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Rodriguez MA. Protein arginine methyltransferases in protozoan parasites. Parasitology 2022; 149:427-435. [PMID: 35331350 PMCID: PMC11010539 DOI: 10.1017/s0031182021002043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 11/15/2021] [Accepted: 11/25/2021] [Indexed: 11/06/2022]
Abstract
Arginine methylation is a post-translational modification involved in gene transcription, signalling pathways, DNA repair, RNA metabolism and splicing, among others, mechanisms that in protozoa parasites may be involved in pathogenicity-related events. This modification is performed by protein arginine methyltransferases (PRMTs), which according to their products are divided into three main types: type I yields monomethylarginine (MMA) and asymmetric dimethylarginine; type II produces MMA and symmetric dimethylarginine; whereas type III catalyses MMA only. Nine PRMTs (PRMT1 to PRMT9) have been characterized in humans, whereas in protozoa parasites, except for Giardia intestinalis, three to eight PRMTs have been identified, where in each group there are at least two enzymes belonging to type I, the majority with higher similarity to human PRMT1, and one of type II, related to human PRMT5. However, the information on the role of most of these enzymes in the parasites biology is limited so far. Here, current knowledge of PRMTs in protozoan parasites is reviewed; these enzymes participate in the cell growth, stress response, stage transitions and virulence of these microorganisms. Thus, PRMTs are attractive targets for developing new therapeutic strategies against these pathogens.
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Affiliation(s)
- Mario Alberto Rodriguez
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de México, México
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Lozano-Amado D, Ávila-López PA, Hernández-Montes G, Briseño-Díaz P, Vargas M, Lopez-Rubio JJ, Carrero JC, Hernández-Rivas R. A class I histone deacetylase is implicated in the encystation of Entamoeba invadens. Int J Parasitol 2020; 50:1011-1022. [PMID: 32822677 DOI: 10.1016/j.ijpara.2020.05.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 05/26/2020] [Accepted: 05/28/2020] [Indexed: 12/29/2022]
Abstract
Epigenetic mechanisms such as histone acetylation and deacetylation participate in regulation of the genes involved in encystation of Entamoeba invadens. However, the histones and target residues involved, and whether the acetylation and deacetylation of the histones leads to the regulation of gene expression associated with the encystation of this parasite, remain unknown. In this study, we found that E. invadens histone H4 is acetylated in both stages of the parasite and is more highly acetylated during the trophozoite stage than in the cyst. Histone hyperacetylation induced by Trichostatin A negatively affects the encystation of E. invadens, and this inhibition is associated with the downregulation of the expression of genes implicated in the synthesis of chitin, polyamines, gamma-aminobutyric acid pathways and cyst wall proteins, all of which are important in the formation of cysts. Finally, in silico analysis and activity assays suggest that a class I histone deacetylase (EiHDAC3) could be involved in control of the expression of a subset of genes that are important in several pathways during encystation. Therefore, the identification of enzymes that acetylate and/or deacetylate histones that control encystation in E. invadens could be a promising therapeutic target for preventing transmission of other amoebic parasites such as E. histolytica, the causative agent of amoebiasis in humans.
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Affiliation(s)
- Daniela Lozano-Amado
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Ciudad de México, Mexico
| | - Pedro Antonio Ávila-López
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Ciudad de México, Mexico
| | - Georgina Hernández-Montes
- Coordinación de la Investigación Científica, Red de Apoyo a la Investigación, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Mexico
| | - Paola Briseño-Díaz
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Ciudad de México, Mexico
| | - Miguel Vargas
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Ciudad de México, Mexico
| | - Jose-Juan Lopez-Rubio
- LPHI - Laboratory of Pathogen Host Interactions - UMR5235, CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Julio César Carrero
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Mexico
| | - Rosaura Hernández-Rivas
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Ciudad de México, Mexico.
