総合生命科学部 バイオフォーラム2013 開催（2013.12.10）
Complex composition of the RNA editosomes in plant organelles
竹中 瑞樹 氏
RNA editing in flowering plant mitochondria and plastids alters 400-500 and 30-40 nucleotides from C to U in mRNAs, respectively. Loss of individual RNA editing events often leads to severe defects in organellar function and plant development. Recent molecular-genetic approaches have assigned more than 40 PPR (Pentatricopeptide repeat) proteins to be involved in different RNA editing sites in plant mitochondria or chloroplasts. The PPR domains in these specific RNA editing factors vary in their numbers and structures. Computational analyses suggest that only few amino acids in a given PPR domain determine the nucleotide specificity. The consecutive cluster of several PPR variants then defines the unique binding sequence for each editing site. In addition to the PPR proteins, we recently identified another class of proteins to play a role in RNA editing in both plant organelles. The loss of one of these MORF proteins (multiple organellar RNA editing factor) abolishes or lowers editing at many sites that also require individual PPR proteins. Y2H and BiFC analyses document selective combinations of interactions between various PPR editing factors and MORF proteins. These homo- and heteromer assemblies are part of the apparently complex structure of the RNA editosomes in plant organelles.