Jiang Ning, Yu Shengchao, Yang Na, Feng Ying, Sang Xiaoyu, Wang Yao, Wahlgren Mats, Chen Qijun
Key Laboratory of Zoonosis, Shenyang Agricultural University, 120 Dongling Road, Shenyang, China.
Key Laboratory of Zoonosis, Jilin University, 53333 Xi An Da Lu, Changchun, 130062, China.
J Eukaryot Microbiol. 2018 Nov;65(6):843-853. doi: 10.1111/jeu.12625. Epub 2018 May 7.
The eukaryotic ribonucleic acid (RNA) exosome is a versatile multiribonuclease complex that mediates the processing, surveillance, and degradation of virtually all classes of RNA in both the nucleus and cytoplasm. The complex, composed of 10 to 11 subunits, has been widely described in many organisms. Bioinformatic analyses revealed that there may be also an exosome-like complex in Plasmodium falciparum, a parasite of great importance in public health, with eight predicted subunits having high sequence similarity to their counterparts in yeast and human. In this work, the putative RNA catalytic components, designated as PfRrp4, PfRrp41, PfDis3, and PfRrp6, were identified and systematically analyzed. Quantitative polymerase chain reaction (QPCR) analyses suggested that all of them were transcribed steadily throughout the asexual stage. The expression of these proteins was determined by Western blot, and their localization narrowed to the cytoplasm of the parasite by indirect immunofluorescence. The recombinant proteins of PfRrp41, PfDis3, and PfRrp6 exhibited catalytic activity for single-stranded RNA (ssRNA), whereas PfRrp4 showed no processing activity of both ssRNA and dsRNA. The identification of these putative components of the RNA exosome complex opens up new perspectives for a deep understanding of RNA metabolism in the malarial parasite P. falciparum.
真核核糖核酸（RNA）外切体是一种多功能的多核糖核酸酶复合体，介导细胞核和细胞质中几乎所有类型RNA的加工、监测和降解。该复合体由10至11个亚基组成，已在许多生物体中得到广泛描述。生物信息学分析表明，在恶性疟原虫（一种对公共卫生至关重要的寄生虫）中可能也存在类似外切体的复合体，预测的8个亚基与酵母和人类中的对应亚基具有高度序列相似性。在这项工作中，鉴定并系统分析了假定为RNA催化成分的PfRrp4、PfRrp41、PfDis3和PfRrp6。定量聚合酶链反应（QPCR）分析表明，它们在整个无性阶段均稳定转录。通过蛋白质免疫印迹法测定了这些蛋白质的表达，并通过间接免疫荧光将它们的定位缩小到寄生虫的细胞质。PfRrp41、PfDis3和PfRrp6的重组蛋白对单链RNA（ssRNA）表现出催化活性，而PfRrp4对ssRNA和双链RNA（dsRNA）均无加工活性。RNA外切体复合体这些假定成分的鉴定为深入了解恶性疟原虫中的RNA代谢开辟了新的视角。
