RNA-seq of Plasmodium berghei PbWT and PbHMGB1KO parasite strains
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ABSTRACT: The purpose of the experiment is to identify the differential gene expression pattern of PbHMGB1KO parasites with respect to the PbWT parasites.
Project description:Protein phosphorylation plays a critical role during the development of malaria parasites. Here, we performed a functional analysis of the Plasmodium berghei Ser/Thr protein phosphatase 6 (PbPP6), which was associated with the plasma membrane of macrogametes and ookinetes. Compared to wild-type P. berghei, genetic disruption/deletion of the pbpp6 gene (∆pbpp6) reduced the asexual growth of the parasites and prolonged the survival of ∆pbpp6-infected mice. The ∆pbpp6 parasites showed impaired gametogenesis, particularly affecting male gametogenesis, which substantially decreased ookinete formation and transmission to mosquitoes. RNA-seq assays revealed that pbpp6 disruption led to over 11-fold down-regulation of the nek3 gene, a regulator of MAPK2 in the PKG-Ca2+ signaling cascade during male gametogenesis. Several PDEs (α, γ, δ) were also affected, indicating that PbPP6 plays a role in the cGMP-PKG-Ca2+ signaling pathway. Additionally, we observed altered expression of messenger ribonucleoproteins in the Δpbpp6 parasites, which may affect translational repression of stored mRNAs in female gametocytes and post-fertilization development in mosquitoes. Consistent with the dysregulated GO terms related to the cGMP-PKG-Ca2+ signaling cascade observed in RNA-seq analysis, the activated gametocytes of ∆pbpp6 exhibited significantly reduced levels of intracellular cGMP, cytosolic Ca2+ mobilization, and DNA replication. Phosphoproteomic analysis detected increased phosphorylation at the Ser508 site of guanylyl cyclase alpha (GCα), suggesting that PbPP6 regulates cGMP-PKG-Ca2+ signaling cascades by modulating the activity of GCα during gametogenesis. This study highlights the potential of targeting PP6 to disrupt malaria transmission.
Project description:Protein phosphorylation plays a critical role during the development of malaria parasites. Here, we performed a functional analysis of the Plasmodium berghei Ser/Thr protein phosphatase 6 (PbPP6), which was associated with the plasma membrane of macrogametes and ookinetes. Compared to wild-type P. berghei, genetic disruption/deletion of the pbpp6 gene (∆pbpp6) reduced the asexual growth of the parasites and prolonged the survival of ∆pbpp6-infected mice. The ∆pbpp6 parasites showed impaired gametogenesis, particularly affecting male gametogenesis, which substantially decreased ookinete formation and transmission to mosquitoes. RNA-seq assays revealed that pbpp6 disruption led to over 11-fold down-regulation of the nek3 gene, a regulator of MAPK2 in the PKG-Ca2+ signaling cascade during male gametogenesis. Several PDEs (α, γ, δ) were also affected, indicating that PbPP6 plays a role in the cGMP-PKG-Ca2+ signaling pathway. Additionally, we observed altered expression of messenger ribonucleoproteins in the Δpbpp6 parasites, which may affect translational repression of stored mRNAs in female gametocytes and post-fertilization development in mosquitoes. Consistent with the dysregulated GO terms related to the cGMP-PKG-Ca2+ signaling cascade observed in RNA-seq analysis, the activated gametocytes of ∆pbpp6 exhibited significantly reduced levels of intracellular cGMP, cytosolic Ca2+ mobilization, and DNA replication. Phosphoproteomic analysis detected increased phosphorylation at the Ser508 site of guanylyl cyclase alpha (GCα), suggesting that PbPP6 regulates cGMP-PKG-Ca2+ signaling cascades by modulating the activity of GCα during gametogenesis. This study highlights the potential of targeting PP6 to disrupt malaria transmission.
Project description:Commitment to and completion of sexual development are essential for malaria parasites to be transmitted through mosquitoes. The molecular mechanism(s) responsible for these processes however, remain largely unknown. We have identified two transcription factors (both belonging to the AP2 family) essential for gametocytogenesis. AP2-G mutants are characterised by a complete inability to produce gametocytes. In AP2-G2 mutants the gametocytaemia is very significantly reduced but not completely abolished. We have performed the microarray experiments in order to cokmpare the transcriptomes of these mutantnts to the WT parasites and between each other. As P.berghei parasites are characterised by asynchronous development in the rodent host, the different stage composition of the sample would impact the analysis. Therefore parasites were harvested and matured in in vitro to the schizont stage Pairwaise comparison between the mutants and parental line was performed. 3 biological replicates of each condition were used.
Project description:The microarray experiments were carried out using a long oligonucleotide DNA microarray that represent all 5363 P. falciparum genes with one oligonucleotide per 1.9kb of coding sequence on average (Hu et al. 2007). Total 247 microarray experiments were carried out including 29-drug treatment time courses with 20 compounds and corresponding untreated controls from different drug or inhibitor treatment. Data of each drug/inhibitor experiment were normalized using a linear normalization and background filtering as implemented by the NOMAD database (http://derisilab.ucsf.edu). Time-series sampling and experiments with synchronized ex vivo culturing parasites. Each experiment has treatment and controls, and starts at a specific time of post invasion. For an example of quinine treatment, the treatments start from late ring stage through trophozoite stage of the parasites. First, IC50 is determined by drug assay with synchronized parasites (5% parasiteomia and 2% RBC). Second, synchronized parasite cultures are splitted into 12 flasks (75ml culture/flask) for a 6 time-point time-series experiment. 6 flasks are treated with quinine (final concentration is IC50) and 6 flasks are negative controls. 1,2,4,6,8 and 10 hrs after the treatment, parasites in each flask were harvested for total RNA isolation and microarray hybridizaiton.
Project description:The aim was to understand the molecular basis of the parasite response to DR. Transcriptomic analysis of synchronized wildtype parasites, collected with 4h intervals, from mice under the two dietary conditions. We found that WT parasites on DR and control diets have different transcriptomes, with a remarkable general repression of transcription in DR.
Project description:To identify protein phosphatases (PP) that are essential during asexual blood stage development in Plasmodium berghei, we attempted systematic deletion of the 30 P. berghei PP genes using double homologous recombination. Of these, we performed strand-specific RNA-sequencing (RNA-Seq) analysis for 2 myristoylated PP mutants _ppm2 and _ppm5 lines across relevant lifestages ( activated gametocyte and schizont stages in both _ppm2 and _ppm5 and ookinete stage in _ppm5 alone). Two to four biological replicates each for _ppm2, _ppm5 and wild-type parasites were processed into strand-specific RNA-seq libraries and sequenced in Illumina Hiseq platform using 100-bp paired end chemistry.
Project description:Transcriptional profiling of gametocyte non-producer lines in Plasmodium berghei Transcriptome of gametocyte non producer lines (natural and genetic KO) and parental (820) lines. The aim of the study was to identify key genes involved in the decision to commit to gametocytogenesis in Plasmodium berghei. These microarrays compare naturally selected lines that do not produce gametocytes, and the parental line and additionally a genetic knock out of AP2-G PBANKA_143750. Data published Sinha, Hughes, et, al Nature tbc. 2- colour microarray comparing to common background pool (containing all life cycle stages). Replicates of different life cycle stages of gametocyte non-producer lines and wild tye (WT) parental control lines