Rho GTPases regulate distinct aspects of dendritic arbor growth in Xenopus central neurons in vivo.
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.
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Cold Spring Harbor Laboratory, Beckman Bldg., 1 Bungtown Rd., Cold Spring Harbor, New York 11724, USA.
Van Aelst
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Cline
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D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000199:Actins / Q000378:metabolism; D000818:Animals; D048429:Cell Size / Q000187:drug effects; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism; D003712:Dendrites / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology* / Q000648:ultrastructure; D004789:Enzyme Activation / Q000235:genetics; D005799:Genes, Dominant / Q000235:genetics; D006801:Humans; D007814:Larva / Q000166:cytology / Q000187:drug effects; D009154:Mutation / Q000235:genetics; D009473:Neuronal Plasticity / Q000187:drug effects; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000502:physiology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013477:Superior Colliculi / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D014616:Vaccinia virus / Q000235:genetics; D014982:Xenopus laevis; D020764:cdc42 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism; D020744:rac GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism; D020741:rho GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein / Q000235:genetics / Q000378:metabolism
D000199:Actins; D016194:Receptors, N-Methyl-D-Aspartate; D011993:Recombinant Fusion Proteins; D015763:2-Amino-5-phosphonovalerate; D020764:cdc42 GTP-Binding Protein; D020744:rac GTP-Binding Proteins; D020741:rho GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein