Activin-like signaling activates Notch signaling during mesodermal induction.
Both activin-like signaling and Notch signaling play fundamental roles during early development. Activin-like signaling is involved in mesodermal induction and can induce a broad range of mesodermal genes and tissues from prospective ectodermal cells (animal caps). On the other hand, Notch signaling plays important roles when multipotent precursor cells achieve a specific cell fate. However, the relationship between these two signal pathways is not well understood. Here, we show that activin A induces Delta-1, Delta-2 and Notch expression and then activates Notch signaling in animal caps. Also, in vivo, ectopic activin-like signaling induced the ectopic expression of Delta-1 and Delta-2, whereas inhibition of activin-like signaling abolished the expression of Delta-1 and Delta-2. Furthermore, we show that MyoD, which is myogenic gene induced by activin A, can induce Delta-1 expression. However, MyoD had no effect on Notch expression, and inhibited Delta-2 expression. These results indicated that activin A induces Delta-1, Delta-2 and Notch by different cascades. We conclude that Notch signaling is activated when activin-like signaling induces various tissues from homogenous undifferentiated cells.
Department of Biological Science, Graduate School of Science, The University of Tokyo, Japan.
Takanori
T
Abe
Miho
M
Furue
Yasufumi
Y
Myoishi
Tetsuji
T
Okamoto
Akiko
A
Kondow
Makoto
M
Asashima
D028341:Activins / Q000494:pharmacology / Q000502:physiology*; D000818:Animals; D004627:Embryonic Induction; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D066298:In Vitro Techniques; D028322:Inhibin-beta Subunits / Q000494:pharmacology / Q000502:physiology*; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D008648:Mesoderm / Q000166:cytology / Q000502:physiology*; D008954:Models, Biological; D017570:MyoD Protein / Q000235:genetics / Q000502:physiology; D051880:Receptors, Notch; D015398:Signal Transduction / Q000187:drug effects; D029867:Xenopus Proteins / Q000235:genetics / Q000502:physiology*; D014982:Xenopus laevis / Q000196:embryology* / Q000235:genetics / Q000502:physiology*
D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D017570:MyoD Protein; D051880:Receptors, Notch; D029867:Xenopus Proteins; C422405:activin A; C064045:delta protein; D028341:Activins; D028322:Inhibin-beta Subunits