Department of Bioscience, College of Life Science and Food Engineering, Nanchang University, Nanchang 330031, China.
Dev Comp Immunol. 2013 Dec;41(4):477-83. doi: 10.1016/j.dci.2013.07.007. Epub 2013 Jul 18.
The virus-induced genes, Gig1 and Gig2, were identified first as IFN-stimulated genes (ISGs) from CAB cells. Previous studies suggested that Gig protein may have some potential antiviral functions. In this study, we cloned and identified the full-length cDNA sequences of Gig1 and Gig2 homologs (designated as CiGig1 and CiGig2, respectively) from grass carp (Ctenopharyngodon idella). The complete cDNA sequences of Gig1 and Gig2 contain 1231 bp and 690 bp, encoding for a 194 amino acid protein and a 158 amino acid protein, respectively. Their structure characteristics of CiGig1 and CiGig2 are highly similar to the corresponding homologues in crucian carp. The tissue-specific expressions of CiGig1 and CiGig2 in liver, spleen, kidney, intestine, gill and heart were significantly up-regulated following GCHV challenge. The results indicated that CiGig1 and CiGig2 may be involved in the antiviral immune responses in cells. To better understand the antiviral functions of CiGig1 and CiGig2 in vivo, CiGig1 or CiGig2 ORF cDNA were inserted into the plasmid pcDNA3.1, respectively. Subsequently, the recombinant plasmids were transfected into C. idellus kidney (CIK) cells. The over-expressions of CiGig1 and CiGig2 were observed in the CIK cells after treatment with GCHV. Cells with pcDNA3.1-CiGig1 or pcDNA-CiGig2 exhibited a relatively higher survival rate of (70.84% or 69.24%) than non-transfection (22.16%) and mock-vehicle controls (24.38%) following the virus infection. Our data showed that both CiGig1 and CiGig2 could exert antiviral effects effectively in vivo. Cycloheximide blocking protein synthesis demonstrated that both CiGig1 and CiGig2 mRNA expression could be induced by GCHV rather than by recombinant grass carp IFN (rCiIFN) directly, suggesting that CiGig1 and CiGig2 may not be IFN-stimulated genes since they display their antivirus activities in an IFN-independent pathway.
病毒诱导基因 Gig1 和 Gig2 最初被鉴定为 CAB 细胞中的 IFN 刺激基因（ISGs）。先前的研究表明，Gig 蛋白可能具有一些潜在的抗病毒功能。在这项研究中，我们从草鱼（Ctenopharyngodon idella）中克隆并鉴定了 Gig1 和 Gig2 同源物（分别命名为 CiGig1 和 CiGig2）的全长 cDNA 序列。Gig1 和 Gig2 的完整 cDNA 序列分别包含 1231bp 和 690bp，编码 194 个氨基酸的蛋白质和 158 个氨基酸的蛋白质。它们的结构特征 CiGig1 和 CiGig2 与鲤鱼中的相应同源物高度相似。GCHV 攻毒后，肝、脾、肾、肠、鳃和心脏中 CiGig1 和 CiGig2 的组织特异性表达明显上调。结果表明，CiGig1 和 CiGig2 可能参与细胞中的抗病毒免疫反应。为了更好地理解 CiGig1 和 CiGig2 在体内的抗病毒功能，将 CiGig1 或 CiGig2 ORF cDNA 分别插入质粒 pcDNA3.1 中。随后，将重组质粒转染草鱼肾脏（CIK）细胞。用 GCHV 处理后，在 CIK 细胞中观察到 CiGig1 和 CiGig2 的过表达。与非转染（22.16%）和空载对照（24.38%）相比，转染 pcDNA3.1-CiGig1 或 pcDNA-CiGig2 的细胞在病毒感染后具有相对较高的存活率（分别为 70.84%或 69.24%）。我们的数据表明，CiGig1 和 CiGig2 均可在体内有效发挥抗病毒作用。环已亚胺阻断蛋白合成表明，CiGig1 和 CiGig2 的 mRNA 表达均能被 GCHV 而非重组草鱼 IFN（rCiIFN）直接诱导，表明 CiGig1 和 CiGig2 可能不是 IFN 刺激基因，因为它们在 IFN 非依赖途径中表现出抗病毒活性。
