Hou Fujun, Liu Tao, Wang Qiai, Liu Yongjie, Sun Chengbo, Liu Xiaolin
College of Animal Science and Technology, Northwest A&F University, Yangling 712100, Shaanxi, China; Shaanxi Key Laboratory of Molecular Biology for Agriculture, Yangling 712100, Shaanxi, China.
Fisheries College, Guangdong Ocean University, Guangdong, 524088, China.
Fish Shellfish Immunol. 2017 Jan;60:1-5. doi: 10.1016/j.fsi.2016.09.047. Epub 2016 Sep 23.
Croquemort, the homologue of human CD36, is a member of class B scavenger receptors, which is involved in bacteria phagocytosis and cytokins release. However, there is still less information about Croquemort in crustaceans. Here, a Croquemort from Pacific white shrimp Litopenaeus vannamei (LvCroquemort) and its truncated form (LvCroquemort-S1) cDNA sequences were identified, characterized and their role in bacteria clearance was investigated. The deduced protein of LvCroquemort is 533 amino acids and contains typical domains of CD36: the N-terminus and C-terminus in cytoplasm, two transmembrane regions and a large extracellular loop-like domain. However, LvCroquemort-S1 losses partial cDNA sequence in its middle and its deduced protein losses the C-terminal transmembrane region and C-terminus in cytoplasm, the latter of which is found participating in cytokins release in human CD36. LvCroquemort transcript is highly expressed in gills, hemocytes, testis and slightly in heart, hepatopancreas and nerve. Besides, its responses to bacteria Vibrio anguillarum and white spot syndrome virus were examined. Knock-down of LvCroquemort by specific dsRNA reduces bacteria clearance. These initial data will help to further understand roles of Croquemort in crustacean innate immunity.
克罗马特（Croquemort）是人类CD36的同源物，属于B类清道夫受体家族成员，参与细菌吞噬作用和细胞因子释放。然而，关于甲壳类动物中克罗马特的信息仍然较少。在此，我们鉴定并表征了南美白对虾（Litopenaeus vannamei）中的一种克罗马特（LvCroquemort）及其截短形式（LvCroquemort-S1）的cDNA序列，并研究了它们在细菌清除中的作用。推导的LvCroquemort蛋白有533个氨基酸，包含CD36的典型结构域：细胞质中的N端和C端、两个跨膜区域以及一个大的细胞外环样结构域。然而，LvCroquemort-S1在其序列中部缺失了部分cDNA序列，其推导的蛋白缺失了C端跨膜区域和细胞质中的C端，而后者在人类CD36中参与细胞因子释放。LvCroquemort转录本在鳃、血细胞、睾丸中高表达，在心脏、肝胰腺和神经中略有表达。此外，还检测了它对鳗弧菌（Vibrio anguillarum）和白斑综合征病毒的反应。通过特异性双链RNA敲低LvCroquemort会降低细菌清除率。这些初步数据将有助于进一步了解克罗马特在甲壳类动物先天免疫中的作用。