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Lozano-Amado D, Herrera-Solorio AM, Valdés J, Alemán-Lazarini L, Almaraz-Barrera MDJ, Luna-Rivera E, Vargas M, Hernández-Rivas R. Identification of repressive and active epigenetic marks and nuclear bodies in Entamoeba histolytica. Parasit Vectors 2016; 9:19. [PMID: 26767976 PMCID: PMC4712492 DOI: 10.1186/s13071-016-1298-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 01/06/2016] [Indexed: 12/04/2022] Open
Abstract
Background In human hosts, Entamoeba histolytica cysts can develop into trophozoites, suggesting that the life cycle of this parasite are regulated by changes in gene expression. To date, some evidence has suggested that epigenetic mechanisms such as DNA methylation and histone modification are involved in the regulation of gene expression in Entamoeba. Some post–translational modifications (PTMs) at the N-terminus of E. histolytica’s histones have been reported experimentally, including tri-methylation in the lysine 4 of histone H3 (H3K4me3) and dimethylation in the lysine 27 of histone H3 (H3K27me2), dimethylation of arginine 3 (H4R3me2) and the indirect acetylation of histone H4 in the N-terminal region. However, it is not known which residues of histone H4 are subject to acetylation and/or methylation or where in the nucleus these epigenetic marks are located. Methods Histones from trophozoites of E. histolytica were obtained and analyzed by LC-MS/MS. WB assays were performed using antibodies against epigenetic marks (acetylated lysines and methylated arginines). Immunofluorescence assays (IFA) were carried out to determine the distribution of PTMs and the localization of DNA methylation as a heterochromatin marker. Nuclear bodies such as the nucleolus were identified by using antibodies against fibrillarin and nucleolin and speckles by using anti-PRP6 antibody. Results Some new PTMs in histone H4 of E. histolytica, such as the acetylation of lysines 5, 8, 12 and 16 and the monomethylation of arginine 3, were identified by WB. IFA demonstrated that some marks are associated with transcriptional activity (such as acetylation and/or methylation) and that these marks are distributed throughout the E. histolytica nucleus. Staining with antibodies against anti-pan-acetylated lysine H4 histone and 5-methyl cytosine showed that the activation and transcriptional repression marks converge. Additionally, two nuclear bodies, the nucleolus and speckles, were identified in this parasite. Conclusions This study provides the first evidence that the nucleus of E. histolytica is not compartmentalized and contains two nuclear bodies, the nucleolus and speckles, the latter of which was not identified previously. The challenge is now to understand how these epigenetic marks and nuclear bodies work together to regulate gene expression in E. histolytica. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1298-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Daniela Lozano-Amado
- Molecular Biomedicine Department, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (IPN), Av. Instituto Politécnico Nacional # 2508, Apartado postal 14-740,, 07360, D. F. Mexico, México.
| | - Abril Marcela Herrera-Solorio
- Molecular Biomedicine Department, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (IPN), Av. Instituto Politécnico Nacional # 2508, Apartado postal 14-740,, 07360, D. F. Mexico, México.
| | - Jesús Valdés
- Biochemistry Department, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (IPN), Av. Instituto Politécnico Nacional # 2508, Apartado postal 14-740,, 07360, D. F. Mexico, México.
| | - Leticia Alemán-Lazarini
- Molecular Biomedicine Department, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (IPN), Av. Instituto Politécnico Nacional # 2508, Apartado postal 14-740,, 07360, D. F. Mexico, México.
| | - Ma de Jesús Almaraz-Barrera
- Molecular Biomedicine Department, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (IPN), Av. Instituto Politécnico Nacional # 2508, Apartado postal 14-740,, 07360, D. F. Mexico, México.
| | - Eva Luna-Rivera
- Molecular Biomedicine Department, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (IPN), Av. Instituto Politécnico Nacional # 2508, Apartado postal 14-740,, 07360, D. F. Mexico, México.
| | - Miguel Vargas
- Molecular Biomedicine Department, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (IPN), Av. Instituto Politécnico Nacional # 2508, Apartado postal 14-740,, 07360, D. F. Mexico, México.
| | - Rosaura Hernández-Rivas
- Molecular Biomedicine Department, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (IPN), Av. Instituto Politécnico Nacional # 2508, Apartado postal 14-740,, 07360, D. F. Mexico, México.
