Project description:Investigation of whole genome gene expression level in Plasmodium falciparum male and female mature gametocytes, and detection of any transcriptional differences between male and female gametocytes. The Plasmodium falciparum parasite with green fluorescent protein (GFP) expression under the control of alpha tubulin II promoter facilitated the separation of male and female gametocyte. This engineered parasite strain in this study are further described in Miao J, Fan Q, Parker D, Li X, Li J, et al. (2013) Puf Mediates Translation Repression of Transmission-Blocking Vaccine Candidates in Malaria Parasites. PLoS Pathog 9(4): e1003268. doi: 10.1371/journal.ppat.1003268
Project description:Investigation of overall expression level in Plasmodium falciparum male and female mature gametocytes, and detection of any transcriptional differences between male and female gametocytes. The Plasmodium falciparum parasite with green fluorescent protein (GFP) expression under the control of alpha tubulin II promoter facilitated the separation of male and female gametocyte. This engineered parasite strain in this study are further described in Miao J, Fan Q, Parker D, Li X, Li J, et al. (2013) Puf Mediates Translation Repression of Transmission-Blocking Vaccine Candidates in Malaria Parasites. PLoS Pathog 9(4): e1003268. doi: 10.1371/journal.ppat.1003268
Project description:Gametocytes are obligate for the transmission of malaria parasite to mosquito. This study reports the first comprehensive proteomes of accurately separated mature male and female Plasmodium falciparum gametocytes using a transgenic line. the proteomes revealed significant differences that are consistent with the divergent functions of the two sexes. While the male proteome is enriched in proteins associated with flagella and genome replication, the female proteome is more abundant in proteins involved in metabolism, translation and organellar functions.
Project description:Plasmodium falciparum parasites alternate between two different obligate hosts during their life cycle: humans and Anopheles mosquitoes. During the blood stage in the human host they proliferate asexually inside erythrocytes. A small proportion of parasites develops into male and female gametocytes, which enter the sexual part of the life cycle once taken up by a mosquito. The production of male and female gametocytes is therefore critical for malaria transmission. It has been shown that epigenetic processes play a role in this differentiation processes, however, the exact mechanisms remain unknown. To gain insight into these processes, we separated male and female gametocytes, based on the female specific expression of an endogenously GFP-tagged ABCG2 gene, using flow cytometry (male parasites as GFP low, female parasites as GFP high population). We subsequently performed ChIP-Seq for several histone variants and modifications (H2A.Z, H2A.Zac, H2B.Z, H3K4me3, H3R17me2, H3K27ac, H3K9me3) on day 6 of gametocytogenesis. Our study reveals a global remodelling of the chromatin landscape in gametocytes compared to asexual parasites, as well as sex specific differences.
Project description:In the human host, Plasmodium falciparum parasites propagate asexually in erythrocytes causing the symptoms of malaria. However, in every asexual cycle, a small proportion of the parasites commits to sexual differentiation, which is critical for transmission. During a period of about 10 days, the sexually committed parasites either develop into male or female gametocytes. In this study, gametocytes carrying an endogenously GFP tagged version of the female specifically expressed ABCG2 gene were FACS sorted to separate male (GFP low) and female (GFP high) gametocyte populations at different days of development. RNA was subsequently extracted from these populations as well as from asexual parasites as controls and subjected to directional RNAseq. These data reveal the transcriptional differences between asexual parasite stages and developing gametocytes, but also between male and female gametocytes as well as for each sex during the course of differentiation. In particular, male gametocytes undergo distinct transcriptional transitions when comparing the transcriptome between day 4, 6 and 10 of gametocytogenesis. In contrast, female gametocyte transcriptomes are more static during the course of gametocytogenesis and only show minimal variation. This is the first study to longitudinally monitor gene expression in developing male and female gametocytes
Project description:Sexual differentiation of malaria parasites into gametocytes in the vertebrate host and subsequent gamete fertilisation in mosquitoes is essential for the spreading of the disease. The molecular processes orchestrating these transitions are far from fully understood. Here we report the first transcriptome analysis of male and female Plasmodium falciparum gametocytes coupled with a comprehensive proteome analysis. In male gametocytes there is an enrichment of proteins involved in the formation of flagellated gametes; proteins involved in DNA replication, chromatin organisation and axoneme formation. On the other hand, female gametocytes are enriched in proteins required for zygote formation and functions after fertilisation; protein-, lipid- and energy-metabolism. Integration of transcriptome and proteome data revealed 512 highly expressed maternal transcripts without corresponding protein expression indicating large scale translational repression in P. falciparum female gametocytes for the first time. Despite a high degree of conservation between Plasmodium species, 260 of these ârepressed transcriptsâ have not been previously described. Moreover, for some of these genes, protein expression is only reported in oocysts and sporozoites indicating that repressed transcripts can be partitioned into short- and long-term storage. Finally, these data sets provide an essential resource for identification of vaccine/drug targets and for further mechanistic studies. Examining the transcriptome of p47-mCherry positive female and pDynGFP positive (or double positive) male gametocytes by RNA-seq.
