Identification of the Zinc Finger Protein ZRANB2 as a Novel Maternal Lipopolysaccharide-binding Protein That Protects Embryos of Zebrafish against Gram-negative Bacterial Infections
Identification of the Zinc Finger Protein ZRANB2 as a Novel Maternal Lipopolysaccharide-binding Protein That Protects Embryos of Zebrafish against Gram-negative Bacterial Infections
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鉴定锌指蛋白 ZRANB2 作为一种新型母体脂多糖结合蛋白，可保护斑马鱼胚胎免受革兰氏阴性细菌感染
DOI：
10.1074/jbc.m115.679167
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发表时间：
2016
影响因子：
4.8
通讯作者：
Zhang Shicui
中科院分区：
文献类型：
--
作者：
Wang Xia;Du Xiaoyuan;Li Hongyan;Zhang Shicui
锌指ZRANB 2蛋白广泛存在于动物中，但其功能和机制仍不清楚。在这里，我们清楚地表明，ZRANB 2是一种新发现的LPS结合蛋白，大量存在于斑马鱼的卵/胚胎中。我们还表明，重组ZRANB 2（rZRANB 2）作为一种模式识别受体，能够识别细菌的签名分子LPS，以及结合革兰氏阴性菌大肠杆菌，鳗弧菌，和气单胞菌，并作为一种抗菌效应分子能够直接杀死细菌的功能。此外，我们发现，N-末端残基11-37组成的第一个ZnF_RBZ结构域是必不可少的ZRANB 2的抗菌活性。重要的是，显微注射rZRANB 2到早期胚胎中显著增强了胚胎对病原体A的抗性。抗ZRANB 2抗体的共注射显著降低了这种增强的细菌耐药性。此外，通过与抗ZRANB 2抗体预孵育在胚胎提取物中沉淀ZRANB 2导致提取物对测试细菌的抗菌活性显著降低。此外，N端肽Z1/37或Z11/37的体外抗菌活性也促进了胚对A. Z38/198无体外抗菌活性。总的来说，这些结果表明，ZRANB 2是一种母体LPS结合蛋白，可以保护斑马鱼早期胚胎免受病原体的攻击，这是ZRANB 2蛋白的一个新角色。这项工作也为广泛分布于各种动物中的锌指蛋白的免疫功能提供了新的见解。
Zinc finger ZRANB2 proteins are widespread in animals, but their functions and mechanisms remain poorly defined. Here we clearly demonstrate that ZRANB2 is a newly identified LPS-binding protein present abundantly in the eggs/embryos of zebrafish. We also show that recombinant ZRANB2 (rZRANB2) acts as a pattern recognition receptor capable of identifying the bacterial signature molecule LPS as well as binding the Gram-negative bacteriaEscherichia coli,Vibrio anguilarum, andAeromonas hydrophilaand functions as an antibacterial effector molecule capable of directly killing the bacteria. Furthermore, we reveal that N-terminal residues 11–37 consisting of the first ZnF_RBZ domain are indispensable for ZRANB2 antimicrobial activity. Importantly, microinjection of rZRANB2 into early embryos significantly enhanced the resistance of the embryos against pathogenicA. hydrophilachallenge, and this enhanced bacterial resistance was markedly reduced by co-injection of anti-ZRANB2 antibody. Moreover, precipitation of ZRANB2 in the embryo extracts by preincubation with anti-ZRANB2 antibody caused a marked decrease in the antibacterial activity of the extracts against the bacteria tested. In addition, the N-terminal peptide Z1/37or Z11/37within vitroantibacterial activity also promoted the resistance of embryos againstA. hydrophila, but the peptide Z38/198withoutin vitroantibacterial activity did not. Collectively, these results indicate that ZRANB2 is a maternal LPS-binding protein that can protect the early embryos of zebrafish against pathogenic attacks, a novel role ever assigned to ZRANB2 proteins. This work also provides new insights into the immunological function of the zinc finger proteins that are widely distributed in various animals.