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Borbolla-Vázquez J, Orozco E, Betanzos A, Rodríguez MA. Entamoeba histolytica: protein arginine transferase 1a methylates arginine residues and potentially modify the H4 histone. Parasit Vectors 2015; 8:219. [PMID: 25889855 PMCID: PMC4393863 DOI: 10.1186/s13071-015-0820-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 03/21/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In eukaryotes, histone arginine methylation associates with both active and repressed chromatin states depending on the residues involved and the status of methylation. Even when the amino-terminus of Entamoeba histolytica histones diverge from metazoan sequences, these regions contain arginine residues that are potential targets for methylation. However, histone arginine methylation as well as the activity of arginine methyltransferases (PRMTs) has not been studied in this parasite. The aim of this work was to examine the dimethylation of arginine 3 of H4 histone (H4R3me2) and to identify the parasite PRMT that could be responsible for this modification (EhPRMT1). METHODS To examine the presence of H4R3me2 in E histolytica, we performed Western blot and immunofluorescence assays on trophozoites using an antibody against this epigenetic mark. To recognize the PRMT1 enzyme of this parasite that possibly perform that modification, we first performed a phylogenetic analysis of E. histolytica and human PRMTs. RT-PCR assays were carried out to analyze the expression of the putative PRMT1 genes. One of these genes was cloned and expressed in Escherichia coli. The recombinant protein was tested by its recognition by an antibody against human PRMT1 and in its ability to form homodimers and to methylate commercial histones. RESULTS The arginine 3 of human H4, which is subjected to post translational methylation, was aligned with the arginine 8 of E. histolytica H4, suggesting that this residue could be methylated. The recognition of an 18 kDa nuclear protein of E. histolytica by an antibody against H4R3me2 confirmed this assumption. We found that this parasite expresses three phylogenetic and structural proteins related to PRMT1. Antibodies against the human PRMT1 detected E. histolytica proteins in cytoplasm and nuclei and recognized a recombinant PRMT1 of this parasite. The recombinant protein was able to form homodimers and homotetramers and displayed methyltransferase activity on arginine 3 of chicken H4. CONCLUSION All these results suggest that E. histolytica contains as a minimum one structural and functional protein ortholog to PRMT1, enzyme that potentially dimethylates H4R8. This modification may play an important role in the gene expression regulation of this microorganism.
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Affiliation(s)
- Jessica Borbolla-Vázquez
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, A.P. 14-740, México, D.F., 07000, Mexico.
| | - Esther Orozco
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, A.P. 14-740, México, D.F., 07000, Mexico.
| | - Abigail Betanzos
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, A.P. 14-740, México, D.F., 07000, Mexico.
| | - Mario A Rodríguez
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, A.P. 14-740, México, D.F., 07000, Mexico.
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Tovy A, Ankri S. Epigenetics in the unicellular parasite Entamoeba histolytica. Future Microbiol 2011; 5:1875-84. [PMID: 21198420 DOI: 10.2217/fmb.10.140] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Amoebiasis is a serious infectious disease that is caused by the unicellular parasite, Entamoeba histolytica. This parasite is mainly found in developing countries, and are named owing to its ability to destroy tissues. The molecular mechanisms that regulate the virulence of this parasite are not well understood. In recent years, an increasing interest in the epigenetic regulation of the parasite's virulence has emerged. In this article, an overview of our current knowledge about the role of DNA methylation, histone modifications and RNA-associated silencing in the biology of E. histolytica is provided. The relevance of some features of the parasite's unique epigenetic machinery to the development of new antiamoebic therapeutic molecules is discussed.
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Affiliation(s)
- Ayala Tovy
- Department of Microbiology, Ruth & Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology & the Rappaport Institute, Haifa, Israel
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Pearson RJ, Singh U. Approaches to characterizing Entamoeba histolytica transcriptional regulation. Cell Microbiol 2010; 12:1681-90. [DOI: 10.1111/j.1462-5822.2010.01524.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Regulation of gene expression in protozoa parasites. J Biomed Biotechnol 2010; 2010:726045. [PMID: 20204171 PMCID: PMC2830571 DOI: 10.1155/2010/726045] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 11/10/2009] [Accepted: 01/08/2010] [Indexed: 12/25/2022] Open
Abstract
Infections with protozoa parasites are associated with high burdens of morbidity and mortality across the developing world. Despite extensive efforts to control the transmission of these parasites, the spread of populations resistant to drugs and the lack of effective vaccines against them contribute to their persistence as major public health problems. Parasites should perform a strict control on the expression of genes involved in their pathogenicity, differentiation, immune evasion, or drug resistance, and the comprehension of the mechanisms implicated in that control could help to develop novel therapeutic strategies. However, until now these mechanisms are poorly understood in protozoa. Recent investigations into gene expression in protozoa parasites suggest that they possess many of the canonical machineries employed by higher eukaryotes for the control of gene expression at transcriptional, posttranscriptional, and epigenetic levels, but they also contain exclusive mechanisms. Here, we review the current understanding about the regulation of gene expression in Plasmodium sp., Trypanosomatids, Entamoeba histolytica and Trichomonas vaginalis.
