Stage-specific expression of a Plasmodium falciparum protein related to the eukaryotic mitogen-activated protein kinases

We have identified a putative protein kinase gene from both Plasmodium falciparum cDNA and genomic DNA libraries. The nucleotide sequence contains an open-reading frame of 2646 bp, which codes for a predicted protein of 882 amino acid residues. Comparison of the predicted amino acid sequence with those in GenBank suggests that this gene codes for a protein similiar to the mitogen-activated protein (MAP) kinase of other organisms. This MAP kinase-related protein, named PfMRP, contains the TDY dual phosphorylation site upstream of the highly conserved VATRWYRAPE sequence in subdomain VIII. PfMRP contains an unusually large and highly charged domain within its carboxyl-terminal segment, which includes two repetitive sequences of either a tetrapeptide or octapeptide motif. PfMRP gene is located on chromosome 14. Northern blot analysis of total RNA reveals the presence of a single mRNA transcript similar to 4.2 kb in length, which is predominantly expressed in gametocytes and gametes/zygotes.