title: Identification of Drosophila melanogaster yellow-f and yellow-f2 proteins as dopachrome-conversion enzymes.
abstract: This study describes the identification of Drosophila yellow-f and yellow-f2 as dopachrome-conversion enzymes responsible for catalysing the conversion of dopachrome into 5,6-dihydroxyindole in the melanization pathway. Drosophila yellow -y gene and yellow -b, -c, -f and -f2 genes were expressed in an insect cell/baculovirus expression system and their corresponding recombinant proteins were screened for dopachrome-conversion enzyme activity. Among the yellow and yellow -related genes, the yellow -f and yellow -f2 genes were identified as the genes coding for Drosophila dopachrome-conversion enzyme based on the high activity of their recombinant proteins in catalysing the production of 5,6-dihydroxyindole from dopachrome. Both yellow-f and yellow-f2 are capable of mediating a decarboxylative structural rearrangement of dopachrome, as well as an isomerization/tautomerization of dopamine chrome and dopa methyl ester chrome. Northern hybridization revealed the transcription of yellow -f in larvae and pupae, but a high abundance of mRNA was observed in later larval and early pupal stages. In contrast, yellow-f2 transcripts were present at all stages, but high abundance of its mRNA was observed in later-stage pupae and adults. These data indicate that yellow-f and yellow-f2 complement each other during Drosophila development and that the yellow-f is involved in larval and pupal melanization, and yellow-f2 plays a major role in melanization reactions in Drosophila during later pupal and adult development. Results from this study provide the groundwork towards a better understanding of the physiological roles of the Drosophila yellow gene family.
authors.affiliation: Department of Veterinary Pathobiology, University of Illinois at Urbana-Champaign, 2001 South Lincoln Avenue, Urbana, IL 61802, U.S.A.
authors.forename: Qian
authors.initials: Q
authors.lastname: Han
authors.forename: Jianmin
authors.initials: J
authors.lastname: Fang
authors.forename: Haizhen
authors.initials: H
authors.lastname: Ding
authors.forename: Jody K
authors.initials: JK
authors.lastname: Johnson
authors.forename: Bruce M
authors.initials: BM
authors.lastname: Christensen
authors.forename: Jianyong
authors.initials: J
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002262:Carboxy-Lyases / Q000235:genetics / Q000302:isolation & purification*; D004298:Dopamine / Q000378:metabolism; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000201:enzymology*; D045563:Indolequinones; D007211:Indoles / Q000378:metabolism*; D019746:Intramolecular Oxidoreductases / Q000235:genetics / Q000302:isolation & purification*; D007527:Isoenzymes / Q000235:genetics / Q000302:isolation & purification*; D007535:Isomerases / Q000235:genetics / Q000302:isolation & purification*; D007700:Kinetics; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000235:genetics / Q000302:isolation & purification*; D011809:Quinones / Q000378:metabolism*; D011994:Recombinant Proteins / Q000302:isolation & purification; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
chemical_list: D029721:Drosophila Proteins; D045563:Indolequinones; D007211:Indoles; D007527:Isoenzymes; D009097:Multienzyme Complexes; D011809:Quinones; D011994:Recombinant Proteins; C469678:yellow-f protein, Drosophila; C469679:yellow-f2 protein, Drosophila; C001123:dopachrome; D002262:Carboxy-Lyases; D007535:Isomerases; D019746:Intramolecular Oxidoreductases; C042501:dopachrome isomerase; D004298:Dopamine