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Watanabe Laboratory, Department of Bioengineering, Nagaoka University of Technology

Neurons and glia are the most important cells in the brain. More than 100 billion of neurons form neural networks. Glia, which outnumber neurons by ten fold, support the function of neurons. For the formation of neural networks, neurons extend neural processes precisely to the targets by communicating with various molecules on the surface of the surrounding cells including glia during development. Neuron-neuron and neuron-glia communication are also important for the brain function during adulthood. In these communications, neural recognition molecules play essential roles.

We are studying the function of neural recognition molecules to understand the molecular mechanisms underlying the neural differentiation, formation of neural network and the higher order function of the brain.

Contactin Subgroup Molecules

TAG-1, NB-2 and NB-3 are neural recognition molecules in the contactin subgroup, which is expressed specifically in the nervous system. Contactin subgroup is a glycosylphosphatidyl inositol-llinked immunoglobuin suprefamily with six immunoglobulin-like domains and four fibronectin type III-like repeats.

Gene-Deficient Mice of Contactin Subgroup Molecules

We generated three kinds of mice, which are deficient for TAG-1, NB-2 or NB-3. All of these mice displayed behavioral abnormalities. TAG-1-null mice are more sensitive to convulsant stimuli than wild-type mice. NB-2-null mice exhibit low incidence of audiogenic seizure and low response to pure tone stimulation. NB-3-null mice are impaired motor coordination. We are currently analyzing these mice using various techniques.