| |
FIG. 7. (A) BMP4 misexpression by bead implantation into the anterior neural plate of stages 13-14 embryos results in the suppression of most neural markers. Left column shows embryos implanted with control, BSA beads in the anterior neural plate. Embryos were fixed at stage 17 and stained by in situ hybridization to the range of neural markers on the left. Right column shows embryos implanted with beads soaked in BMP4 in the anterior neural plate. Suppression of the neural markers listed on the left can be seen in the vicinity of the bead, with the exception of Pax-6, which remained unchanged. Pax-6 was analyzed by double in situ hybridization with XSox3, where XSox3 expression is shown in light blue and Pax-6 in magenta. Note that, while the XSox3 gene was downregulated (i.e., absence of blue stain), Pax-6 expression remains (i.e., presence of magenta stain) in the anterior right neural plate, where the bead was implanted. (B) Suppression of XSox3 (light blue) is also observed when BMP4 beads are implanted at stages 16 and 20 and analyzed at stages 19 and 25, respectively. Bead implantation at stage 13 is shown for comparison. These embryos were analyzed by double in situ hybridization to XSox3 (light blue) and nrp1 (light magenta). Expression of nrp1 is not affected by BMP4 bead implantation throughout the neurula stages (right panel). Note retention of magenta stain (i.e., nrp1 expression), but a significant reduction in light blue stain (i.e., XSox3 expression) in embryos on the right. Embryos implanted with control BSA beads are shown on the left and have no affect on either nrp1 or XSox3. |
