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Sensorimotor Control

開催日 2014/9/11
時間 18:00 - 19:00
会場 Room H(304)
Chairperson(s) 花川 隆 / Takashi Hanakawa (国立精神・神経医療研究センター脳病態統合イメージングセンター 先進脳画像研究部 / Department of Advanced Neuroimaging, Integrative Brain Imaging Center, National Center of Neurology and Psychiatry, Japan)
高草木 薫 / Kaoru Takakusaki (旭川医科大学医学部 脳機能医工学研究センター / Asahikawa Medical University, The Center for Brain Function and Medical Engineering, Japan)

A novel method, time- and cell-specific RNAi, revealed the function of Ras in neurons regulating exploratory behavior

  • O1-H-6-1
  • 濱川 昌之 / Masayuki Hamakawa:1 飯野 雄一 / Yuichi Iino:2 広津 崇亮 / Takaaki Hirotsu:1,3 
  • 1:九州大学大学院 / Graduate School of Systems Life Sciences Kyushu University, Japan 2:東京大学大学院理学系研究科生物化学専攻 / Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Japan 3:九州大学理学部生物学科 / Department of Biology, Graduate School of Sciences, Kyushu University, Japan 

Exploratory behavior is essential for animals to gain food resources. Caenorhabditis elegans employs strategies in deciding to roam or dwell and to explore food resources efficiently in the presence of food. However, little is known about the behavioral strategies that they use under environmental conditions far from food resources.
We found that under poor conditions, abnormal locomotion behavior termed circular locomotion (CL) occurred in mutants of the Ras-MAPK pathway. CL resulted from impaired foraging behavior, which involves exploratory head movements and is regulated by a neural circuit consisting of IL1, OLQ, and RMD neurons. Genetic inhibition of these neurons caused CL and the knockdown of Ras in these neurons by cell-specific RNAi induced CL. Moreover, the expression of Ras in these neurons restored the defects of locomotion in Ras mutants. These results indicate that the function of Ras in the neurons is necessary and required for regulation of the exploratory behavior.
We found mutants of glr-1 which encodes an AMPA-typed glutamate receptor also showed CL. In the animals in which the function of Ras was inhibited, abnormal localization of GLR-1 glutamate receptors in RMD neurons was observed. In addition, to investigate a temporal and cell-specific profile of the functions of Ras, we developed an RNAi method which enables to perform time- and cell-specific knockdown simultaneously. Using this technique, we found that the knockdown of the function of Ras in RMD neurons at the adult stage induced aberrant localization of GLR-1, while the knockdown at embryonic stage did not, suggesting that Ras is important for the control of GLR-1 localization in RMD neurons and regulation of foraging behavior. Furthermore, we confirmed that this novel method can be applied to other genes.

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