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Fig. 4. FGFR-dependent ERK signaling in extra-embryonic ectoderm (exe), heart
primordia (h), frontal nasal process (fnp), midbrain-hindbrain boundary (mhb),
eye primordia (ey), branchial arches (ba) and limb buds (lb) at 6.5, 8.0 and
10.5 dpc. Prior to dp-ERK staining, embryos were cultured in the absence (A-C)
or presence (D-F) of the FGFR inhibitor (40 µM SU5402) for 30-90 minutes.
Note that culturing embryos alters dp-ERK patterns somewhat causing more
diffuse boundaries of dp-ERK, some ectopic regions of dp-ERK and a loss of
dp-ERK staining in some weaker regions of signaling. Dp-ERK staining in the
ectoplacental cone (epc) and left heart ventricle (hv) were unaffected by the
FGFR inhibitor. Scale bars: 50 µm in A,D; 100 µm in B,E; 700 µm in
C,F.