Project description:Phosphatase type 1 is a major enzyme essential to Plasmodium development. However, the detailed mechanisms underlying its regulation remain to be deciphered. In this work, we report the functional characterization of the Plasmodium berghei LRR1, an ortholog of SDS22, one of the most ancient and conserved Phosphatase type 1 (PP1) interactor. SDS22 has been described as a PP1 regulator essential to critical cellular features such as motility, polarity, epithelium integrity or mitosis completion. Our study shows that in Plasmodium berghei, PbLRR1 is expressed during the intra-erythrocytic developmental cycle and up to the zygote stage during sexual development. PbLRR1 can be found in complex with PbPP1 in both asexual and sexual stages and is able to inhibit the phosphatase activity. Then, genetic analysis demonstrated that PbLRR1 deletion affects the course of the parasite development during early sporogony which manifest by the production of fewer and smaller oocysts. Finally, PbLRR1 interactome analysis associated with phospho-proteomics studies led to the identification of several putative PbLRR1/PbPP1 substrates. Although previously unsuspected PP1 substrates, some of them have been characterized as essential to the parasite sexual development. In addition, and for the first time, we identify the PP1 inhibitor 3 as a substrate of the PP1/LRR1 complex. In summary, this study provides insights into previously unrecognized PbPP1 fine regulation of Plasmodium early sporogony development through its interaction with PbLRR1.
Project description:Translational repression of messenger RNAs (mRNAs) plays an important role in sexual differentiation and gametogenesis in multicellular eukaryotes. Translational repression and mRNA turnover were shown to influence stage-specific gene expression in the protozoan Plasmodium. The DDX6-class RNA helicase, DOZI (development of zygote inhibited), is found in a complex with mRNA species in cytoplasmic bodies of female, blood-stage gametocytes. These translationally repressed complexes are normally stored for translation after fertilization. Genetic disruption of pbdozi inhibits the formation of the ribonucleoprotein complexes, and instead, at least 370 transcripts are diverted to a degradation pathway. Keywords: P. berghei, gene expression
Project description:The transmission of the malaria parasite between mosquitoes and mammals requires translational repression to ensure that only the proper proteins are expressed and correct folded at the right time, it will need for the next developmental stage.Due to their essential role for malaria transmission, gametocytes represent prime targets for transmission-blocking strategies intended to prevent spread of the deadly disease. In this study, we generate HspJ62 gene knockout line (ΔHspJ62) that is gametocyte non-producing lines. Transcriptional profiling of wild type Plasmodium berghei and genetic KO Hspj62 genes at single time points during erythrocytic parasite development.
Project description:During the malaria infection, Plasmodium parasites invade the host’s red blood cells where they can differentiate into two different life forms. The majority will replicate asexually and infect new erythrocytes. A small percentage, however, will transform into gametocytes – a specialized sexual stage able to survive and develop when taken up by Anopheles mosquito. As the gametocytes ensure the parasite’s transmission to a new host, their generation is an attractive target for new antimalarial interventions. The molecular mechanisms controlling gametocytogenesis, however, remain largely unknown due to the technical challenges: the early gametocytes are morphologically indistinguishable from asexual parasites and present in very low numbers during the infection. Recently, AP2-G - a transcription factor from an apicomplexa-specific apiAP2 family – was described as indispensable for gametocyte commitment in both human malaria parasite Plasmodium falciparum and rodent malaria model Plasmodium berghei. Therefore, we have decided to test whether the overexpression of this factor alone could increase gametocyte production and enable the investigation of uncharacterised, earliest stages of gametocyte development. To this end, we have engineered PBGAMi - a Plasmodium berghei line, in which all parasites were ap2-g deficient by default but able to overexpress it when induced with rapamycin. While the control parasites (PBGAMi R-), as expected, differentiated into asexual forms (schizonts) only, almost all rapamycin-treated parasites (PBGAMi R+) transformed into gametocytes. We used the generated line to perform RNA-seq analysis of the R- and R+ populations at different time points of their development and identify the changes arising between them, mapping the sequence of events leading to the formation of gametocytes.
Project description:During the malaria infection, Plasmodium parasites invade the host’s red blood cells where they can differentiate into two different life forms. The majority will replicate asexually and infect new erythrocytes. A small percentage, however, will transform into gametocytes – a specialized sexual stage able to survive and develop when taken up by Anopheles mosquito. As the gametocytes ensure the parasite’s transmission to a new host, their generation is an attractive target for new antimalarial interventions. The molecular mechanisms controlling gametocytogenesis, however, remain largely unknown due to the technical challenges: the early gametocytes are morphologically indistinguishable from asexual parasites and present in very low numbers during the infection. Recently, AP2-G - a transcription factor from an apicomplexa-specific apiAP2 family – was described as indispensable for gametocyte commitment in both human malaria parasite Plasmodium falciparum and rodent malaria model Plasmodium berghei. Therefore, we have decided to test whether the overexpression of this factor alone could increase gametocyte production and enable the investigation of uncharacterised, earliest stages of gametocyte development. To this end, we have engineered PBGAMi - a Plasmodium berghei line, in which all parasites were ap2-g deficient by default but able to overexpress it when induced with rapamycin. While the control parasites (PBGAMi R-), as expected, differentiated into asexual forms (schizonts) only, almost all rapamycin-treated parasites (PBGAMi R+) transformed into gametocytes. We used the generated line to perform RNA-seq analysis of the R- and R+ populations at different time points of their development and identify the changes arising between them, mapping the sequence of events leading to the formation of gametocytes. At the same time we have generated purified transcriptomes of male and female gametocytes for the reference
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.
Project description:Proteomic characterization of complexity and dynamics of detergent resistant membranes of sexual and asexual stages of the rodent malaria parasite Plasmodium berghei