title: Biochemical and molecular characterizaton of house cricket (Acheta domesticus, Orthoptera: Gryllidae) Delta9 desaturase.
abstract: Studies of insect fatty acyl-CoA desaturases have heretofore concentrated on the Diptera and Lepidoptera. We report here the isolation and characterization of a fatty acyl-CoA Delta9 desaturase from the house cricket, Acheta domesticus (Orthoptera). Two desaturase cDNAs were isolated from a library, one of which contained two intron sequences. The clones were identical in their respective coding regions, but had divergent 5' and 3' untranslated regions. The cDNAs encode a 359 amino acid desaturase enzyme that could rescue a fatty acyl-CoA desaturase auxotrophic phenotype when expressed in yeast. Biochemical analysis of lipids from transformed yeast cells confirmed that the enzyme is a Delta9 desaturase with activity on both palmitic and stearic acid substrates. Southern blotting indicated multiple Delta9 desaturase genes within the genome. A single message that was up-regulated in fed insects vs. starved insects was observed on northern blots, indicating transcriptional regulation in response to diet.
authors.affiliation: Department of Biochemistry/MS 330, University of Nevada, Reno 89557, USA.
authors.forename: M H
authors.initials: MH
authors.lastname: Riddervold
authors.forename: C
authors.initials: C
authors.lastname: Tittiger
authors.forename: G J
authors.initials: GJ
authors.lastname: Blomquist
authors.forename: C E
authors.initials: CE
authors.lastname: Borgeson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D006135:Gryllidae / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D007313:Insecta / Q000201:enzymology / Q000235:genetics; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013230:Stearoyl-CoA Desaturase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*
chemical_list: D013230:Stearoyl-CoA Desaturase