Interferons (IFNs) are the key coordinators of antiviral immunity by binding to their receptors to orchestrate a complex transcriptional network in vertebrates. Recently, the existence of molluscan IFN-like system has been certified by the identification of important components in IFN system, such as IFN-like protein (CgIFNLP) from oyster Crassostrea gigas. In the present study, a novel CgIFNLP receptor (designed CgIFNLPR-1) was identified from C. gigas. The open reading frame (ORF) of CgIFNLPR-1 cDNA was of 1962 bp encoding a peptide of 653 amino acid residues with five fibronectin type III (FNIII) domains and one transmembrane helix region. The mRNA transcripts of CgIFNLPR-1 were constitutively distributed in all the tested tissues, with the highest level in gonad. After Poly (I:C) stimulation, the mRNA expression of CgIFNLPR-1 in haemocytes was significantly up-regulated to the highest level at 48 h (4.54-fold of that in control group, p < 0.05). CgIFNLPR-1 protein was mainly distributed in the cytoplasm and membrane of oyster haemocytes. CgIFNLP and CgIFNLPR-1 were able to interact with each other in vitro. After the CgIFNLPR-1 was knocked down by RNAi, the mRNA expression of IFN-stimulated genes (ISGs), including CgMx, CgViperin and CgIFNIP-44, were significantly inhibited after Poly (I:C) stimulation, which was 0.17, 0.31 and 0.53-fold of that in EGFP group, respectively (p < 0.01). These findings suggested that CgIFNLPR-1 was a novel CgIFNLP receptor in the oyster to recognize CgIFNLP and regulate the expressions of CgISGs.

干扰素 (IFN) 通过与其受体结合来协调脊椎动物中复杂的转录网络，是抗病毒免疫的关键协调者。近来，通过对 IFN 系统中重要成分的鉴定，证实了软体动物类 IFN 系统的存在，如牡蛎牡蛎中的类 IFN 蛋白（Cg IFNLP）。在本研究中，从C. gigas中鉴定出一种新的Cg IFNLP 受体（设计的Cg IFNLPR-1）。Cg IFNLPR-1 cDNA的开放阅读框 (ORF)为 1962 bp，编码 653 个氨基酸残基的肽，具有五个纤连蛋白 III 型 (FNIII) 结构域和一个跨膜螺旋区。Cg的 mRNA 转录本IFNLPR-1在所有受试组织中呈组成型分布，在性腺中含量最高。Poly(I:C)刺激后，血细胞中Cg IFNLPR-1 mRNA表达显着上调至48 h最高水平（是对照组的4.54倍， p  < 0.05）。Cg IFNLPR-1蛋白主要分布在牡蛎血细胞的细胞质和细胞膜中。Cg IFNLP 和Cg IFNLPR-1 能够在体外相互作用。在Cg IFNLPR-1 被 RNAi 敲低后，IFN 刺激基因 (ISGs) 的 mRNA 表达，包括Cg Mx、Cg Viperin 和CgPoly (I:C) 刺激后 IFNIP-44 明显受到抑制，分别是 EGFP 组的 0.17、0.31 和 0.53 倍（p  < 0.01）。这些发现表明，Cg IFNLPR-1 是牡蛎中一种新的Cg IFNLP 受体，可识别Cg IFNLP 并调节 Cg ISGs 的表达。