Peroxidasin plays a unique role in the formation and stability of extracellular matrix (ECM) in the animal kingdom; however, it was only characterized in Diptera, not in other insect orders. In this study peroxidasin (CsPxd) was first identified and characterized from Chilo suppressalis, a lepidopteran pest. CsPxd complementary DNA with a 4080 bp open reading frame encodes a peptide of 1359 amino acids; the derived amino acid sequence of CsPxd harbors the typical structural characteristics of peroxidasin family in heme‐peroxidase superfamily, including the signal peptide at N‐terminal, leucine‐rich repeat domain, Ig‐loop motifs and peroxidase domain, signifying the extracellular location of protein and the involvement in ECM formation. Eukaryotic expression reveals CsPxd protein displays peroxidase activity on H2O2, justifying the membership of peroxidase. Phyletic analysis shows the monophyletic evolution pattern of peroxidasin in insect phyle, and moreover only one peroxidasin is present in each species of insects, suggesting its evolutionary conservation on function. Peroxidasin messenger RNA is mainly expressed in egg and the final instar larvae stage. Injection of peroxidasin double‐stranded RNA into the final instar larvae impacts the cuticle sclerotization during the metamorphosis from larvae to pupa, and eventually lead to lethality of larvae and pupa. These results suggest the presence of collagen crosslink in chorion and cuticle of insects, and indicate peroxidasin plays a role in the development of chorion and cuticle; furthermore peroxidasin might be the one of potential target genes for pest control using RNA interference.

中文翻译：

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二化螟过氧化物酶的分子鉴定、表达及功能分析


过氧化酶在动物界细胞外基质（ECM）的形成和稳定性中发挥着独特的作用；然而，它仅在双翅目中存在，而在其他昆虫目中则没有。在这项研究中，过氧化物酶 (CsPxd) 首次从鳞翅目害虫二化螟中被鉴定和表征。 CsPxd 互补 DNA 具有 4080 bp 开放阅读框，编码 1359 个氨基酸的肽； CsPxd的衍生氨基酸序列具有血红素过氧化物酶超家族中过氧化物酶家族的典型结构特征，包括N端信号肽、富含亮氨酸的重复结构域、Ig环基序和过氧化物酶结构域，标志着蛋白质的细胞外定位以及参与 ECM 形成。真核表达表明 CsPxd 蛋白对 H2O2 表现出过氧化物酶活性，证明了过氧化物酶的成员资格。系统进化分析显示了过氧化物酶在昆虫门中的单系进化模式，而且每种昆虫中仅存在一种过氧化物酶，表明其功能上的进化保守性。过氧化酶信使RNA主要在卵和末龄幼虫阶段表达。向末龄幼虫注射过氧化物酶双链RNA会影响幼虫到蛹变态过程中角质层的硬化，最终导致幼虫和蛹的致死。这些结果表明昆虫绒毛膜和角质层中存在胶原交联，并表明过氧化物酶在绒毛膜和角质层的发育中发挥作用；此外，过氧化酶可能是利用RNA干扰控制害虫的潜在靶基因之一。