The QM gene that encodes for the ribosomal protein L10 was firstly identified from human tumour cells as a tumour suppressor. In this study, a QM gene was identified in silkworm Bombyx mori (BmQM) and its immunomodulatory function was explored. BmQM messenger RNA (mRNA) and protein were highly expressed in the silk gland and fat body, and expressed in all stages of silkworm growth. After challenged with four different microorganisms, the expression levels of BmQM mRNA in fat body or haemocytes were significantly upregulated compared with the control. After knock‐down of BmQM gene, the expressions of some immune genes (PGRPS6, Gloverin0, Lysozyme and Moricin) were affected, and the transcripts of prophenoloxidase1 and prophenoloxidase2 have different degrees of change. The phenoloxidase activity was significantly reduced when the purified recombinant BmQM protein was injected. Recombinant BmQM protein inhibited systemic melanization and suppressed prophenoloxidase activation stimulated by Micrococcus luteus, but it did not affect phenoloxidase activity. Far‐western blotting assays showed that the BmQM protein interacted with silkworm BmJun protein, which negatively regulates AP‐1 expression. Our results indicated that BmQM protein could affect some immune gene expression and negatively regulate the prophenoloxidase‐activating system, and it may play an important role in regulation of the innate immunity in insects.

中文翻译：

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家蚕的QM蛋白通过与Jun蛋白相互作用而负调节酚氧化酶原激活和黑色素化。

首先从人肿瘤细胞中鉴定出编码核糖体蛋白L10的QM基因作为抑癌基因。在这项研究中，在家蚕（BmQM）中鉴定了一个QM基因，并探讨了其免疫调节功能。BmQM信使RNA（mRNA）和蛋白质在丝腺和脂肪体内高表达，并在蚕生长的所有阶段表达。用四种不同的微生物攻击后，与对照相比，脂肪体或血细胞中BmQM mRNA的表达水平显着上调。敲除BmQM基因后，一些免疫基因（PGRPS6，Gloverin0，溶菌酶和Moricin）受到影响，并且前酚氧化酶1和前酚氧化酶2的转录物有不同程度的变化。注射纯化的重组BmQM蛋白后，酚氧化酶活性显着降低。重组BmQM蛋白抑制黄褐微球菌刺激的全身黑色素化并抑制酚氧化酶原激活，但它不影响酚氧化酶的活性。远古印迹分析表明，BmQM蛋白与家蚕BmJun蛋白相互作用，从而对AP-1的表达产生负调节作用。我们的结果表明，BmQM蛋白可能影响某些免疫基因的表达并负面调节酚氧化酶原激活系统，并且可能在调节昆虫的先天免疫中起重要作用。