DH31 peptide is sufficient to promote visceral contractions.

(A) Phalloidin labelling of posterior midgut of DH31ts>reggie flies maintained at 18°C (control, left) or raised for 24 h at 29°C (right). 20X objective. (B) Measurement of midgut length in conditions described in (A). (C) DH31ts>DH31#9 posterior midguts maintained at 18°C for control (left) or shifted for 48 h at 29°C (right) and stained with phalloidin. 20X objective. Overexpression of DH31 in all EECs induced strong visceral contractions. (D) Measurement of midgut length in the conditions described in (C). (E) mef2ts>t-DH31P2-B9 posterior midguts maintained at 18°C for control (left) or shifted for 24H at 29°C (right) and stained with phalloidin. 20X objective. Ectopic expression of the membrane-tethered form of DH31 in the visceral muscle induced autonomous visceral contractions. (F) Measurement of midgut length in the conditions described in (E).