Fig. 6

Fig. 6 Motoneuron specification is unaltered by STAT3 inactivation. Motoneuron specification was assessed by LIM homeodomain expression. In situ hybridization was performed on uninjected (A and D), STAT3 MO injected (B and E), and DN-STAT3-GFP expressing (C and F) embryos. (A–C) In situ hybridization reveals in all cases two Isl1-positive neurons per hemisegment indicating the specification of one RoP and one MiP per hemisegment. This is inconsistent with the CaP motoneuron trans-specifying into a RoP or MiP, which would result in a third Isl1-positive neuron found in a hemisegment. (D–F) In all cases, in situ hybridization for Isl2 identifies one (arrowheads) or two neurons (asterisk) per hemisegment consistent with the CaP and the variably present VaP. In all images, rostral is to the left, and dorsal is up. Embryos are at 27 h post-fertilization.