Merozoite Proteins Discovered by qRT-PCR-Based Transcriptome Screening of Plasmodium falciparum.

Nan Hou,Ning Jiang,Shanshan Li,Yu Ma,Qijun Chen,Xianyu Piao,Shuai Liu

doi:10.3389/fcimb.2021.777955

Abstract

The development of malaria vaccines and medicines depends on the discovery of novel malaria protein targets, but the functions of more than 40% of P. falciparum genes remain unknown. Asexual parasites are the critical stage that leads to serious clinical symptoms and that can be modulated by malaria treatments and vaccines. To identify critical genes involved in the development of Plasmodium parasites within erythrocytes, the expression profile of more than 5,000 genes distributed across the 14 chromosomes of the PF3D7 strain during its six critical developmental stages (merozoite, early-ring, late-ring, early trophozoite, late-trophozoite, and middle-schizont) was evaluated. Hence, a qRT-PCR-based transcriptome of the erythrocytic developmental process of P. falciparum was revealed. Weighted gene coexpression network analyses revealed that a large number of genes are upregulated during the merozoite release process. Further gene ontology analysis revealed that a cluster of genes is associated with merozoite and may be apical complex components. Among these genes, 135 were comprised within chromosome 14, and 80% of them were previously unknown in functions. Western blot and immunofluorescence assays using newly developed corresponding antibodies showed that some of these newly discovered proteins are highly expressed in merozoites. Further invasion inhibition assays revealed that specific antibodies against several novel merozoite proteins can interfere with parasite invasion. Taken together, our study provides a developmental transcriptome of the asexual parasites of P. falciparum and identifies a group of previously unknown merozoite proteins that may play important roles in the process of merozoite invasion.

Highlights

Malaria management has yield outstanding achievements in the past 20 years, there has been no significant progress in reducing global malaria incidence in recent years as reported in the World Malaria Report 2020 published by the World Health Organization (World Health Organization, 2020)
The collected data provide a developmental transcriptome of the erythrocytic process of P. falciparum (Figure 1 and Supplementary File 3)
Tremendous work have been done on transcriptome screening of P. falciparum with various postgenomic methods, such as RNA-sequence (Toenhake et al, 2018; Wichers et al, 2019) or microarray (Bozdech et al, 2003; Daily et al, 2005)

Summary

Introduction

Malaria management has yield outstanding achievements in the past 20 years, there has been no significant progress in reducing global malaria incidence in recent years as reported in the World Malaria Report 2020 published by the World Health Organization (World Health Organization, 2020). P. falciparum sequencing promoted by the Malaria Genome Project has provided the foundation for the discovery of numerous malaria antigens, but the function of more than 40% of its genes remain unknown (Gardner et al, 2002). Studies on genomic reductions have identified some essential genes of Plasmodium for optimal growth of asexual blood stages in vitro (Bushell et al, 2017; Zhang et al, 2018). These studies provided valuable information about the parasite genes; the proteins expressed at the parasite stages still need to be scrutinized for their functions

Methods

Results

Conclusion