(Downloading may take up to 30 seconds.
If the slide opens in your browser, select File -> Save As to save it.)
Click on image to view larger version.

Fig. 2. Hedgehog signaling controls vasculogenesis and Foxf1
expression. (A-D) Morphology and histology of wt and
Ihh-/-; Shh-/- E9.5 mouse embryos. (A)
E9.5 wt embryo with well-developed yolk sac vasculature. The embryo has
completed turning and reached the fetal position. (B) E9.5
Ihh-/-; Shh-/- embryo with an almost
completely avascular yolk sac. The embryo is still in the primitive, unturned
position and the amnion adheres to the inner surface of the yolk sac
(arrowheads in B). (C) Section of a wt E9.5 yolk sac with large blood vessels
containing embryonic erythrocytes. (D) Section of an
Ihh-/-; Shh-/- E9.5 yolk sac. The yolk
sac mesoderm consists of a thin lining of the inner surface of the yolk sac
which in some areas adheres to the outer, mesodermal layer of the amnion
(arrowhead). (E,F) Whole-mount in situ hybridization of E9.5
embryos with a Foxf1 probe. (E) Wt embryo showing high-level
expression of Foxf1 in the lateral plate and extraembryonic mesoderm
of allantois and yolk sac. (F) Lateral (top) and posterior-dorsal (bottom)
views of an Ihh-/-; Shh-/- embryo.
Foxf1 expression is absent in lateral mesoderm and yolk sac, but
present in allantois and posterior primitive streak (arrowheads). al,
allantois; am, amnion; lp, lateral plate mesoderm; ys, yolk sac; yse, yolk sac
endoderm; ysm, yolk sac mesoderm.