Transcription of the gene for the merozoite surface antigen MSA2 of the human malaria parasite Plasmodium falciparum during the asexual cycle.

The transcription of the Plasmodium falciparum gene for the MSA2 antigen has been studied throughout the parasite's asexual growth cycle. For this purpose poly(A)+ RNA from different times of the cycle was tested for the presence of the mRNA encoding MSA2 by in vitro translation and subsequent analysis of the translation products by immunoprecipitation with an antibody against MSA2. The results revealed that this mRNA is present in trophozoites, reaches the highest concentration during the transition from the trophozoite into the schizont stage, and persists until the cycle end. Minute amounts of this mRNA were also detected in rings. In addition, the data confirmed that the primary translation product is not proteolytically processed at any time of the cycle.