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Cuellar P, Castañeda-Ortiz EJ, Rosales-Zarza C, Martínez-Rodríguez CE, Canela-Pérez I, Rodríguez MA, Valdés J, Azuara-Liceaga E. Genome-Wide Classification of Myb Domain-Containing Protein Families in Entamoeba invadens. Genes (Basel) 2024; 15:201. [PMID: 38397191 PMCID: PMC10887745 DOI: 10.3390/genes15020201] [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: 12/26/2023] [Revised: 01/22/2024] [Accepted: 01/26/2024] [Indexed: 02/25/2024] Open
Abstract
Entamoeba histolytica, the causative agent of amebiasis, is the third leading cause of death among parasitic diseases globally. Its life cycle includes encystation, which has been mostly studied in Entamoeba invadens, responsible for reptilian amebiasis. However, the molecular mechanisms underlying this process are not fully understood. Therefore, we focused on the identification and characterization of Myb proteins, which regulate the expression of encystation-related genes in various protozoan parasites. Through bioinformatic analysis, we identified 48 genes in E. invadens encoding MYB-domain-containing proteins. These were classified into single-repeat 1R (20), 2R-MYB proteins (27), and one 4R-MYB protein. The in-silico analysis suggests that these proteins are multifunctional, participating in transcriptional regulation, chromatin remodeling, telomere maintenance, and splicing. Transcriptomic data analysis revealed expression signatures of eimyb genes, suggesting a potential orchestration in the regulation of early and late encystation-excystation genes. Furthermore, we identified probable target genes associated with reproduction, the meiotic cell cycle, ubiquitin-dependent protein catabolism, and endosomal transport. In conclusion, our findings suggest that E. invadens Myb proteins regulate stage-specific proteins and a wide array of cellular processes. This study provides a foundation for further exploration of the molecular mechanisms governing encystation and unveils potential targets for therapeutic intervention in amebiasis.
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Affiliation(s)
- Patricia Cuellar
- Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de México, Mexico City C.P. 03100, Mexico; (P.C.); (E.J.C.-O.)
| | - Elizabeth J. Castañeda-Ortiz
- Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de México, Mexico City C.P. 03100, Mexico; (P.C.); (E.J.C.-O.)
| | - César Rosales-Zarza
- Licenciatura Ciencias Genómicas, Universidad Autónoma de la Ciudad de México, Mexico City C.P. 03100, Mexico;
| | | | - Israel Canela-Pérez
- Departamento de Bioquímica, CINVESTAV-IPN, Mexico City C.P. 07360, Mexico; (I.C.-P.); (J.V.)
| | - Mario Alberto Rodríguez
- Departamento de Infectómica y Patogénesis Molecular, CINVESTAV-IPN, Mexico City C.P. 07360, Mexico;
| | - Jesús Valdés
- Departamento de Bioquímica, CINVESTAV-IPN, Mexico City C.P. 07360, Mexico; (I.C.-P.); (J.V.)
| | - Elisa Azuara-Liceaga
- Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de México, Mexico City C.P. 03100, Mexico; (P.C.); (E.J.C.-O.)
