Tsuchida T, Ensini M, Morton S B, Baldassare M, Edlund T, Jessell T M, Pfaff S L
Howard Hughes Medical Institute Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032.
Cell. 1994 Dec 16;79(6):957-70. doi: 10.1016/0092-8674(94)90027-2.
Motor neurons located at different positions in the embryonic spinal cord innervate distinct targets in the periphery, establishing a topographic neural map. The topographic organization of motor projections depends on the generation of subclasses of motor neurons that select specific paths to their targets. We have cloned a family of LIM homeobox genes in chick and show here that the combinatorial expression of four of these genes, Islet-1, Islet-2, Lim-1, and Lim-3, defines subclasses of motor neurons that segregate into columns in the spinal cord and select distinct axonal pathways. These genes are expressed prior to the formation of distinct motor axon pathways and before motor columns appear. Our results suggest that LIM homeobox genes contribute to the generation of motor neuron diversity and may confer subclasses of motor neurons with the ability to select specific axon pathways, thereby initiating the topographic organization of motor projections.
位于胚胎脊髓不同位置的运动神经元支配外周的不同靶标，建立起一种拓扑神经图谱。运动投射的拓扑组织取决于运动神经元亚类的产生，这些亚类会选择特定路径到达其靶标。我们在鸡中克隆了一个LIM同源框基因家族，在此表明其中四个基因，即胰岛-1（Islet-1）、胰岛-2（Islet-2）、Lim-1和Lim-3的组合表达，定义了运动神经元的亚类，这些亚类在脊髓中分离成柱，并选择不同的轴突路径。这些基因在不同的运动轴突路径形成之前以及运动柱出现之前就已表达。我们的结果表明，LIM同源框基因有助于运动神经元多样性的产生，并可能赋予运动神经元亚类选择特定轴突路径的能力，从而启动运动投射的拓扑组织。
