Figure 4. POU-IV is essential for touch-response behavior in the sea anemone.

(A-D) Behavior of wildtype (F2 pou-iv +/+, A, B) and mutant (F2 pou-iv -/-, C, D) Nematostella vectensis polyps in response to tactile stimuli to their oral tentacles. A hair held in a tungsten needle holder was used to touch the distal portion of each tentacle. Animals before (A, C) and after (B, D) tentacle touch are shown. Tactile stimuli to tentacles elicit tentacular retraction in the wildtype individual (100%, n = 44; A, B). In contrast, the majority of pou-iv homozygous mutants were touch-insensitive (65%, n = 40; B, D); only 35% of the animals showed any contractile response to touch stimuli. Arrowheads in B point to retracted tentacles. Scale bar: 1 mm.

Figure 4—figure supplement 1. pou-iv mutants respond to brine shrimp extract by tentacular contraction and pharyngeal protrusion.

(A-D) Behavior of wildtype (F2 pou-iv +/+, A, B) and mutant (F2 pou-iv -/-, C, D) Nematostella vectensis polyps in response to exposure to Artemia extract. Both wildtype and mutant animals contracted tentacles (arrowheads in B and D), and protruded the pharynx (ph) within 1 min of exposure to the extract (F2 pou-iv +/+, 100%, n = 3; F2 pou-iv -/-, 100%, n = 9). Scale bar: 1 mm.

Figure 4—video 1. Touch-sensitive behavior of a wildtype (F2 pou-iv +/+) polyp.

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Figure 4—video 2. Touch-insensitive behavior of a pou-iv mutant (F2 pou-iv -/-) polyp.

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Figure 4—video 3. Behavior of a wildtype (F2 pou-iv +/+) polyp upon exposure to brine shrimp extract.

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Figure 4—video 4. Behavior of a pou-iv mutant (F2 pou-iv -/-) polyp upon exposure to brine shrimp extract.

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