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Kim J, Park EA, Shin MY, Park SJ. Functional Differentiation of Cyclins and Cyclin-Dependent Kinases in Giardia lamblia. Microbiol Spectr 2023; 11:e0491922. [PMID: 36877015 PMCID: PMC10100927 DOI: 10.1128/spectrum.04919-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 02/05/2023] [Indexed: 03/07/2023] Open
Abstract
Cyclin-dependent kinases (CDKs) are serine/threonine kinases that control the eukaryotic cell cycle. Limited information is available on Giardia lamblia CDKs (GlCDKs), GlCDK1 and GlCDK2. After treatment with the CDK inhibitor flavopiridol-HCl (FH), division of Giardia trophozoites was transiently arrested at the G1/S phase and finally at the G2/M phase. The percentage of cells arrested during prophase or cytokinesis increased, whereas DNA synthesis was not affected by FH treatment. Morpholino-mediated depletion of GlCDK1 caused arrest at the G2/M phase, while GlCDK2 depletion resulted in an increase in the number of cells arrested at the G1/S phase and cells defective in mitosis and cytokinesis. Coimmunoprecipitation experiments with GlCDKs and the nine putative G. lamblia cyclins (Glcyclins) identified Glcyclins 3977/14488/17505 and 22394/6584 as cognate partners of GlCDK1 and GlCDK2, respectively. Morpholino-based knockdown of Glcyclin 3977 or 22394/6584 arrested cells in the G2/M phase or G1/S phase, respectively. Interestingly, GlCDK1- and Glcyclin 3977-depleted Giardia showed significant flagellar extension. Altogether, our results suggest that GlCDK1/Glcyclin 3977 plays an important role in the later stages of cell cycle control and in flagellar biogenesis. In contrast, GlCDK2 along with Glcyclin 22394 and 6584 functions from the early stages of the Giardia cell cycle. IMPORTANCE Giardia lamblia CDKs (GlCDKs) and their cognate cyclins have not yet been studied. In this study, the functional roles of GlCDK1 and GlCDK2 were distinguished using morpholino-mediated knockdown and coimmunoprecipitation. GlCDK1 with Glcyclin 3977 plays a role in flagellum formation as well as cell cycle control of G. lamblia, whereas GlCDK2 with Glcyclin 22394/6584 is involved in cell cycle control.
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Affiliation(s)
- Juri Kim
- Department of Tropical Medicine, Yonsei University College of Medicine, Seoul, South Korea
| | - Eun-Ah Park
- Department of Tropical Medicine, Yonsei University College of Medicine, Seoul, South Korea
| | - Mee Young Shin
- Department of Tropical Medicine, Yonsei University College of Medicine, Seoul, South Korea
| | - Soon-Jung Park
- Department of Tropical Medicine, Yonsei University College of Medicine, Seoul, South Korea
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3
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Kim J, Park EA, Shin MY, Park SJ. Identification of target genes regulated by encystation-induced transcription factor Myb2 using knockout mutagenesis in Giardia lamblia. Parasit Vectors 2022; 15:360. [PMID: 36207732 PMCID: PMC9547401 DOI: 10.1186/s13071-022-05489-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 09/16/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Encystation is one of the two processes comprising the life cycle of Giardia lamblia, a protozoan pathogen with tetraploid genome. Giardia lamblia Myb2 (GlMyb2) is a distinct encystation-induced transcription factor whose binding sites are found in the promoter regions of many encystation-induced genes, including its own. METHODS Two sequential CRISPR/Cas9 experiments were performed to remove four glmyb2 alleles. The expression level of G. lamblia cyst wall protein 1 (GlCWP1), a well-known target gene of GlMyb2, was measured via western blotting and immunofluorescence assays. Chromatin immunoprecipitation experiments using anti-GlMyb2 antibodies were performed on the encysting G. lamblia cells. Quantitative real-time PCR was performed to confirm an expression of candidate GlMyb2-regulated genes by comparing the transcript level for each target candidate in wild-type and knockout mutant Giardia. The promoter region of glcwp1 was analyzed via deletion and point mutagenesis of the putative GlMyb2 binding sites in luciferase reporters. RESULTS Characterization of the null glmyb2 mutant indicated loss of functions related to encystation, i.e. cyst formation, and expression of GlCWP1. The addition of the wild-type glmyb2 gene to the null mutant restored the defects in encystation. Chromatin immunoprecipitation experiments revealed dozens of target genes. Nineteen genes were confirmed as GlMyb2 regulons, which include the glmyb2 gene, six for cyst wall proteins, five for signal transduction, two for transporter, two for metabolic enzymes, and three with unknown functions. Detailed analysis on the promoter region of glcwp1 defined three GlMyb2 binding sites important in its encystation-induced expression. CONCLUSIONS Our data confirm that GlMyb2 acts as a transcription activator especially during encystation by comparing the glmyb2 knockout mutant with the wild type. Further investigation using glmyb2 null mutant will provide knowledge regarding transcriptional apparatus required for the encystation process of G. lamblia.
