Home ＞GCOE Researchers ＞Ikue MORI

GCOE Researchers

Ikue MORI

Affiliation
/Position		 Graduate School of Science, Division of Biological Science, Professor
Doctorate Ph. D.
Research interests Behavior genetics, Kinetic analysis of neural circuit system
address m46920a＠nucc.cc.nagoya-u.ac.jp
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+81-52-789-4560
  Laboratory

Outline of research

How animals, including humans, respond to stimuli from external environment via the activity of the nervous system is one of the most important issues in neuroscience. To address this issue, our laboratory has been studying thermotaxis behavior of C. elegans, which plastically changes depending on temperature stimuli and feeding condition. Using various merits of C. elegans as a model system, we are conducting multi-level analysis of this behavior- molecule, cell, neural circuit, and organism level- and we have made novel findings that reveal fundamental principles of the nervous system (Figure).

We demonstrated that the AFD thermosensory neuron is the most important for thermosensation. Using laser ablation experiments, we also demonstrated antagonistic neural control between the AIY and AIZ interneurons, and proposed a neural circuit model for thermotaxis (Nature, 1995). Also, we isolated a number of thermotaxis-defective mutants and analyzed functions of the responsible genes. From these genetic studies, we reached several important conclusions: (1) the cyclic nucleotide dependent channel is essential for thermosensation in AFD; (2) calcineurin and protein kinase C are involved in regulation of sensitivity in thermosensory neurons; and (3) the insulin-like signal transduction pathway and neuroendocrine system are involved in associative learning of temperature and feeding conditions (Neuron, 1996, 2002; EMBO J., 2005; Genes & Dev., 2006). Based on these findings, we performed imaging of neural activity in order to analyze the physiology of the thermotaxis neural circuit, and succeeded in capturing changes in neural activity that depend on changes of temperature and feeding conditions (Curr. Biol., 2004; J.Neurosci., 2006). Recently, we have been working on building a behavior-tracking system and computer simulations aimed at elucidating relationships between kinetics of the thermotaxis neural circuit and behavior.

References

  1. Kuhara A.*, Okumura M.* et al. (*equally contributed) (2008) ?Temperature sensing by an olfactory neuron in a circuit controlling behavior of C. elegans. Science, 320: 803-807.
  2. Mori I. et al. (2007) Worm thermotaxis: a model system for analyzing thermosensation and neural plasticity. Curr. Opin. Neurobiol., 17: 712-719.
  3. Tanizawa Y. et al. (2006) Inositol Monophosphatase regulates localization of synaptic components and behavior in the mature nervous system of C. elegans. Genes & Dev., 20: 3296-3310.
  4. Kodama E. et al. (2006) Insulin-like signaling and the neural circuit for integrative behavior in C. elegans. Genes & Dev., 20: 2955-2960.
  5. Kuhara A., & Mori I. (2006) Molecular physiology of the neural circuit for calcineurin-dependent associative learning in Caenorhabditis elegans. J. Neurosci., 26: 9355-9364.
  6. Okochi Y. et al. (2005) Diverse regulation of sensory signaling by nPKC-epsilon/eta TTX-4 in the nematode C. elegans. EMBO J., 24:2127-2137.
  7. Sasakura H. et al. (2005) Maintenance of neuronal positions in organized ganglia by SAX-7, a Caenorhabditis elegans homologue of L1. EMBO J., 24: 1477-1488.
  8. Kimura K. D. et al. (2004) The C. elegans thermosensory neuron responds to warming. Curr. Biol., 14: 1291-1295.
  9. Ishihara I. et al. (2002) HEN-1, a secretory protein with a LDL receptor motif, regulates sensory integration and learning in Caenorhabditis elegans. Cell, 109: 639-649.
  10. Kuhara A. et al. (2002) Negative regulation and gain control of sensory neurons by the C. elegans calcineurin TAX-6. Neuron, 33: 751-763.

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