Project description:Epigenetic mechanisms have been poorly understood in Plasmodium falciparum, the causative agent of malaria. To elucidate stage specific epigenetic regulations in P. falciparum, we performed genome-wide mapping of various histone modifications, nucleosomes and RNA Polymerase II. Our comprehensive analysis suggest that transcription initiation and elongation are distinct in Plasmodium. In this study, by analyzing histone modifications, nucleosome occupancy and RNA Polymerase II (Pol II) at three different IEC developmental stages of Plasmodium; ring, trophozoite and schizont, we tried to unravel the epigenetic mechanism associated with gene regulation. Examination of H3K27me3, H3K4me3, H3K9me3, H3K14ac, H3K4me1, H3K79me3, H3K27ac, H3K4me2, H3K9ac, H4ac, RNA Pol II and Histone H3 at three different stages of Plasmodium falciparum
Project description:Histone post-translational modifications (PTMs) play an essential role in epigenetic gene regulation. The Plasmodium falciparum genome encodes canonical and variant histones and a collection of conserved enzymes for histone PTMs and chromatin remodeling. Herein, we characterized the P. falciparum histone PTMs during the development of gametocytes, the obligatory for parasite transmission, we extracted histones from the early (day 4), middle (day 8), and late (day 12) stages of gametocytes, and analyzed them by advanced mass spectrometry.
Project description:Epigenetic mechanisms have been poorly understood in Plasmodium falciparum, the causative agent of malaria. To elucidate stage specific epigenetic regulations in P. falciparum, we performed genome-wide mapping of various histone modifications, nucleosomes and RNA Polymerase II. Our comprehensive analysis suggest that transcription initiation and elongation are distinct in Plasmodium. In this study, by analyzing histone modifications, nucleosome occupancy and RNA Polymerase II (Pol II) at three different IEC developmental stages of Plasmodium; ring, trophozoite and schizont, we tried to unravel the epigenetic mechanism associated with gene regulation.
Project description:A striking unusual genome architecture characterizes the two related human parasitic pathogens Plasmodium falciparum and Toxoplasma gondii. A major fraction of the bulk parasite genome is packaged as transcriptionally permissive euchromatin with few loci embedded in silenced heterochromatin. Primary chromatin shapers include histone modifications at the nucleosome lateral surface close to the DNA but their mode of action remains unclear. We identify versatile modifications at Lys31 within the globular domain of histone H4 as key determinants of genome organization and expression in Apicomplexa. H4K31 acetylation promotes a relaxed chromatin state at the promoter of active genes through nucleosome disassembly in both parasites. In contrast, monomethylated H4K31 is enriched in the core body of Toxoplasma active genes but inversely correlates with transcription while being astonishingly enriched at transcriptionally inactive pericentromeric heterochromatin in Plasmodium. This is the first evidence for a methylated residue of H4 associating with transcriptional regulation likely by reducing histone turnover hence slowing RNA polymerase progression across transcribed loci.
Project description:Histone post-translational modifications (PTMs) are frequently co-occurring on the same chromatin domains or even the same molecule. It is now established that these ‘histone codes’ are the result of cross-talk between enzymes that catalyse multiple PTMs with univocal readout as compared to these PTMs in isolation. Here, we performed a comprehensive identification and quantification of histone codes of the malaria parasite, Plasmodium falciparum. We used advanced quantitative middle-down proteomics to identify combinations of PTMs in both the proliferative, asexual stages and transmissible, sexual gametocyte stages of P. falciparum. We provide an updated, high-resolution compendium of 72 PTMs on H3 and H3.3, of which 30 newly identified. Several co-existing PTMs with unique stage distinction was identified, indicating that many of these combinatorial PTMs are associated to specific stages of the parasite life cycle. We focused on the code H3R17me2K18acK23ac for its unique presence in mature gametocytes; chromatin proteomics identified a gametocyte-specific SAGA-like effector complex including the transcription factor AP2-G2 which we associated to this specific histone code, as involved in regulating gene expression in mature gametocytes. Ultimately, this study unveils previously undiscovered histone PTMs and their functional relationship with co-existing partners. These results highlight that investigating chromatin regulation in the parasite using single histone PTM assays might overlook higher order gene regulation for distinct proliferation and differentiation processes.
