Key Laboratory of Tumor Molecular Biology, Department of Clinical Medicine, Binzhou Medical University, Yantai, 264003, China.
Key Laboratory of Tumor Molecular Biology, Department of Clinical Medicine, Binzhou Medical University, Yantai, 264003, China.
Dev Comp Immunol. 2021 Apr;117:103981. doi: 10.1016/j.dci.2020.103981. Epub 2020 Dec 17.
Peritrophic membrane (PM) refers to a vital physical barrier enabling shrimp to resist pathogen invasion. It primarily consists of chitin and proteins, mostly chitin-binding protein (CBP). CBPs have been identified from microorganisms to higher organisms. In the present study, a CBP, designated MjCBP, was reported from Marsupenaeus japonicus. The open reading frame of MjCBP was 1854 bp, encoding a protein with 618 amino acids (MH544098). To be specific, the theoretical pI and molecular mass of mature MjCBP reached 5.43 and 66064.00 Da, respectively. MjCBP consisted of seven type Ⅱ chitin-binding domains (ChtB D2), which was up-regulated after being challenged with Vibrio anguillarum and then agglutinating several bacteria. In addition, MjCBP and the first chitin-binding domain (CBD1) could bind to several Gram-positive and Gram-negative bacteria via the binding process to lipopolysaccharides and peptidoglycans, whereas CBD1 was not capable of agglutinating bacteria. Moreover, the anterior and posterior segments of CBD1 were synthesized in vitro, and the posterior segment could bind to lipopolysaccharides. However, both segments fail to agglutinate bacteria. Furthermore, MjCBP and CBD1 facilitated the clearance of V. anguillarum in vivo, and the silencing of MjCBP via RNA interference reduced the ability of bacterial clearance. As revealed from the mentioned results, MjCBP acts as an opsonin or pattern recognition receptor to achieve antibacterial immune response in shrimp.
围食膜（PM）是一种重要的物理屏障，使虾类能够抵抗病原体的入侵。它主要由几丁质和蛋白质组成，主要是几丁质结合蛋白（CBP）。CBPs 已从微生物到高等生物中被鉴定出来。本研究从日本对虾中报道了一种 CBP，命名为 MjCBP。MjCBP 的开放阅读框为 1854bp，编码一个含有 618 个氨基酸的蛋白质（MH544098）。具体来说，成熟 MjCBP 的理论等电点和分子量分别达到 5.43 和 66064.00Da。MjCBP 由七个 Ⅱ型几丁质结合域（ChtB D2）组成，在受到鳗弧菌的挑战后，它被上调，并随后凝集了几种细菌。此外，MjCBP 和第一个几丁质结合域（CBD1）可以通过与脂多糖和肽聚糖的结合过程结合几种革兰氏阳性和革兰氏阴性细菌，而 CBD1 不能凝集细菌。此外，CBD1 的前体和后体在体外被合成，后体可以与脂多糖结合。然而，这两个片段都不能凝集细菌。此外，MjCBP 和 CBD1 促进了体内鳗弧菌的清除，而通过 RNA 干扰沉默 MjCBP 降低了细菌清除的能力。从上述结果可以看出，MjCBP 作为一种调理素或模式识别受体，在虾类中实现了抗菌免疫反应。