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Affiliation(s)
- Juri Kim
- Department of Environmental Medical Biology and Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul, 03722 Korea
| | - Eun-Ah Park
- Department of Environmental Medical Biology and Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul, 03722 Korea
| | - Mee Young Shin
- Department of Environmental Medical Biology and Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul, 03722 Korea
| | - Soon-Jung Park
- Department of Environmental Medical Biology and Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul, 03722 Korea
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Kim J, Shin MY, Park SJ. Functional Identification of a Nuclear Localization Signal of MYB2 Protein in Giardia lamblia. THE KOREAN JOURNAL OF PARASITOLOGY 2021; 58:675-679. [PMID: 33412772 PMCID: PMC7806428 DOI: 10.3347/kjp.2020.58.6.675] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 11/23/2019] [Indexed: 11/23/2022]
Abstract
MYB2 protein was identified as a transcription factor that showed encystation-induced expression in Giardia lamblia. Although nuclear import is essential for the functioning of a transcription factor, an evident nuclear localization signal (NLS) of G. lamblia MYB2 (GlMYB2) has not been defined. Based on putative GlMYB2 NLSs predicted by 2 programs, a series of plasmids expressing hemagglutinin (HA)-tagged GlMYB2 from the promoter of G. lamblia glutamate dehydrogenase were constructed and transfected into Giardia trophozoites. Immunofluorescence assays using anti-HA antibodies indicated that GlMYB2 amino acid sequence #507–#530 was required for the nuclear localization of GlMYB2, and this sequence was named as NLSGlMYB2. We further verified this finding by demonstrating the nuclear location of a protein obtained by the fusion of NLSGlMYB2 and G. lamblia glyceraldehyde 3-phosphate dehydrogenase, a non-nuclear protein. Our data on GlMYB2 will expand our understanding on NLSs functioning in G. lamblia.
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Affiliation(s)
- Juri Kim
- Department of Environmental Medical Biology and Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Mee Young Shin
- Department of Environmental Medical Biology and Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Soon-Jung Park
- Department of Environmental Medical Biology and Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul 03722, Korea
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Salusso A, Zlocowski N, Mayol GF, Zamponi N, Rópolo AS. Histone methyltransferase 1 regulates the encystation process in the parasiteGiardia lamblia. FEBS J 2017; 284:2396-2409. [DOI: 10.1111/febs.14131] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 05/04/2017] [Accepted: 06/07/2017] [Indexed: 11/30/2022]
Affiliation(s)
- Agostina Salusso
- Instituto de Investigación Médica Mercedes y Martín Ferreyra; INIMEC - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Universidad Nacional de Córdoba; Argentina
| | - Natacha Zlocowski
- Instituto de Investigación Médica Mercedes y Martín Ferreyra; INIMEC - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Universidad Nacional de Córdoba; Argentina
| | - Gonzalo F. Mayol
- Instituto de Investigación Médica Mercedes y Martín Ferreyra; INIMEC - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Universidad Nacional de Córdoba; Argentina
| | - Nahuel Zamponi
- Instituto de Investigación Médica Mercedes y Martín Ferreyra; INIMEC - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Universidad Nacional de Córdoba; Argentina
| | - Andrea S. Rópolo
- Instituto de Investigación Médica Mercedes y Martín Ferreyra; INIMEC - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Universidad Nacional de Córdoba; Argentina
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Nageshan RK, Roy N, Ranade S, Tatu U. Trans-spliced heat shock protein 90 modulates encystation in Giardia lamblia. PLoS Negl Trop Dis 2014; 8:e2829. [PMID: 24786776 PMCID: PMC4006730 DOI: 10.1371/journal.pntd.0002829] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Accepted: 03/13/2014] [Indexed: 01/22/2023] Open
