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Figure 5. X-Delta-2 is involved in the segmentation and patterning of the hindbrain. A prime -C prime : X-Delta-2 morpholino (MO) was injected in the left-hand side, and the embryos were analyzed for the expression of different hindbrain markers at stage 21. A-C: Noninjected (Nic) embryos are also shown for all the markers. The expression of Engrailed-2 in the midbrain-hindbrain boundary (En in A,A prime ), Krox-20 in rhombomeres (r) 3 and 5 (A,A prime ), Gbx-2 in the r1 (bracket in B,B prime ), and Hoxb-3 (C,C prime ) in r5 were analyzed. The MyoD expression shows loss of segmentation in the injected side, confirming the loss of X-Delta-2 function. D: The morphology of the brain is shown using the neural antibody 2-G9 in stage 48 embryos. A-D: Embryos at stage 21 are shown from the anterior side with dorsal to the top (A-C), and the brain of a stage 48 embryo is shown from the dorsal side with anterior to the left (D). E: The distance between the posterior border of the Engrailed-2 stripe and the anterior border of the r3 Krox-20 stripe (r1-r2 region) and the distance between the anterior border of the r3 Krox-20 stripe and the posterior border of the r5 Krox-20 stripe (r3-r5 region) was measured in stage 21 (n = 6) and stage 25 (n = 5) embryos. E: The hindbrain regions measured are indicated by brackets in a stage 21 embryo stained for Engrailed-2 and Krox-20. E: Both sides were measured, and the ratio left-hand side/right-hand side (LHS/RHS; Nic/Nic or Delta MO/NIC) was plotted on a graph. Values above 1.0 indicate an increase in the length of the region on the left (injected) side, and values below 1.0 indicate a decrease. In both stages, the r1-r2 region is increased on the X-Delta-2 MO-injected side and the r3-r5 region is decreased. The arrow in D indicates the forebrain, and arrowheads indicate the rhombomere boundaries in the hindbrain. The asterisk indicates the injected side. |
