Discussion

The African trypanosome research community has found RNA interference to be particularly effective for gene knockdown and functional studies, and has also benefitted from a strong history of genetic tool development. Genetic approaches used in high-throughput mode can be particularly powerful and we have found this to be the case for RNA interference coupled to deep sequencing, or RIT-seq. Such approaches can rapidly link genes to phenotypes, even when nothing is known about mechanism at the outset. RIT-seq was initially used to generate genome-scale loss-of-fitness profiles (~7,500 genes), facilitating drug-target prioritisation. Antitrypanosomal drugs were then used to identify genes associated with drug-resistance. Defective drug uptake emerged as a prominent feature and one particular transporter, an aquaglyceroporin, was found to be responsible for the most widespread form of resistance in trypanosomiasis patients. Although we now know more about how certain drugs gain access to their targets, we still know little about how drugs actually kill parasites. From rapidly linking genes to phenotypes, we now hope to move to rapidly linking drugs to drug-targets, information that should certainly help to deliver new and improved therapies.