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Zamorano A, López-Camarillo C, Orozco E, Weber C, Guillen N, Marchat LA. In silico analysis of EST and genomic sequences allowed the prediction of cis-regulatory elements for Entamoeba histolytica mRNA polyadenylation. Comput Biol Chem 2008; 32:256-63. [PMID: 18514032 DOI: 10.1016/j.compbiolchem.2008.03.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2007] [Revised: 03/24/2008] [Accepted: 03/24/2008] [Indexed: 10/22/2022]
Abstract
In most eukaryotic cells, the poly(A) tail at the 3'-end of messenger RNA (mRNA) is essential for nuclear export, translatability, stability and transcription termination. Poly(A) tail formation involves multi-protein complexes that interact with specific sequences in 3'-untranslated region (3'-UTR) of precursor mRNA (pre-mRNA). Here we have performed a computational analysis of a large EST and genomic sequences collection from Entamoeba histolytica, the protozoan parasite responsible for human amoebiasis, to identify conserved elements that could be involved in pre-mRNA polyadenylation. Results evidenced the presence of an AU-rich domain corresponding to the consensus UA(A/U)UU polyadenylation signal or variants, the cleavage and polyadenylation site that is generally denoted by U residue and flanked by two U-rich tracts, and a novel A-rich element. This predicted array was validated through the analysis of genomic sequences and predicted mRNA folding of genes with known polyadenylation site. The molecular organization of pre-mRNA 3'-UTR cis-regulatory elements appears to be roughly conserved through evolutionary scale, whereas the polyadenylation signal seems to be species-specific in protozoan parasites and the novel A-rich element is unique for the primitive eukaryote E. histolytica. To our knowledge, this paper is the first work about the identification of potential pre-mRNA 3'-UTR cis-regulatory sequences through in silico analysis of large sets of cDNA and genomic sequences in a protozoan parasite.
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Affiliation(s)
- Absalom Zamorano
- ENMH-IPN, Programa Institucional de Biomedicina Molecular, Guillermo Massieu Heguera #239, Ticoman, CP 07320, México, D.F., Mexico
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Ramakrishnan G, Gilchrist CA, Musa H, Torok MS, Grant PA, Mann BJ, Petri WA. Histone acetyltransferases and deacetylase in Entamoeba histolytica. Mol Biochem Parasitol 2005; 138:205-16. [PMID: 15555732 DOI: 10.1016/j.molbiopara.2004.09.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2004] [Accepted: 09/02/2004] [Indexed: 11/20/2022]
Abstract
In our efforts to understand how transcription may be regulated in Entamoeba histolytica, we have examined if this parasite has conserved enzymatic mechanisms for targeted acetylation and deacetylation of histones. Western blotting indicated that basic nuclear proteins in the size range of 16-23 kDa were acetylated in amebic trophozoites, suggesting histone acetylation. Single representatives of the GNAT and MYST family of histone acetyltransferases (HATs) were identified in the E. histolytica genome and their expression in amebic trophozoites was detected by reverse transcription of RNA followed by the polymerase chain reaction (RT-PCR). Full-length recombinant EhMYST protein demonstrated HAT activity with calf thymus histones and showed a preference for histone H4, similar to the yeast MYST protein, Esa1. However, ehMYST did not complement a yeast esa1 mutation. Histone deacetylase (HDAC) activity was detected in nuclear extracts from E. histolytica, and characteristically, was inhibited by trichostatin A (TSA). Consistent with the observation of HDAC activity, RT-PCR analysis demonstrated that an amebic hdac1 homolog (ehHDAC) is expressed and appropriately spliced in E. histolytica trophozoites. Our results suggest that mechanisms for histone acetylation and deacetylation are operational in E. histolytica.
