Skip to main content
. 2008 Nov 1;22(21):3037–3049. doi: 10.1101/gad.1682108

Figure 5.

Figure 5.

LR pathway activation in Nodalneo/neo/Smad1−/− embryos. (A–D) At 2–4 sp, Nodal expression is robust in the node (arrowheads) and left LPM in wild-type embryos (A) but is bilateral in the LPM in Smad−/− mutants (D). No Nodal expression is seen in most Nodalneo/neo (Nneo/neo) or Nneo/neo;Smad1−/− embryos (see the text). (E–G) Whole-mount 4–5 sp embryos hybridized with a mixed Nodal/Pitx2 probe. Nodal is barely detectable in the node at this stage (arrowheads), although Pitx2 is expressed strongly in the anterior LPM and weakly in the caudal LPM (arrows). (F) Neither is it expressed in most Nneo/neo embryos. (G) In Nneo/neo; Smad1−/− embryos, Nodal expression is undetectable in the node but Pitx2 is bilaterally expressed cranially and caudally. (H–K) By 8.5 dpc (10 sp), Pitx2 expression in wild-type embryos is restricted to the left sinus venosus region of the heart (star) (H), and this pattern becomes bilateral in Nodalneo/neo;Smad1−/− double mutants (I). (J) Most Nneo/neo embryos show Pitx2 expression in extraembryonic tissues only. (K) A minority of Nneo/neo; Smad1−/− embryos show weak right-sided or bilateral expression (arrows) in sinus venosa.