Neuronal growth cone collapse triggers lateral extensions along trailing axons.
Axonal outgrowth is generally thought to be controlled by direct interaction of the lead growth cone with guidance cues, and, in trailing axons, by fasciculation with pioneer fibers. Responses of axons and growth cones were examined as cultured retinal ganglion cell (RGC) axons encountered repellent cues. Either contact with cells expressing ephrins or mechanical probing increased the probability of lead growth cone retraction. Lateral extension of filopodia and lamellipodia hundreds of microns behind the lead growth cone was correlated with its collapse. Transmission electron microscopy showed that some of the lateral extensions originate from the pioneer axon, whereas others represent growth cones of defasciculating trailing axons.
Davenport
R W
RW
Laboratory of Developmental Neurobiology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-4480, USA. RD127@umail.umd.edu
Thies
E
E
Cohen
M L
ML
D016475:3T3 Cells; D000818:Animals; D001369:Axons / Q000502:physiology* / Q000648:ultrastructure; D002478:Cells, Cultured; D002642:Chick Embryo; D003463:Cues; D036383:Ephrin-A2; D036386:Ephrin-A5; D020439:Growth Cones / Q000502:physiology*; D008565:Membrane Proteins / Q000502:physiology; D051379:Mice; D009474:Neurons / Q000502:physiology*; D010812:Physical Stimulation; D012165:Retinal Ganglion Cells / Q000502:physiology; D014157:Transcription Factors / Q000502:physiology; D014162:Transfection
D036383:Ephrin-A2; D036386:Ephrin-A5; D008565:Membrane Proteins; D014157:Transcription Factors