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Project description:Malaria pathogenicity results from the parasite's ability to invade, multiply within and then egress from the host red blood cell (RBC). Infected RBCs are remodeled, expressing antigenic variant proteins (such as PfEMP1, coded by the var gene family) for immune evasion and survival. These processes require the concerted actions of many proteins, but the molecular regulation is poorly understood. We have characterized an essential Plasmodium specific Apicomplexan AP2 (ApiAP2) transcription factor in Plasmodium falciparum (PfAP2-MRP; Master Regulator of Pathogenesis) during the intraerythrocytic developmental cycle (IDC). An inducible gene knockout approach showed that PfAP2-MRP is essential for development during the trophozoite stage, and critical for var gene regulation, merozoite development and parasite egress. ChIP-seq experiments performed at 16 hour post invasion (h.p.i.) and 40 h.p.i. matching the two peaks of PfAP2-MRP expression, demonstrate binding of PfAP2-MRP to the promoters of genes controlling trophozoite development and host cell remodeling at 16 h.p.i. and antigenic variation and pathogenicity at 40 h.p.i. Using single-cell RNA-seq and fluorescence-activated cell sorting, we show de-repression of most var genes in Δpfap2-mrp parasites that express multiple PfEMP1 proteins on the surface of infected RBCs. In addition, the Δpfap2-mrp parasites overexpress several early gametocyte marker genes at both 16 and 40 h.p.i., indicating a regulatory role in the sexual stage conversion. Using the Chromosomes Conformation Capture experiment (Hi-C), we demonstrate that deletion of PfAP2-MRP results in significant reduction of both intra-chromosomal and inter-chromosomal interactions in heterochromatin clusters. We conclude that PfAP2-MRP is a vital upstream transcriptional regulator controlling essential processes in two distinct developmental stages during the IDC that include parasite growth, chromatin structure and var gene expression.
| S-EPMC10245809 | biostudies-literature
Project description:Malaria-associated pathogenesis such as parasite invasion, egress, host cell remodelling and antigenic variation requires concerted action by many proteins, but the molecular regulation is poorly understood. Here we have characterized an essential Plasmodium-specific Apicomplexan AP2 transcription factor in Plasmodium falciparum (PfAP2-P; pathogenesis) during the blood-stage development with two peaks of expression. An inducible knockout of gene function showed that PfAP2-P is essential for trophozoite development, and critical for var gene regulation, merozoite development and parasite egress. Chromatin immunoprecipitation sequencing data collected at timepoints matching the two peaks of pfap2-p expression demonstrate PfAP2-P binding to promoters of genes controlling trophozoite development, host cell remodelling, antigenic variation and pathogenicity. Single-cell RNA sequencing and fluorescence-activated cell sorting revealed de-repression of most var genes in Δpfap2-p parasites. Δpfap2-p parasites also overexpress early gametocyte marker genes, indicating a regulatory role in sexual stage conversion. We conclude that PfAP2-P is an essential upstream transcriptional regulator at two distinct stages of the intra-erythrocytic development cycle.
| S-EPMC10627835 | biostudies-literature
Project description:The pathogenicity of the malaria parasites results from their ability to invade and remodel red blood cells (RBCs), expressing antigenic variant proteins for immune evasion and survival, and then to egress from the host cell. These sequential processes require concerted actions of a large number of proteins during the intraerythrocytic developmental cycle (IDC)(Boddey and Cowman, 2013; Cowman et al., 2017; Tan and Blackman, 2021), but the molecular basis of the required regulation is only partially understood. Here, we have characterized an essential Apicomplexan AP2 (ApiAP2) transcription factor (we refer to it as PfAP2-MRP; Master Regulator of Pathogenesis) that shows two peaks of expression during the IDC at 16- and 40-hour post-invasion (h.p.i.). When expression of PfAP2-MRP at 40 h.p.i. was disrupted using an inducible gene knockout approach, ∆PfAP2-MRP parasites unable to form mature merozoites and egress from the host RBCs owing to strong down-regulation of several known egress- and invasion-associated genes, in addition to several novel hypothetical genes thought to be involved in these key life cycle processes. Disruption of PfAP2-MRP expression at 16 h.p.i. results in transcriptional activation of the majority of silenced var genes observed at both bulk and single-cell level. This is also reflected by a significantly higher level of immuno-recognition of the exported proteins on the ∆PfAP2-MRP parasite-infected RBCs by pooled sera from malaria-exposed individuals from an endemic region. In addition, overexpression of many early gametocyte marker genes was also observed in ∆PfAP2-MRP parasites at both 40 h.p.i., and at 16 h.p.i. PfAP2-MRP directly regulates these genes by binding to their promoter region or indirectly through 14 other downstream AP2 transcription factors. Taken together, we conclude that PfAP2-MRP is an upstream transcriptional regulator that participates in mutually exclusive expression patterns shown by the var family of genes and is a critical determinant of parasite's growth during the IDC.
