Rhomboid 3 orchestrates Slit-independent repulsion of tracheal branches at the CNS midline.
EGF-receptor ligands act as chemoattractants for migrating epithelial cells during organogenesis and wound healing. We present evidence that Rhomboid 3/EGF signalling, which originates from the midline of the Drosophila ventral nerve cord, repels tracheal ganglionic branches and prevents them from crossing it. rho3 acts independently from the main midline repellent Slit, and originates from a different sub-population of midline cells: the VUM neurons. Expression of dominant-negative Egfr or Ras induces midline crosses, whereas activation of the Egfr or Ras in the leading cell of the ganglionic branch can induce premature turns away from the midline. This suggests that the level of Egfr intracellular signalling, rather than the asymmetric activation of the receptor on the cell surface, is an important determinant in ganglionic branch repulsion. We propose that Egfr activation provides a necessary switch for the interpretation of a yet unknown repellent function of the midline.
Gallio
Marco
M
Department of Developmental Biology, Wenner-Gren Institute, Stockholm University, S-106 96 Stockholm, Sweden.
Englund
Camilla
C
Kylsten
Per
P
Samakovlis
Christos
C
D000818:Animals; D019521:Body Patterning; D002490:Central Nervous System / Q000196:embryology / Q000502:physiology; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000033:anatomy & histology / Q000196:embryology* / Q000235:genetics; D004815:Epidermal Growth Factor / Q000378:metabolism*; D066246:ErbB Receptors / Q000378:metabolism*; D005136:Eye Proteins / Q000378:metabolism; D017403:In Situ Hybridization; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D009024:Morphogenesis; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D019908:Proto-Oncogene Proteins c-raf / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014132:Trachea / Q000196:embryology; D018631:ras Proteins / Q000378:metabolism
C076188:AOP protein, Drosophila; D029721:Drosophila Proteins; D005136:Eye Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D012097:Repressor Proteins; C066819:sli protein, Drosophila; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D019908:Proto-Oncogene Proteins c-raf; D012697:Serine Endopeptidases; C491029:ru protein, Drosophila; D018631:ras Proteins