鱼诺卡氏菌动力蛋白调节蛋白robl/LC7的亚细胞定位和功能初步研究

Subcellular localization and preliminary function study of dynein regulation protein robl/LC7 from Nocardia seriolae

鱼类诺卡氏菌病是一种慢性系统性肉芽肿疾病,鱼诺卡氏菌是其主要病原。鱼诺卡氏菌全基因组生物信息学分析,发现了一个可能靶向定位于宿主细胞线粒体的分泌蛋白——动力蛋白调节蛋白robl/LC7。为了对鱼诺卡氏菌robl/LC7的亚细胞定位和功能进行初步研究,实验对鱼诺卡氏菌robl/LC7进行了基因克隆、真核表达重组质粒构建、分泌蛋白鉴定、亚细胞定位、过表达和凋亡检测。结果显示,成功克隆了鱼诺卡氏菌robl/LC7基因并构建了其真核表达质粒p EGFP-robl/LC7和pc DNA-robl/LC7;鱼诺卡氏菌分泌蛋白质谱鉴定证实robl/LC7为分泌蛋白;亚细胞定位研究显示robl/LC7-GFP融合蛋白呈全细胞分布,不与线粒体共定位;凋亡检测发现robl/LC7过表达能诱导FHM细胞凋亡。研究表明,鱼诺卡氏菌robl/LC7是一个不与线粒体共定位的分泌蛋白,其可能通过参与细胞凋亡调控,协助鱼诺卡氏菌在宿主体内生存和免疫逃避,并在鱼诺卡氏菌的致病过程中具有重要作用。

Fish nocardiosis is a chronic systemic granulomatous disease, and Nocardia seriolae is its main pathogen. A dynein regulation protein robl/LC7, which is likely to be secreted and to target host cell mitochondria, was found by the bioinformatics analysis on the whole genome sequence of N. seriolae. In order to determine the subcellular localization and study the preliminary function of robl/LC7 from N. seriolae, the gene cloning, eukaryotic expression plasmid construction, secreted protein identification, subcellular localization and apoptosis detection of robl/LC7 were carried out in this study. robl/LC7 was successfully cloned from N. seriolae and the eukaryotic expression plasmid of p EGFP-robl/LC7 and pc DNA-robl/LC7 were constructed. Mass spectrometry analysis of extracellular products from N. seriolae confirmed that robl/LC7 was a secreted protein. Subcellular localization of robl/LC7-GFP fusion protein discovered that the green fluorescence was distributed in the whole cell and did not co-localize with mitochondria. In addition, apoptosis assay revealed that apoptosis was induced by the over-expression of robl/LC7 in FHM cell. robl/LC7 from N. seriolae is a secreted protein which does not co-localize with mitochondria. It may help the host cell survival and immune escape of N. seriolae by participating the cell apoptosis regulation and may play an important role in the pathogenesis of N. seriolae.