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Affiliation(s)
- Girija Ramakrishnan
- Department of Medicine, University of Virginia, Charlottesville, VA 22908, USA
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Katz LA, Bornstein JG, Lasek-Nesselquist E, Muse SV. Dramatic diversity of ciliate histone H4 genes revealed by comparisons of patterns of substitutions and paralog divergences among eukaryotes. Mol Biol Evol 2003; 21:555-62. [PMID: 14694079 DOI: 10.1093/molbev/msh048] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The accumulation of divergent histone H4 amino acid sequences within and between ciliate lineages challenges traditional views of the evolution of this essential eukaryotic protein. We analyzed histone H4 sequences from 13 species of ciliates and compared these data with sequences from well-sampled eukaryotic clades. Ciliate histone H4s differ from one another at as many as 46% of their amino acids, in contrast with the highly conserved character of this protein in most other eukaryotes. Equally striking, we find paralogs of histone H4 within ciliate genomes that differ by up to 25% of their amino acids, whereas paralogs in other eukaryotes share identical or nearly identical amino acid sequences. Moreover, the most divergent H4 proteins within ciliates are found in the lineages with highly processed macronuclear genomes. Our analyses demonstrate that the dual nature of ciliate genomes-the presence of a "germline" micronucleus and a "somatic" macronucleus within each cell-allowed the dramatic variation in ciliate histone genes by altering functional constraints or enabling adaptive evolution of the histone H4 protein, or both.
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Affiliation(s)
- Laura A Katz
- Department of Biological Sciences, Smith College, Northampton, Massachusetts, USA.
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11
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Triana O, Galanti N, Olea N, Hellman U, Wernstedt C, Lujan H, Medina C, Toro GC. Chromatin and histones from Giardia lamblia: a new puzzle in primitive eukaryotes. J Cell Biochem 2001; 82:573-82. [PMID: 11500935 DOI: 10.1002/jcb.1159] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The three deepest eukaryote lineages in small subunit ribosomal RNA phylogenies are the amitochondriate Microsporidia, Metamonada, and Parabasalia. They are followed by either the Euglenozoa (e.g., Euglena and Trypanosoma) or the Percolozoa as the first mitochondria-containing eukaryotes. Considering the great divergence of histone proteins in protozoa we have extended our studies of histones from Trypanosomes (Trypanosoma cruzi, Crithidia fasciculata and Leishmania mexicana) to the Metamonada Giardia lamblia, since Giardia is thought to be one of the most primitive eukaryotes. In the present work, the structure of G. lamblia chromatin and the histone content of the soluble chromatin were investigated and compared with that of higher eukaryotes, represented by calf thymus. The chromatin is present as nucleosome filaments which resemble the calf thymus array in that they show a more regular arrangement than those described for Trypanosoma. SDS-polyacrylamide gel electrophoresis and protein characterization revealed that the four core histones described in Giardia are in the same range of divergence with the histones from other lower eukaryotes. In addition, G. lamblia presented an H1 histone with electrophoretic mobility resembling the H1 of higher eukaryotes, in spite of the fact that H1 has a different molecular mass in calf thymus. Giardia also presents a basic protein which was identified as an HU-like DNA-binding protein usually present in eubacteria, indicating a chimaeric composition for the DNA-binding protein set in this species. Finally, the phylogenetic analysis of selected core histone protein sequences place Giardia divergence before Trypanosoma, despite the fact that Trypanosoma branch shows an acceleration in the evolutionary rate pointing to an unusual evolutionary behavior in this lineage.
