RNA-binding proteins related to stress response and differentiation in protozoa

TcZC3HTTP, a regulatory element that contributes to Trypanosoma cruzi cell proliferation

Post-transcriptional regulation of gene expression is a critical process for adapting to and surviving Trypanosoma cruzi, a parasite with a complex life cycle. RNA-binding proteins (RBPs) are key players in this regulation, forming ribonucleoprotein complexes (messenger ribonucleoproteins) and RNA granules that control transcript stability, localization, degradation, and translation modulation. Understanding the specific roles of individual RBPs is crucial for unraveling the details of this regulatory network. In this study, we generated null mutants of the TcZC3HTTP gene, a specific RBP in the Trypanosoma family characterized by a C3H zinc finger and a DNAJ domain associated with RNA and protein binding, respectively. Through cell growth assays, we demonstrated that the absence of TcZC3HTTP or the expression of an additional tagged version impacted epimastigote growth, indicating its contribution to cell proliferation. TcZC3HTTP was found to associate with mRNAs involved in cell cycle and division in epimastigotes, while in nutritionally stressed parasites it exhibited associations with mRNAs coding for other RBPs and rRNA. Furthermore, our analysis identified that TcZC3HTTP protein partners were different during normal growth conditions compared to starvation conditions, with the latter showing enrichment of ribosomal proteins and other RBPs. Therefore, this study provides insights into TcZC3HTTP's role in the post-transcriptional regulation of gene expression during normal growth and nutritional stress in T. cruzi, uncovering its versatile functions in different cellular contexts.IMPORTANCEUnderstanding how Trypanosoma cruzi, the causative agent of Chagas disease, regulates gene expression is crucial for developing targeted interventions. In this study, we investigated the role of TcZC3HTTP, an RNA-binding protein, in post-transcriptional regulation. Our findings demonstrate that TcZC3HTTP is relevant for the growth and proliferation of epimastigotes, a stage of the parasite's life cycle. We identified its associations with specific mRNAs involved in cell cycle and division and its interactions with enzymes and other RNA-binding proteins (RBPs) under normal and starvation conditions. These insights shed light on the regulatory network underlying gene expression in T. cruzi and reveal the multifaceted functions of RBPs in this parasite. Such knowledge enhances our understanding of the parasite's biology and opens avenues for developing novel therapeutic strategies targeting post-transcriptional gene regulation in T. cruzi.

Cell death or survival: Insights into the role of mRNA translational control

Cellular stress is an intrinsic part of cell physiology that underlines cell survival or death. The ability of mammalian cells to regulate global protein synthesis (aka translational control) represents a critical, yet underappreciated, layer of regulation during the stress response. Various cellular stress response pathways monitor conditions of cell growth and subsequently reshape the cellular translatome to optimize translational outputs. On the molecular level, such translational reprogramming involves an intricate network of interactions between translation machinery, RNA-binding proteins, mRNAs, and non-protein coding RNAs. In this review, we will discuss molecular mechanisms, signaling pathways, and targets of translational control that contribute to cellular adaptation to stress and to cell survival or death.

RNA-Binding Proteins: A Role in Neurotoxicity?

Despite sustained efforts to treat neurodegenerative diseases, little is known at the molecular level to understand and generate novel therapeutic approaches for these malignancies. Therefore, it is not surprising that neurogenerative diseases are among the leading causes of death in the aged population. Neurons require sophisticated cellular mechanisms to maintain proper protein homeostasis. These cells are generally sensitive to loss of gene expression control at the post-transcriptional level. Post-translational control responds to signals that can arise from intracellular processes or environmental factors that can be regulated through RNA-binding proteins. These proteins recognize RNA through one or more RNA-binding domains and form ribonucleoproteins that are critically involved in the regulation of post-transcriptional processes from splicing to the regulation of association of the translation machinery allowing a relatively rapid and precise modulation of the transcriptome. Neurotoxicity is the result of the biological, chemical, or physical interaction of agents with an adverse effect on the structure and function of the central nervous system. The disruption of the proper levels or function of RBPs in neurons and glial cells triggers neurotoxic events that are linked to neurodegenerative diseases such as spinal muscular atrophy (SMA), amyotrophic lateral sclerosis (ALS), fragile X syndrome (FXS), and frontotemporal dementia (FTD) among many others. The connection between RBPs and neurodegenerative diseases opens a new landscape for potentially novel therapeutic targets for the intervention of these neurodegenerative pathologies. In this contribution, a summary of the recent findings of the molecular mechanisms involved in the plausible role of RBPs in RNA processing in neurodegenerative disease is discussed.

