Autor(es): Han, D; Fang, JM; Ding, HZ; Johnson, JK; Christensen, BM; Li, JY

Resumo: 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-dihydroxy-indole in the melanization pathway. Drosophila yellow-y gene and yellow-b, -c, -f and 42 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-f 2 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.

Palavras-Chave: 3,4-Dihydroxyphenylalanine (Dopa); Dopa Methyl Ester; Dopamine; Melanization

Imprenta: Biochemical Journal, v. 368, p. 333-340, 2002

Descritores: Aedes aegypti - Cell ; Aedes aegypti - Proteins

Data de publicação: 2002

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