Fig. 3. Altered expression of Msx2 in Splotch mutant embryos. Embryos at E9.5 were allowed to hybridize with digoxygenin-labeled antisense probes against Pax3 (A,D,G,J) and Msx2 (B,C,E,F,H,I,K,L). (A,B,D,E,G,H,J,K) Wild-type embryos; (C,F,I,L) Pax3^Sp/Sp embryos. Brackets indicate the region of the postotic hindbrain from which the cardiac neural crest originates. (D-F) are higher magnification views of hindbrain region of images shown in A-C. (G-L) Cross sections of embryos shown in A-C. Arrows to the right of D-F indicate the levels of the transverse sections. Sense probes did not hybridize detectably (not shown). Note the expansion of Msx2 expression in dorsal (arrowhead) and lateral (arrow) regions of postotic neural tube of Pax3^Sp/Sp embryos (L). o, otic vesicle; r5, rhombomere 5. Scale bars: 100 µm.