Interpretation of a BMP activity gradient in Drosophila embryos depends on synergistic signaling by two type I receptors, SAX and TKV.
Graded activity of the DPP signaling pathway is critical for specification of dorsal embryonic cell fates in Drosophila. We present evidence that a second BMP ligand, SCW, potentiates DPP activity. Using dominant-negative forms of the type I receptors SAX and TKV, we demonstrate that SAX mediates the SCW signal, while TKV is required for both DPP and SCW activity. We find that while DPP/TKV signaling is obligatorily required, SCW/SAX activity is necessary but not sufficient for dorsal patterning. SAX and TKV act synergistically, suggesting a mechanism for integration of the SCW and DPP signals. Further, we show that the extracellular protein SOG can antagonize SCW, thus limiting its ability to augment DPP signaling in a graded manner.
Nguyen
M
M
Department of Developmental and Cell Biology, University of California, Irvine 92697, USA.
Park
S
S
Marqués
G
G
Arora
K
K
D000818:Animals; D019521:Body Patterning / Q000502:physiology; D019485:Bone Morphogenetic Proteins / Q000378:metabolism / Q000502:physiology*; D019281:Dimerization; D004330:Drosophila / Q000196:embryology*; D029721:Drosophila Proteins; D004357:Drug Synergism; D019476:Insect Proteins / Q000502:physiology; D008024:Ligands; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D011956:Receptors, Cell Surface / Q000502:physiology*; D018125:Receptors, Transforming Growth Factor beta / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D016212:Transforming Growth Factor beta / Q000378:metabolism / Q000502:physiology*
D019485:Bone Morphogenetic Proteins; D029721:Drosophila Proteins; D019476:Insect Proteins; D008024:Ligands; D011956:Receptors, Cell Surface; D018125:Receptors, Transforming Growth Factor beta; C090409:SCW protein, Drosophila; D016212:Transforming Growth Factor beta; C064196:dpp protein, Drosophila; C086338:sax protein, Drosophila; C091428:sog protein, Drosophila; C090169:tkv protein, Drosophila; D017346:Protein Serine-Threonine Kinases