Schematic of perinuclear expression site (PES) rganization. (A) The nuclear organization of the var gene family in Plasmodium falciparum is illustrated, with only three out of fourteen chromosomes depicted for clarity. Subtelomeric and central var genes (red rectangles) form multiple foci at the nuclear periphery, alongside other perinuclear compartments such as ribosomal DNA genes and centromeres (not shown here). During the early asexual blood stage, known as the ring stage, the activation of a var gene (green rectangle) requires relocation to a distinct perinuclear expression zone. Black circular shapes represent telomere ends. (B) Hallmarks of silenced (red box), active (green box), and poised (orange box) var genes. Summary of epigenetic mechanisms associated with the different states of var genes during asexual blood stage development. Diffendall G, Scherf A. Deciphering the Plasmodium falciparum perinuclear var gene expression site. Trends Parasitol. 2024 22:S1471-4922(24)00142-9. PMID: 38910098