From the Genome to the Phenome: Tools to Understand the Basic Biology of Plasmodium falciparum

Abstract

Malaria plagues one out of every 30 humans and contributes to almost a million deaths, and the problem could worsen. Our current therapeutic options are compromised by emerging resistance by the parasite to our front line drugs. It is thus imperative to better understand the basic biology of the parasite and develop novel drugs to stem this disease. The most facile approach to analyse a gene's function is to remove it from the genome or inhibit its activity. Although genetic manipulation of the human malaria parasite Plasmodium falciparum is a relatively standard procedure, there is no optimal method to perturb genes essential to the intraerythrocytic development cycle--the part of the life cycle that produces the clinical manifestation of malaria. This is a severe impediment to progress because the phenotype we wish to study is exactly the one that is so elusive. In the absence of any utilitarian way to conditionally delete essential genes, we are prevented from investigating the parasite's most vulnerable points. This review aims to focus on the development of tools identifying essential genes of P. falciparum and our ability to elicit phenotypic mutation.

Mitochondrial ATP synthase is dispensable in blood-stage Plasmodium berghei rodent malaria but essential in the mosquito phase

“…However, there are no robust tools to define whether or not a gene is essential in P. falciparum. Indispensability of a gene is typically inferred from an inability to generate a knockout (43), and artificial maintenance of P. falciparum in culture may not be conducive to retrieval of a PfATPβ knockout. Indeed, the slightly reduced growth rate of PbATPβKO could suggest that recovery of a P. falciparum knockout may be difficult and that inducible knockdowns (43) should be explored.…”

Evidence that the Malaria Parasite Plasmodium falciparum Putative Rhoptry Protein 2 Localizes to the Golgi Apparatus throughout the Erythrocytic Cycle

“…This is further demonstrated by comparing the densitometric ratio of PfPRP2-RFA with the control PfHSP70 ("Fig B in S2 Fig "). It is known that inhibition of parasite growth can sometimes be observed despite the absence of degradation of the RFA-tagged protein of interest and this led to the suggestion that destabilization of the protein could also prevent its correct function by proper formation and/or assembly of protein complexes [ 7 , 19 , 37 ]. To investigate whether this was the case for our PfPRP2-RFA line, growth curve analyses with and without TMP were performed.…”

“…falciparum and T . gondii proteins tagged with degradation systems failed to be knocked down [ 37 – 39 ]. That being said, conditional knockdown of FKBP-tagged PfRESA, a protein exported to the red blood cell cytosol, has been successfully achieved which shows that at least some non cytosolic proteins can be regulated with destabilization domains[ 38 ].…”

GeneTargeter: Automated In Silico Design for Genome Editing in the Malaria Parasite, Plasmodium falciparum

“…Recent analyses anticipate a signi cant increase in malaria mortality for the year 2020 due to disruptions in control programs and antimalarial drug supply caused by the ongoing COVID-19 pandemic [2]. The spread of resistance to the already sparse number of approved antimalarial drugs [3][4][5][6][7] makes discovery of new drug candidates an urgent priority, but this effort has been hindered by a relatively poor understanding of Plasmodium biology [8][9][10]. Substantial improvements in the toolkit for studying gene function in Plasmodium have been made recently, including near genome scale essentiality screens in the human parasite Plasmodium falciparum [11] and the rodent malaria model, Plasmodium berghei [10].…”