Project description:To investigate the DNA-binding property of two tandem AP2 domains of PbSIP2, DNA immunoprecipitation followed by high-throughput sequencing (DIP-seq) analysis were performed. Recombinant AP2 domains fused with maltose-binding protein (MBP) were mixed with the P. berghei genomic DNA fragmented via sonication, and protein-DNA complex was harvested using amylose resin. The obtained DNA fragments were sequenced via the next generation sequencing.
Project description:Plasmodium berghei transcriptomes of pbsip2cKO, a parasite line in which pbsip2 is disrupted by DiCre-mediated recombination in the presence of rapamycin, were analyzed at the schizont stage.
Project description:To investigate the genome-wide binding sites of PbSIP2 in Plasmodium berghei, the chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) analyses were performed. Parasites expressing GFP-fused PbSIP2 (PbSIP2::GFP) in cultures were harvested at 24 h post infection and subjected to ChIP-seq experiments using anti-GFP antibody. Binding sites of PbSIP2 were determined from the sequence data.
Project description:The invasion of Plasmodium merozoites into host erythrocytes is initiated through specific ligand–receptor interactions. This interaction results in subsequent invasion events, facilitated by forming a moving junction through AMA–1 and associated molecular complexes mediating parasite entry into the erythrocytic membrane. Previous studies have implicated erythrocyte surface glycosaminoglycans, particularly heparan sulfate proteoglycans, as critical receptor components in this invasion process. In this study, we sought to elucidate the molecular function of PbMAP2 (encoded by PbANKA_1137800), a previously uncharacterized Plasmodium berghei ANKA protein, in mediating merozoite attachment and invasion via heparan sulfate–dependent pathways. The PbMAP2 protein, predominantly situated at the extreme apical region of the P. berghei merozoite, binds to heparin and the erythrocyte surface during merozoite invasion. Additionally, mice either immunized with the PbMAP2 protein or passively immunized with sera derived from vaccinated mice demonstrated enhanced immunity against lethal challenges. Global mass spectrometric analysis indicates that PbMAP2 engages with several trafficking and secretion proteins associated with parasite invasion. Our findings pinpointed PbMAP2 is predominantly expressed at the extreme apical region of the P. berghei merozoite and engages in binding to the heparin–like receptors on the erythrocyte surface during merozoite invasion.
Project description:The merozoite surface protein-1 (MSP-1) is the most abundant protein on the surface of the erythrocyte-invading Plasmodium merozoite, the causative agent of malaria. MSP-1 is essential for merozoite formation, entry into and escape from erythrocytes, and is a promising vaccine candidate. We solved monomeric and dimeric structures of full-length MSP-1 construct MSP-1D as previously used in a successful phase 1a clinical trial (Blank et al. 2020). CS-MS was used to validate the de novo built atomic model.
Project description:Background: Considerable work has been carried out to understand the biology of the intermediate stages, the tachyzoite and bradyzoite, of Toxoplasma gondii in large part due to the accessible culturing methods for these stages. However, culturing methods for stages beyond the bradyzoite, including the merozoite and sexual stages, have not been developed hindering the ability to study a large portion of the parasite’s life cycle. We begin to unravel the molecular aspects of the merozoite stage focusing on gene expression. Results: To initiate this, we harvested merozoite parasites and hybridized mRNA to the Affymetrix Toxoplasma GeneChip. We analyzed the merozoite data in context of the life cycle by combining it with a previously published study that generated array data for the oocyst, tachyzoite, and bradyzoite stages (Fritz HM et al. PLoS One, 2012). Principal component analysis highlights the unique profile of the merozoite samples, placing them approximately half-way on a continuum between the tachyzoite/bradyzoite and oocyst samples. Prior studies have shown that antibodies to surface antigen p30 (SAG1) and many dense granule proteins do not label merozoites, and our microarray data confirms that these genes are not expressed at this stage. Also, the expression for many rhoptry and microneme proteins is drastically reduced while the expression for many surface antigens is increased at the merozoite stage. Gene Ontology and KEGG analysis reveals that genes involved in transcription/translation and many metabolic pathways are upregulated at the merozoite stage, highlighting unique growth requirements of this stage. We also show that an upstream promoter region of a merozoite specific gene is sufficient to control stage specific expression at the merozoite stage. Conclusion: The merozoite represents the first developmental stage within the gut of the definitive host. Determining the correct conditions that coax the parasite into the merozoite stage in vitro may allow the parasite to complete sexual development. The data presented here describe the global gene expression profile of merozoite stage and the creation of transgenic parasite strains that will be useful in unlocking how the parasite senses and responds to the felid gut environment to initiate coccidian development. The ToxoGeneChip microarray was used to measure both tachyzoite and merozoite mRNA expression in the type II TgNmBr1 strain.
Project description:Background: Considerable work has been carried out to understand the biology of the intermediate stages, the tachyzoite and bradyzoite, of Toxoplasma gondii in large part due to the accessible culturing methods for these stages. However, culturing methods for stages beyond the bradyzoite, including the merozoite and sexual stages, have not been developed hindering the ability to study a large portion of the parasite’s life cycle. We begin to unravel the molecular aspects of the merozoite stage focusing on gene expression. Results: To initiate this, we harvested merozoite parasites and hybridized mRNA to the Affymetrix Toxoplasma GeneChip. We analyzed the merozoite data in context of the life cycle by combining it with a previously published study that generated array data for the oocyst, tachyzoite, and bradyzoite stages (Fritz HM et al. PLoS One, 2012). Principal component analysis highlights the unique profile of the merozoite samples, placing them approximately half-way on a continuum between the tachyzoite/bradyzoite and oocyst samples. Prior studies have shown that antibodies to surface antigen p30 (SAG1) and many dense granule proteins do not label merozoites, and our microarray data confirms that these genes are not expressed at this stage. Also, the expression for many rhoptry and microneme proteins is drastically reduced while the expression for many surface antigens is increased at the merozoite stage. Gene Ontology and KEGG analysis reveals that genes involved in transcription/translation and many metabolic pathways are upregulated at the merozoite stage, highlighting unique growth requirements of this stage. We also show that an upstream promoter region of a merozoite specific gene is sufficient to control stage specific expression at the merozoite stage. Conclusion: The merozoite represents the first developmental stage within the gut of the definitive host. Determining the correct conditions that coax the parasite into the merozoite stage in vitro may allow the parasite to complete sexual development. The data presented here describe the global gene expression profile of merozoite stage and the creation of transgenic parasite strains that will be useful in unlocking how the parasite senses and responds to the felid gut environment to initiate coccidian development.