Coordination of the Cell Cycle in Trypanosomes

Wheeler, Richard J.; Gull, Keith; Sunter, Jack D.

doi:10.1146/annurev-micro-020518-115617

Cited by 63 publications

(78 citation statements)

References 154 publications

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“…Despite intense interest and study (13,15), many cell cycle regulators in trypanosomatids remain to be identified and much remains to be learned about cell cycle control and progression in these parasites. DNA staining followed by flow cytometry is a widely used approach for quantifying cellular DNA content and analysing cell cycle distribution across otherwise asynchronous populations.…”

Section: Discussionmentioning

confidence: 99%

“…For example, the T. brucei flagellum (7) serves as a model for studies on human ciliopathies (8-11). Divergent features, shared with other pathogenic trypanosomatids, such as Trypanosoma cruzi and Leishmania, include glycolysis compartmentalised within glycosomes (12), a single mitochondrion with a complex mitochondrial DNA structure known as the kinetoplast (13) and polycistronic transcription of almost every gene (14). Widespread, and constitutive, polycistronic transcription in trypanosomatids places major emphasis on post-transcriptional controls by mRNA binding proteins (RBPs) and post-translational controls, involving protein phosphorylation in particular.…”

Section: Introductionmentioning

confidence: 99%

“…Studies that focus on cell cycle controls in T. brucei have revealed features that are conserved with other well-studied eukaryotes, but also features that are divergent (13,15).…”

Section: Introductionmentioning

confidence: 99%

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Genome-scale functional profiling of cell cycle controls in African trypanosomes

Marques

Tinti

Cassidy

et al. 2020

Preprint

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Trypanosomatids, which include major pathogens of humans and livestock, are divergent eukaryotes for which cell cycle controls and the underlying mechanisms are not completely understood. Here, we describe a genome-wide RNA-interference library screen for cell cycle regulators in bloodstream form Trypanosoma brucei. We induced massive parallel knockdown and sorted the perturbed population into cell cycle stages using flow cytometry. RNAi-targets were deep-sequenced from each stage and cell cycle profiles were digitally reconstructed at a genomic scale. We identify hundreds of proteins that impact cell cycle progression; glycolytic enzymes required for G1S progression, DNA replication factors, mitosis regulators, proteasome and kinetochore complex components required for G2M progression, flagellar and cytoskeletal components required for cytokinesis, mRNA-binding factors, protein kinases and many previously uncharacterised proteins. The outputs facilitate functional annotation and drug-target prioritisation and provide comprehensive functional genomic evidence for the machineries, pathways and regulators that coordinate progression through the trypanosome cell cycle.The data can be searched and browsed using an interactive, open access, online data visualization tool (https://tryp-cycle.onrender.com).

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Genome-scale functional profiling of cell cycle controls in African trypanosomes

Marques

Tinti

Cassidy

et al. 2020

Preprint

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“…The cell prepares for division in the rst gap phase (G 0 /G 1 ), replicates the DNA during the S phase, and then undergoes mitosis (M) in the second gap phase (G 2 ). In T. brucei, the cell cycle is tightly regulated to ensure that single-copy organelles and structures such as Golgi body, mitochondrion, kinetoplast, nucleus, basal body, and agellum are duplicated, maintained at precise positions in the cell and segregated accurately [37]. Various GO terms related to organelles were over-represented in the black module (Figs.…”

