Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, China.
Fish Shellfish Immunol. 2011 Apr-May;30(4-5):1188-91. doi: 10.1016/j.fsi.2011.02.021. Epub 2011 Mar 5.
Members of the Caspase family play essential roles in apoptosis. In kuruma shrimp Marsupenaeus japonicus the caspase gene (PjCaspase) was previously found dramatically up-regulated in viral-challenged and -resistant shrimp, suggesting that PjCaspase plays an important role in protecting host from viral infection. In order to further delineate the transcriptional regulation of PjCaspase in response to viral infection, the promoter activity was confirmed by fusing the 5'-flanking promoter region of the PjCaspase gene to the enhanced green fluorescence protein (EGFP) gene and transformed to Trichoplusia ni High Five™ cell line. With streptavidin-bead pulldown assay, two envelope proteins VP38 and VP41B of white spot syndrome virus (WSSV) were found to bind to PjCaspase promoter in vitro. Luciferase reporter assay by cotransfection of PjCaspace promoter with VP38 or VP41B revealed that the proteins act as repressor and activator of PjCaspase transcription respectively. Our study suggested a potential role for the two WSSV proteins on shrimp PjCaspase regulation in response to WSSV challenge. To our knowledge this is the first report on WSSV envelope proteins found to be involved in gene regulation. These results provide insights into the molecular regulation of PjCaspase gene expression, which will be helpful for shrimp viral disease control.
Caspase 家族成员在细胞凋亡中发挥着重要作用。在日本对虾（Marsupenaeus japonicus）中，先前发现 caspase 基因（PjCaspase）在受到病毒挑战和具有抗性的虾中显著上调，表明 PjCaspase 在保护宿主免受病毒感染方面发挥着重要作用。为了进一步阐明 PjCaspase 在病毒感染时的转录调控，通过将 PjCaspase 基因的 5'侧翼启动子区域与增强型绿色荧光蛋白（EGFP）基因融合，并转化到 Trichoplusia ni High Five™细胞系中来确认启动子活性。通过链霉亲和素珠下拉测定，发现两种白斑综合征病毒（WSSV）的包膜蛋白 VP38 和 VP41B 在体外与 PjCaspase 启动子结合。通过共转染 PjCaspace 启动子与 VP38 或 VP41B 的荧光素酶报告基因检测，表明这两种蛋白分别作为 PjCaspase 转录的抑制剂和激活剂。我们的研究表明，这两种 WSSV 蛋白在虾 PjCaspase 对 WSSV 挑战的调节中可能发挥作用。据我们所知，这是首次报道 WSSV 包膜蛋白参与基因调控。这些结果为 PjCaspase 基因表达的分子调控提供了新的见解，这将有助于虾类病毒性疾病的控制。