Modulation of Virulence Factors during Trypanosoma cruzi Differentiation

Chagas disease is a neglected tropical disease caused by Trypanosoma cruzi. This protozoan developed several mechanisms to infect, propagate, and survive in different hosts. The specific expression of proteins is responsible for morphological and metabolic changes in different parasite stages along the parasite life cycle. The virulence strategies at the cellular and molecular levels consist of molecules responsible for mediating resistance mechanisms to oxidative damage, cellular invasion, and immune evasion, performed mainly by surface proteins. Since parasite surface coat remodeling is crucial to invasion and infectivity, surface proteins are essential virulence elements. Understanding the factors involved in these processes improves the knowledge of parasite pathogenesis. Genome sequencing has opened the door to high-throughput technologies, allowing us to obtain a deeper understanding of gene reprogramming along the parasite life cycle and identify critical molecules for survival. This review therefore focuses on proteins regulated during differentiation into infective forms considered virulence factors and addresses the current known mechanisms acting in the modulation of gene expression, emphasizing mRNA signals, regulatory factors, and protein complexes.

Effects of microplastics alone and with adsorbed benzo(a)pyrene on the gills proteome of Scrobicularia plana

Microplastics (MPs) are globally present in the marine environment, but the biological effects on marine organisms at the molecular and cellular levels remain scarce. Due to their lipophilic nature, MPs can adsorb other contaminants present in the marine environment, which may increase their detrimental effects once ingested by organisms. This study investigates the effects of low-density polyethylene (PE) MPs with and without adsorbed benzo[a]pyrene (BaP) in the gills proteome of the peppery furrow shell clam, Scrobicularia plana. Clams were exposed to PE MPs (11-13 μm; 1 mg L^-1) for 14 days. BaP was analyzed in whole clams' soft tissues, and a proteomic approach was applied in the gills using SWATH/DIA analysis. Proteomic responses suggest that virgin MPs cause disturbance by altering cytoskeleton and cell structure, energy metabolism, conformational changes, oxidative stress, fatty acids, DNA binding and, neurotransmission highlighting the potential risk of this type of MPs for the clam health. Conversely, when clam gills were exposed to MPs adsorbed with BaP a higher differentiation of protein expression was observed that besides changes in cytoskeleton and cell structure, oxidative stress, energy metabolism and DNA binding also induce changes in glucose metabolism, RNA binding and apoptosis. These results indicate that the presence of both stressors (MPs and BaP) have a higher toxicological risk to the health of S. plana.

A Systems Approach to Interrogate Gene Expression Patterns in African American Men Presenting with Clinically Localized Prostate Cancer

Simple Summary

Men of African origin have a 2–3 times greater chance of developing prostate cancer than those of European origin, and of patients that are diagnosed with the disease, men of African descent are 2 times more likely to die compared to white men. Men of African origin are still greatly underrepresented in genetic studies and clinical trials. This, unfortunately, means that new discoveries in cancer treatment are missing key information on the group with a greater chance of mortality. The objective of this study was to increase our knowledge of prostate cancer in men undergoing a prostate biopsy. We carried out RNA sequencing of biopsy specimens and examined racial differences in prostate gene expression. A gene expression signature was uncovered which separated the men based on their race. Furthermore, within men of African descent this signature separated men with the most severe clinical characteristics.

Abstract

An emerging theory about racial differences in cancer risk and outcomes is that psychological and social stressors influence cellular stress responses; however, limited empirical data are available on racial differences in cellular stress responses among men who are at risk for adverse prostate cancer outcomes. In this study, we undertook a systems approach to examine molecular profiles and cellular stress responses in an important segment of African American (AA) and European American (EA) men: men undergoing prostate biopsy. We assessed the prostate transcriptome with a single biopsy core via high throughput RNA sequencing (RNA-Seq). Transcriptomic analyses uncovered impacted biological pathways including PI3K-Akt signaling pathway, Neuroactive ligand-receptor interaction pathway, and ECM-receptor interaction. Additionally, 187 genes mapping to the Gene Ontology (GO) terms RNA binding, structural constituent of ribosome, SRP-dependent co-translational protein targeting to membrane and the biological pathways, translation, L13a-mediated translational silencing of Ceruloplasmin expression were differentially expressed (DE) between EA and AA. This signature allowed separation of AA and EA patients, and AA patients with the most severe clinical characteristics. AA patients with elevated expression levels of this genomic signature presented with higher Gleason scores, a greater number of positive core biopsies, elevated dehydroepiandrosterone sulfate levels and serum vitamin D deficiency. Protein-protein interaction (PPI) network analysis revealed a high degree of connectivity between these 187 proteins.

