Analysis_of_Plasmodium_vivax_schizont_transcriptomes_from_field_isolates_reveals_heterogeneity_of_expression_of_genes_involved_in_host_parasite_interactions. Analysis_of_Plasmodium_vivax_schizont_transcriptomes_from_field_isolates_reveals_heterogeneity_of_expression_of_genes_involved_in_host_parasite_interactions

Plasmodium vivax gene regulation has been historically difficult to study due to the lack of a robust in vitro culture method, low parasite densities in peripheral circulation and asynchronous parasite development. Progression through the complex P. vivax life cycle is tightly temporally regulated and has been studied previously with microarrays and RNA-seq, yet these studies have been limited either by their inability to capture the full transcriptome or have significant distortion from PCR-induced bias. We have adapted a new method capable of overcoming these limitations (directional, amplification-free RNA-seq protocol or DAFT-seq) to sequence P. vivax field isolates that had been cultured for a short period ex vivo before using a density gradient to enrich for schizonts. While some isolate-specific differences were detected between the four clinical samples, the transcriptional profiles were generally highly conserved. Transcription was detected from 78% of the PvP01 reference genome, and the data was used to define 5’ and 3’ untranslated regions (UTRs), some of which overlapped with neighbouring transcripts. This data was able to improve the gene models of 352 genes in the PvP01 genome, including identifying 20 novel gene transcripts. This dataset has increased the overall resolution of P. vivax schizont transcriptomes from individual patients, which is particularly informative in the context of studying parasite invasion. The majority of genes differentially expressed between isolates lacked Plasmodium falciparum homologs and are predicted to be involved in host-parasite interactions, with an enrichment in reticulocyte binding proteins, merozoite surface proteins and additional exported proteins with unknown function. An improved understanding of the diversity within P. vivax transcriptomes will be essential for the future identification of novel vaccine targets. This data is part of a pre-publication release. For information on the proper use of pre-publication data shared by the Wellcome Trust Sanger Institute (including details of any publication moratoria), please see http://www.sanger.ac.uk/datasharing/