170
C. Niehrs et al.
A
BMP-4
dnBMPR
wt
low
high
low
high
B
BMP-4
noggin
Fig. 2. A Dose-dependent regulation of myf5 by BMP-4 signalling. myf-5 expression occurs in two dorsolateral stripes in the marginal zone of the Xenopus
gastrula, shown in vegetal view, dorsal side up (wt). Ectopic expression of
Bmp-4 or dominant-negative BMP receptor (dnBMPR) mRNAs regulate the
pattern of myf5 expression at different doses (low, high), indicating that stripe
formation occurs within a window of the BMP-4 morphogen gradient. B Direct and long-range action of BMP-4 and Noggin. Left: embryos were microinjected with mRNA encoding ~-galactosidase (lacZ) showing nuclear localization and either Bmp-4 or Xsmadl (XMAD-l) as indicated, followed by
treatment with Liel to inhibit endogenous BMP target gene expression. Expression of induced Xvent-l was detected by whole-mount in situ hybridization in gastrulae. Note that Xvent-l expression extends beyond the injected
cells (labeled nuclei) in the Bmp-4-injected embryo, while it is restricted to the
~-galactosidase positive cells in Xsmadl-injected embryos. Embryos are
shown in lateral view with the animal side up. Right, embryos were microinjected with ~-galactosidase lineage tracer mRNA with or without noggin
mRNA as indicated. Expression of induced Xvent-2 was detected by wholemount in situ hybridization in gastrulae. Note the halo of Xvent-2 repression
beyond the injected cells (labeled nuclei) in the noggin-injected embryos.
(From Dosch et al. 1997)
C. Niehrs et al.
A
BMP-4
dnBMPR
wt
low
high
low
high
B
BMP-4
noggin
Fig. 2. A Dose-dependent regulation of myf5 by BMP-4 signalling. myf-5 expression occurs in two dorsolateral stripes in the marginal zone of the Xenopus
gastrula, shown in vegetal view, dorsal side up (wt). Ectopic expression of
Bmp-4 or dominant-negative BMP receptor (dnBMPR) mRNAs regulate the
pattern of myf5 expression at different doses (low, high), indicating that stripe
formation occurs within a window of the BMP-4 morphogen gradient. B Direct and long-range action of BMP-4 and Noggin. Left: embryos were microinjected with mRNA encoding ~-galactosidase (lacZ) showing nuclear localization and either Bmp-4 or Xsmadl (XMAD-l) as indicated, followed by
treatment with Liel to inhibit endogenous BMP target gene expression. Expression of induced Xvent-l was detected by whole-mount in situ hybridization in gastrulae. Note that Xvent-l expression extends beyond the injected
cells (labeled nuclei) in the Bmp-4-injected embryo, while it is restricted to the
~-galactosidase positive cells in Xsmadl-injected embryos. Embryos are
shown in lateral view with the animal side up. Right, embryos were microinjected with ~-galactosidase lineage tracer mRNA with or without noggin
mRNA as indicated. Expression of induced Xvent-2 was detected by wholemount in situ hybridization in gastrulae. Note the halo of Xvent-2 repression
beyond the injected cells (labeled nuclei) in the noggin-injected embryos.
(From Dosch et al. 1997)