Basic Biology of Trypanosoma cruzi

The present review addresses basic aspects of the biology of the pathogenic protozoa Trypanosoma cruzi and some comparative information of Trypanosoma brucei. Like eukaryotic cells, their cellular organization is similar to that of mammalian hosts. However, these parasites present structural particularities. That is why the following topics are emphasized in this paper: developmental stages of the life cycle in the vertebrate and invertebrate hosts; the cytoskeleton of the protozoa, especially the sub-pellicular microtubules; the flagellum and its attachment to the protozoan body through specialized junctions; the kinetoplast-mitochondrion complex, including its structural organization and DNA replication; glycosome and its role in the metabolism of the cell; acidocalcisome, describing its morphology, biochemistry, and functional role; cytostome and the endocytic pathway; the organization of the endoplasmic reticulum and Golgi complex; the nucleus, describing its structural organization during interphase and division; and the process of interaction of the parasite with host cells. The unique characteristics of these structures also make them interesting chemotherapeutic targets. Therefore, further understanding of cell biology aspects contributes to the development of drugs for chemotherapy.

Unexpected Role of Sterol Synthesis in RNA Stability and Translation in Leishmania

Leishmania parasites are trypanosomatid protozoans that cause leishmaniasis affecting millions of people worldwide. Sterols are important components of the plasma and organellar membranes. They also serve as precursors for the synthesis of signaling molecules. Unlike animals, Leishmania does not synthesize cholesterol but makes ergostane-based sterols instead. C-14-demethylase is a key enzyme involved in the biosynthesis of sterols and an important drug target. In Leishmania parasites, the inactivation of C-14-demethylase leads to multiple defects, including increased plasma membrane fluidity, mitochondrion dysfunction, hypersensitivity to stress and reduced virulence. In this study, we revealed a novel role for sterol synthesis in the maintenance of RNA stability and translation. Sterol alteration in C-14-demethylase knockout mutant leads to increased RNA degradation, reduced translation and impaired heat shock response. Thus, sterol biosynthesis in Leishmania plays an unexpected role in global gene regulation.

Characterization of the RNA-Binding Protein TcSgn1 in Trypanosoma cruzi

RNA-binding proteins (RBPs) participate in several steps of post-transcriptional regulation of gene expression, such as splicing, messenger RNA transport, mRNA localization, and translation. Gene-expression regulation in trypanosomatids occurs primarily at the post-transcriptional level, and RBPs play important roles in the process. Here, we characterized the RBP TcSgn1, which contains one RNA recognition motif (RRM). TcSgn1 is a close ortholog of yeast Saccharomyces cerevisiae protein ScSgn1, which plays a role in translational regulation in the cytoplasm. We found that TcSgn1 in Trypanosoma cruzi is localized in the nucleus in exponentially growing epimastigotes. By performing immunoprecipitation assays of TcSgn1, we identified hundreds of mRNAs associated with the protein, a significant fraction of them coding for nucleic acids binding, transcription, and endocytosis proteins. In addition, we show that TcSgn1 is capable of interacting directly with the poly(A) tail of the mRNAs. The study of parasites under nutritional stress showed that TcSgn1 was localized in cytoplasmic granules in addition to localizing in the nucleus. Similar to ScSgn1, we observed that TcSgn1 also interacts with the PABP1 protein, suggesting that this protein may play a role in regulating gene expression in T. cruzi. Taken together, our results show that RNA-binding protein TcSgn1 is part of ribonucleoprotein complexes associated with nuclear functions, stress response, and RNA metabolism.

Functional Roles of RNA-Binding Proteins in Plant Signaling

RNA-binding proteins (RBPs) are typical proteins that bind RNA through single or multiple RNA-binding domains (RBDs). These proteins have a functional role in determining the fate or function of the bound RNAs. A few hundred RBPs were known through in silico prediction based on computational assignment informed by structural similarity and the presence of classical RBDs. However, RBPs lacking such conventional RBDs were omitted. Owing to the recent mRNA interactome capture technology based on UV-crosslinking and fixing proteins to their mRNA targets followed by affinity capture purification and identification of RBPs by tandem mass spectrometry, several hundreds of RBPs have recently been discovered. These proteome-wide studies have colossally increased the number of proteins implicated in RNA binding and unearthed hundreds of novel RBPs lacking classical RBDs, such as proteins involved in intermediary metabolism. These discoveries provide wide insights into the post-transcriptional gene regulation players and their role in plant signaling, such as environmental stress conditions. In this review, novel discoveries of RBPs are explored, particularly on the evolving knowledge of their role in stress responses. The molecular functions of these RBPs, particularly focusing on those that do not have classical RBDs, are also elucidated at the systems level.

