STRUCTURE-FUNCTION ANALYSIS LYMANTRIA TESTIS ECDYSIOTROPIN - A SEARCHFOR THE ACTIVE CORE

A structure-function study was performed on the synthetic 21 residue n europeptide, Lymantria testis ecdysiotropin (LTE), originally isolated from brains of Lymantria dispar pupae. The peptide induces ecdysteroi d synthesis by testis sheaths of various lepidopteran species. LTE, as well as synthetic LTE 1-11, 11-21, and 11-15, stimulated synthesis in larval and pupal testes of Lymantria dispar at concentrations of 10(- 9) to 10(15) M; LTE 16-21 was weakly active, and an elongated LEU-LTE was inhibitory to synthesis at all but extremely low concentrations (1 0(15)M). Since the sequence and polarity of residues in LTE 1-11, 11-1 5, and 11-21 are quite different, several parts of the molecule must a ctivate receptors which initiate the cascade, resulting in ecdysiogene sis in Lepidopteran testes. (C) 1998 Wiley-Liss, Inc.