Project description:Sporozoite is the stage in which malaria parasites initially infect the vertebrate host. Elucidation of gene regulation in this stage will promote the investigation of mechanisms of liver infection by this parasite and contribute to development of strategies for preventing the malaria transmission. AP2-Sp is a transcription factor essential for formation of sporozoites or sporogony, which take place in oocysts on the midgut of infected mosquitoes. To understand the role of this transcription factor in the transcriptional regulatory system of this stage we performed ChIP-seq analysis using whole mosquito midguts containing late oocysts as start materials and explore its target genes genome-widely. Target genes were composed of 640 genes, which encompassed various functional categories and were contained genes involved in distinct processes parasites pass through in this stage, from sporogony to development into the liver stage. Furthermore, RNA-seq analysis showed that these genes constituted majority of the genes highly expressed in in this stage. These results suggested that this TF determines basal pattern of gene expression of this stage by targeting a broad range of genes directly.
Project description:Sporozoite is the stage in which malaria parasites initially infect the vertebrate host. Elucidation of gene regulation in this stage will promote the investigation of mechanisms of liver infection by this parasite and contribute to development of strategies for preventing the malaria transmission. AP2-Sp is a transcription factor essential for formation of sporozoites or sporogony, which take place in oocysts on the midgut of infected mosquitoes. To understand the role of this transcription factor in the transcriptional regulatory system of this stage we performed ChIP-seq analysis using whole mosquito midguts containing late oocysts as start materials and explore its target genes genome-widely. Target genes were composed of 640 genes, which encompassed various functional categories and were contained genes involved in distinct processes parasites pass through in this stage, from sporogony to development into the liver stage. Furthermore, RNA-seq analysis showed that these genes constituted majority of the genes highly expressed in in this stage. These results suggested that this TF determines basal pattern of gene expression of this stage by targeting a broad range of genes directly.
Project description:Malaria parasites transmitted by mosquito bite are remarkably efficient in establishing human infections. The infection process requires ~30 minutes and is highly complex as quiescent sporozoites injected with mosquito saliva must be rapidly activated in the skin, migrate through the body, and infect the liver. This process is poorly understood for Plasmodium vivax due to low infectivity in the in vitro models. To study this skin-to-liver stage of malaria, we developed quantitative bioassays coupled with transcriptomics to evaluate parasite changes linked with mammalian microenvironmental factors. Our in vitro phenotype and RNA-seq analyses revealedkey microenvironmental relationships with distinct biological functions. M ost notable, preservation of sporozoite quiescence by exposure to insect-like factors coupled with strategic activation limits untimely activation of invasion-associated genes to dramatically increase hepatocyte invasion rates. We also report the first transcriptomic analysis of the P. vivax sporozoite interaction in salivary glands identifying 118 infection-related differentially-regulated Anopheles dirus genes. These results provide important new insights in malaria parasite biology and identify priority targets for antimalarial therapeutic interventions to block P. vivax infection.
Project description:MalariaM-bM-^@M-^Ys cycle of infection requires parasite transmission between a mosquito vector and a vertebrate host. Plasmodium regulates transmission by translationally repressing specific mRNAs until their products are needed. We demonstrate that the Plasmodium yoelii Pumilio-FBF family member Puf2 allows the sporozoite to retain its infectivity in the mosquito salivary glands while awaiting transmission. Puf2 mediates this critical feature solely through its RNA-Binding Domain (RBD) likely by protecting and silencing specific mRNAs. Puf2 storage granules are distinct from stress granules and P-bodies and dissolve rapidly after infection of hepatocytes, likely releasing the protected and silenced transcripts for M-bM-^@M-^Xjust-in-timeM-bM-^@M-^Y translation by early exoerythrocytic forms (EEFs). Further corroborating this model, pypuf2- sporozoites have no apparent defect in host infection early after invading the salivary glands, but become progressively noninfectious and subsequently prematurely transform into EEFs during prolonged salivary gland residence. In contrast, the premature overexpression of Puf2 in oocysts causes striking deregulation of sporozoite maturation, resulting in fewer oocyst sporozoites that are non-infectious and unable to colonize the salivary glands. Maintenance of Puf2 expression in liver stage parasites produces no phenotype, suggesting that a window of permissive expression exists. Finally, by conducting the first comparative RNAseq analysis of Plasmodium sporozoites, we have uncovered that Puf2 may play a role in both the protection of specific transcripts as well as RNA turnover via the CCR4/Not complex. These findings uncover requirements for maintaining a window of opportunity for the malaria parasite to accommodate the unpredictable moment of transmission from mosquito to vertebrate host. Wild-type (Py17XNL) and pypuf2 -salivary gland sporozoites
Project description:Malaria’s cycle of infection requires parasite transmission between a mosquito vector and a vertebrate host. Plasmodium regulates transmission by translationally repressing specific mRNAs until their products are needed. We demonstrate that the Plasmodium yoelii Pumilio-FBF family member Puf2 allows the sporozoite to retain its infectivity in the mosquito salivary glands while awaiting transmission. Puf2 mediates this critical feature solely through its RNA-Binding Domain (RBD) likely by protecting and silencing specific mRNAs. Puf2 storage granules are distinct from stress granules and P-bodies and dissolve rapidly after infection of hepatocytes, likely releasing the protected and silenced transcripts for ‘just-in-time’ translation by early exoerythrocytic forms (EEFs). Further corroborating this model, pypuf2- sporozoites have no apparent defect in host infection early after invading the salivary glands, but become progressively noninfectious and subsequently prematurely transform into EEFs during prolonged salivary gland residence. In contrast, the premature overexpression of Puf2 in oocysts causes striking deregulation of sporozoite maturation, resulting in fewer oocyst sporozoites that are non-infectious and unable to colonize the salivary glands. Maintenance of Puf2 expression in liver stage parasites produces no phenotype, suggesting that a window of permissive expression exists. Finally, by conducting the first comparative RNAseq analysis of Plasmodium sporozoites, we have uncovered that Puf2 may play a role in both the protection of specific transcripts as well as RNA turnover via the CCR4/Not complex. These findings uncover requirements for maintaining a window of opportunity for the malaria parasite to accommodate the unpredictable moment of transmission from mosquito to vertebrate host.
Project description:The goal of OOCYSTOP is based on an innovative concept to block malaria transmission by development of new drugs that will be delivered (1) to oocysts in infected mosquitoes and (2) to early stages in human infection by the sporozoite