Redox Balance Keepers and Possible Cell Functions Managed by Redox Homeostasis in Trypanosoma cruzi

The toxicity of oxygen and nitrogen reactive species appears to be merely the tip of the iceberg in the world of redox homeostasis. Now, oxidative stress can be seen as a two-sided process; at high concentrations, it causes damage to biomolecules, and thus, trypanosomes have evolved a strong antioxidant defense system to cope with these stressors. At low concentrations, oxidants are essential for cell signaling, and in fact, the oxidants/antioxidants balance may be able to trigger different cell fates. In this comprehensive review, we discuss the current knowledge of the oxidant environment experienced by T. cruzi along the different phases of its life cycle, and the molecular tools exploited by this pathogen to deal with oxidative stress, for better or worse. Further, we discuss the possible redox-regulated processes that could be governed by this oxidative context. Most of the current research has addressed the importance of the trypanosomes' antioxidant network based on its detox activity of harmful species; however, new efforts are necessary to highlight other functions of this network and the mechanisms underlying the fine regulation of the defense machinery, as this represents a master key to hinder crucial pathogen functions. Understanding the relevance of this balance keeper program in parasite biology will give us new perspectives to delineate improved treatment strategies.

Proteomic analysis of Paracoccidioides brasiliensis complex isolates: Correlation of the levels of differentially expressed proteins with in vivo virulence

BACKGROUND

Paracoccidioidomycosis (PCM) is a systemic mycosis commonly found in Latin America that is caused by distinct species of Paracoccidioides genus: Paracoccidioides brasiliensis complex (S1, PS2, PS3 and PS4) and Paracoccidioides lutzii. Its pathobiology has been recently explored by different approaches to clarify the mechanisms of host-pathogen interactions underpinning PCM. The diversity of clinical forms of this disease has been attributed to both host- and fungus-related factors.

METHODOLOGY/PRINCIPAL FINDINGS

For better understanding of the molecular underpinnings of host-fungus interactions, we evaluated in vivo virulence of nine Paracoccidioides brasiliensis complex isolates and correlated it to protein expression profiles obtained by two-dimensional gel electrophoresis. Based on the recovery of viable fungi from mouse organs, the isolates were classified as those having low, moderate, or high virulence. Highly virulent isolates overexpressed proteins related to adhesion process and stress response, probably indicating important roles of those fungal proteins in regulating the colonization capacity, survival, and ability to escape host immune system reaction. Moreover, highly virulent isolates exhibited enhanced expression of glycolytic pathway enzymes concomitantly with repressed expression of succinyl-CoA ligase beta chain, a protein related to the tricarboxylic acid cycle.

CONCLUSIONS/SIGNIFICANCE

Our findings may point to the mechanisms used by highly virulent P. brasiliensis isolates to withstand host immune reactions and to adapt to transient iron availability as strategies to survive and overcome stress conditions inside the host.

First evidence of protein modulation by polystyrene microplastics in a freshwater biological model

Microplastics (MPs) are now one of the major environmental problems due to the large amount released in aquatic and terrestrial ecosystems, as well as their diffuse sources and potential impacts on organisms and human health. Still the molecular and cellular targets of microplastics' toxicity have not yet been identified and their mechanism of actions in aquatic organisms are largely unknown. In order to partially fill this gap, we used a mass spectrometry based functional proteomics to evaluate the modulation of protein profiling in zebra mussel (Dreissena polymorpha), one of the most useful freshwater biological model. Mussels were exposed for 6 days in static conditions to two different microplastic mixtures, composed by two types of virgin polystyrene microbeads (size = 1 and 10 μm) each one. The mixture at the lowest concentration contained 5 × 105 MP/L of 1 μm and 5 × 105 MP/L of 10 μm, while the higher one was arranged with 2 × 106 MP/L of 1 μm and 2 × 106 MP/L of 10 μm. Proteomics' analyses of gills showed the complete lack of proteins' modulation after the exposure to the low-concentrated mixture, while even 78 proteins were differentially modulated after the exposure to the high-concentrated one, suggesting the presence of an effect-threshold. The modulated proteins belong to 5 different classes mainly involved in the structure and function of ribosomes, energy metabolism, cellular trafficking, RNA-binding and cytoskeleton, all related to the response against the oxidative stress.

