Laccase 2 is the phenoloxidase gene required for beetle cuticle tanning
Laccase 2 is the phenoloxidase gene required for beetle cuticle tanning
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DOI：
10.1073/pnas.0504982102
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发表时间：
2005-08-09
影响因子：
11.1
通讯作者：
Kramer, KJ
中科院分区：
文献类型：
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作者：
Arakane, Y;Muthukrishnan, S;Kramer, KJ
无脊椎动物的角质层晒黑（或硬化和色素沉着）涉及蛋白质的氧化共轭，这使得它们不溶，并使外骨骼的颜色变硬和变暗。两种酚氧化酶，漆酶和酪氨酸酶，已被提出参与制革，但证明的酶（S）负责这一过程的真实身份一直难以捉摸。我们报告的漆酶和酪氨酸酶的cDNA克隆从红粉甲虫，赤拟谷盗，以及他们的发展模式的表达。为了测试这些类型的酶参与角质层晒黑，我们进行了RNA干扰实验，以降低单个酚氧化酶的水平。在dsRNA介导的转录物耗竭后，除了漆酶2之外，所有测试的酚氧化酶都获得了正常的表型。注射了漆酶2基因的dsRNA的昆虫未能晒黑，身体柔软且变形，随后以dsRNA剂量依赖性方式死亡。这里提出的结果支持的假设，两个异构体的漆酶2产生的选择性剪接催化幼虫，蛹，和成人角质层鞣制拟谷盗。
Cuticle tanning (or sclerotization and pigmentation) in invertebrates involves the oxidative conjugation of proteins, which renders them insoluble and hardens and darkens the color of the exoskeleton. Two kinds of phenoloxidases, laccase and tyrosinase, have been proposed to participate in tanning, but proof of the true identity of the enzyme(s) responsible for this process has been elusive. We report the cloning of cDNAs for laccases and tyrosinases from the red flour beetle, Tribolium castaneum, as well as their developmental patterns of expression. To test for the involvement of these types of enzymes in cuticle tanning, we performed RNA interference experiments to decrease the levels of individual phenoloxidases. Normal phenotypes were obtained after dsRNA-mediated transcript depletion for all phenoloxidases tested, with the exception of laccase 2. Insects injected with dsRNA for the laccase 2 gene failed to tan, were soft-bodied and deformed, and subsequently died in a dsRNA dose-dependent fashion. The results presented here support the hypothesis that two isoforms of laccase 2 generated by alternative splicing catalyze larval, pupal, and adult cuticle tanning in Tribolium.