Plasmodium berghei: cloning of the circumsporozoite protein gene.

A DNA fragment encoding the carboxy terminal 80% of the Plasmodium berghei circumsporozoite protein was selected from a genomic DNA expression library. Sequencing revealed that the P. berghei circumsporozoite protein was similar in overall structure to circumsporozoite proteins from other malaria species, although the central repeat region was unique in comprising two different blocks of tandem peptide repeats: 11 eight amino acid repeats with predominant sequence DPAPPNAN were followed by 16 two amino repeats, predominantly PQ. The P. berghei circumsporozoite protein exhibited limited, but about equal amino acid homology to circumsporozoite proteins from P. knowlesi, P. vivax, and P. falciparum, indicating that P. berghei is not closely related to any of these other malaria species. Cloning of the P. berghei circumsporozoite protein gene will allow direct testing of sporozoite vaccines in mice.