Abstract
Background Hsp90 from Giardia lamblia is expressed by splicing of two independently transcribed RNA molecules, coded by genes named HspN and HspC located 777 kb apart. The reasons underlying such unique trans-splicing based generation of GlHsp90 remain unclear. Principle Finding In this study using mass-spectrometry we identify the sequence of the unique, junctional peptide contributed by the 5′ UTR of HspC ORF. This peptide is critical for the catalytic function of Hsp90 as it harbours an essential “Arg” in its sequence. We also show that full length GlHsp90 possesses all the functional hall marks of a canonical Hsp90 including its ability to bind and hydrolyze ATP. Using qRT-PCR as well as western blotting approach we find the reconstructed Hsp90 to be induced in response to heat shock. On the contrary we find GlHsp90 to be down regulated during transition from proliferative trophozoites to environmentally resistant cysts. This down regulation of GlHsp90 appears to be mechanistically linked to the encystation process as we find pharmacological inhibition of GlHsp90 function to specifically induce encystation. Significance Our results implicate the trans-spliced GlHsp90 from Giardia lamblia to regulate an essential stage transition in the life cycle of this important human parasite. Giardia lamblia is one of the most common causes of diarrhoea across the globe. The disease can result in fatalities especially in small children. The parasite is transmitted by contaminated food through faeco-oral route due to unhygienic habits. The parasite exhibits two stages during its lifecycle; namely cysts and trophozoites. Due to their environmentally resistant hardy nature cysts are transmitted through contaminated food into the human body. Upon entry into the human body they convert into active trophozoites and cause pathogenesis of the disease. In the course of infection within the host, some of the trophozoites convert back into cysts and are released in the environment through the faeces. The mechanisms and signals that convert the parasite from trophozoites to cysts are not yet known. Our study, for the first time, implicates heat shock protein 90 of the parasite in the conversion of trophozoites into cysts in the intestine of the infected human body. Hsp90 is famous for its ability to sense environmental changes and provide cues for stage-switch in related parasites. In addition to providing a glimpse into molecular mechanisms of stage inter-conversion, our results suggest potential new ways of treating this important human infection.
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Affiliation(s)
| | - Nainita Roy
- The Department of Biochemistry, Indian Institute of Sciences, Bangalore, India
| | - Shatakshi Ranade
- The Department of Biochemistry, Indian Institute of Sciences, Bangalore, India
| | - Utpal Tatu
- The Department of Biochemistry, Indian Institute of Sciences, Bangalore, India
- * E-mail:
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Sogame Y, Kojima K, Takeshita T, Kinoshita E, Matsuoka T. Identification of Differentially Expressed Water-insoluble Proteins in the Encystment Process of Colpoda cucullus
by Two-dimensional Electrophoresis and LC-MS/MS Analysis. J Eukaryot Microbiol 2013; 61:51-60. [DOI: 10.1111/jeu.12086] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 09/01/2013] [Accepted: 09/18/2013] [Indexed: 10/26/2022]
Affiliation(s)
- Yoichiro Sogame
- Department of Biological Science; Faculty of Science; Kochi University; Kochi 780-8520 Japan
| | - Katsuhiko Kojima
- Department of Microbiology and Immunology; Shinshu University School of Medicine; 3-1-1 Asahi Matsumoto Nagano 390-8621 Japan
| | - Toshikazu Takeshita
- Department of Microbiology and Immunology; Shinshu University School of Medicine; 3-1-1 Asahi Matsumoto Nagano 390-8621 Japan
| | - Eiji Kinoshita
- Department of Functional Molecular Science; Graduate School of Biomedical Sciences; Hiroshima University; Kasumi 1-2-3 Hiroshima 734-8553 Japan
