title: Crustacean hyperglycaemic hormone (CHH)-like peptides and CHH-precursor-related peptides from pericardial organ neurosecretory cells in the shore crab, Carcinus maenas, are putatively spliced and modified products of multiple genes.
abstract: About 24 intrinsic neurosecretory neurons within the pericardial organs (POs) of the crab Carcinus maenas produce a novel crustacean hyperglycaemic hormone (CHH)-like peptide (PO-CHH) and two CHH-precursor-related peptides (PO-CPRP I and II) as identified immunochemically and by peptide chemistry. Edman sequencing and MS revealed PO-CHH as a 73 amino acid peptide (8630 Da) with a free C-terminus. PO-CHH and sinus gland CHH (SG-CHH) share an identical N-terminal sequence, positions 1-40, but the remaining sequence, positions 41-73 or 41-72, differs considerably. PO-CHH may have different precursors, as cDNA cloning of PO-derived mRNAs has revealed several similar forms, one exactly encoding the peptide. All PO-CHH cDNAs contain a nucleotide stretch coding for the SG-CHH(41-76) sequence in the 3'-untranslated region (UTR). Cloning of crab testis genomic DNA revealed at least four CHH genes, the structure of which suggest that PO-CHH and SG-CHH arise by alternative splicing of precursors and possibly post-transcriptional modification of PO-CHH. The genes encode four exons, separated by three variable introns, encoding part of a signal peptide (exon I), the remaining signal peptide residues, a CPRP, the PO-CHH(1-40)/SG-CHH(1-40) sequences (exon II), the remaining PO-CHH residues (exon III) and the remaining SG-CHH residues and a 3'-UTR (exon IV). Precursor and gene structures are more closely related to those encoding related insect ion-transport peptides than to penaeid shrimp CHH genes. PO-CHH neither exhibits hyperglycaemic activity in vivo, nor does it inhibit Y-organ ecdysteroid synthesis in vitro. From the morphology of the neurons it seems likely that novel functions remain to be discovered.
authors.affiliation: Institut für Zoophysiologie, Universität Bonn, Endenicher Allee 11-13, D-53115 Bonn, Germany. Dircksen@uni-bonn.de
authors.forename: H
authors.initials: H
authors.lastname: Dircksen
authors.forename: D
authors.initials: D
authors.lastname: Böcking
authors.forename: U
authors.initials: U
authors.lastname: Heyn
authors.forename: C
authors.initials: C
authors.lastname: Mandel
authors.forename: J S
authors.initials: JS
authors.lastname: Chung
authors.forename: G
authors.initials: G
authors.lastname: Baggerman
authors.forename: P
authors.initials: P
authors.lastname: Verhaert
authors.forename: S
authors.initials: S
authors.lastname: Daufeldt
authors.forename: T
authors.initials: T
authors.lastname: Plösch
authors.forename: P P
authors.initials: PP
authors.lastname: Jaros
authors.forename: E
authors.initials: E
authors.lastname: Waelkens
authors.forename: R
authors.initials: R
authors.lastname: Keller
authors.forename: S G
authors.initials: SG
authors.lastname: Webster
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D060829:Arthropod Proteins; D001483:Base Sequence; D001681:Biological Assay; D001786:Blood Glucose / Q000378:metabolism; D003386:Brachyura; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D026461:Ecdysteroids; D006458:Hemolymph; D007447:Invertebrate Hormones / Q000235:genetics / Q000302:isolation & purification*; D008297:Male; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009474:Neurons / Q000737:chemistry*; D009490:Neurosecretory Systems / Q000737:chemistry*; D010455:Peptides / Q000235:genetics / Q000302:isolation & purification*; D011498:Protein Precursors / Q000235:genetics / Q000302:isolation & purification*; D017422:Sequence Analysis, DNA; D013256:Steroids / Q000378:metabolism; D014018:Tissue Distribution
chemical_list: D060829:Arthropod Proteins; D001786:Blood Glucose; C116855:CHH-like protein, shrimp; D018076:DNA, Complementary; D026461:Ecdysteroids; D007447:Invertebrate Hormones; D010455:Peptides; D011498:Protein Precursors; D013256:Steroids