Ser/Thr protein phosphatase 2A (PP2A) is one of the type 2 protein phosphatases, which is required for many intracellular physiological processes and pathogen infection. However, the function of PP2A is unclear in silkworm, Bombyx mori. Here, we cloned and identified BmPP2A, a PP2A gene from B. mori, which has two HEAT domains and a high similarity to PP2A from other organisms. Our results showed that BmPP2A is localized in the cytoplasm and highly expressed in silkworm epidermis and midgut, and that Bombyx mori nucleopolyhedrovirus (BmNPV) infection induces down‐regulation of BmPP2A expression. Furthermore, up‐regulation of BmPP2A via overexpression significantly inhibited BmNPV multiplication. In contrast, down‐regulation of BmPP2A via RNA interference and okadaic acid (a PP2A inhibitor) treatment allowed robust BmNPV replication. This is the first report of PP2A having an antiviral effect in silkworm and provides insights into the function of BmPP2A, a potential anti‐BmNPV mechanism, and a possible target for the breeding of silkworm‐resistant strains.

中文翻译：

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家蚕PP2A基因对BmNPV具有抗病毒功能的鉴定

Ser/Thr 蛋白磷酸酶 2A (PP2A) 是 2 型蛋白磷酸酶之一，是许多细胞内生理过程和病原体感染所必需的。然而，PP2A在蚕Bombyx mori中的功能尚不清楚。在这里，我们克隆并鉴定了 BmPP2A，一种来自家蚕的 PP2A 基因，它具有两个 HEAT 结构域并且与来自其他生物的 PP2A 高度相似。我们的研究结果表明，BmPP2A 定位于细胞质中并在蚕表皮和中肠中高表达，家蚕核多角体病毒（BmNPV）感染诱导 BmPP2A 表达下调。此外，通过过表达上调 BmPP2A 显着抑制了 BmNPV 增殖。相比之下，通过 RNA 干扰和冈田酸（一种 PP2A 抑制剂）处理下调 BmPP2A 允许稳健的 BmNPV 复制。