| | - Tatsuomi Matsuoka
- Department of Biological Science; Faculty of Science; Kochi University; Kochi 780-8520 Japan
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Prouse MB, Campbell MM. The interaction between MYB proteins and their target DNA binding sites. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1819:67-77. [DOI: 10.1016/j.bbagrm.2011.10.010] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 10/17/2011] [Accepted: 10/18/2011] [Indexed: 02/02/2023]
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The transcriptional response to encystation stimuli in Giardia lamblia is restricted to a small set of genes. EUKARYOTIC CELL 2010; 9:1566-76. [PMID: 20693303 DOI: 10.1128/ec.00100-10] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The protozoan parasite Giardia lamblia undergoes stage differentiation in the small intestine of the host to an environmentally resistant and infectious cyst. Encystation involves the secretion of an extracellular matrix comprised of cyst wall proteins (CWPs) and a β(1-3)-GalNAc homopolymer. Upon the induction of encystation, genes coding for CWPs are switched on, and mRNAs coding for a Myb transcription factor and enzymes involved in cyst wall glycan synthesis are upregulated. Encystation in vitro is triggered by several protocols, which call for changes in bile concentrations or availability of lipids, and elevated pH. However, the conditions for induction are not standardized and we predicted significant protocol-specific side effects. This makes reliable identification of encystation factors difficult. Here, we exploited the possibility of inducing encystation with two different protocols, which we show to be equally effective, for a comparative mRNA profile analysis. The standard encystation protocol induced a bipartite transcriptional response with surprisingly minor involvement of stress genes. A comparative analysis revealed a core set of only 18 encystation genes and showed that a majority of genes was indeed upregulated as a side effect of inducing conditions. We also established a Myb binding sequence as a signature motif in encystation promoters, suggesting coordinated regulation of these factors.
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Meneses E, Cárdenas H, Zárate S, Brieba LG, Orozco E, López-Camarillo C, Azuara-Liceaga E. The R2R3 Myb protein family in Entamoeba histolytica. Gene 2010; 455:32-42. [DOI: 10.1016/j.gene.2010.02.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2009] [Revised: 02/04/2010] [Accepted: 02/05/2010] [Indexed: 11/16/2022]
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Bae SS, Kim J, Kim TS, Yong TS, Park SJ. Giardia lamblia: immunogenicity and intracellular distribution of GHSP-115, a member of the Giardia head-stalk family of proteins. Exp Parasitol 2009; 122:11-6. [PMID: 19545528 DOI: 10.1016/j.exppara.2009.01.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Revised: 12/16/2008] [Accepted: 01/06/2009] [Indexed: 11/24/2022]
Abstract
Giardia lamblia, a protozoan causing diarrheal outbreaks, is one of the main pathogens monitored in developed countries. Immunoscreening of G. lamblia expression library using the monoclonal antibodies (mAb) against G. lamblia, identified a subset of antigenic proteins in this protozoan, which are proteins belonging to GHSP (Giardia head-stalk protein), GHSP115, GHSP138, and GHSP180. In order to map the epitope region of GHSP115, the corresponding open reading frame was dissected into three parts and expressed as recombinant proteins with histidine tags. Western blot analysis of these recombinant proteins with mAbs reacting with GHSP115 indicated that one-third of the C-terminus of GHSP115 showed immunoreactivity with the mAb. Intracellular location of GHSP115 was examined both in trophozoites and encysting cells of G. lamblia by an immunofluorescence assay, indicating that location of GHSP115 varies during encystation. These results suggest that GHSP115 is an abundant and antigenic protein, which is differentially localized during life cycle of G. lamblia.
