A synthetic promoter for multi-stage expression to probe complementary functions of Plasmodium adhesins

Abstract

Gene expression of malaria parasites is mediated by the apicomplexan Apetala2 (ApiAP2) transcription factor family. Different ApiAP2s control gene expression at distinct stages in the complex life cycle of the parasite ensuring timely expression of stage-specific genes. ApiAP2s recognize short cis-regulatory elements, which are enriched in the upstream/promoter region of their target genes. This should in principle allow the generation of ‘synthetic’ promoters that drive gene expression at desired stages of the Plasmodium life cycle. Here we test this concept by combining cis-regulatory elements of two genes expressed successively within the mosquito part of the life cycle. Our tailored ‘synthetic’ promoters named Spooki 1.0/2.0 activate gene expression in early and late mosquito stages as shown by the expression of a fluorescent reporter. We used these promoters to address the specific functionality of two related adhesins that are exclusively expressed either during the early or late mosquito stage. By modifying the expression profile of both adhesins in absence of their counterpart we could test for complementary functions in gliding and invasion. We discuss the possible advantages and drawbacks of our approach.