DEV041764 Supplementary Material

Files in this Data Supplement:

• Supplemental Figure S1 -

  Fig. S1. Myogenin (MGN), Myosin heavy chain (MHC), MyoD and Myf5 levels were evaluated by RT-PCR in in vitro experiments to assess myogenesis. (A) Bmp4 inhibits myogenesis in stage VII-IX somites that autonomously express myotomal markers (right lane). (B) noggin alone is insufficient for myogenesis (right lane), whereas the combination of both Wnt1 and noggin could lead to upregulation of Pax3 and myogenic markers in the posterior PSM. (C) Administration of soluble Bmp4 in stage IV-VI somites abolishes the expression of MyoD induced by RatB1 Wnt4-expressing cells (right lane).

• Supplemental Figure S2 -

  Fig. S2. The effect of lateral insertion of Wnt1-secreting cells or the combination of ventro-medial Wnt1 cells together with Bmp4 inhibition. (A-D) In this prediction, Wnt1-expressing cells implanted into the ventro-lateral part of the somitic field adjacent to the lateral tissues will increase the levels of Wnt proteins from s₁ to s₂ as defined in TNS. As a result, noggin and myogenic markers will expand ventrally (A; compare with Fig. 1, right field). Ventro-lateral implantation of Wnt1-secreting cells (dashed line) upregulates the lateral expression of somitic noggin (B) and the lateral expansion of MyoD (C) and Pax3 (D) in the dermomyotome. Note that the MyoD expression pattern corresponds to the expression of noggin in two domains, whereas the expression pattern of Pax3 follows the presence of Wnt proteins in the somitic field. (E-G) TNS description (E) of two separate experiments in which Wnt1-secreting cells were implanted into the ventro-medial part of the somitic field together with either noggin-secreting cells in the ventro-lateral part (F) or a lateral barrier (G). According to this description, ventro-medial implantation of Wnt1-secreting cells combined with ventro-lateral implantation of CHO-noggin-secreting cells (left of the slash) or a lateral barrier (cyan bar, right of the slash) will cause a ventro-medial and lateral expansion of myotomal markers. Levels of Wnt proteins will increase from s₀ to s₂ as defined in TNS in the ventral domain of the somite, and noggin levels will increase from s₀ to s₂ (left of the slash) or Bmp4 levels will decrease from s₂ to s₀ and myogenic markers will expand ventrally (compare with Fig. 1, right field). Indeed, in these experiments, MyoD (F) and Myf5 (G) were expanded ventro-medially and laterally as predicted by the TNS model. n, notochord; nt, neural tube; s, somite. Scale bar: 30µm.

• Supplemental Table S1 -

• Supplemental Table S2 -