Abstract
BackgroundRegulation of gene expression in trypanosomatids is mainly posttranscriptional. Tight regulation of mRNA stability and access to polysomes allows Trypanosoma cruzi to adapt to different environmental conditions during its life cycle. Posttranscriptional regulation requires association between mRNAs and specific proteins to form mRNP complexes. Proteins that lack a canonical RNA-binding domain, such as eukaryotic elongation factor-1α (EF-1α), may also associate with mRNPs. EF-1α is conserved in many organisms, and it plays roles in many cellular processes other than translation, including RNA transport, the cell cycle, and apoptosis.ResultsIn a previous study, EF-1α was found associated with mRNP-forming mRNAs in polysome-free fractions both in epimastigotes growing under normal conditions and in nutritionally stressed parasites. This finding suggested the possibility that EF-1α has a non-canonical function. Thus, we investigated the dynamics of EF-1α in association with T. cruzi epimastigote mRNAs under normal and stressed nutritional conditions. EF-1α is expressed throughout the parasite life cycle, but it shows a slight decrease in protein levels in the metacyclic trypomastigote form. The protein is cytoplasmically localized with a granular pattern in all forms analyzed. Following puromycin treatment, EF-1α migrated with the heaviest gradient fractions in a sucrose polysome profile, indicating that its association with large protein complexes was independent of the translation machinery. We next characterized the EF-1α-associated mRNAs in unstressed and stressed epimastigotes. We observed that specific subsets of mRNAs were associated with EF-1α-mRNPs in unstressed or stressed epimastigotes. Some mRNAs were identified in both physiological conditions, whereas others were condition-specific. Gene ontology analysis identified enrichment of gene sets involved in single-organism metabolic processes, amino acid metabolic processes, ATP and metal ion binding, glycolysis, glutamine metabolic processes, and cobalt and iron ion binding.ConclusionThese results indicate that in T. cruzi, as in other eukaryotes, EF-1α may play a non-canonical cellular role. We observed the enrichment of functionally related transcripts bound to EF-1α in normal growth conditions as well as in nutritionally stressed cell indicating a potential role of EF-1α mRNP in stress response.Electronic supplementary materialThe online version of this article (doi:10.1186/s12866-015-0436-2) contains supplementary material, which is available to authorized users.
Highlights
Regulation of gene expression in trypanosomatids is mainly posttranscriptional
The T. cruzi elongation factor-1α (EF-1α) protein has an estimated molecular weight of 43 kDa, and it is highly conserved among trypanosomes and other eukaryotes, with 95 % identity when compared to trypanosomes and 76 % identity when compared to Homo sapiens
The experimental conditions used in the previous work minimize spurious and non-specific binding between proteins and mRNAs [33]
Summary
Regulation of gene expression in trypanosomatids is mainly posttranscriptional. Tight regulation of mRNA stability and access to polysomes allows Trypanosoma cruzi to adapt to different environmental conditions during its life cycle. The life cycle of Trypanosoma cruzi involves two intermediary hosts and at least three well-defined developmental stages that are based on morphology and biological characteristics [1, 2]. Alves et al BMC Microbiology (2015) 15:104 polycistronic unit, which upon processing results in different levels of protein production [6, 7]. These features demonstrate that the regulation of gene expression in these organisms is mainly post-transcriptional and is based on mechanisms involving the localization, translation and degradation of mRNAs [6, 8, 9]. Several mechanisms have been described as possible strategies for gene expression regulation
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have