| Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2012: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2011: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
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| Research Abstract |
Sensory input has been shown to regulate development in a variety of species and in various structures, including the retina, cortex and olfactory bulb (OB). Within the mammalian OB specifically, the development of dendrites in mitral/tufted cells is well known to be odor-evoked activity-dependent. However, little is known about the developmental role of sensory input in the other major OB population of the GABAgenic interneurons, such as granule cells and periglomerular cells. Here, we identified, with DNA microarray and in situ hybridization screenings, a glycoprotein gene 5T4 whose expression in the OB interneurons is dependent on sensory input.5T4 is a type I transmembrane protein, whose extracellular domain contains seven leucine-rich repeats, and a short cytoplasmic domain. 5T4 overexpression in the newborn OB granule cells facilitated their dendritic branching even under the sensory input -deprived condition. By contrast, both 5T4knockdown with RNAi and 5T4 knockout with mice resulted in a significant reduction in the dendritic branching of OB granule cells. Further, we identified the amino-acid sequence in the 5T4 cytoplasmic domain that is necessary and sufficient for the sensory input-dependent dendritic shaping of specific neuronal subtypes in the OB (Yoshihara et al., J. Neurosci. 32, 2217, 2012).Thus, these results demonstrate that 5T4 contribute to regulate the activity-dependent dendritic development of interneurons and the formation of functional neural circuitry in the OB.
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