TcNST2encodes a Golgi-localized UDP-galactose transporter inTrypanosoma cruzi

Survival and infectivity of trypanosomatids rely on cell-surface and secreted glycoconjugates, many of which contain a variable number of galactose residues. Incorporation of galactose to proteins and lipids occurs along the secretory pathway from UDP-galactose (UDP-Gal). Before being used in glycosylation reactions, however, this activated sugar donor must first be transported across the endoplasmic reticulum and Golgi membranes by a specific nucleotide sugar transporter (NST). In this study, we identified an UDP-Gal transporter (named TcNST2 and encoded by the TcCLB.504085.60 gene) fromTrypanosoma cruzi, the etiological agent of Chagas disease. TcNST2 was identified by heterologous expression of selected putative nucleotide sugar transporters in a mutant Chinese Hamster Ovary cell line.TcNST2mRNA levels were detected in allT. cruzilife-cycle forms, with an increase in expression in axenic amastigotes. Confocal microscope analysis indicated that the transporter is specifically localized to the Golgi apparatus. A three-dimensional model of TcNST2 suggested an overall structural conservation as compared with members of the metabolite transporter superfamily and also suggested specific features that could be related to its activity. The identification of this transporter is an important step toward a better understanding of glycoconjugate biosynthesis and the role NSTs play in this process in trypanosomatids.

Unveiling the partners of the DRBD2-mRNP complex, an RBP in Trypanosoma cruzi and ortholog to the yeast SR-protein Gbp2

Background

RNA-binding proteins (RBPs) are well known as key factors in gene expression regulation in eukaryotes. These proteins associate with mRNAs and other proteins to form mRNP complexes that ultimately determine the fate of target transcripts in the cell. This association is usually mediated by an RNA-recognition motif (RRM). In the case of trypanosomatids, these proteins play a paramount role, as gene expression regulation is mostly posttranscriptional. Despite their relevance in the life cycle of Trypanosoma cruzi, the causative agent of Chagas’ disease, to date, few RBPs have been characterized in this parasite.

Results

We investigated the role of DRBD2 in T. cruzi, an RBP with two RRM domains that is associated with cytoplasmic translational complexes. We show that DRBD2 is an ortholog of the Gbp2 in yeast, an SR-rich protein involved in mRNA quality control and export. We used an immunoprecipitation assay followed by shotgun proteomics and RNA-seq to assess the interaction partners of the DRBD2-mRNP complex in epimastigotes. The analysis identified mostly proteins involved in RNA metabolism and regulation, such as ALBA1, ALBA3, ALBA4, UBP1, UBP2, DRBD3, and PABP2. The RNA-seq results showed that most of the transcripts regulated by the DRBD2 complex mapped to hypothetical proteins related to multiple processes, such as to biosynthetic process, DNA metabolic process, protein modification, and response to stress.

Conclusions

The identification of regulatory proteins in the DRBD2-mRNP complex corroborates the important role of DRBD2 in gene expression regulation in T. cruzi. We consider these results an important contribution to future studies regarding gene expression regulation in T. cruzi, especially in the field of RNA-binding proteins.

Electronic supplementary material

The online version of this article (10.1186/s12866-019-1505-8) contains supplementary material, which is available to authorized users.

Assessing the partners of the RBP9-mRNP complex in Trypanosoma cruzi using shotgun proteomics and RNA-seq

Gene expression regulation in trypanosomes differs from other eukaryotes due to absence of transcriptional regulation for most of their genes. RNA-binding proteins (RBPs) associate with mRNAs and other regulatory proteins to form ribonucleoprotein complexes (mRNPs), which play a major role in post-transcriptional regulation. Here, we show that RBP9 is a cytoplasmic RBP in Trypanosoma cruzi with one RNA-recognition motif (RRM). The RBP9 sedimentation profile in a sucrose gradient indicated its presence in cytoplasmic translational complexes, suggesting its involvement in translation regulation. Taking this result as a motivation, we used shotgun proteomics and RNA-seq approaches to assess the core of the RBP9-mRNP complex. In epimastigotes in exponential growth, the complex was composed mostly by RBPs involved in RNA metabolism, such as ZC3H39, UBP1/2, NRBD1, and ALBA3/4. When parasites were subjected to nutritional stress, our analysis identified regulatory RBPs and the translation initiation factors eIF4E5, eIF4G5, eIF4G1, and eIF4G4. The RNA-seq results showed that RBP9-mRNP complex regulates transcripts encoding some RBPs - e.g. RBP5, RBP6, and RBP10 -, and proteins involved in metabolic processes. Therefore, we argue that RBP9 is part of cytoplasmic mRNPs complexes associated with mRNA metabolism and translation regulation in T. cruzi.

