Whole-mount IF shows broader detection of CDX2 (red) in the tailbud of P2-ΔRarb mutants (I and J) versus the control (H) at somite-matched stages. WTRarb embryos display a caudal limit of HOXB4 that extends to somite 10 (H), versus a caudal limit at somite 9 in P2-ΔRarb mutants (I and J). Abnormal tailbud morphology is most apparent in the P2-ΔRarb mutant presented in (J). Somites are numbered in white; green, white, and yellow arrows indicate the approximate anterior limit of CDX2 expression in the lateral plate mesoderm, PSM, and neural tube, respectively. Scale bar represents 500 μm. (A), (B), and (D) were created withBioRender.com. Data are represented as mean ± SEM. *pvalue < 0.05, **pvalue < 0.01, ****pvalue < 0.0001.
