Plasmodium falciparum
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA117793 | ENA |
REPOSITORIES: ENA
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Project description: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. PfEMP1 also mediates sequestration of infected erythrocytes in the microvasculature, which is directly linked to severe malaria outcomes. 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 the P. falciparum ortholog of heterochromatin protein 1 (PfHP1) binds to H3K9me3 and 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 non-syntenic virulence gene arrays in subtelomeric and chromosome-internal islands. These include not only var genes but the majority of P. falciparum lineage-specific gene families coding for exported proteins involved in host-parasite interactions. Over-expression of PfHP1 resulted in decreased expression of a small number of (virulance) genes and indicated the presence of well-defined heterochromatic boundaries.. In summary, we uncover an unprecedented function of HP1 as a mayor regulator of virulence gene silencing and phenotypic variation, which will be instrumental for our understanding of this widely used survival strategy of unicellular pathogens.
2009-09-03 | GSE17029 | GEO
Project description: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. PfEMP1 also mediates sequestration of infected erythrocytes in the microvasculature, which is directly linked to severe malaria outcomes. 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 the P. falciparum ortholog of heterochromatin protein 1 (PfHP1) binds to H3K9me3 and 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 non-syntenic virulence gene arrays in subtelomeric and chromosome-internal islands. These include not only var genes but the majority of P. falciparum lineage-specific gene families coding for exported proteins involved in host-parasite interactions. Over-expression of PfHP1 resulted in decreased expression of a small number of (virulance) genes and indicated the presence of well-defined heterochromatic boundaries.. In summary, we uncover an unprecedented function of HP1 as a mayor regulator of virulence gene silencing and phenotypic variation, which will be instrumental for our understanding of this widely used survival strategy of unicellular pathogens. one experimental sample
2010-05-06 | E-GEOD-17029 | biostudies-arrayexpress
Project description:Plasmodium falciparum heterochromatin formation
| PRJDB15278 | ENA
Project description:The three-dimensional (3D) genome structure of human malaria parasite Plasmodium falciparum is highly organized and plays important roles in regulating coordinated expression patterns of specific genes such as virulence genes which are involved in antigenic variation and immune escape. However, the molecular mechanisms that control 3D genome of the parasite remain elusive. Here by analyzing genome organization in P. falciparum, we identify high-interacting regions (HIRs) with strong chromatin interactions telomeres and virulence genes loci. Specifically, HIRs are highly enriched with repressive histone marks (H3K36me3 and H3K9me3) and form the transcriptional repressive center. Deletion of PfSETvs, which controls H3K36me3 level, results in marked reduction of both intra-chromosomal and inter-chromosomal interactions for HIRs. Importantly, such chromatin reorganization coordinates with dymamic changes in epigenetic feature in HIRs and specifically activation of var genes. Our results uncover a fundamental mechanism that the epigenetic factor PfSETvs controls the 3D organization of heterochromatin in regulating the transcription activities of var genes family in P. falciparum.
2022-12-16 | GSE193761 | GEO
Project description:The three-dimensional (3D) genome structure of human malaria parasite Plasmodium falciparum is highly organized and plays important roles in regulating coordinated expression patterns of specific genes such as virulence genes which are involved in antigenic variation and immune escape. However, the molecular mechanisms that control 3D genome of the parasite remain elusive. Here by analyzing genome organization in P. falciparum, we identify high-interacting regions (HIRs) with strong chromatin interactions telomeres and virulence genes loci. Specifically, HIRs are highly enriched with repressive histone marks (H3K36me3 and H3K9me3) and form the transcriptional repressive center. Deletion of PfSETvs, which controls H3K36me3 level, results in marked reduction of both intra-chromosomal and inter-chromosomal interactions for HIRs. Importantly, such chromatin reorganization coordinates with dymamic changes in epigenetic feature in HIRs and specifically activation of var genes. Our results uncover a fundamental mechanism that the epigenetic factor PfSETvs controls the 3D organization of heterochromatin in regulating the transcription activities of var genes family in P. falciparum.
