Unravelling a histone code for malaria virulence

SummaryEpigenetic phenomena have been shown to play a role in the regulated expression of virulence genes in several pathogenic organisms, including the var gene family in Plasmodium falciparum. A better understanding of how P. falciparum can both maintain a single active var gene locus through many erythrocytic cycles and also achieve successive switching to different loci in order to evade the host immune system is greatly needed. Disruption of this tightly co‐ordinated expression system presents an opportunity for increased clearance of the parasites by the immune system and, in turn, reduced mortality and morbidity. In the current issue of Molecular Microbiology, Lopez‐Rubio and colleagues investigate the correlation of specific post‐translational histone modifications with different transcriptional states of a single var gene, var2csa. Quantitative chromatin immunoprecipitation is used to demonstrate that different histone methylation marks are enriched at the 5′ flanking and coding regions of active, poised or silenced var genes. They identify an increase of H3K4me2 and H3K4me3 in the 5′ flanking region of an active var locus and expand on an earlier finding that H3K9me3 is e