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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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2
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Black A, Williams TD, Soubigou F, Joshua IM, Zhou H, Lamoliatte F, Rousseau A. The ribosome-associated chaperone Zuo1 controls translation upon TORC1 inhibition. EMBO J 2023; 42:e113240. [PMID: 37984430 PMCID: PMC10711665 DOI: 10.15252/embj.2022113240] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 10/23/2023] [Accepted: 10/26/2023] [Indexed: 11/22/2023] Open
Abstract
Protein requirements of eukaryotic cells are ensured by proteostasis, which is mediated by tight control of TORC1 activity. Upon TORC1 inhibition, protein degradation is increased and protein synthesis is reduced through inhibition of translation initiation to maintain cell viability. Here, we show that the ribosome-associated complex (RAC)/Ssb chaperone system, composed of the HSP70 chaperone Ssb and its HSP40 co-chaperone Zuo1, is required to maintain proteostasis and cell viability under TORC1 inhibition in Saccharomyces cerevisiae. In the absence of Zuo1, translation does not decrease in response to the loss of TORC1 activity. A functional interaction between Zuo1 and Ssb is required for proper translational control and proteostasis maintenance upon TORC1 inhibition. Furthermore, we have shown that the rapid degradation of eIF4G following TORC1 inhibition is mediated by autophagy and is prevented in zuo1Δ cells, contributing to decreased survival in these conditions. We found that autophagy is defective in zuo1Δ cells, which impedes eIF4G degradation upon TORC1 inhibition. Our findings identify an essential role for RAC/Ssb in regulating translation in response to changes in TORC1 signalling.
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Affiliation(s)
- Ailsa Black
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life SciencesUniversity of DundeeDundeeUK
| | - Thomas D Williams
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life SciencesUniversity of DundeeDundeeUK
| | - Flavie Soubigou
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life SciencesUniversity of DundeeDundeeUK
| | - Ifeoluwapo M Joshua
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life SciencesUniversity of DundeeDundeeUK
| | - Houjiang Zhou
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life SciencesUniversity of DundeeDundeeUK
| | - Frederic Lamoliatte
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life SciencesUniversity of DundeeDundeeUK
| | - Adrien Rousseau
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life SciencesUniversity of DundeeDundeeUK
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3
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Fumagalli S, Pende M. S6 kinase 1 at the central node of cell size and ageing. Front Cell Dev Biol 2022; 10:949196. [PMID: 36036012 PMCID: PMC9417411 DOI: 10.3389/fcell.2022.949196] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 07/07/2022] [Indexed: 11/17/2022] Open
Abstract
Genetic evidence in living organisms from yeast to plants and animals, including humans, unquestionably identifies the Target Of Rapamycin kinase (TOR or mTOR for mammalian/mechanistic) signal transduction pathway as a master regulator of growth through the control of cell size and cell number. Among the mTOR targets, the activation of p70 S6 kinase 1 (S6K1) is exquisitely sensitive to nutrient availability and rapamycin inhibition. Of note, in vivo analysis of mutant flies and mice reveals that S6K1 predominantly regulates cell size versus cell proliferation. Here we review the putative mechanisms of S6K1 action on cell size by considering the main functional categories of S6K1 targets: substrates involved in nucleic acid and protein synthesis, fat mass accumulation, retrograde control of insulin action, senescence program and cytoskeleton organization. We discuss how S6K1 may be involved in the observed interconnection between cell size, regenerative and ageing responses.
