Identification of the gene for a Plasmodium yoelii rhoptry protein. Multiple copies in the parasite genome.

Serum from mice hyperimmune to Plasmodium yoelii was used to screen a P. yoelii genomic DNA library. Antibodies selected from hyperimmune serum by lambda gt11 clone J7 or raised against a specific fusion protein or peptide produced a punctate pattern of immunofluorescence on fixed smears of parasitised erythrocytes and immunoprecipitated a 235-kDa protein apparently identical to a rhoptry protein previously implicated in red cell invasion. The cloned DNA hybridised to at least seven RsaI fragments of P. yoelii genomic DNA and to three DraI fragments of similar but not identical sequence. These results suggest that the gene encoding the 235-kDa rhoptry protein may be represented more than once in the P. yoelii genome.