mRNA应激颗粒的形成对新孢子虫活力影响的研究

Roles of the Formation of mRNA Stress Granules in the Viability of Extracellular Neospora caninum

新孢子虫是一种专性细胞内寄生原虫。速殖子从细胞内释放到再次入侵新的细胞会受到细胞内外离子环境改变的刺激,出现一系列应激反应。目前,新孢子虫的应激反应机制尚不清楚。该研究用高浓度的钠离子或钾离子分别作用于纳虫空泡内和新鲜释放的新孢子虫速殖子,使其处于应激状态,通过RNA fish检测虫体应激颗粒的形成情况。研究发现,新孢子虫在高钾离子缓冲液的刺激下会形成大量的mRNA颗粒。随后,通过噬斑实验、入侵实验以及增殖实验证明,应激颗粒的形成提高了新孢子虫的入侵能力以及胞内增殖能力。结果表明,新孢子虫mRNA应激颗粒的形成提高了新孢子虫适应应激环境的能力,有助于其入侵新的细胞并进行增殖,更有利于新孢子虫的生存。

Neospora caninum is an obligate intracellular apicomplexan parasite. When searching for a new cell to invade after egress, the parasites are directly exposed to the stress of extracellular environment. So far, the mechanism of stress response outside the host cells of this parasite is still to be revealed. In this study, we used two different buffers that mimics the extracellular and intracellular environment respectively, to stimulate the newly egressed tachyzoites. Using RNA fish, we found that extracellular tachyzoites stimulated by intracellular buffer formed stronger mRNA granules. Lytic cycle assays were performed to evaluate the role of granules formation in maintaining the viability of extracellular N. caninum. The results demonstrated that mRNA granules formation leaded to a growth advantage, increased invasion and proliferation ability. Overall, m RNA granules formation improved the fitness of extracellular tachyzoites under stress conditions, contributed to the proliferation of newlyinvaded tachyzoites, and enhanced the survival of N. caninum.