Genome-wide RNAi selection identifies a regulator of transmission stage-enriched gene families and cell-type differentiation in Trypanosoma brucei

Rico, Eva; Ivens, Alasdair; Glover, Lucy; Horn, David; Matthews, Keith R.

doi:10.1371/journal.ppat.1006279

Cited by 33 publications

(48 citation statements)

References 50 publications

(69 reference statements)

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“…The TbPIP39/TbPTP1 node was also similar to the location of REG9.1, a regulator of stumpy specific transcripts previously observed at the periflagellar pocket region of stumpy forms, in addition to along the flagellum or FAZ (26). Therefore, we colocalised REG9.1 with TbPIP39 using a REG9.1 specific antibody and YFP-tagged TbPIP39 during differentiation and observed redistribution form the periflagellar pocket node to the cytoplasmic distribution previously in stumpy forms within 4 h (Figure 7C).…”

Section: Resultssupporting

confidence: 77%

Positional dynamics and glycosomal recruitment of developmental regulators during trypanosome differentiation

Szöőr

Simon

Rojas

et al. 2019

Preprint

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27Glycosomes are peroxisome-related organelles that compartmentalise the glycolytic enzymes 28 in kinetoplastid parasites. These organelles are developmentally regulated in their number 29 and composition, allowing metabolic adaptation to the parasite's needs in the blood of 30 mammalian hosts or within their arthropod vector. A protein phosphatase cascade regulates 31 differentiation between parasite developmental forms, comprising a tyrosine phosphatase, 32TbPTP1, that dephosphorylates and inhibits a serine threonine phosphatase TbPIP39 that 33 promotes differentiation. When TbPTP1 is inactivated, TbPIP39 is activated and during 34 differentiation becomes located in glycosomes. Here we have tracked TbPIP39 recruitment to 35 glycosomes during differentiation from bloodstream stumpy forms to procyclic forms. 36Detailed microscopy and live cell imaging during the synchronous transition between life 37 cycle stages revealed that in stumpy forms, TbPIP39 is located at a periflagellar pocket site 38 closely associated with TbVAP, that defines the flagellar pocket endoplasmic reticulum. 39 TbPTP1 is also located at the same site in stumpy forms, as is REG9.1, a regulator of 40 stumpy-enriched mRNAs. This site provides a molecular node for the interaction between 41 TbPTP1 and TbPIP39. Within 30 minutes of the initiation of differentiation TbPIP39 42 relocates to glycosomes whereas TbPTP1 disperses to the cytosol. Overall, the study 43 identifies a 'stumpy regulatory nexus' (STuRN) that co-ordinates the molecular components 44 of life cycle signalling and glycosomal development during transmission of Trypanosoma 45 brucei. 46 47 48 49 3 50 Importance 51 52 African trypanosomes are parasites of sub-Saharan Africa responsible for both human and 53 animal disease. The parasites are transmitted by tsetse flies and completion of their life cycle 54 involves progression through several development steps. The initiation of differentiation 55between blood and tsetse forms is signalled by a phosphatase cascade, ultimately trafficked 56 into peroxisome-related organelles called glycosomes that are unique to this group of 57 organisms. Glycosomes undergo substantial remodelling of their composition and function 58 during the differentiation step but how this is regulated is not understood. Here we identify a 59 cytological site where the signalling molecules controlling differentiation converge before the 60 dispersal of one of them into glycosomes. This coincides with a specialised ER site that may 61 contribute to glycosome developmental biogenesis or regeneration. In combination, the study 62 provides the first insight into the spatial co-ordination of signalling pathway components in 63 trypanosomes as they undergo cell-type differentiation. 64 65 66 4 67 Introduction 68The dynamic regulation of organelle biogenesis or composition often involves intimate 69 contact between the endoplasmic reticulum and the membrane of the target organelle (1). 70This enables the maturation and modification of organellar protein content, influ...

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Section: Resultssupporting

confidence: 77%

Positional dynamics and glycosomal recruitment of developmental regulators during trypanosome differentiation

Szöőr

Simon

Rojas

et al. 2019

Preprint

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“…The relative control of stumpy-and slender-enriched gene expression represents an interesting regulatory question given that slender and stumpy forms share the same environment (unlike Trends in Parasitology bloodstream and procyclic forms). To explore this regulation, a genome-wide RNAi screen was exploited to isolate repressors of stumpy-enriched gene expression [45]. This identified several negative regulators, including one (REG9.1; REGulator of ESAG9), whose depletion by RNAi upregulated members of the ESAG9 family.…”

Section: Reg91mentioning

confidence: 99%

A Leap Into the Unknown – Early Events in African Trypanosome Transmission

Szöőr

Silvester

Matthews

2020

Trends in Parasitology

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HighlightsAfrican trypanosomes are mainly transmitted by tsetse flies.During uptake in a blood meal, T. brucei can use several potential environmental cues to stimulate the initiation of differentiation.Signal transduction involves a phosphatase signaling cascade and spatial control of key regulatory proteins.Once differentiation is initiated, several gene regulatory processes control the differentiation from bloodstream to tsetse midgut procyclic forms.T. brucei and T. congolense show a similar route of establishment in the tsetse gut but show different developmental mechanisms.

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“…The stage-specific regulation of both RNA pol I transcribed VSG (13) and procyclin (14), and the RNA pol II transcribed COX genes (15) has been demonstrated to occur, at least in part, due to recognition of motifs within their respective 3’UTRs. The developmental regulation of ESAG9 depends on a 34-nucleotide bifunctional element in the 3’UTR that confers both positive and negative regulation (16), and an RNA binding protein that negatively regulates ESAG9 has recently been identified through a genome-wide RNA interference screen (17). Here, we investigate the importance of the Tb TfR 3’UTR in the dynamic regulation of Tb TfR in response to iron starvation using a simplified reporter system.…”

Section: Introductionmentioning

confidence: 99%

Dynamic regulation of the Trypanosoma brucei transferrin receptor in response to iron starvation is mediated via the 3’UTR

Benz

Fathallah

et al. 2018

Preprint

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The bloodstream form of the parasite Trypanosoma brucei obtains iron from its mammalian host by receptor-mediated endocytosis of host transferrin through its own unique transferrin receptor (TbTfR). Expression of TbTfR rapidly increases upon iron starvation by post-transcriptional regulation through a currently undefined mechanism that is distinct from the mammalian iron response system. We have created reporter cell lines by fusing the TbTfR 3′UTR or a control Aldolase 3’UTR to reporter genes encoding GFP or firefly Luciferase, and inserted the fusions into a bloodstream form cell line at a tagged ribosomal RNA locus. Fusion of the TbTfR 3’UTR is sufficient to significantly repress the expression of the reporter proteins under normal growth conditions. Under iron starvation conditions we observed upregulation of the TbTfR 3’UTR fusions only, with a magnitude and timing consistent with that reported for upregulation of the TbTfR. We conclude that the dynamic regulation of the T. brucei transferrin receptor in response to iron starvation is mediated via its 3’UTR, and that the effect is independent of genomic location.

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Genome-wide RNAi selection identifies a regulator of transmission stage-enriched gene families and cell-type differentiation in Trypanosoma brucei

Cited by 33 publications

References 50 publications

Positional dynamics and glycosomal recruitment of developmental regulators during trypanosome differentiation

Positional dynamics and glycosomal recruitment of developmental regulators during trypanosome differentiation

A Leap Into the Unknown – Early Events in African Trypanosome Transmission

Dynamic regulation of the Trypanosoma brucei transferrin receptor in response to iron starvation is mediated via the 3’UTR

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