title: Isolation, characterization and expression analysis of the ornithine decarboxylase gene (ODC1) of the entomopathogenic fungus, Metarhizium anisopliae.
abstract: The gene ODC1, which codes for the ornithine decarboxylase enzyme, was isolated from the entomopathogenic fungus, Metarhizium anisopliae. The deduced amino acid sequence predicted a protein of 447 amino acids with a molecular weight of 49.3 kDa that contained the canonical motifs of ornithine decarboxylases. The ODC1 cDNA sequence was expressed in Escherichia coli cells; radiometric enzyme assays showed that the purified recombinant protein had ornithine decarboxylase activity. The optimum pH of the purified Odc1 protein was 8.0-8.5, and the optimum reaction temperature was 37°C. The apparent K(m) for ornithine at a pyridoxal phosphate concentration of 20mM was 22 μM. The competitive inhibitor of ODC activity, 1,4-diamino-2-butanone (DAB), at 0.25 mM inhibited 95% of ODC activity. The ODC1 mRNA showed an increase at the beginning of appressorium formation in vitro. During the M. anisopliae invasion process into Plutella xylostella larvae, the ODC1 mRNA showed a discrete increase within the germinating spore and during appressorium formation. The second expression peak was higher and prolonged during the invasion and death of the insect. The ODC1 gene complements the polyamine auxotrophy of Yarrowia lipolytica odc null mutant.
authors.affiliation: Departamento de Biología, Universidad de Guanajuato, Guanajuato, Gto., Mexico.
authors.forename: Jaime
authors.initials: J
authors.lastname: Madrigal Pulido
authors.forename: Israel
authors.initials: I
authors.lastname: Padilla Guerrero
authors.forename: Isaura de J
authors.initials: Ide J
authors.lastname: Magaña Martínez
authors.forename: Briseida
authors.initials: B
authors.lastname: Cacho Valadez
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Torres Guzman
authors.forename: Eduardo
authors.initials: E
authors.lastname: Salazar Solis
authors.forename: J
authors.initials: J
authors.lastname: Felix Gutierrez Corona
authors.forename: Augusto
authors.initials: A
authors.lastname: Schrank
authors.forename: Francisco
authors.initials: F
authors.lastname: Jiménez Bremont
authors.forename: Angélica
authors.initials: A
authors.lastname: González Hernandez
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D015870:Gene Expression; D007700:Kinetics; D052981:Metarhizium / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D008969:Molecular Sequence Data; D009036:Moths / Q000382:microbiology*; D009955:Ornithine Decarboxylase / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D009955:Ornithine Decarboxylase