title: Stimulus-dependent regulation and cellular expression of genes encoding neuropeptides, prohormone convertases, alpha-amidating enzyme and 7B2 in identified Lymnaea neurons.
abstract: Synthesis of bioactive peptides is regulated by several post-translational processing events, including cleavage of peptides from a prohormone, and chemical modifications. Using quantitative in situ hybridization and neuron-specific macro-arrays, we first demonstrated cell-type specific expression levels of transcripts encoding prohormone convertases, peptide alpha-amidating enzyme as well as the chaperone 7B2 in Lymnaea neurons. Second, we demonstrated a strict correlation between alpha-amidating enzyme and its neuropeptide substrates. However, this strict relationship of gene expression of the three prohormone convertases and types of cleavage site used is not present. Third, we showed by a physiological stimulus, i.e. clean water, which leads to a stereotyped egg-laying behaviour resulting in successful egg-mass deposition, the co-regulated induction of transcript levels of processing enzymes, 7B2, and egg-laying hormone. These data indicate that (i) these enzymes (and chaperone) are involved in egg-laying hormone neuropeptide biosynthesis, and (ii) neuropeptide release and transcript levels of both prohormones and processing enzymes are regulated in accordance with physiological demands.
authors.affiliation: Department Molecular and Cellular Neurobiology, Institute of Neurosciences, Faculty of Earth and Life sciences, Vrije Universiteit Amsterdam, De Boelelaan, Amsterdam, the Netherlands. sspijker@falw.vu.nl
authors.forename: Sabine
authors.initials: S
authors.lastname: Spijker
authors.forename: Hilary E
authors.initials: HE
authors.lastname: Sharp-Baker
authors.forename: Wijnand P M
authors.initials: WP
authors.lastname: Geraerts
authors.forename: Jan
authors.initials: J
authors.lastname: Van Minnen
authors.forename: August B
authors.initials: AB
authors.lastname: Smit
mesh_terms: D000818:Animals; D005786:Gene Expression Regulation / Q000502:physiology*; D007447:Invertebrate Hormones / Q000235:genetics / Q000378:metabolism; D008195:Lymnaea / Q000378:metabolism*; D006899:Mixed Function Oxygenases / Q000235:genetics* / Q000378:metabolism; D018832:Molecular Chaperones / Q000235:genetics* / Q000378:metabolism; D009097:Multienzyme Complexes / Q000235:genetics* / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D009479:Neuropeptides / Q000235:genetics* / Q000378:metabolism; D010812:Physical Stimulation; D043484:Proprotein Convertases / Q000235:genetics* / Q000378:metabolism; D011499:Protein Processing, Post-Translational / Q000235:genetics
chemical_list: C488970:7B2 protein, Lymnaea stagnalis; D007447:Invertebrate Hormones; D018832:Molecular Chaperones; D009097:Multienzyme Complexes; D009479:Neuropeptides; C026880:egg-laying hormone, Mollusca; D006899:Mixed Function Oxygenases; C035189:peptidylglycine monooxygenase; D043484:Proprotein Convertases