Characterization of the essential chromatin remodeling enzyme pfSnf2L in Plasmodium falciparum

恶性疟原虫中必需染色质重塑酶 pfSnf2L 的表征

• 批准号: 534335380
• 负责人: Professor Dr. Gernot M. Längst
• 金额: --
• 依托单位: Experimentelle Parasitologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/534335380?language=en
• 关键词: Characterization; essential; chromatin; remodeling; enzyme

The malaria causing parasite Plasmodium falciparum (Pf) is an unicellular eukaryote with a complex life cycle between human host and mosquito vector. Each life cycle stage can be characterized by a specific transcriptional profile, suggesting a complex transcriptional regulation mechanism. The parasite is unique, having the AT-richest genome sequenced to date, the most divergent histone proteins in the eukaryotic domain, resulting in a lack of global nucleosome positioning and exhibiting a 10-fold reduction in number of transcription factors, when compared to organisms of similar complexity. Therefore, it is not understood how the tightly regulated gene expression profile during developmental stage transition is established. It is suggested that the regulation of the gene expression cascade depends on epigenetic mechanisms involving nucleosome remodeling.In contrast to other eukaryotes, Pf has a non-redundant set of chromatin remodeling enzymes. This allows the study of the function of individual classes of chromatin remodelers in the cell by inducible knockout systems and associated functional studies. We chose the ISWI-type enzyme pfSnf2L, created inducible knockout parasite lines, and show that pfSnf2L is an essential enzyme for parasite survival. Conditional deletion of pfSnf2L resulted in parasites unable to exit the erythrocyte. In good agreement with this phenotype, gene expression analysis demonstrated that exportome genes are not activated at the correct stage of the intraerythrocytic cycle, in the absence of pfSnf2L. This conditional mutant will allow us to address the effects of pfSnf2L on chromatin structure and gene regulation during the erythrocyte life cycle of Pf. The study is combined with the functional characterization of the recombinant pfSnf2L enzyme, to draw a mechanistic picture of the cellular chromatin changes. We aim to unravel the mechanism of chromatin remodeling and nucleosome positioning on gene expression networks and phenotypical changes of Plasmodium falciparum.

引起疟疾的寄生虫恶性疟原虫（Pf）是一种单细胞真核生物，在人类宿主和蚊子媒介之间具有复杂的生命周期。每个生命周期阶段的特点是一个特定的转录谱，表明一个复杂的转录调控机制。该寄生虫是独特的，具有迄今为止测序的AT最丰富的基因组，是真核结构域中最分歧的组蛋白，导致缺乏全局核小体定位，并且与具有类似复杂性的生物体相比，转录因子的数量减少了10倍。因此，目前还不清楚发育阶段转换期间严格调控的基因表达谱是如何建立的。与其他真核生物相比，Pf具有一组非冗余的染色质重塑酶，这表明Pf的基因表达级联调控依赖于涉及核小体重塑的表观遗传机制。这允许通过诱导型敲除系统和相关的功能研究来研究细胞中个别类别的染色质重塑物的功能。我们选择了ISWI型酶pfSnf2L，创建诱导敲除寄生虫系，并表明pfSnf2L是寄生虫生存的必需酶。pfSnf2L的条件性缺失导致寄生虫无法离开红细胞。与该表型非常一致，基因表达分析表明，在pfSnf2L不存在的情况下，输出基因组基因在红细胞内循环的正确阶段不被激活。这种条件突变体将使我们能够解决pfSnf2L对染色质结构和基因调控的影响，在红细胞生命周期的Pf.The研究是结合重组pfSnf2L酶的功能特性，绘制细胞染色质变化的机制图片。本研究旨在阐明恶性疟原虫染色质重塑和核小体定位对基因表达网络和表型改变的影响机制。