Plasmodium falciparum translational machinery condones polyadenosine repeats
- Washington University School of Medicine, United States
- Iowa State University, United States
- Washington University in St Louis, United States
- Institute of Biochemistry and Biophysics Polish Academy of Sciences, Poland
Abstract
Plasmodium falciparum is causative agent of human malaria. Sixty percent of mRNAs from its extremely AT-rich (81%) genome harbor long polyadenosine (polyA) runs within their ORFs, distinguishing the parasite from its hosts and other sequenced organisms. Recent studies indicate polyA runs cause ribosome stalling and frameshifting, triggering mRNA surveillance pathways and attenuating protein synthesis. Here, we show that the P. falciparum is an exception to this rule. We demonstrate that both endogenous genes and reporter sequences containing long polyA runs are efficiently and accurately translated in P. falciparum cells. We show that polyA runs do not elicit any response from No Go Decay (NGD) or result in the production of frameshifted proteins. This is in stark contrast to what we observe in human cells or T. thermophile, an organism with similar AT-content. Finally, using stalling reporters we show that Plasmodium cells evolved not to have a fully functional NGD pathway.
Data availability
All data generated or analysed during this study are included in the manuscript, supporting files or referenced. Source data files have been referenced for Figures 1, 3 and 5, as well as for supplementary figures.
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Ribosome Profiling in P. falciparum asexual blood stagesNCBI Gene Expression Omnibus, GSE58402.
Article and author information
Author details
Funding
National Institute of General Medical Sciences (GM112824)
- Sergej Djuranovic
Washington University in St. Louis (CDI-CORE-2015-505)
- James AJ Fitzpatrick
National Science Foundation (MCB 1412336)
- Douglas L Chalker
National Institute of General Medical Sciences (GM112877)
- Walter N Moss
National Institute of General Medical Sciences (GM007067)
- Jessey Erath
Washington University in St. Louis (CDI-CORE-2019-813)
- James AJ Fitzpatrick
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2020, Pavlovic Djuranovic et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Plasmodium falciparum translational machinery condones polyadenosine repeats
eLife 9:e57799.
https://doi.org/10.7554/eLife.57799
Further reading
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- Biochemistry and Chemical Biology
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Teichoic acids (TA) are linear phospho-saccharidic polymers and important constituents of the cell envelope of Gram-positive bacteria, either bound to the peptidoglycan as wall teichoic acids (WTA) or to the membrane as lipoteichoic acids (LTA). The composition of TA varies greatly but the presence of both WTA and LTA is highly conserved, hinting at an underlying fundamental function that is distinct from their specific roles in diverse organisms. We report the observation of a periplasmic space in Streptococcus pneumoniae by cryo-electron microscopy of vitreous sections. The thickness and appearance of this region change upon deletion of genes involved in the attachment of TA, supporting their role in the maintenance of a periplasmic space in Gram-positive bacteria as a possible universal function. Consequences of these mutations were further examined by super-resolved microscopy, following metabolic labeling and fluorophore coupling by click chemistry. This novel labeling method also enabled in-gel analysis of cell fractions. With this approach, we were able to titrate the actual amount of TA per cell and to determine the ratio of WTA to LTA. In addition, we followed the change of TA length during growth phases, and discovered that a mutant devoid of LTA accumulates the membrane-bound polymerized TA precursor.
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- Biochemistry and Chemical Biology
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