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A Trypanosoma cruzi zinc finger protein that is implicated in the control of epimastigote-specific gene expression and metacyclogenesis. Parasitology 2020; 148:1171-1185. [PMID: 33190649 PMCID: PMC8312218 DOI: 10.1017/s0031182020002176] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Trypanosoma cruzi has three biochemically and morphologically distinct developmental stages that are programmed to rapidly respond to environmental changes the parasite faces during its life cycle. Unlike other eukaryotes, Trypanosomatid genomes contain protein coding genes that are transcribed into polycistronic pre-mRNAs and have their expression controlled by post-transcriptional mechanisms. Transcriptome analyses comparing three stages of the T. cruzi life cycle revealed changes in gene expression that reflect the parasite adaptation to distinct environments. Several genes encoding RNA binding proteins (RBPs), known to act as key post-transcriptional regulatory factors, were also differentially expressed. We characterized one T. cruzi RBP, named TcZH3H12, which contains a zinc finger domain and is up-regulated in epimastigotes compared to trypomastigotes and amastigotes. TcZC3H12 knockout (KO) epimastigotes showed decreased growth rates and increased capacity to differentiate into metacyclic trypomastigotes. Transcriptome analyses comparing wild type and TcZC3H12 KOs revealed a TcZC3H12-dependent expression of epimastigote-specific genes such as genes encoding amino acid transporters and proteins associated with differentiation (PADs). RNA immunoprecipitation assays showed that transcripts from the PAD family interact with TcZC3H12. Taken together, these findings suggest that TcZC3H12 positively regulates the expression of genes involved in epimastigote proliferation and also acts as a negative regulator of metacyclogenesis.
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Romagnoli BAA, Holetz FB, Alves LR, Goldenberg S. RNA Binding Proteins and Gene Expression Regulation in Trypanosoma cruzi. Front Cell Infect Microbiol 2020; 10:56. [PMID: 32154189 PMCID: PMC7045066 DOI: 10.3389/fcimb.2020.00056] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 02/03/2020] [Indexed: 01/24/2023] Open
Abstract
The regulation of gene expression in trypanosomatids occurs mainly at the post-transcriptional level. In the case of Trypanosoma cruzi, the characterization of messenger ribonucleoprotein (mRNP) particles has allowed the identification of several classes of RNA binding proteins (RBPs), as well as non-canonical RBPs, associated with mRNA molecules. The protein composition of the mRNPs as well as the localization and functionality of the mRNAs depend on their associated proteins. mRNPs can also be organized into larger complexes forming RNA granules, which function as stress granules or P-bodies depending on the associated proteins. The fate of mRNAs in the cell, and consequently the genes expressed, depends on the set of proteins associated with the messenger molecule. These proteins allow the coordinated expression of mRNAs encoding proteins that are related in function, resulting in the formation of post-transcriptional operons. However, the puzzle posed by the combinatorial association of sets of RBPs with mRNAs and how this relates to the expressed genes remain to be elucidated. One important tool in this endeavor is the use of the CRISPR/CAS system to delete genes encoding RBPs, allowing the evaluation of their effect on the formation of mRNP complexes and associated mRNAs in the different compartments of the translation machinery. Accordingly, we recently established this methodology for T. cruzi and deleted the genes encoding RBPs containing zinc finger domains. In this manuscript, we will discuss the data obtained and the potential of the CRISPR/CAS methodology to unveil the role of RBPs in T. cruzi gene expression regulation.
