Biology subjects

Bushell, E.

Publications and source records attributed to Bushell, E..

3 recordsLinked to original sources

bioRxiv2024

A novel chemogenomic screening platform for scalable antimalarial drug target identification

Large-scale chemical-genetic screening, or chemogenomics, can faciliate rapid and scalable drug target identification. To establish a chemogenomic screen for antimalarial drug target identification, we leveraged [~]600 Plasmodium berghei artificial chromosomes (PbACs) encoding potential drug targets to generate a systematic overexpression library. PbACs were engineered with DNA barcodes, enabling their quantification within mixed pools using next generation sequencing (barcode sequencing or BarSeq). Pooled transfection of PbACs into the highly genetically tractable Plasmodium knowlesi demonstrated efficient vector uptake and transcription of encoded P. berghei genes. Parasite pools were exposed to antimalarial candidates, with pilot screens probing for known gene-compound associations identifying their targets with high sensitivity. Screening antimalarial inhibitors with unknown mechanisms of action successfully identified pi4k as the target for one novel compound, which was subsequently validated using in vitro evolution in Plasmodium falciparum parasites. This sensitive and scalable chemogenomics platform therefore represents a valuable early-stage tool for antimalarial target identification.

microbiology↗

bioRxiv2021

Regulators of male and female sexual development critical for transmission of a malaria parasite

The transmission of malaria parasites from vertebrate host to mosquito vector requires a developmental switch in asexually dividing blood-stage parasites to sexual reproduction. In Plasmodium berghei the transcription factor AP2-G is required and sufficient for this switch, but how a particular sex is determined in a haploid parasite remains unknown. Using a global screen of barcoded mutants, we here identify ten genes essential for the formation of either male or female sexual forms and validate their importance for transmission. High-resolution single-cell transcriptomics of wild-type and mutant parasites portrays the developmental bifurcation and reveals a regulatory cascade of putative gene functions in determination and subsequent differentiation of each sex. A male-determining gene with a LOTUS/OST-HTH domain points towards unexpected conservation of molecular mechanisms of gametogenesis in animals and a distantly related eukaryotic parasite.

genomics↗

bioRxiv2016

Complete avian malaria parasite genomes reveal host-specific parasite evolution in birds and mammals

Avian malaria parasites are prevalent around the world, and infect a wide diversity of bird species. Here we report the sequencing and analysis of high quality draft genome sequences for two avian malaria species, Plasmodium relictum and Plasmodium gallinaceum. We identify 50 genes that are specific to avian malaria, located in an otherwise conserved core of the genome that shares gene synteny with all other sequenced malaria genomes. Phylogenetic analysis suggests that the avian malaria species form an outgroup to the mammalian Plasmodium species and using amino acid divergence between species, we estimate the avian and mammalian-infective lineages diverged in the order of 10 million years ago. Consistent with their phylogenetic position, we identify orthologs of genes that had previously appeared to be restricted to the clades of parasites containing P. falciparum and P. vivax - the species with the greatest impact on human health. From these orthologs, we explore differential diversifying selection across the genus and show that the avian lineage is remarkable in the extent to which invasion related genes are evolving. The subtelomeres of the P. relictum and P. gallinaceum genomes contain several novel gene families, including an expanded surf multigene family. We also identify an expansion of reticulocyte binding protein homologs in P. relictum and within these proteins, we detect distinct regions that are specific to non-human primate, humans, rodent and avian hosts. For the first time in the Plasmodium lineage we find evidence of transposable elements, including several hundred fragments of LTR-retrotransposons in both species and an apparently complete LTR-retrotransposon in the genome of P. gallinaceum.

genomics↗