LAUSR

Four major human infecting protozoan parasites (Plasmodium, Toxoplasma, Leishmania, and Trypanosoma) impose a substantial threat to health and socio-economic status causing significant morbidity and mortality in tropics and subtropics each year. Lack of effective drugs, the emergence of drug-resistance, and toxicity have made the existing treatment regimen insufficient for most of these parasitic infections ranging from acutely lethal to chronic to almost asymptomatic. These pathogens have developed intricate life-cycle stages altering between multiple hosts and initiating a network of developmental processes in response to environmental stimulus for differentiating within the host without evoking host protective immune surveillance. These differentiation events and successful intracellular survival events require drastic and rapid modulation of the parasites and parasite-driven host gene expression which is achieved by substantial chromatin modifications. Histone posttranslational modifications have a marked effect on chromatin structure organization allowing these pathogens to cope with multiple host survival. In this review, we have described the advancements made in interpreting the role of histone modifications and their impact on gene expression throughout the life-cycle stages of these pathogens. Moreover, we have analyzed available genome-wide transcriptomics datasets for each of these pathogens to identify those parasite-specific histone-modifiers which show a preferential expression in human infective stages, with a perspective of anti-parasitic therapies.