Joint research results of Assistant Professor Kenji Okuda (Faculty of Science and Engineering, Department of Biological Sciences, Hiroyuki Koike Laboratory) will be published in The Plant Cell magazine (five-year impact factor: 10.224), the preeminent academic journal in the field of plant science. The result has been published in the September 22nd online version.

The thesis which will be published is entitled "Two Interacting Proteins are Necessary for the Editing of the NdhD-1 Site in Arabidopsis Plastids."

In the subcellular organelle of plants, in the mitochondria and chloroplast which possess unique genomes, RNA editing which converts C base to U in RNA is performed frequently. Research on the RNA editing of plant organelle focuses on the molecular mechanism of editing site recognition in which only specific Cs are edited, as well as the clarification of existing conditions for editing mechanism which is related to the editing of those Cs. Regarding the former theme, it has been explained that a protein known as pentatrico-peptide repeat (PPR) protein gives specific recognition to sequences surrounding editing sites. The majority of PPR proteins related to RNA editing possess a field called DYW domain in the C-terminal. The DYW contains a sequence which shows homology with the catalytic site of human RNA-editing enzymes, and is therefore thought to be the identity of the editing activation (catalyst for the conversion reaction from C to U). However, it was not clear whether or not the DYW domain is important for RNA editing.

In the current research, genetic analysis was conducted for the protein DYW1 which possess only DYW domain that exists within Arabidopsis thaliana. The analysis clarified that DYW1 interacts with PPR protein CRR4, and that DYW1 is required for RNA editing which occurs in the chloroplast ndhD-1 site. As a result, great progress has been made towards clarifying the true identity of the editing enzyme which is the essence of the plant organelle RNA editing mechanism, something which has been a mystery for many years

These results were produced through joint research by an international research group which includes Group Director Clair Lurin of the French National Institute for Agricultural Science, Professor Ian Small of The University of Western Australia, and Professor Toshiharu Shikanai of Kyoto University.

Please visit the following links for further information.

• Link: The Plant Cell
• Link: Clarifying the tricks of multiple RNA sequence recognition mechanism through PPR protein
• Link: Thesis published in Nucleic Acids Research magazine
• Link: Faculty of Sciene and Engineering, Department of Biological Sciences