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Affiliation(s)
- Bruno A A Romagnoli
- Gene Expression Regulation Laboratory, Institute Carlos Chagas, Curitiba, Brazil
| | - Fabiola B Holetz
- Gene Expression Regulation Laboratory, Institute Carlos Chagas, Curitiba, Brazil
| | - Lysangela R Alves
- Gene Expression Regulation Laboratory, Institute Carlos Chagas, Curitiba, Brazil
| | - Samuel Goldenberg
- Gene Expression Regulation Laboratory, Institute Carlos Chagas, Curitiba, Brazil
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Knockout of the CCCH zinc finger protein TcZC3H31 blocks Trypanosoma cruzi differentiation into the infective metacyclic form. Mol Biochem Parasitol 2018; 221:1-9. [DOI: 10.1016/j.molbiopara.2018.01.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 01/21/2018] [Accepted: 01/29/2018] [Indexed: 01/23/2023]
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Oliveira C, Faoro H, Alves LR, Goldenberg S. RNA-binding proteins and their role in the regulation of gene expression in Trypanosoma cruzi and Saccharomyces cerevisiae. Genet Mol Biol 2017; 40:22-30. [PMID: 28463381 PMCID: PMC5409782 DOI: 10.1590/1678-4685-gmb-2016-0258] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 01/10/2017] [Indexed: 02/07/2023] Open
Abstract
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.
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Affiliation(s)
- Camila Oliveira
- Instituto Carlos Chagas, Fiocruz-Paraná, Curitiba, PR, Brazil
| | - Helisson Faoro
- Instituto Carlos Chagas, Fiocruz-Paraná, Curitiba, PR, Brazil
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Alves LR, Goldenberg S. RNA-binding proteins related to stress response and differentiation in protozoa. World J Biol Chem 2016; 7:78-87. [PMID: 26981197 PMCID: PMC4768126 DOI: 10.4331/wjbc.v7.i1.78] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2015] [Revised: 09/23/2015] [Accepted: 11/17/2015] [Indexed: 02/05/2023] Open
Abstract
RNA-binding proteins (RBPs) are key regulators of gene expression. There are several distinct families of RBPs and they are involved in the cellular response to environmental changes, cell differentiation and cell death. The RBPs can differentially combine with RNA molecules and form ribonucleoprotein (RNP) complexes, defining the function and fate of RNA molecules in the cell. RBPs display diverse domains that allow them to be categorized into distinct families. They play important roles in the cellular response to physiological stress, in cell differentiation, and, it is believed, in the cellular localization of certain mRNAs. In several protozoa, a physiological stress (nutritional, temperature or pH) triggers differentiation to a distinct developmental stage. Most of the RBPs characterized in protozoa arise from trypanosomatids. In these protozoa gene expression regulation is mostly post-transcriptional, which suggests that some RBPs might display regulatory functions distinct from those described for other eukaryotes. mRNA stability can be altered as a response to stress. Transcripts are sequestered to RNA granules that ultimately modulate their availability to the translation machinery, storage or degradation, depending on the associated proteins. These aggregates of mRNPs containing mRNAs that are not being translated colocalize in cytoplasmic foci, and their numbers and size vary according to cell conditions such as oxidative stress, nutritional status and treatment with drugs that inhibit translation.
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Alves LR, Oliveira C, Mörking PA, Kessler RL, Martins ST, Romagnoli BAA, Marchini FK, Goldenberg S. The mRNAs associated to a zinc finger protein from Trypanosoma cruzi shift during stress conditions. RNA Biol 2014; 11:921-33. [PMID: 25180711 PMCID: PMC4179965 DOI: 10.4161/rna.29622] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Trypanosome gene expression is regulated almost exclusively at the posttranscriptional level, through mRNA stability, storage and degradation. Here, we characterize the ribonucleoprotein complex (mRNPs) corresponding to the zinc finger protein TcZC3H39 from T. cruzi comparing cells growing in normal conditions and under nutritional stress. The nutritional stress is a key step during T. cruzi differentiation from epimastigote form to human infective metacyclic trypomastigote form. The mechanisms by which the stress, altogether with other stimuli, triggers differentiation is not well understood. This work aims to characterize the TcZC3H39 protein during stress response. Using cells cultured in normal and stress conditions, we observed a dynamic change in TcZC3H39 granule distribution, which appeared broader in stressed epimastigotes. The protein core of the TcZC3H39-mRNP is composed of ribosomes, translation factors and RBPs. The TcZC3H39-mRNP could act sequestering highly expressed mRNAs and their associated ribosomes, potentially slowing translation in stress conditions. A shift were observed in the mRNAs associated with TcZC3H39: the number of targets in unstressed epimastigotes was smaller than that in stressed parasites, with no clear functional clustering in normal conditions. By contrast, in stressed parasites, the targets of TcZC3H39 were mRNAs encoding ribosomal proteins and a remarkable enrichment in mRNAs for the cytochrome c complex (COX), highly expressed mRNAs in the replicative form. This identification of a new component of RNA granules in T. cruzi, the TcZC3H39 protein, provides new insight into the mechanisms involved in parasite stress responses and the regulation of gene expression during T. cruzi differentiation.
