The chromatin-bound proteome of the human malaria parasite, Plasmodium falciparum
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ABSTRACT:
ORGANISM(S): Plasmodium falciparum
PROVIDER: GSE116219 | GEO | 2019/09/16
REPOSITORIES: GEO
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Project description:Gene expression is controlled at multiple levels, including transcription, stability, translation, and degradation. Over the years, it has become apparent that Plasmodium falciparum exerts limited transcriptional control of gene expression, while at least part of Plasmodium's genome is controlled by post-transcriptional mechanisms. To generate insights into the mechanisms that regulate gene expression at the post-transcriptional level, we undertook complementary computational, comparative genomics, and experimental approaches to identify and characterize mRNA-binding proteins (mRBPs) in P. falciparum.Close to 1000 RNA-binding proteins are identified by hidden Markov model searches, of which mRBPs encompass a relatively large proportion of the parasite proteome as compared to other eukaryotes. Several abundant mRNA-binding domains are enriched in apicomplexan parasites, while strong depletion of mRNA-binding domains involved in RNA degradation is observed. Next, we experimentally capture 199 proteins that interact with mRNA during the blood stages, 64 of which with high confidence. These captured mRBPs show a significant overlap with the in silico identified candidate RBPs (p?<?0.0001). Among the experimentally validated mRBPs are many known translational regulators active in other stages of the parasite's life cycle, such as DOZI, CITH, PfCELF2, Musashi, and PfAlba1-4. Finally, we also detect several proteins with an RNA-binding domain abundant in Apicomplexans (RAP domain) that is almost exclusively found in apicomplexan parasites.Collectively, our results provide the most complete comparative genomics and experimental analysis of mRBPs in P. falciparum. A better understanding of these regulatory proteins will not only give insight into the intricate parasite life cycle but may also provide targets for novel therapeutic strategies.
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Project description:The chromatin-bound proteome of the human malaria parasite, Plasmodium falciparum
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Project description:We compared transcript levels at several points along the asexual blood cycle between 21 P. falciparum lines. These 21 parasite lines are organized in 4 sets of parasite lines, with all parasite lines within a set sharing a clonal origin. We compared transcript levels within each set. We also performed comparative genome hybridization (CGH) for all 21 parasite lines.
2012-02-07 | E-MTAB-673 | biostudies-arrayexpress
Project description:The malaria parasite Plasmodium falciparum replicates via schizogony: a fundamentally unusual type of cell cycle involving asynchronous replication of multiple nuclei within the same cytoplasm. It also has one of the most A/T-biased genomes ever sequenced. Here, we present the first comprehensive study of the specification and activation of DNA replication origins during Plasmodium schizogony. Potential replication origins were found to be abundant, with ORC1-binding sites detected every ~800 bp throughout the genome. They had no motif enrichment, but were biased towards areas of higher G/C content. Origin activation was then measured at single-molecule resolution via DNAscent technology, and was much less dense than ORC1-binding sites, with origins activated preferentially in areas of low transcriptional activity. Consistently, replication forks moved slowest through the most highly transcribed genes, suggesting that conflicts between transcription and origin firing inhibit efficient replication, and that P. falciparum has evolved its S-phase to minimise such conflicts.
2023-01-30 | GSE208757 | GEO
Project description:Epigenetic regulatory mechanisms are central to the development and survival of all eukaryotic organisms. These mechanisms critically depend on the marking of chromatin domains with distinctive histone tail modifications (PTMs) and their recognition by effector protein complexes. In this project, histone peptide pull-downs and protein-protein interaction quantitative proteomics were used to unveil interactions between PTMs and associated reader protein complexes of Plasmodium falciparum, a unicellular parasite causing malaria. One of the identified bromodomain proteins (BDP5, PF3D7_1234100) has previously been proposed to be the P. falciparum homologue of TBP-associated factor 1 (TAF1). As the bdp5/taf1 locus was refractory to disruption, knock-sideways strategy was employed to disrupt BDP5/TAF1 function by tethering it to the cell membrane (Birnbaum, 2017, Nature Methods). To gain insight in the transcriptional defects upon BDP5/TAF1 knock-sideways (KS), directional RNA seq libraries were generated at 2, 6 and 12 hours after knock-sideways induction.
2019-10-15 | GSE138499 | GEO
Project description:Purpose: The goal of this study was to identify genes associated with increased sexual differentiation in P. falciparum. Method: RNAseq analysis of two different P. falciparum strains (NF54 and Pf2004/164tdTom) cultured under sexual differentiation-inducing (-SerM) and non-inducing (-SerM/LysoPC and -SerM/Serum) conditions Results: We found a total of 342 genes significantly induced in response to LysoPC depletion, thereby determining changes associated with sexual differentiation and limiting Kenndedy pathway substrates.