Project description:Male and female Plasmodium falciparum gametocytes are the parasite lifecycle stage responsible for transmission of malaria from the human host to the mosquito vector. Not only are gametocytes able to survive in radically different host environments, but they are also precursors for male and female gametes that reproduce sexually soon after ingestion by the mosquito. Here, we investigate the sex-specific lipid metabolism of gametocytes within their host red blood cell. Comparison of the male and female lipidome identifies cholesteryl esters and dihydrosphingomyelin enrichment in female gametocytes. Chemical inhibition of each of these lipid types in mature gametocytes suggests dihydrosphingomyelin synthesis but not cholesteryl ester synthesis is important for gametocyte viability. Genetic disruption of each of the two sphingomyelin synthase genes points towards sphingomyelin synthesis contributing to gametocytogenesis. This study shows that gametocytes are distinct from asexual stages, and that the lipid composition is also vastly different between male and female gametocytes, reflecting the different cellular roles these stages play. Taken together, our results highlight the sex-specific nature of gametocyte lipid metabolism, which has the potential to be targeted to block malaria transmission. This article has an associated First Person interview with the first author of the paper.
Project description:The Apicomplexa constitute a large phylum of parasitic protozoans with complex life cycles that typically include meiotic sex. The life cycle of the malaria parasite, Plasmodium falciparum, includes obligate transition and stage development between a human and mosquito host. Asexual parasite replication in the human erythrocytes is followed by differentiation which leads to the formation of a precursor gamete stage, referred to as gametocytes. The gametocyte stage is solely responsible for malaria transmission into the mosquito vector where gamete fusion followed by meiosis occurs. How the parasite differentiates into male and female gametocytes in the absence of sex chromosomes largely remains an open question. Here, we combine FACS-based cell enrichment of a gametocyte reporter line followed by single-cell RNA-seq, to enable targeted characterization of the entire gametocyte developmental stage. Our data defines differential transcription programs during male and female gametocyte development and highlights a bifurcation point for sexual cell fate. We perform prediction analyses of novel candidate driver genes underlying P. falciparum sexual cell fate. Additionally, we delineate the timing of expression of members of the ApiAP2 family of transcription factors and predict their specificity in male or female P. falciparum gametocyte development.
Project description:Plasmodium falciparum gametocyte stages represent a small fraction of the entire parasite biomass that is present during human malaria infection, yet they alone lead to the transmission of this devastating disease. One of the critical gaps in malaria transmission biology and surveillance is our lack of knowledge about gametocyte biology, especially sexual dimorphic development that may influence transmission from the human to the mosquito. Ratios of male and female gametocytes in the peripheral blood can vary significantly; influenced in part by asexual blood stage and gametocyte density as well as vertebrate and invertebrate host factors. Moreover, the role of sex ratios on gametocyte transmission potential to mosquitoes is unknown and dissecting this process has been hampered by the lack of sex-specific protein markers for the circulating, mature stage V gametocytes. The current evidence suggests a high degree of conservation in gametocyte gene complement across Plasmodium, and therefore presumably for sex-specific genes as well. Therefore, to better our understanding of gametocyte development and subsequent infectiousness to mosquitoes, we undertook a two pronged approach. First, we acquired the mixed, male and female stage V gametocyte proteomes of the NF54 isolate and mature stage V female proteome from Dd2, a strain that is defective in producing mature males. Second, we then undertook a Systematic Subtractive Bioinformatic analysis (filtering) approach to identify sex-specific P. falciparum NF54 protein markers based on a comparison with the Dd2 strain and syntenic male and female proteins from the reanalyzed and updated P. berghei (related rodent malaria parasite) gametocyte proteomes. This has produced a short list of putative 174 male- and 258 female-specific P. falciparum stage V proteins. Furthermore, we generated antibodies against three putative female-specific gametocyte stage V proteins in P. falciparum and confirmed sex-specificity for two proteins and also the loss sex-partitioning for a putative female-specific protein in rodent malaria parasites.