| Summary: | <p>Abstract</p> <p>Background</p> <p>Heterologous promoter analysis in <it>Plasmodium </it>has revealed the existence of conserved <it>cis </it>regulatory elements as promoters from different species can drive expression of reporter genes in heterologous transfection assays. Here, the functional characterization of different <it>Plasmodium vivax </it>promoters in <it>Plasmodium falciparum </it>using luciferase as the reporter gene is presented.</p> <p>Methods</p> <p>Luciferase reporter plasmids harboring the upstream regions of the <it>msp1</it>, <it>dhfr</it>, and <it>vir3 </it>genes as well as the full-length intergenic regions of the <it>vir23/24 </it>and <it>ef-1α </it>genes of <it>P. vivax </it>were constructed and transiently transfected in <it>P. falciparum</it>.</p> <p>Results</p> <p>Only the constructs with the full-length intergenic regions of the <it>vir23/24 </it>and <it>ef-1α </it>genes were recognized by the <it>P. falciparum </it>transcription machinery <it>albeit </it>to values approximately two orders of magnitude lower than those reported by <it>luc </it>plasmids harbouring promoter regions from <it>P. falciparum </it>and <it>Plasmodium berghei</it>. A bioinformatics approach allowed the identification of a motif (GCATAT) in the <it>ef-1α </it>intergenic region that is conserved in five <it>Plasmodium </it>species but is degenerate (GCANAN) in <it>P. vivax</it>. Mutations of this motif in the <it>P. berghei ef-1α </it>promoter region decreased reporter expression indicating it is active in gene expression in <it>Plasmodium</it>.</p> <p>Conclusion</p> <p>Together, this data indicates that promoter regions of <it>P. vivax </it>are poorly or not recognized by the <it>P. falciparum </it>transcription machinery suggesting the existence of <it>P. vivax</it>-specific transcription regulatory elements.</p>
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