Identification of Drosophila melanogaster yellow-f and yellow-f2 proteins as dopachrome-conversion enzymes.
Identification of Drosophila melanogaster yellow-f and yellow-f2 proteins as dopachrome-conversion enzymes.
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DOI：
10.1042/bj20020272
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发表时间：
2002-11
期刊：
影响因子：
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通讯作者：
Q. Han;Jianmin Fang;H. Ding;Jody K Johnson;B. M. Christensen;Jianyong Li
中科院分区：
文献类型：
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作者：
Q. Han;Jianmin Fang;H. Ding;Jody K Johnson;B. M. Christensen;Jianyong Li
本研究鉴定了果蝇黄-f和黄-f2作为多巴胺转化酶，在黑化途径中催化多巴胺转化为5,6-二羟基吲哚。在昆虫细胞/杆状病毒表达系统中表达果蝇黄-y基因和黄-b、黄-c、黄-f和黄-f2基因，并对其对应的重组蛋白进行多巴胺转换酶活性筛选。在黄色及黄色相关基因中，黄-f和黄-f2基因是果蝇多巴胺转化酶的编码基因，其重组蛋白在催化多巴胺生成5,6-二羟基吲哚方面具有较高的活性。黄-f和黄-f2都能介导多巴胺的脱羧结构重排，以及多巴胺铬和多巴甲酯铬的异构化/互变异构化。Northern杂交发现黄-f在幼虫和蛹中均有转录，但在幼虫后期和蛹早期均有高丰度的mRNA表达。相反，黄f2转录本在所有阶段都存在，但在后期蛹和成虫中观察到其mRNA的高丰度。这些数据表明，在果蝇的发育过程中，黄-f和黄-f2是互补的，黄-f参与了幼虫和蛹的黑化过程，黄-f2在果蝇后期蛹和成虫发育过程中的黑化反应中起主要作用。本研究结果为更好地理解果蝇黄色基因家族的生理作用提供了基础。
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.