The role of chromatin in Plasmodium gene expression.

The malaria parasite Plasmodium falciparum dynamically regulates transcription of the majority of its genes during its intraerythrocytic developmental cycle. Chromatin is an important contributor to this tight regulation of gene expression. P. falciparum appears to utilize most of the mechanisms of chromatin creation and modification found in other eukaryotes, although it occasionally uses them in surprising ways. Much of the P. falciparum genome is maintained in a euchromatic state, potentially permissive for transcription and heterochromatin appears to have a specialized role limited to silencing islands of genes involved in redundant host-parasite interactions. P. falciparum histones share canonical modifications with other eukaryotes but also have unique modifications of unknown function including hyperacetylations of two alternative histones possibly involved in gene regulation. Much of our knowledge of chromatin regulation of gene expression in P. falciparum derives from the study of virulence genes that are subject to chromatin regulatory mechanisms ranging from histone modifications and nucleosomal occupancy to non-protein-coding RNAs and subnuclear architecture. These mechanisms will be discussed along with other characterized components of P. falciparum chromatin.