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Affiliation(s)
- Sung Su Bae
- Department of Environmental Medical Biology and Institute of Tropical Medicine, The Brain Korea 21 Project, Yonsei University College of Medicine, Seoul 120-752, South Korea
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Kim J, Bae SS, Sung MH, Lee KH, Park SJ. Comparative proteomic analysis of trophozoites versus cysts of Giardia lamblia. Parasitol Res 2008; 104:475-9. [PMID: 18853189 DOI: 10.1007/s00436-008-1223-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Accepted: 09/26/2008] [Indexed: 10/21/2022]
Abstract
The proteome of Giardia lamblia at its cyst stage was compared with that of trophozoites by using two-dimensional SDS-PAGE gel electrophoresis. Protein spots that increased in the extracts of cysts compared to trophozoites were identified by MALDI-TOF mass spectroscopy and categorized as cytoskeletal proteins, metabolic enzymes, a cell-cycle-specific kinase, stress resistance proteins, and a protein involved in translation. Expression patterns of five of the identified proteins were examined during encystation by real-time PCR. Expression of cwp1 (encoding cyst wall protein 1), a marker for encystation, was increased 11-fold. In contrast, tim (encoding triose-1-phosphate isomerase) was expressed constitutively during encystation, and its transcription level was therefore used as a mRNA loading control. Expression of three genes encoding beta-tubulin, vacuolar ATPase, and never-in-mitosis-A-related protein kinase did not vary significantly during encystation. Interestingly, genes encoding two heat shock proteins (Hsp70 and Hsp90) showed increased expression during encystation, suggesting that this differentiation process accompanies a cellular response to stress in G. lamblia.
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Affiliation(s)
- Juri Kim
- Department of Environmental Medical Biology and Institute of Tropical Medicine, Post Brain Korea 21 Program, Yonsei University College of Medicine, Seoul 120-752, South Korea
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Encystation of Giardia lamblia: a model for other parasites. Curr Opin Microbiol 2007; 10:554-9. [PMID: 17981075 DOI: 10.1016/j.mib.2007.09.011] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2007] [Revised: 09/20/2007] [Accepted: 09/20/2007] [Indexed: 01/24/2023]
Abstract
To colonize the human small intestine, Giardia lamblia monitors a dynamic environment. Trophozoites attach to enterocytes that mature and die. The parasites must 'decide' whether to re-attach or differentiate into cysts that survive in the environment and re-activate when ingested. Other intestinal parasites face similar challenges. Study of these parasites is limited because they do not encyst in vitro. Giardia trophozoites were persuaded to encyst in vitro by mimicking physiological stimuli. Cysts are dormant, yet 'spring-loaded for action' to excyst upon ingestion. Giardial encystation has been studied from morphological, cell biological, biochemical, and molecular viewpoints. Yet important gaps remain and the mechanisms that co-ordinate responses to external signals remain enigmatic.
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Yang HW, Kim J, Yong TS, Park SJ. In vivo determination of the gap2 gene promoter activity in Giardia lamblia. THE KOREAN JOURNAL OF PARASITOLOGY 2006; 44:21-6. [PMID: 16514278 PMCID: PMC2532645 DOI: 10.3347/kjp.2006.44.1.21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A shuttle vector for Escherichia coli and Giardia lamblia was modified to produce a reporter plasmid, which monitors the expression of prescribed gene in G. lamblia by measuring its luciferase activity. Promoter regions of the gap2 gene, one of the genes induced during encystation, were cloned into this plasmid, and the resultant constructs were then transfected into trophozoites of G. lamblia. Transgenic trophozoites containing one of the 3 gap2-luc reporters were induced to encystation, and characterized with respect to gap2 gene expression by measuring their luciferase activities. Giardia containing a gap2-luc fusion of 112-bp upstream region showed full induction of luciferase activity during encystation.
