DESCRIPTION (provided by applicant): The increasing burden of malaria, in part, due to drug resistance in the parasite Plasmodium falciparum, demands new therapies. Recent research in the field of transcription has demonstrated the functional importance of chromatin in regulating gene expression in eukaryotes. Enzymes that modulate chromatin structures have a profound effect on controlling gene expression. Among these enzymes, histone acetyltransferases (HATs), which transfer the acetyl group from acetyl-CoA to the lysine residues in the N- terminal tails of histones, are the best studied. The anti-parasitic effects of drugs that disturb histone acetylation and recent studies from our group on the chromatin remodeling factors in P. falciparum demonstrated that dynamic histone acetylation is an important epigenetic mechanism of transcription regulation and plays a prominent role in development of the malaria parasite. Thus, we propose to 1) characterize two families of transcription-related HAT proteins, 2) determine their functional roles in global transcription regulation, and 3) identify the subunits of multiprotein HAT complexes in P. falciparum. HAT proteins will be characterized using molecular and biochemical approaches, and their functions in parasite development and transcription regulation will be determined by targeted gene disruption and genome-wide expression analysis. This proposed research aims to reveal the epigenetic mechanisms in transcription regulation that controls the parasite development and virulence. The fundamental importance of histone acetylation in gene regulation and the great potential of HAT and histone deacetylase as drug targets underline the significance of research in this area, which may lead to novel antimalarial drugs. Malaria is still a major public health problem in many countries. Its recent resurgence in prevalence is partially due to drug resistance. This study aims to characterize the functions of a group of enzymes that regulate parasite gene expression, which may lead to the design of novel antimalarial drugs.