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Mörking PA, Rampazzo RDCP, Walrad P, Probst CM, Soares MJ, Gradia DF, Pavoni DP, Krieger MA, Matthews K, Goldenberg S, Fragoso SP, Dallagiovanna B. The zinc finger protein TcZFP2 binds target mRNAs enriched during Trypanosoma cruzi metacyclogenesis. Mem Inst Oswaldo Cruz 2012; 107:790-9. [DOI: 10.1590/s0074-02762012000600014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Accepted: 04/12/2012] [Indexed: 11/22/2022] Open
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Frézard F, Silva H, Pimenta AMDC, Farrell N, Demicheli C. Greater binding affinity of trivalent antimony to a CCCH zinc finger domain compared to a CCHC domain of kinetoplastid proteins. Metallomics 2012; 4:433-40. [DOI: 10.1039/c2mt00176d] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Araújo PR, Teixeira SM. Regulatory elements involved in the post-transcriptional control of stage-specific gene expression in Trypanosoma cruzi: a review. Mem Inst Oswaldo Cruz 2011; 106:257-66. [PMID: 21655811 DOI: 10.1590/s0074-02762011000300002] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Accepted: 04/07/2011] [Indexed: 11/22/2022] Open
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Quintal SM, dePaula QA, Farrell NP. Zinc finger proteins as templates for metal ion exchange and ligand reactivity. Chemical and biological consequences. Metallomics 2011; 3:121-39. [PMID: 21253649 DOI: 10.1039/c0mt00070a] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Zinc finger reactions with inorganic ions and coordination compounds are as diverse as the zinc fingers themselves. Use of metal ions such as Co(2+) and Cd(2+) has given structural, thermodynamic and kinetic information on zinc fingers and zinc-finger-DNA/RNA interactions. It is a general truism that alteration of the coordination sphere in the finger environment will disrupt the recognition with DNA/RNA and this has implications for mechanism of toxicity and carcinogenesis of metal ions. Structural zinc fingers are susceptible to electrophilic attack and the recognition that the coordination sphere of inorganic compounds may be modulated for control of electrophilic attack on zinc fingers raises the possibility of systematic studies of zinc fingers as drug targets using inorganic chemistry. Some inorganic compounds such as those of As(III) and Au(I) may exert their biological effects through inactivation of zinc fingers and novel approaches to specifically attack the zinc-bound ligands using Co(III)-Schiff bases and Platinum(II)-Nucleobase compounds have been proposed. The genomic importance of zinc fingers suggests that the "coordination chemistry" of zinc fingers themselves is ripe for exploration to design new targets for medicinal inorganic chemistry.
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Affiliation(s)
- Susana M Quintal
- Department of Chemistry, Virginia Commonwealth University, 1001 W. Main St., Richmond, VA 23284-2006, USA
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Kramer S, Carrington M. Trans-acting proteins regulating mRNA maturation, stability and translation in trypanosomatids. Trends Parasitol 2010; 27:23-30. [PMID: 20609625 PMCID: PMC3070815 DOI: 10.1016/j.pt.2010.06.011] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Revised: 06/05/2010] [Accepted: 06/07/2010] [Indexed: 12/30/2022]
Abstract
In trypanosomatids, alterations in gene expression in response to intrinsic or extrinsic signals are achieved through post-transcriptional mechanisms. In the last 20 years, research has concentrated on defining the responsible cis-elements in the untranslated regions of several regulated mRNAs. More recently, the focus has shifted towards the identification of RNA-binding proteins that act as trans-acting factors. Trypanosomatids have a large number of predicted RNA-binding proteins of which the vast majority have no orthologues in other eukaryotes. Several RNA-binding proteins have been shown to bind and/or regulate the expression of a group of mRNAs that code for functionally related proteins, indicating the possible presence of co-regulated mRNA cohorts.
