COMPARISON OF THE ALLATOSTATIN NEUROPEPTIDE PRECURSORS IN THE DISTANTLY RELATED COCKROACHES PERIPLANETA-AMERICANA AND DIPLOPTERA-PUNCTATA

Allatostatins are a family of insect neuropeptides that inhibit juveni le hormone biosynthesis by the corpora allata. We have characterized c DNA and genomic DNA sequences that specify a preproallatostatin precur sor in the oviparous cockroach Periplaneta americana. Comparison of th is precursor with that previously described [Donly, B. C., Ding, Q., T obe, S. S. & Bendena, W. G. (1993) Proc. Natl Acad. Sci. USA 90, 8807- 8811] for the viviparous cockroach Diploptera punctata revealed severa l common features. First, the precursors are remarkably similar in siz e and the organization of the peptides within the precursor is conserv ed. The separation of the peptides into groups by acidic domains withi n the precursor has been maintained. The P. americana precursor contai ns 14 allatostatin-like peptides that contain the core C-terminal sequ ence (Tyr/Phe)-Xaa-Phe-Gly-(Leu/Ile)-NH2, as compared to the D. puncta ta precursor, which contains 13. Five of the peptides are perfectly co nserved between the two species. The remainder, with one exception, co ntain amino acid substitutions in the N-terminal address portion of th e peptide. Several features of expression are also similar between the se two species. In both, a single copy gene specifies a large allatost atin transcript of 5.0 kb in P. americana and 9.2 kb in D. punctata. I n P. americana, allatostatin transcripts appear to be produced by nume rous cells in different regions of the brain.