Clip domain serine protease (cSPs) play an important role in the innate immune defense of crustaceans. In this study, a clip domain serine protease (MncSP) and its alternative transcript (MncSP-isoform) were identified from Macrobrachium nipponense. The full-length cDNA sequences of MncSP and MncSP-isoform were 2447 and 2351 bp with open reading frames comprising 1497 and 1401 bp nucleotides and encoding 498 and 466 amino acids, respectively. The genome of MncSP had 10 exons and 9 introns. MncSP contained all 10 exons, whereas MncSP-isoform lacked the second exon. MncSP and MncSP-isoform contained a signal peptide, a clip domain, and a Tryp_SPc domain. Phylogenetic tree analysis showed that MncSP and MncSP-isoform clustered with cSPs from Palaemonidae. MncSP and MncSP-isoform were widely distributed in hemocytes, heart, hepatopancreas, gills, stomach, and intestine. The expression profiles of MncSP and MncSP-isoform in the hemocytes of M. nipponense changed after simulation by Vibrio parahaemolyticus or Staphylococcus aureus. The RNAi of MncSP could inhibit the expression of antimicrobial peptides (AMPs), including crustins and anti-lipopolysaccharide factors. Phenoloxidase activity was also down-regulated in MncSP-silenced prawns. This study indicated that MncSP participated in the synthesis of AMPs and the activation of prophenoloxidase.

剪辑域丝氨酸蛋白酶 (cSPs) 在甲壳类动物的先天免疫防御中发挥着重要作用。在这项研究中，从日本沼虾中鉴定出一种剪辑域丝氨酸蛋白酶 ( MncSP)及其替代转录物 ( MncSP-isoform ) 。MncSP和MncSP 异构体的全长 cDNA 序列分别为 2447 和 2351 bp，开放阅读框包括 1497 和 1401 bp 核苷酸，分别编码 498 和 466 个氨基酸。Mn cSP的基因组有10个外显子和9个内含子。MncSP包含所有 10 个外显子，而MncSP-isoform缺少第二个外显子。MncSP 和 MncSP 同种型包含一个信号肽、一个剪辑域和一个 Tryp_SPc 域。系统发育树分析表明，MncSP 和 MncSP 亚型与来自 Palaemonidae 的 cSP 聚集在一起。MncSP和MncSP 异构体广泛分布于血细胞、心脏、肝胰腺、鳃、胃和肠中。在副溶血性弧菌或金黄色葡萄球菌模拟后，日本分枝杆菌血细胞中MncSP和MncSP 亚型的表达谱发生了变化。MncSP的RNAi可以抑制抗菌肽 (AMPs) 的表达，包括硬皮素和抗脂多糖因子。在MncSP沉默的虾中，酚氧化酶活性也被下调。本研究表明 MncSP 参与了 AMPs 的合成和酚氧化酶原的激活。