Expression of an extracellular deletion of Xotch diverts cell fate in Xenopus embryos.
Xotch is a Xenopus homolog of Notch, a receptor involved in cell fate decisions in Drosophila. Using an extracellular deletion construct, Xotch delta E, we show that Xotch has a similar role in Xenopus embryos. Broad expression causes the loss of dorsal structures and the expansion and disorganization of the brain. Single blastomere injections of Xotch delta E induce autonomous neural and mesodermal hypertrophy, even in the absence of cell division. Xotch delta E inhibits the early expression of epidermal and neural crest markers yet enhances and extends the response of animal caps to mesodermal and neural induction. Our data suggest a mechanism for the function of Notch homologs in which they delay differentiation and leave undetermined cells competent to respond to later inductive signals.
Coffman
C R
CR
Department of Biology, University of California, San Diego, La Jolla 92093.
Skoglund
P
P
Harris
W A
WA
Kintner
C R
CR
D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation / Q000235:genetics; D002455:Cell Division; D007301:Insect Hormones / Q000502:physiology; D008565:Membrane Proteins / Q000502:physiology; D008845:Microinjections; D008969:Molecular Sequence Data; D009030:Mosaicism; D009132:Muscles / Q000196:embryology; D009420:Nervous System / Q000196:embryology; D010641:Phenotype; D051880:Receptors, Notch; D017384:Sequence Deletion; D014981:Xenopus / Q000196:embryology* / Q000235:genetics
D007301:Insect Hormones; D008565:Membrane Proteins; D051880:Receptors, Notch