Plexin a-semaphorin-1a reverse signaling regulates photoreceptor axon guidance in Drosophila.
While it is well established that Semaphorin family proteins function as axon guidance ligands in invertebrates and vertebrates, several recent studies indicate that the Drosophila Semaphorin-1a (Sema1a), a transmembrane Semaphorin, can also function as a receptor during neural development. The regulator of Sema1a reverse signaling, however, remains unknown. In this study, we show that like Sema1a, the well known Semaphorin receptor Plexin A (PlexA), is required for the proper guidance of photoreceptor (R cell) axons in the Drosophila visual system. Loss of PlexA, like loss of semala, disrupted the association of R-cell growth cones in the optic lobe. Conversely, overexpression of PlexA, like overexpression of sema1a, induced the hyperfasciculation of R-cell axons. Unlike Sema1a, however, the cytoplasmic domain of PlexA is dispensable. Epistasis analysis suggests that PlexA functions upstream of semala. And PlexA and sema1a interact genetically with Rho1. We propose that PlexA regulates Semala reverse signaling in the Drosophila visual system.
Yu
Li
L
McGill Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, Department of Medicine, McGill University Health Centre, Montreal, Quebec, Canada.
Zhou
Yating
Y
Cheng
Songting
S
Rao
Yong
Y
D000818:Animals; D030801:Animals, Genetically Modified; D001369:Axons / Q000502:physiology*; D004330:Drosophila; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004625:Embryo, Nonmammalian; D018507:Gene Expression Regulation, Developmental / Q000235:genetics / Q000502:physiology; D049452:Green Fluorescent Proteins / Q000235:genetics; D020439:Growth Cones / Q000502:physiology; D009154:Mutation / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009899:Optic Lobe, Nonmammalian / Q000166:cytology / Q000196:embryology / Q000502:physiology; D017956:Photoreceptor Cells, Invertebrate / Q000166:cytology*; D034622:RNA Interference / Q000502:physiology; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D039961:Semaphorins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology
D029721:Drosophila Proteins; D009419:Nerve Tissue Proteins; D011956:Receptors, Cell Surface; D039961:Semaphorins; C116483:plexA protein, Drosophila; C477531:semaphorin 1a, Drosophila; D049452:Green Fluorescent Proteins
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