Stage specific expression of proliferating cell nuclear antigen and DNA polymerase δ from Plasmodium falciparum

Abstract

Antisera raised against proliferating cell nuclear antigen (PfPCNA) and DNA polymerase δ (PfDNA Polδ) have been used against extracts from synchronised parasites to show that both proteins accumulate in trophozoites and persist in schizonts. The steady-state transcripts from both PfPCNA and PfDNA Polδ also accumulate at the trophozoite stage. However, nuclear run on analysis shows that, whereas PfDNA Polδ promoter activity is absent in rings but present in trophozoites and schizonts, the PfPCNA promoter is active throughout the intraerythrocytic cycle. This suggests that mechanisms regulating the expression of these two genes may be different although their coordinated activity is required for DNA replication.