嗜肺军团菌类真核效应蛋白LegK3抑制酿酒酵母的生长并影响其小泡运输途径  

Legionella pneumophila eukaryotic-like effector LegK3inhibits growth of Saccharomyces cerevisiae and modulates its vesicle trafficking pathway

作　　者：王嘉铭[1,2] 李向辉[2,3] 陈爱枫[1] 陆勇军[2] 

机构地区：[1]广东省微生物研究所 省部共建华南应用微生物国家重点实验室,广东广州510070 [2]中山大学生命科学学院/生物医药中心,广东广州510275 [3]江苏省科学技术情报研究所,江苏南京210042

出　　处：《微生物学报》2014年第4期417-423,共7页Acta Microbiologica Sinica

基　　金：国家自然科学基金(30970123)~~

摘　　要：【目的】为了探索嗜肺军团菌类真核效应蛋白LegK3的功能,并进一步筛选得到其在宿主细胞内的作用靶点,我们利用酿酒酵母作为替代模型研究LegK3对宿主细胞的毒力效应,并针对其作用途径进行了初步分析。【方法】设计引物完整扩增LegK3、RalF、LidA的ORF,其中已知效应蛋白RalF、LidA基因作为对照实验组;扩增片段与酵母表达载体pESC-HK连接构建成重组载体,转化酿酒酵母菌株W303-1A,使用含2%半乳糖的选择培养基进行诱导培养,分别观察酵母细胞的生长抑制和CPY延迟情况;提取诱导前、后的酵母菌体总蛋白用c-myc抗体检测效应蛋白的表达情况;用anti-PGK、anti-CPY抗体检测酿酒酵母CPY的延迟情况。【结果】表达LegK3的酵母菌株出现了生长抑制的现象,并且CPY的成熟受到延迟影响。【结论】LegK3的异源表达能够抑制酿酒酵母的生长并延迟其囊泡蛋白CPY的成熟,推测LegK3可能通过作用于小泡运输途径来抑制真核宿主细胞的生长和分裂,以维持适合嗜肺军团菌繁殖的稳定胞内环境。[ Objective ] To study biochemical functions of the Legionella pneumophila eukaryotic-like effector protein LegK3, the budding yeast Saccharomyces cerevisiae was used as an alternative host in which growth defect induced by the ectopic expression of LegK3 was assessed. [ Methods ] Using genomic DNA of the L. pneumophila strain Lp02 as template, we respectively amplified and inserted the ORF sequences of legK3, ralF or lidA into the plasmid pESC-HK to yield the ectopic-expression plasmids. Then, the recombination plasmids were transformed into the yeast strain W301-1A. With 2%-galactose induction, growth defect and carboxypeptidase Y （CPY） delay were determined simultaneously. In parallel, total yeast proteins before or after induction were extracted and subjected to Immunoblot assay. For detecting the expression of effector proteins or determining CPY delay, anti-c-myc or anti-PGK/ anti-CPY antibodies were utilized respectively. [ Results] The expression of LegK3 resulted in visible growth defect in yeast cells, together with obvious retard in CPY processing. [ Conclusion] L. pneumophila eukaryotic-like effector LegK3 might target and interfere with the vesicle-trafficking pathways, thereby to inhibit the growth and division of host cells.

关 键 词：嗜肺军团菌 效应蛋白 LegK3 酿酒酵母 

分 类 号：Q93[生物学—微生物学]