Evolution of CYP6B Genes Associated with Furanocoumarin Metabolism in the Papilio Glaucus Group

绝大多数毛虫以范围狭窄的植物为食，通常只在一个科内。这种特殊饲养器的显著特征之一是酶解毒系统，包括细胞色素P450单加氧酶，它是代谢寄主植物特有的毒素的理想配置。然而，虎燕尾(Papilio Glaucus)和它的近亲在毛虫中是特别的，因为它们可以吃更广泛的植物家族。在这样做的过程中，他们遇到了更多多样性的植物毒素，这些毒素在生物合成来源和结构上有所不同。该项目的目的是确定虎燕尾及其多面手近亲细胞色素P450单加氧酶的生化和分子生物学与其特殊近亲凤蝶属P450系统的不同之处。大多数Papilio物种专门以含有呋喃香豆素毒素的植物为食，这些物种依赖CyP6B家族中的P450来解毒。虽然它们很少遇到这些化合物，但老虎燕尾也可以代谢这些化合物，尽管速度较慢。在这个项目中，将在Papilio属内绘制CYP6B基因结构和调控的差异图谱(1)以了解特定谱系中如何产生普遍习惯，以及(2)确定P450进化如何有助于排毒能力的变化。

The vast majority of caterpillars feed on a narrow range of plants, often within only a single family. Among the distinguishing characteristics of such specialized feeders are enzymatic detoxification systems, including cytochrome P450 monooxygenases, that are ideally configured for metabolizing the toxins that typify their hostplants. The tiger swallowtail (Papilio glaucus) and its relatives, however, are exceptional among caterpillars in that they can feed on a much broader range of plant families. In doing so they encounter a substantially greater diversity of plant toxins, which differ in their biosynthetic origin and structure. This project is aimed at determining how the biochemistry and molecular biology of the cytochrome P450 monooxygenases of the tiger swallowtail and its generalist relatives differ from the P450 systems in their specialized relatives in the genus Papilio. Most Papilio species are specialized for feeding on plants containing toxins called furanocoumarins, and these species rely on P450s in the CYP6B family for detoxification. Although they rarely encounter them, tiger swallowtails can metabolize these compounds too, albeit at lower rates. In this project, differences in the structure and regulation of the CYP6B genes will be mapped within the genus Papilio (1) in order to understand how generalized habits can arise within specialized lineages and (2) to determine how P450 evolution can contribute to changes in detoxification capabilities.