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Affiliation(s)
- Susanne Kramer
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, UK, CB2 1QW
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Alves LR, Avila AR, Correa A, Holetz FB, Mansur FCB, Manque PA, de Menezes JPB, Buck GA, Krieger MA, Goldenberg S. Proteomic analysis reveals the dynamic association of proteins with translated mRNAs in Trypanosoma cruzi. Gene 2010; 452:72-8. [PMID: 20060445 DOI: 10.1016/j.gene.2009.12.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 11/22/2009] [Accepted: 12/26/2009] [Indexed: 01/09/2023]
Abstract
Gene regulation is mainly post-transcriptional in trypanosomatids. The stability of mRNA and access to polysomes are thought to be tightly regulated, allowing Trypanosoma cruzi to adapt to the different environmental conditions during its life cycle. Post-transcriptional regulation requires the association between mRNAs and certain proteins to form mRNP complexes. We investigated the dynamic association between proteins and mRNAs, using poly(T) beads to isolate and characterize proteins and protein complexes bound to poly-A+ mRNAs. The protein content of these fractions was analyzed by mass spectrometry (LC-MS/MS). We identified 542 protein component of the mRNP complexes associated with mRNAs. Twenty-four of the proteins obtained were present in all fractions, whereas some other proteins were exclusive to a particular fraction: epimastigote polysomal (0.37%) and post-polysomal (2.95%) fractions; stress polysomal (13.8%) and post-polysomal (40.78%) fractions. Several proteins known to be involved in mRNA metabolism were identified, and this was considered important as it made it possible to confirm the reliability of our mRNP isolation approach. This procedure allowed us to have a first insight into the composition and dynamics of mRNPs in T. cruzi.
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Affiliation(s)
- Lysangela R Alves
- Instituto Carlos Chagas, Laboratório de Regulação da Expressão Gênica, Curitiba, Paraná, Brazil
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Pérez-Díaz L, Duhagon MA, Smircich P, Sotelo-Silveira J, Robello C, Krieger MA, Goldenberg S, Williams N, Dallagiovanna B, Garat B. Trypanosoma cruzi: molecular characterization of an RNA binding protein differentially expressed in the parasite life cycle. Exp Parasitol 2007; 117:99-105. [PMID: 17475252 PMCID: PMC2020836 DOI: 10.1016/j.exppara.2007.03.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2006] [Revised: 03/02/2007] [Accepted: 03/14/2007] [Indexed: 12/18/2022]
Abstract
Molecular studies have shown several peculiarities in the regulatory mechanisms of gene expression in trypanosomatids. Protein coding genes are organized in long polycistronic units that seem to be constitutively transcribed. Therefore, post-transcriptional regulation of gene expression is considered to be the main point for control of transcript abundance and functionality. Here we describe the characterization of a 17 kDa RNA-binding protein from Trypanosoma cruzi (TcRBP19) containing an RNA recognition motive (RRM). This protein is coded by a single copy gene located in a high molecular weight chromosome of T. cruzi. Orthologous genes are present in the TriTryp genomes. TcRBP19 shows target selectivity since among the different homoribopolymers it preferentially binds polyC. TcRBP19 is a low expression protein only barely detected at the amastigote stage localizing in a diffuse pattern in the cytoplasm.
