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.
Department of Biology, University of California, San Diego, La Jolla 92093.
C R
CR
Coffman
P
P
Skoglund
W A
WA
Harris
C R
CR
Kintner
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