Defective primitive streak formation in Hexd<sup>act/+</sup> mutants.

<p>(A–C) <i>Eomes, T</i> and <i>Cripto</i> expression in wildtype and Hexd<sup>act/+</sup> mutant embryos at 6.5dpc. (D–N) Expression of <i>Eomes</i>, <i>T</i>, <i>Chordin</i>, <i>Noggin</i>, <i>Foxa2</i>, <i>Wnt3</i>, <i>Tbx6</i>, <i>Fgf8</i>, <i>Snail</i>, <i>Sox17</i> and <i>Cerl</i> in control and Hexd<sup>act/+</sup> mutant embryos at 7.5dpc. Hexd<sup>act/+</sup> embryos with normal expression: <i>T</i> (6.5dpc) n = 7/7; <i>Cripto</i> n = 9/9 <i>Wnt3</i> n = 11/11; <i>Tbx6</i> n = 13/13; <i>Foxa2</i> n = 8/8; <i>Cerl</i> n = 14/14; <i>Sox17</i> n = 14/14. Hexd<sup>act/+</sup> embryos with reduced or lost expression <i>Eomes</i> (6.5dpc) n = 2/11; <i>Eomes</i> (7.5dpc) n = 3/18; <i>T</i> (7.5dpc) n = 3/14; <i>Chordin</i> n = 2/11; <i>Noggin</i> n = 6/15, <i>Fgf8</i> n = 5/17; <i>Snail</i> n = 3/14. (O) <i>T</i> expression in control and (O′) Hexd<sup>+/−</sup>;Sox2Cre<sup>+/−</sup> embryos at 7.5dpc (n = 16/16). Blue arrow indicates the anterior primitive streak in D and E. Scale bar 90 µm.</p>