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Affiliation(s)
- Leticia Pérez-Díaz
- Laboratorio de Interacciones Moleculares, Facultad de Ciencias, Iguá 4225, 11400 Montevideo, Uruguay
| | - María Ana Duhagon
- Laboratorio de Interacciones Moleculares, Facultad de Ciencias, Iguá 4225, 11400 Montevideo, Uruguay
| | - Pablo Smircich
- Laboratorio de Interacciones Moleculares, Facultad de Ciencias, Iguá 4225, 11400 Montevideo, Uruguay
| | - José Sotelo-Silveira
- Departamento de Biología Celular y Molecular, Facultad de Ciencias, Iguá 4225, 11400 Montevideo, Uruguay
- Departamento de Neurobiología Celular y Molecular, Instituto de Investigaciones Biológicas Clemente Estable Avda Italia 3318, Montevideo, Uruguay
| | - Carlos Robello
- Departamento de Bioquímica, Facultad de Medicina, Gral Flores 2125, 11800, Montevideo, Uruguay
| | - Marco Aurelio Krieger
- Instituto de Biología Molecular do Paraná, Rua Profesor Algacyr Munhoz Mader 3775, Curitiba 81350-010, Brazil
| | - Samuel Goldenberg
- Instituto de Biología Molecular do Paraná, Rua Profesor Algacyr Munhoz Mader 3775, Curitiba 81350-010, Brazil
| | - Noreen Williams
- Dept. of Microbiology and Immunology. 253 Biomedical Research Building. University at Buffalo. Buffalo 14214, NY. USA
| | - Bruno Dallagiovanna
- Instituto de Biología Molecular do Paraná, Rua Profesor Algacyr Munhoz Mader 3775, Curitiba 81350-010, Brazil
- Corresponding authors: fax: +598 2 525 86 17 E-mail: (B. Garat); or fax: +55 41 33163267 E-mail: (B. Dallagiovanna)
| | - Beatriz Garat
- Laboratorio de Interacciones Moleculares, Facultad de Ciencias, Iguá 4225, 11400 Montevideo, Uruguay
- Corresponding authors: fax: +598 2 525 86 17 E-mail: (B. Garat); or fax: +55 41 33163267 E-mail: (B. Dallagiovanna)
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Russo J, Balogh GA, Heulings R, Mailo DA, Moral R, Russo PA, Sheriff F, Vanegas J, Russo IH. Molecular basis of pregnancy-induced breast cancer protection. Eur J Cancer Prev 2007; 15:306-42. [PMID: 16835503 DOI: 10.1097/00008469-200608000-00006] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
We have postulated that the lifetime protective effect of an early pregnancy against breast cancer is due to the complete differentiation of the mammary gland characterized by a specific genomic signature imprinted by the physiological process of pregnancy. In the present work, we show evidence that the breast tissue of postmenopausal parous women has had a shifting of stem cell 1 to stem cell 2 with a genomic signature different from similar structures derived from postmenopausal nulliparous women that have stem cell 1. Those genes that are significantly different are grouped in major categories on the basis of their putative functional significance. Among them are those gene transcripts related to immune surveillance, DNA repair, transcription, chromatin structure/activators/co-activators, growth factor and signal transduction pathway, transport and cell trafficking, cell proliferation, differentiation, cell adhesion, protein synthesis and cell metabolism. From these data, it was concluded that during pregnancy there are significant genomic changes that reflect profound alterations in the basic physiology of the mammary gland that explain the protective effect against carcinogenesis. The implication of this knowledge is that when the genomic signature of protection or refractoriness to carcinogenesis is acquired by the shifting of stem cell 1 to stem cell 2, the hormonal milieu induced by pregnancy or pregnancy-like conditions is no longer required. This is a novel concept that challenges the current knowledge that a chemopreventive agent needs to be given for a long period to suppress a metabolic pathway or abrogate the function of an organ.
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Affiliation(s)
- Jose Russo
- Breast Cancer Research Laboratory, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111, USA.
