Abstract Peptidoglycan recognition proteins (PGRPs) are pattern recognition receptors that can recognize bacterial peptidoglycans and trigger the innate immune response of insects. Here, we identified and characterized a novel short-type Bombyx mori peptidoglycan recognition proteins short-4 (BmPGRP-S4) in a lepidopteran insect, Bombyx mori. BmPGRP-S4 exhibited a cDNA sequence length of 600 bp, encoding 199 aa with a protein molecular weight of 22 kDa. Multiple sequence alignment revealed that BmPGRP-S4 contains a conserved PGRP domain. Quantitative real-time polymerase chain reaction analysis showed that BmPGRP-S4 is highly expressed in the early developmental stages of silkworm larvae and presents tissue-specific expression in hemocytes. Interestingly, BmPGRP-S4 expression is significantly induced by bacterial infection in the midgut, fat body, and hemocytes. Furthermore, a dual luciferase reporter gene assay revealed that BmPGRP-S4 can activate the expression of the antimicrobial peptide genes lebocin, moricin, cecropin D, cecropin B, and attacin. Taken together, these results suggest that BmPGRP-S4 plays an important role in the innate immune response of silkworms.

中文翻译：

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家蚕新型短型 BmPGRP-S4 的鉴定和表征，家蚕，参与先天免疫

摘要 肽聚糖识别蛋白（PGRPs）是一种模式识别受体，可以识别细菌肽聚糖并触发昆虫的先天免疫反应。在这里，我们在鳞翅目昆虫家蚕中鉴定并表征了一种新型短型家蚕肽聚糖识别蛋白 short-4 (BmPGRP-S4)。BmPGRP-S4 的 cDNA 序列长度为 600 bp，编码 199 个氨基酸，蛋白质分子量为 22 kDa。多序列比对显示 BmPGRP-S4 包含一个保守的 PGRP 结构域。定量实时聚合酶链反应分析表明，BmPGRP-S4在家蚕幼虫早期发育阶段高表达，在血细胞中呈现组织特异性表达。有趣的是，中肠、脂肪体、和血细胞。此外，双荧光素酶报告基因检测显示 BmPGRP-S4 可以激活抗菌肽基因 lebocin、moricin、cecropin D、cecropin B 和 attacin 的表达。总之，这些结果表明 BmPGRP-S4 在家蚕的先天免疫反应中起着重要作用。