title: An estimate of the number of serine protease genes expressed in sheep blowfly larvae (Lucilia cuprina).
abstract: A large and diverse family of serine protease genes was identified in first-instar larval cDNA of the sheep blowfly (Lucilia cuprina). This complex repertoire of genes was identified via a PCR approach using highly degenerate primers based on structurally conserved regions which surround the active site His and Ser residues found in all serine proteases. PCR products from entire first-instar larval cDNA, or from third-instar larval salivary glands or cardia, generated using a microscale RT-PCR method, were cloned into a plasmid vector. Comparison of the restriction fragment patterns of PCR products generated from the three different sources suggests a highly diverse tissue-specific pattern of serine protease expression in this organism. Detailed analysis of the restriction fragment patterns of sixty-nine randomly selected clones from entire first-instar larvae revealed forty-nine different classes of PCR product. Maximum likelihood analysis of these data indicate that between 125 and 220 different serine protease genes are expressed in first-instar larvae of L. cuprina. DNA sequence analysis of ten randomly-selected clones, derived from the three tissue sources, indicated that all ten encoded serine protease gene fragments. A frequently occurring PCR product, generated from both first-instar total cDNA and third-instar cardia cDNA, showed 73% amino acid identity to a digestive protease expressed in Drosophila melanogaster larval gut cells.
authors.affiliation: CSIRO Division of Tropical Animal Production, Indooroopilly, Queensland, Australia.
authors.forename: C M
authors.initials: CM
authors.lastname: Elvin
authors.forename: T
authors.initials: T
authors.lastname: Vuocolo
authors.forename: W J
authors.initials: WJ
authors.lastname: Smith
authors.forename: C H
authors.initials: CH
authors.lastname: Eisemann
authors.forename: P W
authors.initials: PW
authors.lastname: Riddles
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001482:Base Composition; D001483:Base Sequence; D003062:Codon / Q000235:genetics; D017124:Conserved Sequence; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D004175:Diptera / Q000201:enzymology* / Q000235:genetics*; D004331:Drosophila melanogaster / Q000201:enzymology / Q000235:genetics; D015870:Gene Expression; D017344:Genes, Insect; D007814:Larva / Q000201:enzymology / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases / Q000235:genetics*; D012756:Sheep; D014018:Tissue Distribution
chemical_list: D003062:Codon; D017931:DNA Primers; D018076:DNA, Complementary; D012697:Serine Endopeptidases