The role of transition fibre proteins in regulating CEP164C assembly and localisation to the flagellum in the African Sleeping Sickness parasite Trypanosoma brucei
Introduction: This study investigates the hypothesis that four transition fibre proteins, TFP122, TFP39, TFP104, and CEP90, regulate CEP164C recruitment to control flagellar assembly and length in Trypanosoma brucei, a paristie responsible for African trypanosomiasis. We focus on proteins within the transition fibres of the basal bodies, essential for flagellum assembly and cell division in the procyclic cycle.. In particular, CEP164C is thought to be a key organiser of the transition fibres and an integral part of the “Grow and lock model”, which prevents the old flagellum from growing and directs resources towards the new flagellum. Methodology: Trypanosoma brucei cell lines already expressing CEP164C tagged with mScarlet, each of the four transition fibre proteins (TFP122, TFP39, TFP104, and CEP90) were individually tagged with mNeonGreen. By using Inducible RNAi to deplete each protein, we were able to observe the effects on CEP164C localisation through fluorescence microscopy. Quantative analyses included the assessment of growth dynamics, flagellar lengths and cell distribution in both knockdown and control groups. Results: The key result of this study was that CEP164C was consistently only localising on only the old flagellum in dividing cells, which aligns with previous studies. The percentages of cells with a 1N1K1F morphology were recorded 24 hours post-knockdown for TFP122, TFP104, TFP39, and CEP90, at 18%, 26%, 35%, and 48%, respectively. At 72 hours post-induction, the cell lines for TFP122, TFP104, and TFP39 were remeasured, showing CEP164C present in 31%, 5%, and 21% of cells, respectively. For CEP90 knockdown after 48 hours the percentage of cells were 12%. Discussion: The study advances our understanding of the molecular regulation of T. brucei life cycle, enphasisng the need for further work on how cell density influences Cep164C localisation in the 1N1K1F stage. While the findings suggest differential requirements among the transition fiber proteins for CEP164C recruitment, further quantitative analyses could clarify these relationships and support the “Grow and lock model”. Conclusion: These findings provide important insights into the molecular mechanisms that govern the life cycle of T. brucei. The results suggest that future research should focus on how different cell densities affect CEP164C binding in the 1N1K1F cell cycle stage.
Networked Digital Library of Theses and Dissertations