Plasmodium yoelii: differences in the transcription of the 235-kDa rhoptry protein multigene family in lethal and nonlethal lines.

We have compared the transcription of the 235-kDa rhoptry protein (p235) multigene family in the lethal (YM) and nonlethal (17X) lines of the rodent malaria parasite Plasmodium yoelii. This protein is thought to be involved in erythrocyte invasion by the parasite. Using a PCR-based approach we demonstrated that both lines have similar p235 families. However, RT-PCR analysis revealed that this similarity is not evident at the level of transcription, with the lethal line not transcribing a whole subset of its p235 gene repetoire. Specific anti-p235 immune pressure induces differences in invasion properties of the lethal line; we were, however, unable to detect any changes in the transcription pattern of the p235 genes associated with this event.