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Affiliation(s)
| | - Mario Pende
- *Correspondence: Stefano Fumagalli, ; Mario Pende,
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4
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Inhibitor of DNA-Binding Protein 4 Suppresses Cancer Metastasis through the Regulation of Epithelial Mesenchymal Transition in Lung Adenocarcinoma. Cancers (Basel) 2019; 11:cancers11122021. [PMID: 31847356 PMCID: PMC6966672 DOI: 10.3390/cancers11122021] [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] [Received: 09/29/2019] [Revised: 12/10/2019] [Accepted: 12/12/2019] [Indexed: 02/06/2023] Open
Abstract
Metastasis is a predominant cause of cancer death and the major challenge in treating lung adenocarcinoma (LADC). Therefore, exploring new metastasis-related genes and their action mechanisms may provide new insights for developing a new combative approach to treat lung cancer. Previously, our research team discovered that the expression of the inhibitor of DNA binding 4 (Id4) was inversely related to cell invasiveness in LADC cells by cDNA microarray screening. However, the functional role of Id4 and its mechanism of action in lung cancer metastasis remain unclear. In this study, we report that the expression of Id4 could attenuate cell migration and invasion in vitro and cancer metastasis in vivo. Detailed analyses indicated that Id4 could promote E-cadherin expression through the binding of Slug, cause the occurrence of mesenchymal-epithelial transition (MET), and inhibit cancer metastasis. Moreover, the examination of the gene expression database (GSE31210) also revealed that high-level expression of Id4/E-cadherin and low-level expression of Slug were associated with a better clinical outcome in LADC patients. In summary, Id4 may act as a metastatic suppressor, which could not only be used as an independent predictor but also serve as a potential therapeutic for LADC treatment.
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5
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Barilari M, Bonfils G, Treins C, Koka V, De Villeneuve D, Fabrega S, Pende M. ZRF1 is a novel S6 kinase substrate that drives the senescence programme. EMBO J 2017; 36:736-750. [PMID: 28242756 PMCID: PMC5350561 DOI: 10.15252/embj.201694966] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 01/20/2017] [Accepted: 01/23/2017] [Indexed: 11/26/2022] Open
Abstract
The inactivation of S6 kinases mimics several aspects of caloric restriction, including small body size, increased insulin sensitivity and longevity. However, the impact of S6 kinase activity on cellular senescence remains to be established. Here, we show that the constitutive activation of mammalian target of rapamycin complex 1 (mTORC1) by tuberous sclerosis complex (TSC) mutations induces a premature senescence programme in fibroblasts that relies on S6 kinases. To determine novel molecular targets linking S6 kinase activation to the control of senescence, we set up a chemical genetic screen, leading to the identification of the nuclear epigenetic factor ZRF1 (also known as DNAJC2, MIDA1, Mpp11). S6 kinases phosphorylate ZRF1 on Ser47 in cultured cells and in mammalian tissues in vivo. Knock‐down of ZRF1 or expression of a phosphorylation mutant is sufficient to blunt the S6 kinase‐dependent senescence programme. This is traced by a sharp alteration in p16 levels, the cell cycle inhibitor and a master regulator of senescence. Our findings reveal a mechanism by which nutrient sensing pathways impact on cell senescence through the activation of mTORC1‐S6 kinases and the phosphorylation of ZRF1.
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Affiliation(s)
- Manuela Barilari
- Institut Necker-Enfants Malades, Paris, France.,Inserm, U1151, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Gregory Bonfils
- Institut Necker-Enfants Malades, Paris, France.,Inserm, U1151, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Caroline Treins
- Institut Necker-Enfants Malades, Paris, France.,Inserm, U1151, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Vonda Koka
- Institut Necker-Enfants Malades, Paris, France.,Inserm, U1151, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Delphine De Villeneuve
- Institut Necker-Enfants Malades, Paris, France.,Inserm, U1151, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Sylvie Fabrega
- Plateforme Vecteurs Viraux et Transfert de Gènes, IFR94, Hôpital Necker Enfants-Malades, Paris, France
| | - Mario Pende
- Institut Necker-Enfants Malades, Paris, France .,Inserm, U1151, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
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6
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Abstract
Inhibitors of DNA binding and cell differentiation (Id) proteins are members of the large family of the helix-loop-helix (HLH) transcription factors, but they lack any DNA-binding motif. During development, the Id proteins play a key role in the regulation of cell-cycle progression and cell differentiation by modulating different cell-cycle regulators both by direct and indirect mechanisms. Several Id-protein interacting partners have been identified thus far, which belong to structurally and functionally unrelated families, including, among others, the class I and II bHLH transcription factors, the retinoblastoma protein and related pocket proteins, the paired-box transcription factors, and the S5a subunit of the 26 S proteasome. Although the HLH domain of the Id proteins is involved in most of their protein-protein interaction events, additional motifs located in their N-terminal and C-terminal regions are required for the recognition of diverse protein partners. The ability of the Id proteins to interact with structurally different proteins is likely to arise from their conformational flexibility: indeed, these proteins contain intrinsically disordered regions that, in the case of the HLH region, undergo folding upon self- or heteroassociation. Besides their crucial role for cell-fate determination and cell-cycle progression during development, other important cellular events have been related to the Id-protein expression in a number of pathologies. Dysregulated Id-protein expression has been associated with tumor growth, vascularization, invasiveness, metastasis, chemoresistance and stemness, as well as with various developmental defects and diseases. Herein we provide an overview on the structural properties, mode of action, biological function and therapeutic potential of these regulatory proteins.
