins carrying the DYW domain. IPI1/emb175/PPR103 is a nuclear gene encoding a PLS-type PPR protein essential for survival in Arabidopsis thaliana and maize. Arabidopsis IPI1 was identified as likely interacting with ISE2, a chloroplast-localized RNA helicase associated with C-to-U RNA editing in Arabidopsis and maize. Notably, while the Arabidopsis and Nicotiana IPI1 orthologs possess complete DYW motifs at their C-termini, the maize homolog, ZmPPR103, lacks this triplet of residues which are essential for editing. In this study we examined the function of IPI1 in chloroplast RNA processing in N. benthamiana to gain insight into the importance of the DYW domain to the function of the EMB175/PPR103/ IPI1 proteins. Structural predictions suggest that evolutionary loss of residues identified as critical for catalyzing C-to-U editing in other members of this class of proteins, were likely to lead to reduced or absent editing activity in the Nicotiana and Arabidopsis IPI1 orthologs. Virus-induced gene silencing of NbIPI1 led to defects in chloroplast ribosomal RNA processing and changes to stability of rpl16 transcripts, revealing conserved function with its maize ortholog. NbIPI1-silenced plants also had defective C-to-U RNA editing in several chloroplast transcripts, a contrast from the finding that maize PPR103 had no role in editing. The results indicate that in addition to its role in transcript stability, NbIPI1 may contribute to C-to-U editing in N. benthamiana chloroplasts.
期刊介绍:
Plant Molecular Biology is an international journal dedicated to rapid publication of original research articles in all areas of plant biology.The Editorial Board welcomes full-length manuscripts that address important biological problems of broad interest, including research in comparative genomics, functional genomics, proteomics, bioinformatics, computational biology, biochemical and regulatory networks, and biotechnology. Because space in the journal is limited, however, preference is given to publication of results that provide significant new insights into biological problems and that advance the understanding of structure, function, mechanisms, or regulation. Authors must ensure that results are of high quality and that manuscripts are written for a broad plant science audience.