The insect group II chitinase (ChtII, also known as Cht10) is a unique chitinase with multiple catalytic and chitin binding domains. It has been proved to be an essential chitinase for molting genetically. However, ChtII's role in chitin degradation during insect development remains poorly understood. Obtaining this knowledge is the key to fully understanding the chitin degradation system in insect. Here, we investigated the role of OfChtII during the molting of Ostrinia furnacalis, a model lepidopteran pest insect. OfChtII was expressed earlier than OfChtI (OfCht5) and OfChi-h, at both the gene and protein levels during larva-pupa molting as evidenced by qPCR and western blot analyses. A truncated OfChtII, OfChtII-B4C1, was recombinantly expressed in Pichia pastoris cells and purified to homogeneous. The recombinant OfChtII-B4C1 loosened compacted chitin particles and produced holes in the cuticle surface as evidenced by scanning electron microscopy. It synergized with OfChtI and OfChi-h when hydrolyzing insoluble α-chitin. These findings suggested an important role for ChtII during insect molting and also provided a strategy for the coordinated degradation of the cuticular chitin during insect molting by ChtII, ChtI and Chi-h. This article is protected by copyright. All rights reserved.

中文翻译：

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昆虫组II几丁质酶OfChtII促进幼虫-蛹蜕皮过程中几丁质降解

昆虫组 II 几丁质酶（ChtII，也称为 Cht10）是一种独特的几丁质酶，具有多个催化和几丁质结合域。它已被证明是遗传蜕皮的必需几丁质酶。然而，ChtII 在昆虫发育过程中几丁质降解中的作用仍然知之甚少。获得这些知识是全面了解昆虫几丁质降解系统的关键。在这里，我们调查了 OfChtII 在 Ostrinia furnacalis（一种模型鳞翅目害虫）蜕皮过程中的作用。正如qPCR和蛋白质印迹分析所证明的那样，OfChtII在幼虫-蛹蜕皮期间在基因和蛋白质水平上的表达早于OfChtI（OfCht5）和OfChi-h。截短的OfChtII，OfChtII-B4C1，在毕赤酵母细胞中重组表达并纯化至均质。重组OfChtII-B4C1 使压实的几丁质颗粒松散，并在角质层表面产生孔洞，如扫描电子显微镜所示。当水解不溶性α-几丁质时，它与OfChtI和OfChi-h协同作用。这些发现表明 ChtII 在昆虫蜕皮过程中的重要作用，也为 ChtII、ChtI 和 Chi-h 在昆虫蜕皮过程中协调降解表皮几丁质提供了策略。本文受版权保护。版权所有。这些发现表明 ChtII 在昆虫蜕皮过程中的重要作用，也为 ChtII、ChtI 和 Chi-h 在昆虫蜕皮过程中协调降解表皮几丁质提供了策略。本文受版权保护。版权所有。这些发现表明 ChtII 在昆虫蜕皮过程中的重要作用，也为 ChtII、ChtI 和 Chi-h 在昆虫蜕皮过程中协调降解表皮几丁质提供了策略。本文受版权保护。版权所有。