Effect of very low concentrations (< 10 μM) of glucose on T. brucei gene expression
Ontology highlight
ABSTRACT: The ability to adapt to varying nutrient availability in changing environments is critical for successful parasitism. The lifecycle stages of the African trypanosome, Trypanosoma brucei, that infect the host mammalian bloodstream utilize glucose exclusively for ATP production. The finding that trypanosomes also inhabit other tissues that frequently contain lower glucose concentrations suggests blood stage parasites may have to respond to a dynamic environment with changing nutrient availability in order to survive. However, little is known about how the parasites coordinate gene expression with nutrient availability. Through transcriptome analysis, we have found blood stage parasites deprived of glucose alter gene expression in a pattern similar to transcriptome changes triggered by other stresses. A surprisingly low concentration of glucose (<10 μM) was required to initiate the response. To further understand the dynamic regulation of gene expression that occurs in response to altered glucose availability in the environment, we have interrogated the 3’UTR of cytochrome c oxidase subunit VI, a known lifecycle stage regulated gene, and have identified a stem-loop structure that confers glucose-responsive regulation at the translational level.
Project description:The ability to sense, respond and adapt to changes in nutrient availability is a survival requisite. This might be particularly important for malaria parasites, which encounter major alterations in nutrients levels throughout infection. How these parasites deal with nutrient fluctuations and maintain infection without killing their hosts before transmission remains unknown. Here, we show that blood-stage malaria parasites respond to dietary-restriction through a rearrangement of their transcriptome accompanied by a significant reduction in their multiplication rate. A kinome analysis combined with chemical and genetic approaches identified KIN, a putative AMP-activated kinase homologue, as a master regulator that senses host nutrients both in vitro and in vivo, and mediates the transcriptional response to the host nutritional status. Diet-responsive genes include the plant-like ApiAP2 transcription regulators, which appear to act as downstream effectors of KIN. Overall, these findings reveal key components of a parasite nutrient-sensing mechanism that is critical to modulate replication and virulence in malaria parasites.
Project description:Transmission of Trypanosoma brucei by tsetse flies involves the deposition of the infective quiescent metacyclic stage into the mammalian skin at the site of the fly’s bite. In the skin, the metacyclic parasites reactivate and differentiate into proliferative trypanosomes before colonizing the host's blood and tissues. We have generated an advanced human skin equivalent and used tsetse flies to naturally infect the artificial skin with trypanosomes. We have detailed the chronological order of the parasites' development in the skin and found a rapid activation and differentiation of the tsetse-transmitted cell cycle‑arrested metacyclic trypanosomes to proliferative parasites. Single-parasite transcriptomics documented the biological events during differentiation and host invasion at five different time points. After the establishment of a proliferative trypanosome population in the skin, the parasites entered a reversible quiescence program characterized by slow replication and a strongly reduced metabolism. We termed these quiescent trypanosomes skin tissue forms (STF), which may play an important role in maintaining the trypanosome infection in aparasitemic, asymptomatic individuals.
Project description:How flagellar signaling regulates the host interaction of parasites remains a challenge due to poor conservation of signaling systems with those in cilia of higher organisms. The trypanosome-specific cAMP response protein 3 (CARP3) shows developmentally regulated localization at the flagellar tip membrane, where it is essential for parasite swarming and colonization of the tsetse fly insect vector. This project describes a label-free, quantitative proteomics approach that identifies proteins changing in abundance upon inducible CARP3 knock down in bloodstream stage Trypanosoma brucei.
Project description:Microarray studies using synchronized Plasmodium falciparum parasites have revealed a ‘continuous cascade’ of gene expression. Reports vary regarding the stability in these transcriptional patterns in the presence of external stressors. Using Plasmodium yoelii 17X parasites replicating in vivo, we have examined differential gene expression in parasites isolated from individual mice, from independent infections, during ascending and peak parasitemia and in the presence and absence of host antibody responses. Across experimental conditions, transcription was surprisingly stable. Differential gene expression was greatest when comparing differences due to parasite load and/or host cell availability; however, even these changes were modest. Of genes that were differentially expressed, many are of unknown function. There was little to no differential expression of members of the yir and pyst-a multigene families, although a relatively large number of these were expressed during blood-stage infection regardless of experimental condition. Taken together, these results indicate that 1) P. yoelii gene expression remains stable in the presence of a changing host environment and 2) concurrent expression of a large number of the yir and pyst-a genes may function to divert host immune responses away from invariant protective antigens.
Project description:The malaria parasite has a complex lifecycle, including several events of differentiation and stage progression, while actively evading immunity in both its mosquito and human hosts. Important parasite gene expression and regulation during these events remain hidden in rare populations of cells. Here, we combine a capillary-based platform for cell isolation with single-cell RNA-sequencing to transcriptionally profile 165 single infected red blood cells (sc.iRBCs) during the intra- erythrocyte developmental cycle (IDC). Unbiased analyses of single-cell data grouped the cells into eight transcriptional states during IDC. Interestingly, we uncovered a gene signature from the single iRBC analyses that can successfully discriminate between developing asexual and sexual stage parasites at cellular resolution, and we verify five, previously undefined, gametocyte stage specific genes. Moreover, we show the capacity of detecting expressed genes from the variable gene families in single parasites, despite the sparse nature of data. In total, the single parasite transcriptomics holds promise for molecular dissection of rare parasite phenotypes throughout the malaria lifecycle.
Project description:How does the abundance of different proteins change over the caurse of the yeast respirator oscillation and with nutrient availability (through changing dilution rate).
Project description:Stage-specific transcription is a fundamental biological process in the lifecycle of the Plasmodium parasite. Proteins containing the AP2 DNA-binding domain are responsible for stage-specific transcriptional regulation, and belong to the only known family of transcription factors in Plasmodium parasites. A comprehensive identification of their target genes will advance our understanding of the molecular basis of stage-specific parasite development. In this study, we have used ChIP-seq technology to identify the target genes of the ookinete-specific AP2 transcription factor AP2-O.
Project description:Stage-specific transcription is a fundamental biological process in the lifecycle of the Plasmodium parasite. Proteins containing the AP2 DNA-binding domain are responsible for stage-specific transcriptional regulation, and belong to the only known family of transcription factors in Plasmodium parasites. A comprehensive identification of their target genes will advance our understanding of the molecular basis of stage-specific parasite development. In this study, we have used ChIP-seq technology to identify the target genes of the ookinete-specific AP2 transcription factor AP2-O.
Project description:Stage-specific transcription is a fundamental biological process in the lifecycle of the Plasmodium parasite. Proteins containing the AP2 DNA-binding domain are responsible for stage-specific transcriptional regulation, and belong to the only known family of transcription factors in Plasmodium parasites. A comprehensive identification of their target genes will advance our understanding of the molecular basis of stage-specific parasite development. In this study, we have used ChIP-seq technology to identify the target genes of the ookinete-specific AP2 transcription factor AP2-O.
Project description:Stage-specific transcription is a fundamental biological process in the lifecycle of the Plasmodium parasite. Proteins containing the AP2 DNA-binding domain are responsible for stage-specific transcriptional regulation, and belong to the only known family of transcription factors in Plasmodium parasites. A comprehensive identification of their target genes will advance our understanding of the molecular basis of stage-specific parasite development. In this study, we have used ChIP-seq technology to identify the target genes of the ookinete-specific AP2 transcription factor AP2-O.