Figure 6

Treatment with retinoic acid eliminated expression of hhex in the thyroid but not liver. When embryos were treated at stage 24/26 and cultured to stage 36, expression could be detected near the thyroid even in RA treated embryos but in ventral view it can be clearly seen that midline expression of hhex (red arrow) is eliminated by RA but there is an additional region of expression lateral to the thyroid (blue arrows) that is not lost when embryos were treated with RA. There is also no obvious change in the expression of the large liver expression domain found caudal to the thyroid expression.