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Affiliation(s)
- O Triana
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago 7, Chile
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12
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Wu G, McArthur AG, Fiser A, Sali A, Sogin ML, Mllerm M. Core histones of the amitochondriate protist, Giardia lamblia. Mol Biol Evol 2000; 17:1156-63. [PMID: 10908635 DOI: 10.1093/oxfordjournals.molbev.a026398] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Genes coding for the core histones H2a, H2b, H3, and H4 of Giardia lamblia were sequenced. A conserved organism- and gene-specific element, GRGCGCAGATTTVGG, was found upstream of the coding region in all core histone genes. The derived amino acid sequences of all four histones were similar to their homologs in other eukaryotes, although they were among the most divergent members of this protein family. Comparative protein structure modeling combined with energy evaluation of the resulting models indicated that the G. lamblia core histones individually and together can assume the same three-dimensional structures that were established by X-ray crystallography for Xenopus laevis histones and the nucleosome core particle. Since G. lamblia represents one of the earliest-diverging eukaryotes in many different molecular trees, the structure of its histones is potentially of relevance to understanding histone evolution. The G. lamblia proteins do not represent an intermediate stage between archaeal and eukaryotic histones.
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Affiliation(s)
- G Wu
- Laboratory of Biochemical Parasitology, The Rockefeller University, New York, NY 10021, USA
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Abstract
Estimation of genome size of Entamoeba histolytica by different methods has failed to give comparable values due to the inherent complexities of the organism, such as the uncertain level of ploidy, presence of multinucleated cells and a poorly demarcated cell division cycle. The genome of E. histolytica has a low G+C content (22.4%), and is composed of both linear chromosomes and a number of circular plasmid-like molecules. The rRNA genes are located exclusively on some of the circular DNAs. Karyotype analysis by pulsed field gel electrophoresis suggests the presence of 14 conserved linkage groups and an extensive size variation between homologous chromosomes from different isolates. Several repeat families have been identified, some of which have been shown to be present in all the electrophoretically separated chromosomes. The typical nucleosomal structure has not been demonstrated, though most of the histone genes have been identified. Most Entamoeba genes lack introns, have short 3' and 5' untranslated regions, and are tightly packed. Promoter analysis revealed the presence of three conserved motifs and several upstream regulatory elements. Unlike typical eukaryotes, the transcription of protein coding genes is alpha-amanitin resistant. Expressed Sequence Tag analysis has identified a group of highly abundant polyadenylated RNAs which are unlikely to be translated. The Expressed Sequence Tag approach has also helped identify several important genes which encode proteins that may be involved in different biochemical pathways, signal transduction mechanisms and organellar functions.
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Affiliation(s)
- A Bhattacharya
- School of Life Sciences, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, India.
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14
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Willhoeft U, Hamann L, Tannich E. A DNA sequence corresponding to the gene encoding cysteine proteinase 5 in Entamoeba histolytica is present and positionally conserved but highly degenerated in Entamoeba dispar. Infect Immun 1999; 67:5925-9. [PMID: 10531249 PMCID: PMC96975 DOI: 10.1128/iai.67.11.5925-5929.1999] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cysteine proteinases of Entamoeba histolytica are considered to be one of the most important classes of molecules responsible for the parasite's ability to destroy human tissues. Interestingly, one particular cysteine proteinase, located on the surface of E. histolytica trophozoites and designated cysteine proteinase 5 (CP5), is not expressed in the closely related but nonpathogenic species Entamoeba dispar. By comparing the E. histolytica and E. dispar genomic loci containing the gene for CP5 (cp5), it was found that the position of cp5 within the genomic context is conserved between the two organisms, but that the gene is highly degenerated in E. dispar, as it contains numerous nucleotide exchanges, insertions, and deletions, resulting in multiple stop codons within the cp5 reading frame. An alignment of all available orthologous E. histolytica and E. dispar DNA sequences suggested that cp5 started to degenerate in E. dispar coincidently when the two organisms began to diverge from a common ancestor.
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Affiliation(s)
- U Willhoeft
- Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany
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15
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Abstract
Although knowledge about gene organization and transcription control in the protozoan parasite Entamoeba histolytica has increased substantially during the last few years, questions remain open about ploidy, organization and number of chromosomes in this human pathogen. To get insight into these questions conditions were elaborated to consistently separate E. histolytica chromosomes using pulsed-field gel electrophoresis. Southern blot analyses indicated variations in number and size of homologous chromosomes between various E. histolytica isolates, but only minor differences were observed between clones of a given isolate. Depending on the isolate used 31-35 chromosomes were identified ranging in size from 0.3 to 2.2 megabases. The assignment of 68 independent cDNA probes to the chromosomes of three axenically cultured E. histolytica isolates identified 14 linkage groups, which suggested a haploid genome-size of < or =20 megabases. As single copy probes bound to as many as four chromosome-sized bands, it is most likely that E. histolytica has a functional ploidity of at least 4.
