Nose A, Umeda T, Takeichi M
National Institute for Basic Biology, Myodaiji-cho, Ohazaki, Japan.
Development. 1997 Apr;124(8):1433-41. doi: 10.1242/dev.124.8.1433.
Drosophila Connectin (CON) is a cell surface protein of the leucine-rich repeat family. During the formation of neuromuscular connectivity, CON is expressed on the surface of a subset of embryonic muscles and on the growth cones and axons of the motoneurons that innervate these muscles, including primarily SNa motoneurons and their synaptic targets (lateral muscles). In vitro, CON can mediate homophilic cell adhesion. In this study, we generated transgenic lines that ectopically expressed CON on all muscles. In the transformant embryos and larvae, SNa motoneurons often inappropriately innervated a neighboring non-target muscle (muscle 12) that ectopically expressed CON. Furthermore, the ectopic synapse formation was dependent on the endogenous CON expression on the SNa motoneurons. These results show that CON can function as an attractive and homophilic target recognition molecule in vivo.
果蝇连接蛋白（CON）是富含亮氨酸重复序列家族的一种细胞表面蛋白。在神经肌肉连接形成过程中，CON在一部分胚胎肌肉表面以及支配这些肌肉的运动神经元的生长锥和轴突上表达，这些运动神经元主要包括SNa运动神经元及其突触靶点（侧肌）。在体外，CON可介导同种型细胞黏附。在本研究中，我们构建了在所有肌肉中异位表达CON的转基因品系。在转基因胚胎和幼虫中，SNa运动神经元常常错误地支配了异位表达CON的相邻非靶肌肉（肌肉12）。此外，异位突触的形成依赖于SNa运动神经元上内源性CON的表达。这些结果表明，CON在体内可作为一种有吸引力的同种型靶标识别分子发挥作用。