Polysome Profiling in Leishmania, Human Cells and Mouse Testis

Proper protein expression at the right time and in the right amounts is the basis of normal cell function and survival in a fast-changing environment. For a long time, the gene expression studies were dominated by research on the transcriptional level. However, the steady-state levels of mRNAs do not correlate well with protein production, and the translatability of mRNAs varies greatly depending on the conditions. In some organisms, like the parasite Leishmania, the protein expression is regulated mostly at the translational level. Recent studies demonstrated that protein translation dysregulation is associated with cancer, metabolic, neurodegenerative and other human diseases. Polysome profiling is a powerful method to study protein translation regulation. It allows to measure the translational status of individual mRNAs or examine translation on a genome-wide scale. The basis of this technique is the separation of polysomes, ribosomes, their subunits and free mRNAs during centrifugation of a cytoplasmic lysate through a sucrose gradient. Here, we present a universal polysome profiling protocol used on three different models - parasite Leishmania major, cultured human cells and animal tissues. Leishmania cells freely grow in suspension and cultured human cells grow in adherent monolayer, while mouse testis represents an animal tissue sample. Thus, the technique is adapted to all of these sources. The protocol for the analysis of polysomal fractions includes detection of individual mRNA levels by RT-qPCR, proteins by Western blot and analysis of ribosomal RNAs by electrophoresis. The method can be further extended by examination of mRNAs association with the ribosome on a transcriptome level by deep RNA-seq and analysis of ribosome-associated proteins by mass spectroscopy of the fractions. The method can be easily adjusted to other biological models.

Translational control of aberrant stress responses as a hallmark of cancer

Altered mRNA translational control is emerging as a critical factor in cancer development and progression. Targeting specific elements of the translational machinery, such as mTORC1 or eIF4E, is emerging as a new strategy for innovative cancer therapy. While translation of most mRNAs takes place through cap-dependent mechanisms, a sub-population of cellular mRNA species, particularly stress-inducible mRNAs with highly structured 5'-UTR regions, are primarily translated through cap-independent mechanisms. Intriguingly, many of these mRNAs encode proteins that are involved in tumour cell adaptation to microenvironmental stress, and thus linked to aggressive behaviour including tumour invasion and metastasis. This necessitates a rigorous search for links between microenvironmental stress and aggressive tumour phenotypes. Under stress, cells block global protein synthesis to preserve energy while maintaining selective synthesis of proteins that support cell survival. One highly conserved mechanism to regulate protein synthesis under cell stress is to sequester mRNAs into cytosolic aggregates called stress granules (SGs), where their translation is silenced. SGs confer survival advantages and chemotherapeutic resistance to tumour cells under stress. Recently, it has been shown that genetically blocking SG formation dramatically reduces tumour invasive and metastatic capacity in vivo. Therefore, targeting SG formation might represent a potential treatment strategy to block cancer metastasis. Here, we present the critical link between selective mRNA translation, stress adaptation, SGs, and tumour progression. Further, we also explain how deciphering mechanisms of selective mRNA translation occurs under cell stress holds great promise for the identification of new targets in the treatment of cancer. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

RNA-binding proteins and their role in the regulation of gene expression in Trypanosoma cruzi and Saccharomyces cerevisiae

RNA-binding proteins (RBPs) have important functions in the regulation of gene expression. RBPs play key roles in post-transcriptional processes in all eukaryotes, such as splicing regulation, mRNA transport and modulation of mRNA translation and decay. RBPs assemble into different mRNA-protein complexes, which form messenger ribonucleoprotein complexes (mRNPs). Gene expression regulation in trypanosomatids occurs mainly at the post-transcriptional level and RBPs play a key role in all processes. However, the functional characterization of RBPs in Trypanosoma cruzi has been impaired due to the lack of reliable reverse genetic manipulation tools. The comparison of RBPs from Saccharomyces cerevisiae and T. cruzi might allow inferring on the function of these proteins based on the information available for the orthologous RNA-binding proteins from the S. cerevisiae model organism. In this review, we discuss the role of some RBPs from T. cruzi and their homologues in regulating gene expression in yeast.