Li Z, Van Aelst L, Cline H T
Cold Spring Harbor Laboratory, Beckman Bldg., 1 Bungtown Rd., Cold Spring Harbor, New York 11724, USA.
Nat Neurosci. 2000 Mar;3(3):217-25. doi: 10.1038/72920.
The development and structural plasticity of dendritic arbors are governed by several factors, including synaptic activity, neurotrophins and other growth-regulating molecules. The signal transduction pathways leading to dendritic structural changes are unknown, but likely include cytoskeleton regulatory components. To test whether GTPases regulate dendritic arbor development, we collected time-lapse images of single optic tectal neurons in albino Xenopus tadpoles expressing dominant negative or constitutively active forms of Rac, Cdc42 or RhoA. Analysis of images collected at two-hour intervals over eight hours indicated that enhanced Rac activity selectively increased branch additions and retractions, as did Cdc42 to a lesser extent. Activation of endogenous RhoA decreased branch extension without affecting branch additions and retractions, whereas dominant-negative RhoA increased branch extension. Finally, we provide data suggesting that RhoA mediates the promotion of normal dendritic arbor development by NMDA receptor activation.
树突分支的发育和结构可塑性受多种因素调控，包括突触活动、神经营养因子和其他生长调节分子。导致树突结构变化的信号转导通路尚不清楚，但可能包括细胞骨架调节成分。为了测试GTP酶是否调节树突分支发育，我们收集了表达Rac、Cdc42或RhoA显性负性或组成型活性形式的白化非洲爪蟾蝌蚪单个视顶盖神经元的延时图像。对在八小时内每隔两小时收集的图像进行分析表明，增强的Rac活性选择性地增加了分支的添加和回缩，Cdc42在较小程度上也有同样作用。内源性RhoA的激活减少了分支延伸，但不影响分支的添加和回缩，而显性负性RhoA增加了分支延伸。最后，我们提供的数据表明，RhoA介导NMDA受体激活对正常树突分支发育的促进作用。
