Gas1 expression in the paraxial mesoderm is regulated by WNT and SHH.
(A) E9.5 mouse psm explants were cultured in collagen
gels. The inductive tissues were isolated from E2.5 chick. (Left
to Right) psm was cultured alone, next to a notochord (nc), a
ventral neural tube (vnt), a dorsal neural tube (dnt), or inside a
surface ectoderm (se). Dashed lines, the boundary between psm and the
chick tissues. Explants were assessed for Gas1
expression. (B) (Left to Right) psms were
cocultured with control COS cells (COS-con) or cells expressing SHH-N
(COS-SHH-N), BMP4/Furin (COS-BMP4/Furin), and WNT1 (COS-WNT1).
Explants were assessed for Gas1 induction. Four samples
are represented by each image. (C) Parental 3T3 cells
(3T3-con) did not induce Gas1. WNT1-expressing cells
(3T3-WNT1) induced Gas1 over 200 μm. The induction was
reduced in the presence of 500 ng/ml SHH-N. WNT3A- and
WNT4-expressing 3T3 cells also induced Gas1.