2022-12-16 | GSE169028 | GEO
Project description:The three-dimensional (3D) genome structure of human malaria parasite Plasmodium falciparum is highly organized and plays important roles in regulating coordinated expression patterns of specific genes such as virulence genes which are involved in antigenic variation and immune escape. However, the molecular mechanisms that control 3D genome of the parasite remain elusive. Here by analyzing genome organization in P. falciparum, we identify high-interacting regions (HIRs) with strong chromatin interactions telomeres and virulence genes loci. Specifically, HIRs are highly enriched with repressive histone marks (H3K36me3 and H3K9me3) and form the transcriptional repressive center. Deletion of PfSETvs, which controls H3K36me3 level, results in marked reduction of both intra-chromosomal and inter-chromosomal interactions for HIRs. Importantly, such chromatin reorganization coordinates with dymamic changes in epigenetic feature in HIRs and specifically activation of var genes. Our results uncover a fundamental mechanism that the epigenetic factor PfSETvs controls the 3D organization of heterochromatin in regulating the transcription activities of var genes family in P. falciparum.
2022-12-16 | GSE169027 | GEO
Project description:The process of erythrocyte invasion by merozoites of Plasmodium falciparum involves multiple steps, including the formation of a moving junction characterized by the redundancy of many of the receptor-ligand interactions involved. Several of the parasite proteins that interact with erythrocyte receptors or participate in other steps of the process of invasion are encoded by small subtelomerically-located multigene families of four to seven members. We report here that members of the multigene families pfRh, eba, rhopH1/clag and acbp exist in either an active or a silenced state. In the case of two members of the rhopH1/clag family, clag3.1 and clag3.2, expression was mutually exclusive. Silencing occurred in the absence of detectable DNA alterations, suggesting that it is transmitted epigenetically. This was unambiguously demonstrated for eba-140, which was silenced by the formation of facultative heterochromatin. Our data demonstrate that variant expression, epigenetic silencing and mutually exclusive expression in Plasmodium are not unique to genes encoding proteins exported to the surface of the erythrocyte like var genes but also occur for genes involved in host cell invasion..
2007-11-26 | E-SGRP-9 | biostudies-arrayexpress
Project description:DNA helicase RecQ1 regulates expression of virulence genes in Plasmodium falciparum via heterochromatin alteration
| PRJNA506122 | ENA
Project description:Variation of surface adhesins is a critical mediator of virulence and immune evasion in many medically important microbes. Phenotypic switching has been linked to transcriptional changes and the function of chromatin proteins, but the determinants of the rate of phenotypic switching remain poorly defined. We analyzed epigenetic switching of the Plasmodium falciparum erythrocyte invasion ligand PfRh4. By introducing a prokaryotic Dam methylase, we demonstrate that parasites selected for in vivo PfRh4 activation show a reversible increase in promoter accessibility while exhibiting perinuclear repositioning of the locus from a silent to a conserved activation domain. Forced activation of a proximal gene results in a similar level of repositioning of the PfRh4 locus into this domain and a concomitant increase in PfRh4 activation in a sub-population of parasites, with promoter accessibility occurring only at actively transcribed loci. Thus, we reveal two distinct epigenetic mechanisms regulating the expression of a malaria virulence gene. To examine the correlation between changes in gene expression induced by treatment with a high dose of trichostatin A (TSA) and the associated changes in chromatin accessibility. Plasmodium falciparum was treated (or not, control) with 100nm or 500nm TSA, and then the expression profiles were analyzed.
2012-10-13 | E-GEOD-41567 | biostudies-arrayexpress
Project description:The malaria parasite, Plasmodium falciparum, traffics the virulence protein erythrocyte membrane protein 1 (EMP1) to the surface of infected red blood cells (RBCs) via membranous organelles known as the Maurer’s clefts. How EMP1 is trafficked from the clefts to its site of action at the RBC surface is poorly understood. Here we build upon previous studies (DOI: 10.1128/mBio.03320-19) which had identified the exported Plasmodium protein PF3D7_0301700, or PTP7, as a protein of interest in post-cleft EMP1 trafficking. Transfectants expressing PTP7-GFP confirmed PTP7’s localization to the cleft and association with vesicles and soluble chaperoned complexes also implicated in EMP1 trafficking. Co-immunoprecipitation and mass spectrometry of PTP7-GFP confirmed associations with Maurer’s cleft, vesicle, and chaperone complex proteins as observed by light and electron microscopy. This experiment also expands the network map of exported protein-protein associations characterized to date.
2022-07-04 | PXD027566 | Pride