Anzo Marie, Sekine Sayaka, Makihara Shirin, Chao Kinhong, Miura Masayuki, Chihara Takahiro
Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
Japan Agency for Medical Research and Development (AMED)-CREST, Japan Agency for Medical Research and Development, Chiyoda-ku, Tokyo 100-0004, Japan.
Genes Dev. 2017 May 15;31(10):1054-1065. doi: 10.1101/gad.297424.117.
Proper function of the neural network results from the precise connections between axons and dendrites of presynaptic and postsynaptic neurons, respectively. In the olfactory system, the dendrites of projection neurons (PNs) stereotypically target one of ∼50 glomeruli in the antennal lobe (AL), the primary olfactory center in the brain, and form synapses with the axons of olfactory receptor neurons (ORNs). Here, we show that Eph and Ephrin, the well-known axon guidance molecules, instruct the dendrodendritic segregation during the discrete olfactory map formation. The Eph receptor tyrosine kinase is highly expressed and localized in the glomeruli related to reproductive behavior in the developing AL. In one of the pheromone-sensing glomeruli (DA1), the Eph cell-autonomously regulates its dendrites to reside in a single glomerulus by interacting with Ephrins expressed in adjacent PN dendrites. Our data demonstrate that the interaction between dendritic Eph and Ephrin is essential for the PN dendritic boundary formation in the DA1 olfactory circuit, potentially enabling strict segregation of odor detection between pheromones and the other odors.
神经网络的正常功能分别源于突触前神经元和突触后神经元的轴突与树突之间的精确连接。在嗅觉系统中，投射神经元（PNs）的树突刻板地靶向大脑初级嗅觉中枢触角叶（AL）中约50个嗅小球之一，并与嗅觉受体神经元（ORNs）的轴突形成突触。在这里，我们表明，著名的轴突导向分子Eph和Ephrin在离散嗅觉图谱形成过程中指导树突-树突分离。Eph受体酪氨酸激酶在发育中的AL中与生殖行为相关的嗅小球中高度表达并定位。在一个信息素感应嗅小球（DA1）中，Eph通过与相邻PN树突中表达的Ephrin相互作用，自主调节其树突驻留在单个嗅小球中。我们的数据表明，树突Eph和Ephrin之间的相互作用对于DA1嗅觉回路中PN树突边界的形成至关重要，这可能使信息素与其他气味之间的气味检测严格分离。
