<i>NvHoxF/Anthox1</i> and <i>NvSoxB(1)</i> have distinct roles in the regulation of aboral domain and apical organ genes.

<p>(A–C) Schematic drawings illustrating the morphology of <i>NvHoxF/Anthox1</i> (B) and <i>NvSoxB(1)</i> MO-injected planulae. Both genes are required for apical tuft formation, but only <i>NvSoxB(1)</i> morphants show a slightly elongated body column (C). (D–O) In situ hybridizations, lateral views (left) with the aboral pole to the left are shown next to aboral views (right) at the midplanula stage (72 hpf). In situ probes are indicated on the left, with morpholinos on top. <i>NvHoxF/Anthox1</i> and <i>NvSoxB(1)</i> are required for the expression <i>of NvFGFa1</i> (D–F) but not <i>NvFGFa2</i> (G–I). <i>NvSoxB(1)</i> morphants lack the gap in the expression of <i>NvSix3/6</i> and <i>NvFoxQ2a</i> (L, O), while <i>NvHoxF/Anthox1</i> morphants only lack the gap in <i>NvSix3/6</i> expression (K, N). Scale bar, 100 µm.