John F. Hardesty, MD Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Saint Louis, MO 63110, USA.
John F. Hardesty, MD Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Saint Louis, MO 63110, USA; Graduate Program in Neuroscience, Washington University School of Medicine, Saint Louis, MO 63110, USA.
Cell Rep. 2019 Nov 5;29(6):1568-1578.e4. doi: 10.1016/j.celrep.2019.09.085.
The size of dendrite arbors shapes their function and differs vastly between neuron types. The signals that control dendritic arbor size remain obscure. Here, we find that in the retina, starburst amacrine cells (SACs) and rod bipolar cells (RBCs) express the homophilic cell-surface protein AMIGO2. In Amigo2 knockout (KO) mice, SAC and RBC dendrites expand while arbors of other retinal neurons remain stable. SAC dendrites are divided into a central input region and a peripheral output region that provides asymmetric inhibition to direction-selective ganglion cells (DSGCs). Input and output compartments scale precisely with increased arbor size in Amigo2 KO mice, and SAC dendrites maintain asymmetric connectivity with DSGCs. Increased coverage of SAC dendrites is accompanied by increased direction selectivity of DSGCs without changes to other ganglion cells. Our results identify AMIGO2 as a cell-type-specific dendritic scaling factor and link dendrite size and coverage to visual feature detection.
树突棘的大小决定了其功能，而且不同神经元类型之间差异巨大。控制树突棘大小的信号仍然不清楚。在这里，我们发现在视网膜中，星形胶质细胞（SACs）和杆状双极细胞（RBCs）表达同源细胞表面蛋白 AMIGO2。在 Amigo2 敲除（KO）小鼠中，SAC 和 RBC 树突扩展，而其他视网膜神经元的树突保持稳定。SAC 树突分为中央输入区和外周输出区，为方向选择性节细胞（DSGCs）提供不对称抑制。在 Amigo2 KO 小鼠中，输入和输出区与树突棘的大小增加精确匹配，SAC 树突与 DSGCs 保持不对称连接。SAC 树突的覆盖范围增加伴随着 DSGC 方向选择性的增加，而其他节细胞没有变化。我们的结果将 AMIGO2 确定为一种特定于细胞类型的树突扩展因子，并将树突大小和覆盖范围与视觉特征检测联系起来。
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