title: Semaphorin breaks symmetry.
abstract: Axon-dendrite polarity is likely instructed by extrinsic cues in the developing nervous system, though the mechanisms governing this process remain to be fully elucidated. In this issue of Neuron, Shelly et al. show that the axon guidance cue Semaphorin 3A can promote dendrite growth by inhibiting axon specification.
authors.affiliation: Howard Hughes Medical Institute, Department of Biology, Stanford University, Stanford, CA 94305, USA.
authors.forename: Audrey S
authors.initials: AS
authors.lastname: Howell
authors.forename: Kang
authors.initials: K
authors.lastname: Shen