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Affiliation(s)
- Cornelia Roschger
- Department of Molecular Biology, University of Salzburg, Billrothstrasse 11, Salzburg, 5020, Austria
| | - Chiara Cabrele
- Department of Molecular Biology, University of Salzburg, Billrothstrasse 11, Salzburg, 5020, Austria.
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7
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Roschger C, Cabrele C. The Id-protein family in developmental and cancer-associated pathways. Cell Commun Signal 2017; 15:7. [PMID: 28122577 PMCID: PMC5267474 DOI: 10.1186/s12964-016-0161-y] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 12/29/2016] [Indexed: 01/15/2023] Open
Abstract
Inhibitors of DNA binding and cell differentiation (Id) proteins are members of the large family of the helix-loop-helix (HLH) transcription factors, but they lack any DNA-binding motif. During development, the Id proteins play a key role in the regulation of cell-cycle progression and cell differentiation by modulating different cell-cycle regulators both by direct and indirect mechanisms. Several Id-protein interacting partners have been identified thus far, which belong to structurally and functionally unrelated families, including, among others, the class I and II bHLH transcription factors, the retinoblastoma protein and related pocket proteins, the paired-box transcription factors, and the S5a subunit of the 26 S proteasome. Although the HLH domain of the Id proteins is involved in most of their protein-protein interaction events, additional motifs located in their N-terminal and C-terminal regions are required for the recognition of diverse protein partners. The ability of the Id proteins to interact with structurally different proteins is likely to arise from their conformational flexibility: indeed, these proteins contain intrinsically disordered regions that, in the case of the HLH region, undergo folding upon self- or heteroassociation. Besides their crucial role for cell-fate determination and cell-cycle progression during development, other important cellular events have been related to the Id-protein expression in a number of pathologies. Dysregulated Id-protein expression has been associated with tumor growth, vascularization, invasiveness, metastasis, chemoresistance and stemness, as well as with various developmental defects and diseases. Herein we provide an overview on the structural properties, mode of action, biological function and therapeutic potential of these regulatory proteins.
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Affiliation(s)
- Cornelia Roschger
- Department of Molecular Biology, University of Salzburg, Billrothstrasse 11, Salzburg, 5020, Austria
| | - Chiara Cabrele
- Department of Molecular Biology, University of Salzburg, Billrothstrasse 11, Salzburg, 5020, Austria.
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8
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Aloia L, Gutierrez A, Caballero JM, Di Croce L. Direct interaction between Id1 and Zrf1 controls neural differentiation of embryonic stem cells. EMBO Rep 2014; 16:63-70. [PMID: 25361733 DOI: 10.15252/embr.201439560] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Id proteins are dominant-negative regulators within the HLH family of proteins. In embryonic stem cells (ESCs), Id1 and Id3 maintain the pluripotent state by preventing neural differentiation. The Id1-interacting protein Zrf1 plays a crucial role as a chromatin-bound factor in specification of the neural fate from ESCs. Here, we show that Id1 blocks Zrf1 recruitment to chromatin, thus preventing the activation of neural genes in ESCs. Upon differentiation, Id1 expression decreases thus inducing Zrf1 binding to neural genes. Importantly, depletion of Zrf1 rescues the expression of Polycomb targets involved in neural specification which are up-regulated in Id1 knock-out ESCs. We therefore identified Zrf1 as transcriptional regulator of neural fate downstream of Id1 in ESCs.
