The stabilization of housekeeping transcripts in<i>Trypanosoma cruzi</i>epimastigotes evidences a global regulation of RNA decay during stationary phase

Cevallos, Ana Marı́a; Pérez-Escobar, Mariana; Espinosa, Norma; Herrera, Juliana; López‐Villaseñor, Imelda; Hernández, Roberto

doi:10.1016/j.femsle.2005.04.017

Cited by 14 publications

(7 citation statements)

References 19 publications

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“…Up to now, general and conserved mechanisms controlling gene expression in trypanosomes undergoing environmental stresses have eluded detection. It has been proposed that T. cruzi epimastigotes growing logarithmically have higher mRNA degradation rates than parasites in the stationary phase of growth (Cevallos et al ., 2005), where parasites have decreased transcription (Elias et al ., 2001). Also, RNA synthesis is known to be repressed in stationary‐phase T. brucei parasites (Pays et al ., 1993).…”

Section: Discussionmentioning

confidence: 99%

Recruitment of mRNAs to cytoplasmic ribonucleoprotein granules in trypanosomes

Cassola

Gaudenzi

Frasch³

2007

Molecular Microbiology

116

184

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SummaryTrypanosomes are outstanding examples of the importance of mRNA metabolism in the regulation of gene expression, as these unicellular eukaryotes mostly control protein synthesis by posttranscriptional mechanisms. Here, we show that mRNA metabolism in these organisms involves recruitment of mRNAs and proteins to microscopically visible ribonucleoprotein granules in the cytoplasm. These structures engage transcripts that are being translated and protect mRNAs from degradation. Analysis of the protein composition of trypanosomal mRNA granules indicated that they contain orthologous proteins to those present in P bodies and stress granules from metazoan organisms. Formation of mRNA granules was observed after carbon-source deprivation of parasites in axenic culture. More important, mRNA granules are formed naturally in trypanosomes present in the intestinal tract of the insect vector. We suggest that trypanosomes make use of mRNA granules for transient transcript protection as a strategy to cope with periods of starvation that they have to face during their complex life cycles.

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Section: Discussionmentioning

confidence: 99%

Recruitment of mRNAs to cytoplasmic ribonucleoprotein granules in trypanosomes

Cassola

Gaudenzi

Frasch³

2007

Molecular Microbiology

116

184

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“…When total transcription activity was compared between actively growing epimastigotes and cultures at the stationary phase, it was found that epimastigotes from the exponential phase are about six-to to tenfold more active in transcription than stationary cells (Nepomuceno-Mejia et al 2010). In such a scenario, the steady-state abundance of individual housekeeping mRNAs such as actin, triosephosphate isomerase, trypanothion reductase, and the ribosomal protein S4 is reduced to less than half throughout the stationary phase (Cevallos et al 2005). Quite interestingly, the half-life of these transcripts (and of precursor rRNA species) is expanded by three-to sevenfold in these stationary cultures.…”

Section: Transcriptional and Posttranscriptional Eventsmentioning

confidence: 99%

Stationary phase in Trypanosoma cruzi epimastigotes as a preadaptive stage for metacyclogenesis

et al. 2012

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Trypanosoma cruzi is a species of parasitic protozoa that causes American trypanosomiasis or Chagas disease. These parasites go through a complex life cycle in Triatominae insects and vertebrate hosts. Epimastigotes are replicative forms that colonize the digestive tract of the vector and can be cultured in axenic media. The growth curve of epimastigotes allows assessment of differences in cells undergoing growth rate transitions from an exponential growth to a stationary phase. Since the classical descriptions of T. cruzi, it has been noted that the growth curve of epimastigotes in culture can give rise, in the stationary phase, to nonreplicating forms of metacyclic trypomastigotes. Metacyclogenesis therefore regards to the development process by which epimastigote transform into infective metacyclic trypomastigotes. In nature, these metacyclic forms allow the spread of Chagas disease when transmitted from an infected vector to a vertebrate host. This work reviews cellular phenomena that occur during the growth rate transitions of epimastigotes in culture, which may be related to very early physiological conditions for metacyclogenesis. Many of these events have not been thoroughly investigated. Their analysis can stimulate new hypotheses and future research in an important area not fully exploited.

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“…Agreeing with these findings, an expanded mRNA half-life could be shown in EMFs of T . cruzi [ 49 ]. By global down regulation of RNA decay in non-dividing EMFs, housekeeping transcripts could be stabilized to ensure basic functions a life cycle stage of generally repressed metabolism [ 49 ].…”

Section: Resultsmentioning

confidence: 99%

“…Transcripts in EMFs have exceptionally long half-lives in T . cruzi [ 49 ], emphasizing the relevance of post-transcriptional gene regulation to limit the amount of protein translated from the stable mRNA stock. This concept of minimizing cell metabolism is considered to secure a pool of long living, non-dividing EMFs in the tsetse fly, which can return to proliferation when nutrition is provided [ 49 ].…”

Section: Resultsmentioning

confidence: 99%

Life cycle adapted upstream open reading frames (uORFs) in Trypanosoma congolense: A post-transcriptional approach to accurate gene regulation

Fervers

Makałowski

et al. 2018

PLoS ONE

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The presented work explores the regulatory influence of upstream open reading frames (uORFs) on gene expression in Trypanosoma congolense. More than 31,000 uORFs in total were identified and characterized here. We found evidence for the uORFs’ appearance in the transcriptome to be correlated with proteomic expression data, clearly indicating their repressive potential in T. congolense, which has to rely on post-transcriptional gene expression regulation due to its unique genomic organization. Our data show that uORF’s translation repressive potential does not only correlate with elemental sequence features such as length, position and quantity, but involves more subtle components, in particular the codon and amino acid profiles. This corresponds with the popular mechanistic model of a ribosome shedding initiation factors during the translation of a uORF, which can prevent reinitiation at the downstream start codon of the actual protein-coding sequence, due to the former extensive consumption of crucial translation components. We suggest that uORFs with uncommon codon and amino acid usage can slow down the translation elongation process in T. congolense, systematically deplete the limited factors, and restrict downstream reinitiation, setting up a bottleneck for subsequent translation of the protein-coding sequence. Additionally we conclude that uORFs dynamically influence the T. congolense life cycle. We found evidence that transition to epimastigote form could be supported by gain of uORFs due to alternative trans-splicing, which down-regulate housekeeping genes’ expression and render the trypanosome in a metabolically reduced state of endurance.

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The stabilization of housekeeping transcripts inTrypanosoma cruziepimastigotes evidences a global regulation of RNA decay during stationary phase

Cited by 14 publications

References 19 publications

Recruitment of mRNAs to cytoplasmic ribonucleoprotein granules in trypanosomes

Recruitment of mRNAs to cytoplasmic ribonucleoprotein granules in trypanosomes

Stationary phase in Trypanosoma cruzi epimastigotes as a preadaptive stage for metacyclogenesis

Life cycle adapted upstream open reading frames (uORFs) in Trypanosoma congolense: A post-transcriptional approach to accurate gene regulation

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