Organization and expression of the Drosophila Phe-Met-Arg-Phe-NH2 neuropeptide gene.

We have studied a Drosophila gene that encodes multiple neuropeptides related to Phe-Met-Arg-Phe-NH2 (FMRFamide). Using a combination of genomic sequencing, Northern blot analysis, primer extensions, and nuclease protection assays, we have described its organization and expression. The results indicate that this Drosophila neuropeptide gene contains two exons separated by an intron of approximately 2.5 kilobase pairs, and that its expression is limited to a single predominant RNA species of approximately 1.7 kilobases. The FMRFamide gene contains a 5' untranslated region that is 106 nucleotides long and is encoded in its entirety by exon I. The open reading frame (encoding a 347-amino acid neuropeptide precursor) begins with the first nucleotide of exon II.