SYSTEMATIC ISOLATION OF PEPTIDE SIGNAL MOLECULES REGULATING DEVELOPMENT IN HYDRA - LWAMIDE AND PW FAMILIES

To isolate new peptide signal molecules involved in regulating develop mental processes in hydra, a novel screening project was developed. Pe ptides extracted from the tissue of Hydra magnipapillata were systemat ically purified to homogeneity using HPLC. A fraction of each purified peptide was examined by differential display-PCR for its ability to a ffect gene expression in hydra. Another fraction was used to determine the tentative structure using an amino acid sequence analyzer and/or a mass spectrometer. Based on the results, peptides of potential inter est were selected for chemical synthesis, followed by confirmation of the identity of the synthetic with the native peptides using HPLC. Usi ng this approach, 286 peptides have been isolated, tentative amino aci d sequences have been determined for 95 of them, and 19 synthetic pept ides identical to native ones were produced. The 19 synthetic peptides were active in a variety of biological tests. For example, Hym-54 sti mulated muscle contraction in adult polyps of hydra and sea anemone, A nthopleura fuscoviridis, and induced metamorphosis of planula, the lar val stage, into polyps in a marine hydrozoan species, Hydractinia serr ata. Another peptide, Hym-33H, inhibited nerve cell differentiation in hydra and induced tissue contraction in planula of Hydractinia serrat a. The evidence obtained so far suggests that hydra contains a large n umber (>350) of peptide signal molecules involved in regulating develo pmental or other processes in cnidaria. These peptides can be isolated and their functions examined systematically with the new approach dev eloped in this study.