Int. J. Dev. Biol. 48: 327 - 332 (2004)

https://doi.org/10.1387/ijdb.041838ta

Vol 48, Issue 4

Activin-like signaling activates Notch signaling during mesodermal induction

Open Access | Original Article | Published: 1 July 2004

Takanori Abe¹, Miho Furue², Yasufumi Myoishi³, Tetsuji Okamoto³, Akiko Kondow⁴ and Makoto Asashima*^{,1, 4, 5}

¹Department of Biological Science, Graduate School of Science, The University of Tokyo, Japan ²Department of Biochemistry and Molecular Biology, Kanagawa Dental College, Yokosuka, Japan

Abstract

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.

Keywords

Xenopus laevis, activin, Notch signaling, MyoD, mesoderm induction