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Paterou A, Walrad P, Craddy P, Fenn K, Matthews K. Identification and stage-specific association with the translational apparatus of TbZFP3, a CCCH protein that promotes trypanosome life-cycle development. J Biol Chem 2006; 281:39002-13. [PMID: 17043361 PMCID: PMC2688685 DOI: 10.1074/jbc.m604280200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The post-transcriptional control of gene expression is becoming increasingly important in the understanding of regulated events in eukaryotic cells. The parasitic kinetoplastids have a unique reliance on such processes, because their genome is organized into polycistronic transcription units in which adjacent genes are not coordinately regulated. Indeed, the number of RNA-binding proteins predicted to be encoded in the genome of kinetoplastids is unusually large, invoking the presence of unique RNA regulators dedicated to gene expression in these evolutionarily ancient organisms. Here, we report that a small CCCH zinc finger protein, TbZFP3, enhances development between life-cycle stages in Trypanosoma brucei. Moreover, we demonstrate that this protein interacts both with the translational machinery and with other small CCCH proteins previously implicated in trypanosome developmental control. Antibodies to this protein also co-immunoprecipitate EP procyclin mRNA and encode the major surface antigen of insect forms of T. brucei. Strikingly, although TbZFP3 is constitutively expressed, it exhibits developmentally regulated association with polyribosomes, and mutational analysis demonstrates that this association is essential for the expression of phenotype. TbZFP3 is therefore a novel regulator of developmental events in kinetoplastids that acts at the level of the post-transcriptional control of gene expression.
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Affiliation(s)
| | | | - Paul Craddy
- Institute of Immunology and Infection Research, School of Biological Sciences, Ashworth Laboratories, King’s Buildings, University of Edinburgh, West Mains Road, Edinburgh EH9 3JT, Scotland, United Kingdom
| | - Katelyn Fenn
- Institute of Immunology and Infection Research, School of Biological Sciences, Ashworth Laboratories, King’s Buildings, University of Edinburgh, West Mains Road, Edinburgh EH9 3JT, Scotland, United Kingdom
| | - Keith Matthews
- Institute of Immunology and Infection Research, School of Biological Sciences, Ashworth Laboratories, King’s Buildings, University of Edinburgh, West Mains Road, Edinburgh EH9 3JT, Scotland, United Kingdom
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Heras SR, López MC, García-Pérez JL, Martin SL, Thomas MC. The L1Tc C-terminal domain from Trypanosoma cruzi non-long terminal repeat retrotransposon codes for a protein that bears two C2H2 zinc finger motifs and is endowed with nucleic acid chaperone activity. Mol Cell Biol 2005; 25:9209-20. [PMID: 16227574 PMCID: PMC1265797 DOI: 10.1128/mcb.25.21.9209-9220.2005] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
L1Tc, a non-long terminal repeat retrotransposon from Trypanosoma cruzi, is a 4.9-kb actively transcribed element which contains a single open reading frame coding for the machinery necessary for its autonomous retrotransposition. In this paper, we analyze the protein encoded by the L1Tc 3' region, termed C2-L1Tc, which contains two zinc finger motifs similar to those present in the TFIIIA transcription factor family. C2-L1Tc binds nucleic acids with different affinities, such that RNA > tRNA > single-stranded DNA > double-stranded DNA, without any evidence for sequence specificity. C2-L1Tc also exhibits nucleic acid chaperone activity on different DNA templates that may participate in the mechanism of retrotransposition of the element. C2-L1Tc promotes annealing of complementary oligonucleotides, prevents melting of perfect DNA duplexes, and facilitates the strand exchange between DNAs to form the most stable duplex DNA in competitive displacement assays. Mapping of regions of C2-L1Tc using specific peptides showed that nucleic acid chaperone activity required a short basic sequence accompanied by a zinc finger motif or by another basic region such as RRR. Thus, a short basic polypeptide containing the two C(2)H(2) motifs promotes formation of the most stable duplex DNA at a concentration only three times higher than that required for C2-L1Tc.
