The protocadherin Flamingo is required for axon target selection in the Drosophila visual system.
Photoreceptor neurons (R cells) in the Drosophila visual system elaborate a precise map of visual space in the brain. The eye contains some 750 identical modules called ommatidia, each containing eight photoreceptor cells (R1-R8). Cells R1-R6 synapse in the lamina; R7 and R8 extend through the lamina and terminate in the underlying medulla. In a screen for visual behavior mutants, we identified alleles of flamingo (fmi) that disrupt the precise maps elaborated by these neurons. These mutant R1-R6 neurons select spatially inappropriate targets in the lamina. During target selection, Flamingo protein is dynamically expressed in R1-R6 growth cones. Loss of fmi function in R cells also disrupts the local pattern of synaptic terminals in the medulla, and Flamingo is transiently expressed in R8 axons as they enter the target region. We propose that Flamingo-mediated interactions between R-cell growth cones within the target field regulate target selection.
Lee
Roger C
RC
Department of Biological Chemistry, David Geffen School of Medicine at UCLA, Howard Hughes Medical Institute, Box 951662, Los Angeles, California 90095-1662, USA.
Clandinin
Thomas R
TR
Lee
Chi-Hon
CH
Chen
Pei-Ling
PL
Meinertzhagen
Ian A
IA
Zipursky
S Lawrence
SL
D000483:Alleles; D000818:Animals; D019521:Body Patterning / Q000235:genetics; D001921:Brain / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure; D001931:Brain Mapping; D015820:Cadherins / Q000235:genetics / Q000378:metabolism*; D002448:Cell Adhesion / Q000235:genetics; D002450:Cell Communication / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics*; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D020439:Growth Cones / Q000378:metabolism* / Q000648:ultrastructure; D008854:Microscopy, Electron; D009030:Mosaicism / Q000235:genetics; D009154:Mutation / Q000235:genetics; D017956:Photoreceptor Cells, Invertebrate / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure; D013569:Synapses / Q000378:metabolism / Q000648:ultrastructure; D014795:Visual Pathways / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure
D015820:Cadherins; D029721:Drosophila Proteins; C121420:stan protein, Drosophila