Multiple roles of the ER stress sensor IRE1 demonstrated by gene targeting in rice

• Published in: Scientific reports Vol. 2; no. 1; p. 944
• Main Authors: Wakasa, Yuhya, Hayashi, Shimpei, Ozawa, Kenjirou, Takaiwa, Fumio
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 10-12-2012; Nature Publishing Group
• Subjects: 631/1647/1513/1967; 631/208/2491/2046; 631/449/2661/2665; 631/449/2675; Alleles; Amino Acid Sequence; Endoplasmic reticulum; Endoplasmic Reticulum Stress; Gene targeting; Genetic analysis; Homologous recombination; Humanities and Social Sciences; Kinases; multidisciplinary; Mutation, Missense; Oryza - genetics; Oryza - metabolism; Plant Proteins - genetics; Plant Proteins - metabolism; Plants, Genetically Modified - growth & development; RNA, Messenger - metabolism; Science; Splicing
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep00944

The endoplasmic reticulum (ER) stress sensor, IRE1, contains a kinase domain and a ribonuclease domain. Ribonuclease mediates the unconventional splicing of mRNA encoding the transcription factor AtbZIP60 in Arabidopsis, or OsbZIP50 in rice and thereby transduces signals from stressed ER. Here, we demonstrate the additional roles of plant IRE1 using genetically modified rice plants. Using a gene targeting system based on homologous recombination, genomic
IRE1
was replaced with two types of missense alleles, leading to a defect in the kinase or ribonuclease activity of IRE1. Genetic analysis of these alleles demonstrated that the kinase activity of IRE1 plays a vital role independent of ribonuclease activity. Furthermore, the existence of ribonuclease substrates other than
OsbZIP50
mRNA is demonstrated for the first time. This study provides new insights into higher plant signalling using a gene targeting approach.