2024-01-26 | PXD030308 | Pride
Project description:Malarial parasite pathogenicity results from its ability to invade and remodel red blood cells (RBCs), expressing antigenic variant proteins for immune evasion and survival, and then to egress from the host cell. These sequential processes require concerted actions of a large number of proteins during the intraerythrocytic developmental cycle (IDC), but the molecular basis of the required regulation is only partially understood. Here, we have characterized an essential Apicomplexan AP2 (ApiAP2) transcription factor (we refer to it as PfAP2-P; Pathogenesis) that shows two peaks of expression during the IDC at 16- and 40-hour post invasion (h.p.i.). When expression of PfAP2-P at 40 h.p.i. was disrupted using an inducible gene knockout approach, ∆PfAP2-P parasites unable to form mature merozoites and egress from the host RBCs owing to strong down-regulation of several known egress- and invasion-associated genes, in addition to several novel hypothetical genes of thought to be involved in these key life cycle processes during the IDC. Disruption of PfAP2-P expression at 16 h.p.i. results in transcriptional activation of virtually majority of silenced var genes observed at both bulk and single cell level. This is also reflected by significantly higher level of recognition of the exported proteins on the ∆PfAP2-P parasite-infected RBCs by pooled sera from malaria-exposed individuals from endemic region. In addition, over-expression of many early gametocyte marker genes was also observed in ∆PfAP2-P parasites at both 40 h.p.i., and at 16 h.p.i. PfAP2-P directly regulates these genes by binding to their promoter region or indirectly through 14 other down-stream AP2 transcription factors. Taken together, we conclude that PfAP2-P is an upstream transcriptional regulator that participates in mutually exclusive expression pattern shown by the var family of genes and a critical determinant of parasite’s growth during the IDC.
2023-08-07 | GSE191025 | GEO
Project description:Malarial parasite pathogenicity results from its ability to invade and remodel red blood cells (RBCs), expressing antigenic variant proteins for immune evasion and survival, and then to egress from the host cell. These sequential processes require concerted actions of a large number of proteins during the intraerythrocytic developmental cycle (IDC), but the molecular basis of the required regulation is only partially understood. Here, we have characterized an essential Apicomplexan AP2 (ApiAP2) transcription factor (we refer to it as PfAP2-P; Pathogenesis) that shows two peaks of expression during the IDC at 16- and 40-hour post invasion (h.p.i.). When expression of PfAP2-P at 40 h.p.i. was disrupted using an inducible gene knockout approach, ∆PfAP2-P parasites unable to form mature merozoites and egress from the host RBCs owing to strong down-regulation of several known egress- and invasion-associated genes, in addition to several novel hypothetical genes of thought to be involved in these key life cycle processes during the IDC. Disruption of PfAP2-P expression at 16 h.p.i. results in transcriptional activation of virtually majority of silenced var genes observed at both bulk and single cell level. This is also reflected by significantly higher level of recognition of the exported proteins on the ∆PfAP2-P parasite-infected RBCs by pooled sera from malaria-exposed individuals from endemic region. In addition, over-expression of many early gametocyte marker genes was also observed in ∆PfAP2-P parasites at both 40 h.p.i., and at 16 h.p.i. PfAP2-P directly regulates these genes by binding to their promoter region or indirectly through 14 other down-stream AP2 transcription factors. Taken together, we conclude that PfAP2-P is an upstream transcriptional regulator that participates in mutually exclusive expression pattern shown by the var family of genes and a critical determinant of parasite’s growth during the IDC.
2023-08-07 | GSE190342 | GEO
Project description:Malarial parasite pathogenicity results from its ability to invade and remodel red blood cells (RBCs), expressing antigenic variant proteins for immune evasion and survival, and then to egress from the host cell. These sequential processes require concerted actions of a large number of proteins during the intraerythrocytic developmental cycle (IDC), but the molecular basis of the required regulation is only partially understood. Here, we have characterized an essential Apicomplexan AP2 (ApiAP2) transcription factor (we refer to it as PfAP2-P; Master Regulator of Pathogenesis) that shows two peaks of expression during the IDC at 16- and 40-hour post invasion (h.p.i.). When expression of PfAP2-P at 40 h.p.i. was disrupted using an inducible gene knockout approach, ∆PfAP2-P parasites unable to form mature merozoites and egress from the host RBCs owing to strong down-regulation of several known egress- and invasion-associated genes, in addition to several novel hypothetical genes of thought to be involved in these key life cycle processes during the IDC. Disruption of PfAP2-P expression at 16 h.p.i. results in transcriptional activation of virtually majority of silenced var genes observed at both bulk and single cell level. This is also reflected by significantly higher level of recognition of the exported proteins on the ∆PfAP2-P parasite-infected RBCs by pooled sera from malaria-exposed individuals from endemic region. In addition, over expression of many early gametocyte marker genes was also observed in ∆PfAP2-P parasites at both 40 h.p.i., and at 16 h.p.i. PfAP2-P directly regulates these genes by binding to their promoter region or indirectly through 14 other down-stream AP2 transcription factors. Taken together, we conclude that PfAP2-P is an upstream transcriptional regulator that participates in mutually exclusive expression pattern shown by the var family of genes and a critical determinant of parasite’s growth during the IDC.
