CHARACTERIZATION OF THE CDC2-RELATED KINASE-2 GENE FROM PLASMODIUM-KNOWLESI AND PLASMODIUM-BERGHEI

The complete sequence of the cdc2-related kinase 2 (CRK2) gene from Pl asmodium knowlesi and from P. berghei was determined. In both species, the CRK2 gene is closely linked to an elongation factor 1 alpha gene. The two CRK2 proteins are highly homologous to the P. falciparum PfPK 5 protein. The CRK2 gene of both species is expressed at a low level d uring the asexual cell-cycle within the host erythrocytes. The P. berg hei CRK2 mRNA is also present in gametocytes and in stages during deve lopment in the mosquito, suggesting a role of this protein in differen t parts of the life cycle. A conserved sequence located in the 5' untr anslated region immediately upstream of the initiator ATG has the pote ntial to form a stem-loop structure, Although the CRK2 protein possess es most of the domains that are conserved among cdc2-proteins, neither a recombinant P. knowlesi CRK2 protein nor a recombinant P. berghei p rotein was able to complement a yeast cdc28(ts) mutant. Furthermore an d in contrast to the P. falciparum PfPK5 protein, a recombinant monome ric P. knowlesi CRK2 protein showed no kinase activity. (C) 1998 Elsev ier Science B.V. All rights reserved.