title: An unusual myosuppressin from the blood-feeding bug Rhodnius prolixus.
abstract: The myosuppressin (MS) gene was cloned from a central nervous system (CNS) cDNA library of the hematophagous insect Rhodnius prolixus and is predicted to contain two introns and three exons. The mRNA transcribed from the myosuppressin gene encodes an 88 amino acid prepropeptide, which results in a mature decapeptide after post-translational modification. When compared with the myosuppressins isolated from other insects, the R. prolixus myosuppressin has a unique amino acid sequence (pQDIDHVFMRFamide), with isoleucine (I) in position 3 and methionine (M) in position 8. Reverse transcriptase (RT)-PCR shows that Rhopr-MS is expressed in the CNS and posterior midgut in R. prolixus and immunohistochemistry suggests that an RFamide-like peptide is present in endocrine-like cells in the midgut. Physiological assays using Rhopr-MS indicate that, despite the unusual M at position 8, it still retains myoinhibitory activity, inhibiting the frequency and reducing the amplitude of contractions in the anterior midgut and hindgut, and decreasing heart rate.
authors.affiliation: University of Toronto Mississauga, Department of Biology, 3359 Mississauga Road, Mississauga, ON, Canada, L5L 1C6. dohee.lee@utoronto.ca
authors.forename: Dohee
authors.initials: D
authors.lastname: Lee
authors.forename: Hamza
authors.initials: H
authors.lastname: Taufique
authors.forename: Rosa
authors.initials: R
authors.lastname: da Silva
authors.forename: Angela B
authors.initials: AB
authors.lastname: Lange
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D018076:DNA, Complementary / Q000235:genetics; D015870:Gene Expression; D006339:Heart Rate; D008969:Molecular Sequence Data; D009119:Muscle Contraction; D009479:Neuropeptides / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D010802:Phylogeny; D012239:Rhodnius / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D016415:Sequence Alignment
chemical_list: D018076:DNA, Complementary; D009479:Neuropeptides