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Affiliation(s)
- Sara R Heras
- Departamento de Biología Molecular, Instituto de Parasitología y Biomedicina López Neyra, CSIC, Avda del Conocimiento s/n, 18100 Granada, Spain
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Vanchinathan P, Brewer JL, Harb OS, Boothroyd JC, Singh U. Disruption of a locus encoding a nucleolar zinc finger protein decreases tachyzoite-to-bradyzoite differentiation in Toxoplasma gondii. Infect Immun 2005; 73:6680-8. [PMID: 16177345 PMCID: PMC1230886 DOI: 10.1128/iai.73.10.6680-6688.2005] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During its life cycle in intermediate hosts, Toxoplasma gondii exists in two interconverting developmental stages: tachyzoites and bradyzoites. This interconversion is essential for the survival and pathogenicity of the parasite, but little is known about the genetic mechanisms that control this process. We have previously generated tachyzoite-to-bradyzoite differentiation (Tbd(-)) mutants using chemical mutagenesis and a green fluorescent protein-based selection strategy. The genetic loci responsible for the Tbd(-) phenotype, however, could not be identified. We have now used an insertional mutagenesis strategy to generate two differentiation mutants: TBD-5 and TBD-6 that switch to bradyzoites at 10 and 50% of wild-type levels, respectively. In TBD-6 there is a single insertion of the mutagenesis vector 164 bp upstream of the transcription start site of a gene encoding a zinc finger protein (ZFP1). Disruption of this locus in wild-type parasites reproduces the decreased stage conversion phenotype. ZFP1 is targeted to the parasite nucleolus by CCHC motifs and significantly altered expression levels are toxic to the parasites. This represents the first identification of a gene necessary for efficient conversion of tachyzoites to bradyzoites.
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Affiliation(s)
- Padmini Vanchinathan
- Department of Internal Medicine, Division of Infectious Diseases, Stanford University School of Medicine, California 94305-5124, USA
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Caro F, Bercovich N, Atorrasagasti C, Levin MJ, Vázquez MP. Protein interactions within the TcZFP zinc finger family members of Trypanosoma cruzi: implications for their functions. Biochem Biophys Res Commun 2005; 333:1017-25. [PMID: 15964555 DOI: 10.1016/j.bbrc.2005.06.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2005] [Accepted: 06/03/2005] [Indexed: 11/15/2022]
Abstract
The small zinc finger proteins tbZFP1 and tbZFP2 have been implicated in the control of Trypanosoma brucei differentiation to the procyclic form. Here, we report that the complete ZFP family in Trypanosoma cruzi is composed by four members, ZFP1A and B, and ZFP2A and B. ZFP1B is a paralog specific gene restricted to T. cruzi, while the ZFP2A and B paralogs diverged prior to the trypanosomatid lineage separation. Moreover, we demonstrate that TcZFP1 and TcZFP2 members interact with each other and that this interaction is mediated by a WW domain in TcZFP2. Also, TcZFP2B strongly homodimerizes by a glycine rich region absent in TcZFP2A. We propose a model to discuss the relevance of these protein-protein interactions in terms of the functions of these proteins.
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Affiliation(s)
- Florence Caro
- Laboratorio de Biología Molecular de la Enfermedad de Chagas-INGEBI-CONICET, Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, University of Buenos Aires, Buenos Aires, Argentina
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19
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Hendriks EF, Matthews KR. Disruption of the developmental programme of Trypanosoma brucei by genetic ablation of TbZFP1, a differentiation-enriched CCCH protein. Mol Microbiol 2005; 57:706-16. [PMID: 16045615 PMCID: PMC2686838 DOI: 10.1111/j.1365-2958.2005.04679.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The regulation of differentiation is particularly important in microbial eukaryotes that inhabit multiple environments. The parasite Trypanosoma brucei is an extreme example of this, requiring exquisite gene regulation during transmission from mammals to the tsetse fly vector. Unusually, trypanosomes rely almost exclusively on post-transcriptional mechanisms for regulated gene expression. Hence, RNA binding proteins are potentially of great significance in controlling stage-regulated processes. We have previously identified TbZFP1 as a trypanosome molecule transiently enriched during differentiation to tsetse midgut procyclic forms. This small protein (101 amino acids) contains the unusual CCCH zinc finger, an RNA binding motif. Here, we show that genetic ablation of TbZFP1 compromises repositioning of the mitochondrial genome, a specific event in the strictly regulated differentiation programme. Despite this, other events that occur both before and after this remain intact. Significantly, this phenotype correlates with the TbZFP1 expression profile during differentiation. This is the first genetic disruption of a developmental regulator in T. brucei. It demonstrates that programmed events in parasite development can be uncoupled at the molecular level. It also further supports the importance of CCCH proteins in key aspects of trypanosome cell function.
