Promoter regions of Plasmodium vivax are poorly or not recognized by Plasmodium falciparum.
BACKGROUND
Heterologous promoter analysis in Plasmodium has revealed the existence of conserved cis regulatory elements as promoters from different species can drive expression of reporter genes in heterologous transfection assays. Here, the functional characterization of different Plasmodium vivax promoters in Plasmodium falciparum using luciferase as the reporter gene is presented.


METHODS
Luciferase reporter plasmids harboring the upstream regions of the msp1, dhfr, and vir3 genes as well as the full-length intergenic regions of the vir23/24 and ef-1alpha genes of P. vivax were constructed and transiently transfected in P. falciparum.


RESULTS
Only the constructs with the full-length intergenic regions of the vir23/24 and ef-1alpha genes were recognized by the P. falciparum transcription machinery albeit to values approximately two orders of magnitude lower than those reported by luc plasmids harbouring promoter regions from P. falciparum and Plasmodium berghei. A bioinformatics approach allowed the identification of a motif (GCATAT) in the ef-1alpha intergenic region that is conserved in five Plasmodium species but is degenerate (GCANAN) in P. vivax. Mutations of this motif in the P. berghei ef-1alpha promoter region decreased reporter expression indicating it is active in gene expression in Plasmodium.


CONCLUSIONS
Together, this data indicates that promoter regions of P. vivax are poorly or not recognized by the P. falciparum transcription machinery suggesting the existence of P. vivax-specific transcription regulatory elements.
Azevedo
Mauro F
MF
Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brasil. maurousp@gmail.com <maurousp@gmail.com>
del Portillo
Hernando A
HA
D000818:Animals; D019295:Computational Biology; D019143:Evolution, Molecular; D008156:Luciferases / Q000235:genetics; D020066:Merozoite Surface Protein 1 / Q000235:genetics; D010963:Plasmodium falciparum / Q000235:genetics*; D010966:Plasmodium vivax / Q000235:genetics*; D011401:Promoter Regions, Genetic
D020066:Merozoite Surface Protein 1; D008156:Luciferases