Visual circuit development in Drosophila.
Fly visual circuits are organized into lattice-like arrays and layers. Recent genetic studies have provided insights into how these reiterated structures are assembled through stepwise processes and how precise connections are established during development. Afferent-derived morphogens, such as Hedgehog, play a key role in organizing the overall structure by inducing and recruiting target neurons and glia. In turn, the target-derived ligand DWnt4 guides Frizzled2-expressing photoreceptor afferents to their proper destination. Photoreceptor afferents select specific synaptic targets by forming adhesive interactions and regulating actin cytoskeleton in growth cones. Target specificity is probably achieved by restricting the expression of adhesive molecules, such as Capricious, to appropriate presynaptic and postsynaptic partners, and by differentially regulating the function of broadly expressed adhesive molecules such as N-cadherin.
Ting
Chun-Yuan
CY
Unit on Neuronal Connectivity, Laboratory of Gene Regulation and Development, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20817, USA.
Lee
Chi-Hon
CH
D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D004330:Drosophila / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D020439:Growth Cones / Q000378:metabolism / Q000648:ultrastructure; D009414:Nerve Growth Factors / Q000235:genetics / Q000378:metabolism*; D009899:Optic Lobe, Nonmammalian / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D017956:Photoreceptor Cells, Invertebrate / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D012160:Retina / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D014795:Visual Pathways / Q000166:cytology / Q000196:embryology* / Q000378:metabolism
D009414:Nerve Growth Factors