Fig. 6

Overexpression of Cdx4 results in different effects on gene expression compared to increased RA. In situ hybridization for aldh1a2 (A–D) shows the anterior boundary of expression relative to expression of ntl in the notochord (white bracket, A) shifts rostrally in Hsp70.cdx4 (B) compared to HS controls (A). Aldh1a2 expression shifts caudally in Talarozole-treated embryos (black arrowhead, D) compared to DMSO-treated controls (C). The distance between the rostral boundary of aldh1a2 and ntl expression was quantified and normalized relative to the yolk diameter in M. (E–H) Expression of cyp26a in trunk mesoderm relative to the anterior neuroectoderm is unaffected in Hsp70.cdx4 (F) compared to HS controls (white bracket, E). Cyp26a expression the trunk mesoderm of Talarozole-treated fish (H) is upregulated and shifted rostrally compared to DMSO-treated controls (G). The distance between expression in the trunk mesoderm and neuroectoderm was quantified in N (white bracket in E). (I–L) Expression of hoxd4a is shown relative to ntl expression and rostral shifts are indicated by yellow arrowheads (J, L). (O) Diagram of the presumed RA distribution (blue) relative to Cyp26a and the fin field (green) in DMSO and Talarozole-treated embryos at the tailbud stage. The threshold between high and low levels of RA is indicated by dashed lines. Embryos are shown in dorsal view with anterior towards the top. Statistical significance was calculated using student t-test (*, p < 0.05, ****, p < 0.00001). Non-significant differences are indicated NS. Scale bar represents 100 μm.