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Berná L, Chiribao ML, Greif G, Rodriguez M, Alvarez-Valin F, Robello C.2017. Transcriptomic analysis reveals metabolic switches and surface remodeling as key processes for stage transition in Trypanosoma cruzi. PeerJ Preprints5:e2782v1https://doi.org/10.7287/peerj.preprints.2782v1
American trypanosomiasis is a chronic and endemic disease, which affects millions of people. Trypanosoma cruzi, its causative agent, has a life cycle that involves complex morphological and functional transitions, as well as a variety of environmental conditions. This requires a tight regulation of gene expression, which is achieved mainly by post-transcriptional regulation. In this work we conducted an RNAseq analysis of the three major life cycle stages of T. cruzi, amastigotes, epimastigotes and trypomastigotes. This analysis allowed us to delineate specific transcriptomic profiling for each stage, and also to identify those biological processes of major relevance in each state. Stage specific expression profiling evidenced the plasticity of T. cruzi to adapt quickly to the different conditions, with particular focus on membrane remodeling and metabolic shifts along the life cycle. Epimastigotes, which replicate in the gut of insect vector, showed higher expression on genes related to energy metabolism, mainly Krebs cycle, respiratory chain and oxidative phosphorylation related genes, and anabolism related genes associated to nucleotide and steroid biosynthesis; also a general down regulation of surface glycoproteins was seen at this stage. Trypomastigotes, living extracellularly in the bloodstream of mammals, express a plethora of surface proteins and signaling genes involved in invasion and evasion of immune response. Amastigotes mostly express membrane transporters and genes involved in regulation of cell cycle, an also express a specific subset of surface glycoproteins coding genes. In addition, these results allowed to improve the annotation of Dm28c genome, identifying new ORFs and set the stage for construction of networks of co-expression, which can give clues about coded proteins of unknown functions.
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Table S1. Highly expressed genes and GO analyses
Comparison of 500 highest expressed genes among stages and Gene Ontology analysis
Representation of predicted molecular weights of trans-sialidases specific from amastigotes (aTS, green), epimastigotes (eTS, blue) and trypomastigotes (tTS, orange). T test was performed, ** represents p-value<0.01.
Figure S2. Surface gene composition in different T. cruzi stages
A) Expression of each gene in normalized read counts is shown for the different group of membrane component. At the X axis each gene is plotted at the same order,for the three stages. B) Sum of total normalized read counts per gene Kb of each family group in the three stages. Different cycle stages are represented: amastigote (green), epimastigote (blue) and trypomastigote (orange).
Comparison to known protein expression profiles. A) flagellum associated genes down-regulated in amastigotes. B) genes related to conversion of histidine to glutamate up-regulated in epimastigotes. C) mucins up regulated in trypomastigotes.