Spätzle regulates the shape of the Dorsal gradient in the Drosophila embryo.
Dorsal-ventral polarity of the Drosophila embryo is established by a nuclear gradient of Dorsal protein, generated by successive gurken-Egfr and spätzle-Toll signaling. Overexpression of extracellular Spätzle dramatically reshapes the Dorsal gradient: the normal single peak is broadened and then refined to two distinct peaks of nuclear Dorsal, to produce two ventral furrows. This partial axis duplication, which mimics the ventralized phenotype caused by reduced gurken-Egfr signaling, arises from events in the perivitelline fluid of the embryo and occurs at the level of Spätzle processing or Toll activation. The production of two Dorsal peaks is addressed by a model that invokes action of a diffusible inhibitor, which is proposed to normally regulate the slope of the Dorsal gradient.
Morisato
D
D
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA. dmorisato@mhs.harvard.edu
D000818:Animals; D019521:Body Patterning; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000196:embryology; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000235:genetics; D009866:Oogenesis / Q000502:physiology; D011956:Receptors, Cell Surface / Q000235:genetics; D015398:Signal Transduction; D015238:Sulfotransferases / Q000235:genetics; D051193:Toll-Like Receptors; D016211:Transforming Growth Factor alpha; D015291:Transforming Growth Factors / Q000235:genetics / Q000378:metabolism
D029721:Drosophila Proteins; D019476:Insect Proteins; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; C068721:Tl protein, Drosophila; D051193:Toll-Like Receptors; D016211:Transforming Growth Factor alpha; C083730:grk protein, Drosophila; C086179:spz protein, Drosophila; D015291:Transforming Growth Factors; D066246:ErbB Receptors; D015238:Sulfotransferases; C115847:pip protein, Drosophila