2017-11-16 | GSE104114 | GEO
Project description:ChIP-seq experiments were performed for the putative telomere repeat-binding factor (PfTRF) in the malaria parasite Plasmodium falciparum strain 3D7. The gene encoding this factor (PF3D7_1209300) was endogenously tagged with either a GFP- or a 3xHA-tag and these transgenic parasite lines were used in ChIP-sequencing experiments. Sequencing of the ChIP and input libraries showed enrichment of PfTRF at all telomere-repeat containing chromosome ends (reference genome Plasmodium falciparum 3D7 from PlasmoDB version 6.1) as well as in all upsB var promoters.In addition,PfTRF was enriched at seven additional, intra-chromosomal sites and called in the PfTRF-HA ChIP-seq only. Plasmodium falciparum 3D7 parasites were generated with -GFP or -3xHA C-terminal tagged TRF (PF3D7_1209300). Nuclei were isolated from formaldehyde cross-linked schizont-stage transgenic parasites and used to prepare chromatin. Chromatin immunoprecipitations were performed using mouse anti-GFP (Roche Diagnostics, #11814460001) or rat anti-HA 3F10 (Roche Diagnostics, #12158167001). Sequencing libraries were prepared according to a Plasmodium-optimized library preparation procedure including KAPA polymerase-mediated PCR amplification.
2016-07-15 | E-GEOD-76537 | biostudies-arrayexpress
Project description:Tetracyclines are effective but slow-acting antimalarial drugs whose mechanism of action remains uncertain. To characterize the antimalarial mechanism of tetracyclines, we evaluated their stage-specific activities, impacts on parasite transcription, and effects on two predicted organelle targets, the apicoplast and the mitochondrion, in cultured Plasmodium falciparum. Antimalarial effects were much greater after two 48-h life cycles than after one cycle, even if the drugs were removed at the end of the first cycle. Doxycycline-treated parasites appeared morphologically normal until late in the second cycle of treatment but failed to develop into merozoites. Doxycycline specifically impaired the expression of apicoplast genes. Apicoplast morphology initially appeared normal in the presence of doxycycline. However, apicoplasts were abnormal in the progeny of doxycycline-treated parasites, as evidenced by a block in apicoplast genome replication, a lack of processing of an apicoplast-targeted protein, and failure to elongate and segregate during schizogeny. Replication of the nuclear and mitochondrial genomes and mitochondrial morphology appeared normal. Our results demonstrate that tetracyclines specifically block expression of the apicoplast genome, resulting in the distribution of nonfunctional apicoplasts into daughter merozoites. The loss of apicoplast function in the progeny of treated parasites leads to a slow but potent antimalarial effect. Keywords: Plasmodium falciparum treated with Doxycycline
2006-07-11 | GSE5267 | GEO
Project description:Background: Human malaria is a major cause of disease and poverty in developing countries being P. falciparum the most deadly of malaria parasites. To successfully develop and adapt within hosts, P. falciparum undergoes drastic switches in chromatin structure and gene expression, but the identity and function of regulatory elements driving these events remain poorly understood. In this work, we performed genome-wide profiling of chromatin accessibility in two culture-adapted subclones and four developmental stages during the intraerythrocytic development by the Assay for Transposase-Accessible Chromatin by sequencing (ATAC-seq). Results: ATAC Tn5 hypersensitivity sites (THSSs) localize preferentially at known Transcriptional Start Sites (TSSs). Chromatin accessibility by ATAC-seq is predictive of active transcription and of the levels of histone marks H3K9ac and H3K4me3 in a quantitative manner. Our assay allows us to characterize novel regulatory regions including TSS and enhancers-like elements. We show that the dynamics in the accessible chromatin profile matches temporal differences in gene expression during development, and that gene activation occurs concomitantly to DNA binding events. Motif analysis of stage-specific ATAC-seq footprints predicts the in vivo binding sites and function of a number of ApiAP2 transcription factors. Finally, the mutually exclusive expression and epigenetic switch of several clonally variant genes associates with a differential enrichment of ATAC-seq signal at their promoters. Conclusion: Overall, this study allows us to characterize at a genome-wide level cis-regulatory regions likely to play an essential function in the developmental transitions and in clonally variant gene expression in P. falciparum.
2018-07-06 | GSE109599 | GEO
Project description:Tetracyclines are effective but slow-acting antimalarial drugs whose mechanism of action remains uncertain. To characterize the antimalarial mechanism of tetracyclines, we evaluated their stage-specific activities, impacts on parasite transcription, and effects on two predicted organelle targets, the apicoplast and the mitochondrion, in cultured Plasmodium falciparum. Antimalarial effects were much greater after two 48-h life cycles than after one cycle, even if the drugs were removed at the end of the first cycle. Doxycycline-treated parasites appeared morphologically normal until late in the second cycle of treatment but failed to develop into merozoites. Doxycycline specifically impaired the expression of apicoplast genes. Apicoplast morphology initially appeared normal in the presence of doxycycline. However, apicoplasts were abnormal in the progeny of doxycycline-treated parasites, as evidenced by a block in apicoplast genome replication, a lack of processing of an apicoplast-targeted protein, and failure to elongate and segregate during schizogeny. Replication of the nuclear and mitochondrial genomes and mitochondrial morphology appeared normal. Our results demonstrate that tetracyclines specifically block expression of the apicoplast genome, resulting in the distribution of nonfunctional apicoplasts into daughter merozoites. The loss of apicoplast function in the progeny of treated parasites leads to a slow but potent antimalarial effect. We analyzed a series of 12 microarrays covering 55 hours of Plasmodium falciparum treated with doxycycline and 12 microarrays covering the same 55 hours with no doxycycline treatment
2010-07-01 | E-GEOD-5267 | biostudies-arrayexpress