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Affiliation(s)
- Edward F. Hendriks
- Centre for Molecular Microbiology and Infection, Department of Biological Sciences, Flowers Building Room 3.21, South Kensington Campus, Imperial College London, London SW7 2AZ, UK
- School of Biological Sciences, Division of Biochemistry, 2.205 Stopford Building, University of Manchester, Oxford Road, Manchester, M13 9PT, UK
| | - Keith R. Matthews
- Institute of Immunology and Infection Research, School of Biological Sciences, Ashworth Laboratories, University of Edinburgh, West Mains Road, Edinburgh EH9 3JT, UK
- School of Biological Sciences, Division of Biochemistry, 2.205 Stopford Building, University of Manchester, Oxford Road, Manchester, M13 9PT, UK
- For correspondence. E-mail ; Tel. (+44) 131 651 3639; Fax (+44) 131 650 6564
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Vinuesa CG, Cook MC, Angelucci C, Athanasopoulos V, Rui L, Hill KM, Yu D, Domaschenz H, Whittle B, Lambe T, Roberts IS, Copley RR, Bell JI, Cornall RJ, Goodnow CC. A RING-type ubiquitin ligase family member required to repress follicular helper T cells and autoimmunity. Nature 2005; 435:452-8. [PMID: 15917799 DOI: 10.1038/nature03555] [Citation(s) in RCA: 697] [Impact Index Per Article: 34.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2004] [Accepted: 03/15/2005] [Indexed: 11/09/2022]
Abstract
Despite the sequencing of the human and mouse genomes, few genetic mechanisms for protecting against autoimmune disease are currently known. Here we systematically screen the mouse genome for autoimmune regulators to isolate a mouse strain, sanroque, with severe autoimmune disease resulting from a single recessive defect in a previously unknown mechanism for repressing antibody responses to self. The sanroque mutation acts within mature T cells to cause formation of excessive numbers of follicular helper T cells and germinal centres. The mutation disrupts a repressor of ICOS, an essential co-stimulatory receptor for follicular T cells, and results in excessive production of the cytokine interleukin-21. sanroque mice fail to repress diabetes-causing T cells, and develop high titres of autoantibodies and a pattern of pathology consistent with lupus. The causative mutation is in a gene of previously unknown function, roquin (Rc3h1), which encodes a highly conserved member of the RING-type ubiquitin ligase protein family. The Roquin protein is distinguished by the presence of a CCCH zinc-finger found in RNA-binding proteins, and localization to cytosolic RNA granules implicated in regulating messenger RNA translation and stability.
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MESH Headings
- Amino Acid Sequence
- Animals
- Autoantibodies/immunology
- Autoimmunity/immunology
- Cell Line, Tumor
- Disease Models, Animal
- Female
- Humans
- Lupus Erythematosus, Systemic/genetics
- Lupus Erythematosus, Systemic/immunology
- Lupus Erythematosus, Systemic/metabolism
- Lupus Erythematosus, Systemic/pathology
- Male
- Mice
- Molecular Sequence Data
- Mutation, Missense/genetics
- Receptors, Antigen, T-Cell/immunology
- Receptors, Antigen, T-Cell/metabolism
- T-Lymphocytes, Helper-Inducer/immunology
- T-Lymphocytes, Helper-Inducer/metabolism
- T-Lymphocytes, Helper-Inducer/pathology
- Ubiquitin-Protein Ligases/chemistry
- Ubiquitin-Protein Ligases/classification
- Ubiquitin-Protein Ligases/genetics
- Ubiquitin-Protein Ligases/metabolism
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Affiliation(s)
- Carola G Vinuesa
- Division of Immunology and Genetics, John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2601, Australia.
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