Characterization of mouse Ire1 alpha: cloning, mRNA localization in the brain and functional analysis in a neural cell line.
In yeast, an endoplasmic reticulum (ER)-associated protein, Ire1p, is believed to initiate the unfolded protein response (UPR), that is responsible for protein folding in the ER under stressed conditions. Two mammalian homologs of Ire1p have been identified, Ire1 alpha and Ire1 beta. We have previously reported that familial Alzheimer's disease linked presenilin-1 variants downregulate the signaling pathway of the UPR by affecting the phosphorylation of Ire1 alpha. In the present study, we cloned the mouse homolog of Ire1 alpha for generating genetically modified mice. Ire1 alpha was ubiquitously expressed in all mouse tissues examined, and was expressed preferentially in neuronal cells in mouse brain. This led us to investigate the effects of the downregulation of the UPR on the survival of neuronal cells under conditions of ER stress. Morphological and biochemical studies using a dominant-negative form of mouse Ire1 alpha have revealed that cell death caused by ER stress can be attributed to apoptosis, and that the downregulation of the UPR enhances the apoptotic process in the mouse neuroblastoma cell line, Neuro2a. Our results indicate that genetically modified mice such as transgenic mice with a dominant-negative form of Ire1 alpha might provide further understanding of the pathogenic mechanisms of Alzheimer's disease and other neurodegenerative disorders.
Miyoshi
K
K
Department of Anatomy and Neuroscience, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan. miyoshi@anat2.med.osaka-u.ac.jp
Katayama
T
T
Imaizumi
K
K
Taniguchi
M
M
Mori
Y
Y
Hitomi
J
J
Yui
D
D
Manabe
T
T
Gomi
F
F
Yoneda
T
T
Tohyama
M
M
D000544:Alzheimer Disease / Q000503:physiopathology; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D017209:Apoptosis / Q000502:physiology; D001921:Brain / Q000166:cytology* / Q000201:enzymology; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D003001:Cloning, Molecular; D003574:Cytochrome c Group / Q000378:metabolism; D018076:DNA, Complementary / Q000302:isolation & purification; D004721:Endoplasmic Reticulum / Q000737:chemistry / Q000201:enzymology; D015971:Gene Expression Regulation, Enzymologic; D017403:In Situ Hybridization; D008565:Membrane Proteins; D051379:Mice; D008969:Molecular Sequence Data; D009447:Neuroblastoma; D009474:Neurons / Q000166:cytology / Q000201:enzymology*; D017510:Protein Folding; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D017386:Sequence Homology, Amino Acid; D013312:Stress, Physiological / Q000503:physiopathology; D014407:Tumor Cells, Cultured; D014415:Tunicamycin / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D003574:Cytochrome c Group; D018076:DNA, Complementary; D008565:Membrane Proteins; D012333:RNA, Messenger; D014415:Tunicamycin; C486556:Ern2 protein, mouse; D017346:Protein Serine-Threonine Kinases; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases