Research Article | Open Access
Analysis of PfEMP1—var Gene Sequences in Different Plasmodium falciparum Malarial Parasites
Plasmodium falciparum synthesizes P. falciparum erythrocyte membrane protein-1 (PfEMP-1), a product of the multicopy var gene family, which localizes on the surface of infected erythrocytes. This protein plays an important role in cytoadherence and immune evasion. Comparative analysis of the molecular sequences of the DBLα domain of the var gene from different isolates of the parasite reveals variations in the number of cysteines and presence of small conserved motifs like DGEA, RGD, GAG-binding motifs. Phylogenetic analysis while highlighting the extensive diversity leads to clustered them in separate clades far apart from each other. Discriminant factor analysis of physicochemical properties of amino acid sequences revealed that the aliphatic index, isoelectric point, and instability index have more effect in deciding the variance of different isolates sequences. The origin of diverse repertoire of the DBLα domain in the parasites highlights the complexity of host-parasite relationship in the context of parasite survival.
DBLα primers of var gene were used for amplification of parasite genomic DNA. The primers were specific for the two highly conserved sites in DBLα domain and flank the polymorphic segment of DBLα domain. The amino acid sequences were DIGDIIRG and DYVPQYLR. The genomic DNA from parasites amplifies multiple bands in the size range of 350–700 base pair (bp) when amplified with the primer1 and primer 2.
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