Chromodomain protein regulates the expression of a subset of RIFINs in P. falciparum

Plasmodium falciparum expresses clonally variant proteins on the surface of infected erythrocytes to evade the host immune system. The clonally variant multigenes include var, rifin, and stevor, which express EMP1, RIFIN, and STEVOR proteins, respectively. The rifins are the largest multigene family and are essentially involved in the RBC rosetting, the hallmark of severe malaria. The regulators that control the RIFINs expression in P. falciparum have not been reported so far. This study reports a chromodomain-containing protein (PfCDP) that binds to H3K9me3 modification on P. falciparum chromatin. The ChIP- sequencing analysis revealed that the PfCDP is majorly associated with clonally variant gene families, primarily rifins in P. falciparum. Conditional deletion of the chromodomain (CD) gene in P. falciparum leads to the up-regulation of a subset of virulence genes, including rifins, a few var, and stevor genes. Further, we show that Pf{Delta}CDP P. falciparum lines promote the RBC rosetting. This study provides evidence of an epigenetic regulator mediated control on a subset of RIFINs expression and RBC rosetting by P. falciparum.