The Structure and Expression of a Preprohormone of a Neuropeptide, Hym-176 in Hydra Magnipapillata

Hym-176 (APFIFPGPKVamide) is a novel myoactive neuropeptide which was identified in systematic screening of signaling peptides in Hydra magnipapillata. By using PCR and library screening, we cloned and sequenced a full length cDNA which encoded a preprohormone of Hym-176. In the preprohormone, a typical signal sequence, one copy of Hym-176 precursor peptide and one copy of precursor sequence of another novel peptide, Hym-357 (KPAFLFKGYKPamide), were detected. In situ hybridization analysis revealed a strong signal in peduncle neurons. Signals were also detected, though weaker, in neurons in the gastric region and around the mouth. No signals were detected in the two extremities of the body, tentacles and basal disk. The expression pattern is correlated with the distribution of Hym-176 and its myoactive function.