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Hoeijmakers WAM, Salcedo-Amaya AM, Smits AH, Françoijs KJ, Treeck M, Gilberger TW, Stunnenberg HG, Bártfai R. H2A.Z/H2B.Z double-variant nucleosomes inhabit the AT-rich promoter regions of the Plasmodium falciparum genome. Mol Microbiol 2013; 87:1061-73. [PMID: 23320541 PMCID: PMC3594968 DOI: 10.1111/mmi.12151] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/02/2013] [Indexed: 02/06/2023]
Abstract
Histone variants are key components of the epigenetic code and evolved to perform specific functions in transcriptional regulation, DNA repair, chromosome segregation and other fundamental processes. Although variants for histone H2A and H3 are found throughout the eukaryotic kingdom, variants of histone H2B and H4 are rarely encountered. H2B.Z is one of those rare H2B variants and is apicomplexan-specific. Here we show that in Plasmodium falciparum H2B.Z localizes to euchromatic intergenic regions throughout intraerythrocytic development and together with H2A.Z forms a double-variant nucleosome subtype. These nucleosomes are enriched in promoters over 3′ intergenic regions and their occupancy generally correlates with the strength of the promoter, but not with its temporal activity. Remarkably, H2B.Z occupancy levels exhibit a clear correlation with the base-composition of the underlying DNA, raising the intriguing possibility that the extreme AT content of the intergenic regions within the Plasmodium genome might be instructive for histone variant deposition. In summary, our data show that the H2A.Z/H2B.Z double-variant nucleosome demarcates putative regulatory regions of the P. falciparum epigenome and likely provides a scaffold for dynamic regulation of gene expression in this deadly human pathogen.
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Affiliation(s)
- Wieteke A M Hoeijmakers
- Department of Molecular Biology, Radboud University, Nijmegen Centre for Molecular Life Sciences, Nijmegen 6525GA, the Netherlands
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Trelle MB, Salcedo-Amaya AM, Cohen AM, Stunnenberg HG, Jensen ON. Global histone analysis by mass spectrometry reveals a high content of acetylated lysine residues in the malaria parasite Plasmodium falciparum. J Proteome Res 2009; 8:3439-50. [PMID: 19351122 DOI: 10.1021/pr9000898] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Post-translational modifications (PTMs) of histone tails play a key role in epigenetic regulation of gene expression in a range of organisms from yeast to human; however, little is known about histone proteins from the parasite that causes malaria in humans, Plasmodium falciparum. We characterized P. falciparum histone PTMs using advanced mass spectrometry driven proteomics. Acid-extracted proteins were resolved in SDS-PAGE, in-gel trypsin digested, and analyzed by reversed-phase LC-MS/MS. Through the combination of Q-TOF and LTQ-FT mass spectrometry we obtained high mass accuracy of both precursor and fragment ions, which is a prerequisite for high-confidence identifications of multisite peptide modifications. We utilize MS/MS fragment marker ions to validate the identification of histone modifications and report the m/z 143 ion as a novel MS/MS marker ion for monomethylated lysine. We identified all known P. falciparum histones and mapped 44 different modifications, providing a comprehensive view of epigenetic marks in the parasite. Interestingly, the parasite exhibits a histone modification pattern that is distinct from its human host. A general preponderance for modifications associated with a transcriptionally permissive state was observed. Additionally, a novel differentiation in the modification pattern of the two histone H2B variants (H2B and H2Bv) was observed, suggesting divergent functions of the two H2B variants in the parasite. Taken together, our results provide a first comprehensive map of histone modifications in P. falciparum and highlight the utility of tandem MS for detailed analysis of peptides containing multiple PTMs.
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Affiliation(s)
- Morten B Trelle
- Department of Biochemistry and Molecular Biology, Protein Research Group, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
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Flueck C, Bartfai R, Volz J, Niederwieser I, Salcedo-Amaya AM, Alako BTF, Ehlgen F, Ralph SA, Cowman AF, Bozdech Z, Stunnenberg HG, Voss TS. Plasmodium falciparum heterochromatin protein 1 marks genomic loci linked to phenotypic variation of exported virulence factors. PLoS Pathog 2009; 5:e1000569. [PMID: 19730695 PMCID: PMC2731224 DOI: 10.1371/journal.ppat.1000569] [Citation(s) in RCA: 217] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Accepted: 08/07/2009] [Indexed: 02/01/2023] Open
Abstract
Epigenetic processes are the main conductors of phenotypic variation in eukaryotes. The malaria parasite Plasmodium falciparum employs antigenic variation of the major surface antigen PfEMP1, encoded by 60 var genes, to evade acquired immune responses. Antigenic variation of PfEMP1 occurs through in situ switches in mono-allelic var gene transcription, which is PfSIR2-dependent and associated with the presence of repressive H3K9me3 marks at silenced loci. Here, we show that P. falciparum heterochromatin protein 1 (PfHP1) binds specifically to H3K9me3 but not to other repressive histone methyl marks. Based on nuclear fractionation and detailed immuno-localization assays, PfHP1 constitutes a major component of heterochromatin in perinuclear chromosome end clusters. High-resolution genome-wide chromatin immuno-precipitation demonstrates the striking association of PfHP1 with virulence gene arrays in subtelomeric and chromosome-internal islands and a high correlation with previously mapped H3K9me3 marks. These include not only var genes, but also the majority of P. falciparum lineage-specific gene families coding for exported proteins involved in host-parasite interactions. In addition, we identified a number of PfHP1-bound genes that were not enriched in H3K9me3, many of which code for proteins expressed during invasion or at different life cycle stages. Interestingly, PfHP1 is absent from centromeric regions, implying important differences in centromere biology between P. falciparum and its human host. Over-expression of PfHP1 results in an enhancement of variegated expression and highlights the presence of well-defined heterochromatic boundaries. In summary, we identify PfHP1 as a major effector of virulence gene silencing and phenotypic variation. Our results are instrumental for our understanding of this widely used survival strategy in unicellular pathogens.
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Affiliation(s)
- Christian Flueck
- Department of Medical Parasitology and Infection Biology, Swiss Tropical Institute, Basle, Switzerland
| | - Richard Bartfai
- Department of Molecular Biology, Nijmegen Center of Molecular Life Sciences, Radboud University, Nijmegen, The Netherlands
| | - Jennifer Volz
- Division of Infection and Immunity, The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Igor Niederwieser
- Department of Medical Parasitology and Infection Biology, Swiss Tropical Institute, Basle, Switzerland
| | - Adriana M. Salcedo-Amaya
- Department of Molecular Biology, Nijmegen Center of Molecular Life Sciences, Radboud University, Nijmegen, The Netherlands
| | - Blaise T. F. Alako
- Department of Molecular Biology, Nijmegen Center of Molecular Life Sciences, Radboud University, Nijmegen, The Netherlands
| | - Florian Ehlgen
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia
| | - Stuart A. Ralph
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia
| | - Alan F. Cowman
- Division of Infection and Immunity, The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Zbynek Bozdech
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Hendrik G. Stunnenberg
- Department of Molecular Biology, Nijmegen Center of Molecular Life Sciences, Radboud University, Nijmegen, The Netherlands
| | - Till S. Voss
- Department of Medical Parasitology and Infection Biology, Swiss Tropical Institute, Basle, Switzerland
- * E-mail:
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