Previous studies have revealed that some proteins in Bombyx mori larvae digestive juice show antiviral activity. Here, based on the label-free proteomics data, BmLipase member H-A (BmLHA) was identified as being involved in the response to BmNPV infection in B. mori larvae digestive juice. In the present study, a gene encoding the BmLHA protein in B. mori was characterized. The protein has an open reading fragment of 999 bp, encoding a predicted 332 amino acid residue-protein with a molecular weight of approximately 35.9 kDa. The phylogenetic analysis revealed that BmLHA shares a close genetic distance with Papilio xuthus Lipase member H-A. BmLHA was highly expressed in the middle part of the B. mori gut, and the expression level increased with instar rising in larvae. There was higher expression of BmLHA in A35 than in P50 strains, and it was upregulated in both A35 and P50 strains, following BmNPV infection. The expression level of VP39 decreased significantly in appropriate recombinant-BmLHA-treated groups compared with the PBS-treated group in B. mori larvae and BmN cells. Meanwhile, overexpression of BmLHA significantly reduced the infectivity of BmNPV in BmN cells. These results indicated that BmLHA did not have digestive function but had anti-BmNPV activity. Taken together, our work provides valuable data for the clarification of the molecular characterization BmLHA and supplements research on proteins of anti-BmNPV activity in B. mori.

中文翻译：

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家蚕中的一种新型的消化蛋白酶脂肪酶成员HA有助于消化汁抗家蚕核仁多角体病毒的抗病毒活性。

先前的研究表明，家蚕幼虫消化液中的某些蛋白质具有抗病毒活性。在这里，基于无标记的蛋白质组学数据，BmLipase成员HA（BmLHA）被确定参与家蚕双歧杆菌幼虫消化液中对BmNPV感染的反应。在本研究中，特征在于编码家蚕中BmLHA蛋白的基因。该蛋白质具有一个999 bp的开放阅读片段，编码一个预测的332个氨基酸残基蛋白质，分子量约为35.9 kDa。系统发育分析表明，BmLHA与Papilio xuthus脂肪酶成员HA的遗传距离很近。BmLHA在家蚕肠中部高表达，且其表达水平随着幼虫龄的增加而增加。A35中BmLHA的表达高于P50菌株，在BmNPV感染后，它在A35和P50菌株中均上调。在家蚕幼虫和BmN细胞中，适当的重组BmLHA处理组与PBS处理组相比，VP39的表达水平显着降低。同时，BmLHA的过表达显着降低了BmNV在BmN细胞中的感染性。这些结果表明，BmLHA不具有消化功能，但具有抗BmNPV活性。综上所述，我们的工作为阐明BmLHA的分子特征提供了有价值的数据，并补充了对桑蚕BmNPV活性蛋白的研究。同时，BmLHA的过表达显着降低了BmNV在BmN细胞中的感染性。这些结果表明，BmLHA不具有消化功能，但具有抗BmNPV活性。综上所述，我们的工作为阐明BmLHA的分子特征提供了有价值的数据，并补充了对桑蚕BmNPV活性蛋白的研究。同时，BmLHA的过表达显着降低了BmNV在BmN细胞中的感染性。这些结果表明，BmLHA不具有消化功能，但具有抗BmNPV活性。综上所述，我们的工作为阐明BmLHA的分子特征提供了有价值的数据，并补充了对桑蚕BmNPV活性蛋白的研究。