State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
Pest Manag Sci. 2010 Jan;66(1):65-73. doi: 10.1002/ps.1832.
Helicoverpa armigera (Hübner) causes severe losses in many crops including cotton. Cytochrome P450s play crucial roles in the metabolism of many important compounds in various organisms. The authors attempt to identify new cytochrome P450 genes and investigate their expression profile and xenobiotic response in order to understand the nature and roles of cytochrome P450s in this important pest.
A novel P450 cDNA (CYP9A17), encoding a protein of 531 amino acid residues, was isolated from H. armigera. CYP9A17 is a typical microsomal P450, showing the highest (93.9%) amino acid identity with CYP9A12 from H. armigera. The high similarity is not only found between cDNAs, but also between the intron-exon organisation. CYP9A12 is constitutively universally expressed in all four life stages and in all tested larval tissues, whereas CYP9A17 is specifically expressed in the larval midgut and fat body. Real-time quantitative RT-PCR showed that the level of both CYP9A12 and CYP9A17 mRNA is affected in dose-dependent and tissue-specific manners by deltamethrin, gossypol and phenobarbital.
CYP9A12 and CYP9A17 showed high sequence identity, but with differential expression patterns, suggesting that CYP9A12 and CYP9A17 genes in H. armigera might diverge via subfunctionalisation after the gene duplication event.
棉铃虫（Hübner）会对包括棉花在内的许多作物造成严重损失。细胞色素 P450 在各种生物体中对许多重要化合物的代谢起着至关重要的作用。作者试图鉴定新的细胞色素 P450 基因，并研究其表达谱和对外源化合物的反应，以了解细胞色素 P450 在这种重要害虫中的性质和作用。
从棉铃虫中分离到一个新的 P450 cDNA（CYP9A17），编码一个由 531 个氨基酸残基组成的蛋白质。CYP9A17 是一种典型的微粒体 P450，与棉铃虫的 CYP9A12 具有最高的（93.9%）氨基酸同一性。这种高度相似性不仅存在于 cDNA 之间，也存在于内含子-外显子组织之间。CYP9A12 在所有四个生命阶段和所有测试的幼虫组织中都持续普遍表达，而 CYP9A17 则特异性表达在幼虫中肠和脂肪体中。实时定量 RT-PCR 显示，CYP9A12 和 CYP9A17 的 mRNA 水平均受溴氰菊酯、棉酚和苯巴比妥剂量依赖性和组织特异性的影响。
CYP9A12 和 CYP9A17 具有高度的序列同一性，但表达模式不同，表明棉铃虫中的 CYP9A12 和 CYP9A17 基因可能在基因复制事件后通过亚功能化而分化。
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