Fig. 8

RA signaling is altered in pbx depleted embryos.

To determine if the loss of hindbrain identity is due to defects in RA signaling, aldh1a2 expression was examined. Pbx4^−/− mutants that are treated with pbx2/4 morpholinos have a near complete knockdown of both maternal and zygotic Pbx. At early stages of hindbrain specification there is a decrease in aldh1a2 expression in wildtype embryos treated with pbx2/4 morpholinos (C) as compared to uninjected wildtype (A) or pbx4^−/− mutants (B). There is a decrease in both aldh1a2 expression level and domain in pbx4^−/− mutants injected with pbx2/4 morpholinos (22/22 embryos)(D). The area of aldh1a2 expression was measured using Image J, and the average was calculated (E). Zygotic pbx4^−/− mutants treated with pbx2/4 morpholinos have a 21% decrease in the area of aldh1a2 expression compared to uninjected wildtype embryos. Error bars indicate standard deviation. Uninjected wildtype: 135890.431 μm², Uninjected pbx4^−/−: 130628.408 μm², pbx2/4MO injected wildtype: 110737.578 μm², pbx2/4MO injected pbx4^−/−: 107364.171 μm². (ANOVA, post-hoc Tukey's: Uninjected wildtype vs pbx2/4MO injected wildtype, p-value 0.003; Uninjected wildtype vs pbx2/4MO injected pbx4^−/−, p-value 0.001) All embryos have been genotyped for pbx4^b557. All images are dorsal views, anterior to the top, 90% epiboly.