DA dendrite formation

Dendrite guidance

Clock model: axonal and dendritic growth are internally regulated, depending on how to

respond to guidance molecules

WT

Robo3 over-expression in TTMn

Robo3 over-expression in both GF & TTMn

GF, giant fiber interneuronTTMn: tergotrochantral motor neuron

Neuropil model: same guidance molecules for attracting (or including) axon and

dendrite together for synapse

TRENDS in Neurosciences Vol.27 No.4 April 2004

achaete scute

atonal

amos

Proneural genesSensory organs

+ + associated associated

MD MD neuronsneurons

+ + associated associated

MD MD neuronsneurons

solo-MD solo-MD neuronsneurons

ES MD / mono-ES MD / poly-ES

CH MD / CH solo-MD

ASC ASCASC

ato ato amos

Brewster and Bodmer, 1995

ES

CH

MDamos

hamlet, a binary switch gene for MD/ES neuron determination

Control of dendrite developmentControl of dendrite development

Luo. et al. Trends Neuroscience (2003)

DA Dendrite formation

Constitutive active CDC42 induce supernumerary primary dendrites that fail to extend dorsally and grow secondary dendrites

WT

CDC42

pros mutations causes routing defect

Lateral branch defects: (A) WT, (B) reduced, (C) fail to extend, (E, F) over shrinking

Increased density

Sequotia (水杉 ), Zn finger protein

No repulsion in dorsal groupNo invasion into ablated region in dorsal region in third instar

Competition between two dorsal groups of contralateral dorsal groups

Dorsal dendrite overextension in flamingo mutants

Class I Class II

Class III

Development (2002) Grueber et al

Tiling of dendrites within the same class of DA neuronsTiling of dendrites within the same class of DA neurons

Cell (2003) Grueber et al

Dendrites of different classes overlap extensively

Class IV tiling

Differential Cut levels in four types of DA neurons

cut mutant phenotypes in class III

Class II

Class I

Class I

Class II

Class IV

No effect on class III

Dendrites over-branching and over-lapping phenotypes

Defect in like-dendrite avoidance response

WT

fry

Heteroneuronal tiling defect

Trc kinase

Rac

Fry

branching

tiling