ABSTRACT: Tanning is a complex extracellular process that is a mechanism for stabilizing proteinaceous extracellular structures. Phenoloxidases play important roles in cross-linking during tanning, and laccase (EC 1.10.3.2) is a member of the phenoloxidase enzyme class. In this study, we identified a laccase gene (MpLac) from the clam Meretrix petechialis and found that MpLac might be involved in shell periostracal tanning of clams. Using whole-mount in situ hybridization, we found that MpLac mRNA in the larval clam was mainly expressed in the mantle edge. In the adult clam, our quantitative real-time PCR results showed that the mantle was also a tissue with a high MpLac expression level; in addition, by combining the results of fluorescence in situ hybridization, H&E staining and transmission electron microscopy, we found that the inner epithelium of the outer fold of the mantle edge, which is involved in periostracum formation, was the exact region in which MpLac mRNA was expressed. Furthermore, knocking down the expression of MpLac by RNA interference (RNAi) bleached the new shell periostracum. All of our results suggest the involvement of MpLac in shell periostracal tanning of M. petechialis.

中文翻译：

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漆酶基因的鉴定涉及蛤reMeretrix petechialis的壳周鞣制

摘要：鞣制是一个复杂的细胞外过程，是稳定蛋白质性细胞外结构的一种机制。酚氧化酶在鞣制过程中的交联中起重要作用，漆酶（EC 1.10.3.2）属于酚氧化酶类。在这项研究中，我们从蛤Me Meretrix petechialis中鉴定了一个漆酶基因（MpLac），并发现MpLac可能与蛤的壳周皮鞣制有关。使用整个原位杂交，我们发现幼虫蛤中的MpLac mRNA主要表达在地幔边缘。在成年蛤中，我们的定量实时PCR结果显示，套子也是MpLac高的组织表达水平 此外，通过结合荧光原位杂交，H＆E染色和透射电子显微镜的结果，我们发现与骨膜周形成有关的地幔边缘外褶皱的内部上皮是MpLac mRNA的确切区域被表达了。此外，通过RNA干扰（RNAi）抑制MpLac的表达可漂白新的壳骨膜。我们所有的结果都表明参与MpLac在外壳periostracal晒黑M. petechialis。