Section: Discussionmentioning

confidence: 99%

Gene Co-Expression Network Analysis of Trypanosoma brucei in Tsetse Fly Vector

Mwangi

Macharia

Bargul

2020

Preprint

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BackgroundTrypanosoma brucei species are motile protozoan parasites that are cyclically transmitted by tsetse fly (genus Glossina) causing human sleeping sickness and nagana in livestock in sub-Saharan Africa. African trypanosomes display digenetic life cycle stages in the tsetse fly vector and in their mammalian host. Experimental work on insect-stage trypanosomes is challenging due to the difficulty in setting up successful in vitro cultures. Therefore, there is limited knowledge on the trypanosome biology during its development in the tsetse fly. Consequently, this limits the development of new strategies for blocking parasite transmission in the tsetse fly. MethodsIn this study, RNA-Seq data of insect-stage trypanosomes were used to construct a T. brucei gene co-expression network using weighted gene co-expression analysis (WGCNA) method. The study identified significant enriched modules for genes that play key roles during the parasite’s development in tsetse fly. Further, potential 3’ untranslated region (UTR) regulatory elements for genes that clustered in the same module were identified using Finding Informative Regulatory Elements (FIRE) tool.ResultsA fraction of gene modules (12 out of 27 modules) in the constructed network were found to be enriched in functional roles associated with cell division, protein biosynthesis, mitochondrion, and cell surface. Additionally, 12 hub genes encoding proteins such as RNA-binding protein 6 (RBP6), Arginine kinase 1 (AK1), brucei alanine rich protein (BARP), among others, were identified for the 12 significantly enriched gene modules. In addition, the potential regulatory elements located in the 3’ untranslated regions of genes within the same module were predicted. ConclusionsThe constructed gene co-expression network provides a useful resource for network-based data mining to identify candidate genes for functional studies. This will enhance understanding of the molecular mechanisms that underlie important biological processes during parasite’s development in tsetse fly. Ultimately, these findings will be key in the identification of potential molecular targets for disease control.

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“…Furthermore, the cell division cycle of African trypanosomes has been studied extensively (Farr and Gull, 2012;Vaughan and Gull, 2008;Wheeler et al, 2019), identifying various processes that are important for both proliferative and differentiation-linked cell division.…”

Section: Introductionmentioning

confidence: 99%

TheTrypanosoma bruceiCytoskeletal Protein KHARON Associates with Partner Proteins to Mediate Both Cytokinesis and Trafficking of Flagellar Membrane Proteins

Landfear

2020

Preprint

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In the African trypanosome Trypanosoma brucei, the cytoskeletal protein TbKHARON is required for trafficking of a putative Ca2+ channel to the flagellar membrane, and it is essential for parasite viability in both the mammalian stage bloodstream forms and the tsetse fly procyclic forms. This protein is located at the base of the flagellum, in the pellicular cytoskeleton, and in the mitotic spindle in both life cycle forms, and it likely serves multiple functions for these parasites. To begin to deconvolve the functions of KHARON, we have investigated partners associated with this protein and their roles in parasite biology. One KHARON associated protein, TbKHAP1, is a close interaction partner that can be crosslinked to KHARON by formaldehyde and pulled down in a molecular complex, and it colocalizes with TbKHARON at the base of the flagellum. Knockdown of TbKHAP1 mRNA has similar phenotypes to knockdown of its partner TbKHARON, impairing trafficking of the Ca2+ channel to the flagellar membrane and blocking cytokinesis, implying that the TbKHARON/TbKHAP1 complex mediates trafficking of flagellar membrane proteins. Two other KHAPs, TbKHAP2 and TbKHAP3, are in close proximity to TbKHARON but may not be direct interaction partners, and knockdown of their mRNAs does not affect trafficking of the Ca2+ channel. Two different flagellar membrane proteins, which are extruded from the flagellar membrane into extracellular vesicles, are also dependent upon TbKHARON for flagellar trafficking. These studies confirm that TbKHARON acts in complexes with other proteins to carry out various biological functions, and that some partners are involved in the core activity of targeting membrane proteins to the flagellum.Summary StatementThis study investigates the essential role in African trypanosomes of the KHARON protein and its molecular partners in trafficking of membrane proteins to the flagellum.

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Coordination of the Cell Cycle in Trypanosomes

Cited by 63 publications

References 154 publications

Genome-scale functional profiling of cell cycle controls in African trypanosomes

Genome-scale functional profiling of cell cycle controls in African trypanosomes

Gene Co-Expression Network Analysis of Trypanosoma brucei in Tsetse Fly Vector

TheTrypanosoma bruceiCytoskeletal Protein KHARON Associates with Partner Proteins to Mediate Both Cytokinesis and Trafficking of Flagellar Membrane Proteins

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