2023-08-07 | GSE230206 | GEO
Project description:Malarial parasite pathogenicity results from its ability to invade and remodel red blood cells (RBCs), expressing antigenic variant proteins for immune evasion and survival, and then to egress from the host cell. These sequential processes require concerted actions of a large number of proteins during the intraerythrocytic developmental cycle (IDC), but the molecular basis of the required regulation is only partially understood. Here, we have characterized an essential Apicomplexan AP2 (ApiAP2) transcription factor (we refer to it as PfAP2-P; Pathogenesis) that shows two peaks of expression during the IDC at 16- and 40-hour post invasion (h.p.i.). When expression of PfAP2-P at 40 h.p.i. was disrupted using an inducible gene knockout approach, ∆PfAP2-P parasites unable to form mature merozoites and egress from the host RBCs owing to strong down-regulation of several known egress- and invasion-associated genes, in addition to several novel hypothetical genes of thought to be involved in these key life cycle processes during the IDC. Disruption of PfAP2-P expression at 16 h.p.i. results in transcriptional activation of virtually majority of silenced var genes observed at both bulk and single cell level. This is also reflected by significantly higher level of recognition of the exported proteins on the ∆PfAP2-P parasite-infected RBCs by pooled sera from malaria-exposed individuals from endemic region. In addition, over-expression of many early gametocyte marker genes was also observed in ∆PfAP2-P parasites at both 40 h.p.i., and at 16 h.p.i. PfAP2-P directly regulates these genes by binding to their promoter region or indirectly through 14 other down-stream AP2 transcription factors. Taken together, we conclude that PfAP2-P is an upstream transcriptional regulator that participates in mutually exclusive expression pattern shown by the var family of genes and a critical determinant of parasite’s growth during the IDC.
2023-08-07 | GSE190497 | GEO
Project description:Obligate intracellular parasites must efficiently invade host cells in order to mature and be transmitted. For the malaria parasite Plasmodium falciparum, invasion of host red blood cells (RBCs) is essential. Here we describe a parasite-specific transcription factor PfAP2-I, belonging to the Apicomplexan AP2 (ApiAP2) family, that is responsible for regulating the expression of genes involved in RBC invasion. Our genome-wide analysis by ChIP-seq shows that PfAP2-I interacts with a specific DNA motif in the promoters of target genes. Although PfAP2-I contains three AP2 DNA-binding domains, only one is required for binding of the target genes during blood stage development. Furthermore, we find that PfAP2-I associates with several chromatin-associated proteins, including the Plasmodium bromodomain protein PfBDP1 and that complex formation is associated with transcriptional regulation. As a key regulator of red blood cell invasion, PfAP2-I represents a potential new antimalarial therapeutic target.
| S-EPMC5855115 | biostudies-literature
Project description:Cyclic nucleotide signalling is a major regulator of malaria parasite differentiation. Phosphodiesterase (PDE) enzymes are known to control cyclic GMP (cGMP) levels in the parasite, but the mechanisms by which cyclic AMP (cAMP) is regulated remain enigmatic. Here, we demonstrate that Plasmodium falciparum phosphodiesterase ? (PDE?) hydrolyses both cAMP and cGMP and is essential for blood stage viability. Conditional gene disruption causes a profound reduction in invasion of erythrocytes and rapid death of those merozoites that invade. We show that this dual phenotype results from elevated cAMP levels and hyperactivation of the cAMP-dependent protein kinase (PKA). Phosphoproteomic analysis of PDE?-null parasites reveals a >2-fold increase in phosphorylation at over 200 phosphosites, more than half of which conform to a PKA substrate consensus sequence. We conclude that PDE? plays a critical role in governing correct temporal activation of PKA required for erythrocyte invasion, whilst suppressing untimely PKA activation during early intra-erythrocytic development.
| S-EPMC6402698 | biostudies-literature
Project description:Malaria is a vector-borne infectious disease caused by unicellular, obligate intracellular parasites of the genus Plasmodium. During host switch the malaria parasite employs specialized latent stages that colonize the new host environment. Previous work has established that gametocytes, sexually differentiated stages that are taken up by the mosquito vector, control expression of genes required for mosquito colonization by translational repression. Sexual parasite development is controlled by a DEAD-box RNA helicase of the DDX6 family, termed DOZI. Latency of sporozoites, the transmission stage injected during an infectious blood meal, is controlled by the eIF2alpha kinase IK2, a general inhibitor of protein synthesis. Whether RNA-binding proteins participate in translational regulation in sporozoites remains to be studied. Here, we investigated the roles of two RNA-binding proteins of the Puf-family, Plasmodium Puf1 and Puf2, during sporozoite stage conversion. Our data reveal that, in the rodent malaria parasite P. berghei, Puf2 participates in the regulation of IK2 and inhibits premature sporozoite transformation. Inside mosquito salivary glands puf2? sporozoites transform over time to round forms resembling early intra-hepatic stages. As a result, mutant parasites display strong defects in initiating a malaria infection. In contrast, Puf1 is dispensable in vivo throughout the entire Plasmodium life cycle. Our findings support the notion of a central role for Puf2 in parasite latency during switch between the insect and mammalian hosts.
| S-EPMC3097211 | biostudies-literature