title: Identification of a proctolin preprohormone gene (Proct) of Drosophila melanogaster: expression and predicted prohormone processing.
abstract: Proctolin was the first insect neuropeptide to be sequenced and has been the subject of many physiological and pharmacological studies in insects and crustaceans. We have identified a Drosophila gene (CG7105, Proct) encoding a precursor protein containing the neuropeptide proctolin (RYLPT). In situ hybridization with a riboprobe to the Proct gene revealed a distribution of transcript in neurons of the larval central nervous system (CNS) matching that seen with antiserum to proctolin. An antiserum raised to a sequence in the precursor downstream of proctolin labeled the same neurons as those seen with the antiproctolin antisera. The predicted protein encoded by Proct has a single copy of the RYLPT sequence that directly follows the predicted signal peptidase cleavage point and precedes a consensus recognition site for a furinlike processing endoprotease. Ectopic expression of Proct in the CNS and midgut via the GAL4-UAS system, using an Actin5C-GAL4 driver, confirmed that the predicted preproproctolin can be processed to generate immunoreactive proctolin peptide. Pupae over-expressing Proct displayed a 14% increase in heart rate, providing evidence in support of a cardioacceleratory endocrine function for proctolin in Drosophila. The distribution of proctolin suggests roles as a neuromodulator in motoneurons and interneurons, and as a neurohormone that could be released from brain neurosecretory cells with terminations in the ring gland.
authors.affiliation: Biological Sciences, University of Lancaster, LA1 4YQ, United Kingdom.
authors.forename: Christine A M
authors.initials: CA
authors.lastname: Taylor
authors.forename: Asa M E
authors.initials: AM
authors.lastname: Winther
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Siviter
authors.forename: Alan D
authors.initials: AD
authors.lastname: Shirras
authors.forename: R Elwyn
authors.initials: RE
authors.lastname: Isaac
authors.forename: Dick R
authors.initials: DR
authors.lastname: Nässel
mesh_terms: D000595:Amino Acid Sequence / Q000235:genetics; D000818:Animals; D001483:Base Sequence / Q000235:genetics; D002490:Central Nervous System / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D018076:DNA, Complementary / Q000032:analysis / Q000235:genetics; D029721:Drosophila Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics* / Q000378:metabolism; D010450:Endopeptidases / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D015698:Genomic Library; D006339:Heart Rate / Q000235:genetics; D007814:Larva / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D008969:Molecular Sequence Data; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D009479:Neuropeptides; D009490:Neurosecretory Systems / Q000166:cytology / Q000378:metabolism; D009842:Oligopeptides / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D010455:Peptides / Q000235:genetics / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D029721:Drosophila Proteins; D009479:Neuropeptides; D009842:Oligopeptides; D010455:Peptides; D012333:RNA, Messenger; C011536:proctolin; D010450:Endopeptidases