Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, PR China; College of Fishery, Guangdong Ocean University, Zhanjiang 524025, China.
Fish Shellfish Immunol. 2013 Dec;35(6):1858-66. doi: 10.1016/j.fsi.2013.09.023. Epub 2013 Sep 30.
Lipopolysaccharide-induced TNFα factor (LITAF) is an important transcription factor that mediates cell apoptosis and inflammatory response. In the present study, we cloned and characterized a LITAF gene from orange-spotted grouper (Epinephelus coioides) (Ec-LITAF). Ec-LITAF encoded a predicted 142 amino acid protein which shared 74% identity to sablefish (Anoplopoma fimbria) LITAF homolog. Multiple amino acid alignment showed that Ec-LITAF contained a typical LITAF domain with two CXXC motifs. Phylogenetic analysis indicated that Ec-LITAF was closely related to that of sablefish. Ec-LITAF mRNA was widely expressed in different tissues and its expression level in spleen was up-regulated after Singapore grouper iridovirus (SGIV) infection. Subcellular localization analysis revealed that the distribution of Ec-LITAF showed diffuse and aggregated patterns in cytoplasm. Interestingly, the distribution of Ec-LITAF overlayed with a viral LITAF homolog (vLITAF) encoded by SGIV. Overexpression of Ec-LITAF in vitro up-regulated the expression of tumor necrosis factors (TNF1 and TNF2) and TNF receptors (TNFR1 and TNFR2), and the expression of itself initiated apoptosis in fish cells. In addition, overexpression of Ec-LITAF not only accelerated SGIV infection induced CPE and cell death, but also increased viral gene transcription. Taken together, our data suggested that Ec-LITAF might play crucial roles during SGIV replication.
脂多糖诱导的肿瘤坏死因子因子（LITAF）是一种重要的转录因子，介导细胞凋亡和炎症反应。本研究从鞍带石斑鱼（Epinephelus coioides）（Ec-LITAF）中克隆和鉴定了一个 LITAF 基因。Ec-LITAF 编码一个预测的 142 个氨基酸的蛋白质，与条纹鲈（Anoplopoma fimbria）的 LITAF 同源物具有 74%的同一性。多序列比对表明，Ec-LITAF 含有一个典型的 LITAF 结构域，包含两个 CXXC 基序。系统进化分析表明，Ec-LITAF 与条纹鲈的亲缘关系最为密切。Ec-LITAF mRNA 在不同组织中广泛表达，其在脾脏中的表达水平在新加坡石斑鱼虹彩病毒（SGIV）感染后上调。亚细胞定位分析表明，Ec-LITAF 在细胞质中呈现弥散和聚集的分布模式。有趣的是，Ec-LITAF 的分布与 SGIV 编码的病毒 LITAF 同源物（vLITAF）重叠。体外过表达 Ec-LITAF 上调了肿瘤坏死因子（TNF1 和 TNF2）和 TNF 受体（TNFR1 和 TNFR2）的表达，并且自身的表达引发了鱼类细胞的凋亡。此外，过表达 Ec-LITAF 不仅加速了 SGIV 感染诱导的 CPE 和细胞死亡，还增加了病毒基因的转录。综上所述，我们的数据表明 Ec-LITAF 可能在 SGIV 复制过程中发挥关键作用。
