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Human myo ‐inositol monophosphatase 2 rescues the nematode thermotaxis mutant ttx‐7 more efficiently than IMPA 1: functional and evolutionary considerations of the two mammalian myo ‐inositol monophosphatase genes
Author(s) -
Ohnishi Tetsuo,
Tanizawa Yoshinori,
Watanabe Akiko,
Nakamura Takemichi,
Ohba Hisako,
Hirata Haruna,
Kaneda Chizu,
Iwayama Yoshimi,
Arimoto Takafumi,
Watanabe Kazutada,
Mori Ikue,
Yoshikawa Takeo
Publication year - 2013
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/jnc.12112
Subject(s) - biology , caenorhabditis elegans , mutant , gene , phenotype , genetics , microbiology and biotechnology
Mammals express two myo ‐inositol monophosphatase ( IMP ase) genes, IMPA 1/Impa1 and IMPA 2/Impa2 . In this study, we compared the spatial expression patterns of the two IMP ase gene transcripts and proteins in mouse tissues. Results indicated discrete expression of the two IMP ase genes and their protein products in various organs, including the brain. In Caenorhabditis elegans, loss of the IMP ase gene, ttx‐7 , disrupts cellular polarity in RIA neurons, eliciting abnormal thermotaxis behavior. We performed a rescue experiment in mutant nematodes using mammalian IMP ases. Human IMPA 2 rescued the abnormal behavioral phenotype in the ttx‐7 mutants more efficiently than IMPA 1. These results raise a question about the phylogenetic origin of IMP ases and the biological roles of mammalian IMP ase 2 in mammals. Impa2 knockout mice generated in our laboratory, exhibited neither behavioral abnormalities nor a significant reduction in myo ‐inositol content in the brain and other examined tissues. Given the ability of human IMPA 2 to rescue the ttx‐7 mutant, and its genetic association with multiple neuropsychiatric disorders, close scrutiny of IMPA 2 function and the evolutionary origin of IMP ase genes is warranted.