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Affiliation(s)
- Hye-Won Yang
- Department of Parasitology and Institute of Tropical Medicine, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, Korea
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15
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Lalle M, Salzano AM, Crescenzi M, Pozio E. The Giardia duodenalis 14-3-3 protein is post-translationally modified by phosphorylation and polyglycylation of the C-terminal tail. J Biol Chem 2005; 281:5137-48. [PMID: 16368691 DOI: 10.1074/jbc.m509673200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The flagellated protozoan Giardia duodenalis (syn. lamblia or intestinalis) has been chosen as a model parasite to further investigate the multifunctional 14-3-3s, a family of highly conserved eukaryotic proteins involved in many cellular processes, such as cell cycle, differentiation, apoptosis, and signal transduction pathways. We confirmed the presence of a single 14-3-3 homolog gene (g14-3-3) by an in silico screening of the complete genome of Giardia, and we demonstrated its constitutive transcription throughout the life stages of the parasite. We cloned and expressed the g14-3-3 in bacteria, and by protein-protein interaction assays we demonstrated that it is a functional 14-3-3. Using an anti-peptide antibody raised against a unique 18-amino acid sequence at the N terminus, we observed variations both in the intracellular localization and in the molecular size of the native g14-3-3 during the conversion of Giardia from trophozoites to the cyst stage. An affinity chromatography, based on the 14-3-3 binding to the polypeptide difopein, was set to purify the native g14-3-3. By matrix-assisted laser desorption ionization mass spectroscopy analysis, we showed that polyglycylation, an unusual post-translational modification described only for tubulin, occurred at the extreme C terminus of the native g14-3-3 on Glu246, Glu247, or both and that the Thr214, located in the loop between helices 8 and 9, is phosphorylated. We propose that the addition of the polyglycine chain can promote the binding of g14-3-3 to alternative ligands and that the differential rate of polyglycylation/deglycylation during the encystation process can act as a novel mechanism to regulate the intracellular localization of g14-3-3.
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MESH Headings
- 14-3-3 Proteins/chemistry
- 14-3-3 Proteins/metabolism
- Amino Acid Sequence
- Animals
- Apoptosis
- Blotting, Northern
- Blotting, Western
- Cell Cycle
- Cell Differentiation
- Chromatography, Affinity
- Chromatography, Liquid
- Cloning, Molecular
- Densitometry
- Dimerization
- Escherichia coli/metabolism
- Genetic Vectors
- Giardia/metabolism
- Mass Spectrometry
- Microscopy, Fluorescence
- Molecular Sequence Data
- Peptides/chemistry
- Phosphorylation
- Polymerase Chain Reaction
- Protein Binding
- Protein Interaction Mapping
- Protein Processing, Post-Translational
- Protein Structure, Tertiary
- Recombinant Proteins/chemistry
- Sequence Homology, Amino Acid
- Signal Transduction
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Tubulin/chemistry
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Affiliation(s)
- Marco Lalle
- Department of Infectious, Parasitic and Immunomediated Diseases and Department of Environment and Primary Prevention, Istituto Superiore di Sanità, 00161 Rome, Italy
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Abstract
Given that resistance to antiprotozoal drugs exists and is likely to increase and given that currently no reliable treatments exist for some of these infections, efforts to find new targets for chemotherapy must be continued. In the case of cyst-forming pathogenic protozoa, one such target might be encystment pathways and cyst-wall assembly. Information is increasing on protozoan encystment and, as it does, we can begin to answer the question of whether targeting it for chemotherapy is a viable drug strategy. Currently, there are significant efforts to understand encystment in Giardia and Entamoeba, and potential targets are being discovered as work on their encystment mechanisms progress. We know with certainty now that Giardia and Entamoeba cyst walls contain unique proteins and polysaccharides which differ from those of their hosts and thus make them potentially interesting targets for a variety of chemotherapeutic attacks. Although we lack detailed information about the other protozoan cyst formers, enough evidence exists for Giardia and Entamoeba that it seems prudent to screen them with some of the antifungal drugs, especially those that target mannoproteins, chitin synthesis, and beta (1, 3) glucan synthesis to ascertain if they target elements in these protozoan pathways that are similar to those found in fungi.
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Affiliation(s)
- Edward L Jarroll
- Department of Biology, Northeastern University, 106 Egan Bldg., 360 Huntington Avenue, Boston, MA 02115, USA.
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