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Affiliation(s)
- U Willhoeft
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
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16
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Soto M, Quijada L, Alonso C, Requena JM. Molecular cloning and analysis of expression of the Leishmania infantum histone H4 genes. Mol Biochem Parasitol 1997; 90:439-47. [PMID: 9476792 DOI: 10.1016/s0166-6851(97)00178-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In the present work, we describe the sequence, organization and expression of histone H4 genes in the protozoan parasite Leishmania infantum. The predicted L. infantum histone H4 is a polypeptide of 100 amino acids with a molecular mass of 11.5 kDa. Comparison of the amino acid sequence of Leishmania histone H4 with the rest of histone H4 sequences indicates that this is the most divergent sequence reported to date. The genomic distribution analysis of histone H4 genes indicates that there must be up to seven gene copies. A single size-class histone H4 mRNA of 0.6 kb was detected, whose level dramatically decreases from logarithmic to stationary phase. However, the Leishmania histone H4 mRNAs do not decrease in abundance following treatment with inhibitors of DNA synthesis, suggesting a regulation by a replication-independent mechanism.
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Affiliation(s)
- M Soto
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, Spain
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17
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Fogel GB, Brunk CF. Expression of Tetrahymena histone H4 in yeast. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1354:116-26. [PMID: 9396628 DOI: 10.1016/s0167-4781(97)00078-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Histone H4 is one of the most conserved proteins known. The very low rate of nonsynonymous substitution in H4 suggests that it fulfills an essential function in virtually all eukaryotes. While the majority of histone H4 sequences differ only slightly from the general consensus H4 sequence, yeast and Tetrahymena sequences diverge substantially from both the consensus and from each other. This study demonstrates that despite this divergence, when Saccharomyces cerevisiae cells are forced to use the Tetrahymena thermophila histone H4 protein, they are viable although they have a reduced growth rate, are temperature-sensitive relative to wild-type, have a lengthened G2 phase, and show a dramatic repression of mating. An amino acid replacement at position 33 in the protein improves the growth rate of these cells growing at temperatures above 28 degrees C. This replacement changes a proline to a serine and is a further divergence from both the Tetrahymena thermophila and Saccharomyces cerevisiae histone H4 sequences. Thus, the replacement and expression of a non wild-type histone H4 in yeast offers measurable effects on cell growth, identifying amino acids required for optimal yeast functioning.
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Affiliation(s)
- G B Fogel
- Department of Biology, University of California, Los Angeles, 90095-1606, USA
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Marinets A, Müller M, Johnson PJ, Kulda J, Scheiner O, Wiedermann G, Duchêne M. The sequence and organization of the core histone H3 and H4 genes in the early branching amitochondriate protist Trichomonas vaginalis. J Mol Evol 1996; 43:563-71. [PMID: 8995053 DOI: 10.1007/bf02202104] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Among the unicellular protists, several of which are parasitic, some of the most divergent eukaryotic species are found. The evolutionary distances between protists are so large that even slowly evolving proteins like histones are strongly divergent. In this study we isolated cDNA and genomic histone H3 and H4 clones from Trichomonas vaginalis. Two histone H3 and three histone H4 genes were detected on three genomic clones with one complete H3 and two complete H4 sequences. H3 and H4 genes were divergently transcribed with very short intergenic regions of only 194 bp, which contained T. vaginalis-specific as well as histone-specific putative promoter elements. Southern blot analysis showed that there may be several more histone gene pairs. The two complete histone H4 genes were different on the nucleotide level but encoded the same amino acid sequence. Comparison of the amino acid sequences of the T. vaginalis H3 and H4 histones with sequences from animals, fungi, and plants as well as other protists revealed a significant divergence not only from the sequences in multicellular organisms but especially from the sequences in other protists like Entamoeba histolytica, Trypanosoma cruzi, and Leishmania infantum.
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Affiliation(s)
- A Marinets
- Institute for Specific Prophylaxis and Tropical Medicine, University of Vienna, Austria
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