First published online November 7, 2006
Development 133, 2301e (2006)
© The Company of Biologists Limited
Shisa2: red light to morphogen receptor traffic
Somites form transiently in the presomitic mesoderm (PSM) and organize the
segmental pattern of vertebrate embryos. FGF and Wnt gradients that decrease
caudorostrally control the maturation of the PSM, and also the position in the
embryo where the transition to segmental units occurs (the `differentiation
wavefront'). But what regulates these gradients? On
p. 4643, Nagano and
co-workers reveal that Shisa2, a member of the novel Shisa gene
family, regulates FGF and Wnt signals during somitogenesis in
Xenopus. The researchers show that Shisa2, like its relative Shisa1,
encodes an endoplasmic reticulum protein that inhibits signalling by Wnt and
FGF by preventing the maturation and cell-surface expression of their
receptors. Knockdown of Shisa2, they report, delays PSM maturation and shifts
the differentiation wavefront anteriorly, thus reducing somite numbers. This
phenotype can only be rescued by inhibiting both Wnt and FGF signals. Thus,
the researchers conclude, Shisa2 plays an essential role in establishing the
segmental pattern in Xenopus embryos by individually inhibiting both
these signals.
Related articles in Development:
- Shisa2 promotes the maturation of somitic precursors and transition to the segmental fate in Xenopus embryos
- Takashi Nagano, Shoko Takehara, Maiko Takahashi, Shinichi Aizawa, and Akihito Yamamoto
Development 2006 133: 4643-4654.
[Abstract]
[Full Text]