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Affiliation(s)
- Luigi Aloia
- Centre for Genomic Regulation (CRG), Barcelona, Spain Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Arantxa Gutierrez
- Centre for Genomic Regulation (CRG), Barcelona, Spain Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | | | - Luciano Di Croce
- Centre for Genomic Regulation (CRG), Barcelona, Spain Universitat Pompeu Fabra (UPF), Barcelona, Spain Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
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9
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Chen DH, Huang Y, Liu C, Ruan Y, Shen WH. Functional conservation and divergence of J-domain-containing ZUO1/ZRF orthologs throughout evolution. PLANTA 2014; 239:1159-1173. [PMID: 24659052 DOI: 10.1007/s00425-014-2058-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 03/05/2014] [Indexed: 06/03/2023]
Abstract
Heat shock protein 40s (Hsp40s), also known as J-proteins, are conserved in prokaryotes and eukaryotes. The Zuotin/Zuotin-related factor (ZUO1/ZRF) family belongs to a novel Hsp40 clade exclusively found in eukaryotes. Zuotin/Zuotin-related factor proteins are characterized by a large N terminal ZUO1 domain originally identified in the yeast ZUO1 protein. The ZUO1 domain is characterized by a highly conserved J-domain, together with an atypical UBD domain first identified in the human ZRF1 protein. Furthermore, ZUO1/ZRF protein families in animals and plants harbor a pair of C terminal SANT domains, suggesting the divergence of their functions with those in fungi. Zuotin/Zuotin-related factor proteins retain the ancestral function as an Hsp70co-chaperone implicated in protein folding and renaturation after stress; these proteins also perform diverse neofunctions in the cytoplasm and transcriptional and/or epigenetic regulatory functions in the nucleus. Therefore, these proteins are involved in translational fidelity control, ribosomal biogenesis, asymmetric cell division, cell cycle, apoptosis, differentiation, and tumorigenesis. The results of sequence and domain organization analysis of proteins from diverse organisms provided valuable insights into the evolutionary conservation and diversity of ZUO1/ZRF protein family. Further, phylogenetic analysis provides a platform for future functional investigation on the ZUO1/ZRF protein family, particularly in higher plants.
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10
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Aloia L, Di Stefano B, Sessa A, Morey L, Santanach A, Gutierrez A, Cozzuto L, Benitah SA, Graf T, Broccoli V, Di Croce L. Zrf1 is required to establish and maintain neural progenitor identity. Genes Dev 2014; 28:182-97. [PMID: 24449271 PMCID: PMC3909791 DOI: 10.1101/gad.228510.113] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The molecular mechanisms underlying specification from embryonic stem cells (ESCs) and maintenance of neural progenitor cells (NPCs) are largely unknown. Recently, we reported that the Zuotin-related factor 1 (Zrf1) is necessary for chromatin displacement of the Polycomb-repressive complex 1 (PRC1). We found that Zrf1 is required for NPC specification from ESCs and that it promotes the expression of NPC markers, including the key regulator Pax6. Moreover, Zrf1 is essential to establish and maintain Wnt ligand expression levels, which are necessary for NPC self-renewal. Reactivation of proper Wnt signaling in Zrf1-depleted NPCs restores Pax6 expression and the self-renewal capacity. ESC-derived NPCs in vitro resemble most of the characteristics of the self-renewing NPCs located in the developing embryonic cortex, which are termed radial glial cells (RGCs). Depletion of Zrf1 in vivo impairs the expression of key self-renewal regulators and Wnt ligand genes in RGCs. Thus, we demonstrate that Zrf1 plays an essential role in NPC generation and maintenance.
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Affiliation(s)
- Luigi Aloia
- Centre for Genomic Regulation (CRG), Universitat Pompeu Fabra, 08003 Barcelona, Spain
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11
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ZRF1 controls the retinoic acid pathway and regulates leukemogenic potential in acute myeloid leukemia. Oncogene 2013; 33:5501-10. [DOI: 10.1038/onc.2013.501] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 10/15/2013] [Accepted: 10/18/2013] [Indexed: 11/09/2022]
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12
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Cekanova M, Uddin MJ, Legendre AM, Galyon G, Bartges JW, Callens A, Martin-Jimenez T, Marnett LJ. Single-dose safety and pharmacokinetic evaluation of fluorocoxib A: pilot study of novel cyclooxygenase-2-targeted optical imaging agent in a canine model. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:116002. [PMID: 23117797 PMCID: PMC3484194 DOI: 10.1117/1.jbo.17.11.116002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
We evaluated preclinical single-dose safety, pharmacokinetic properties, and specific uptake of the new optical imaging agent fluorocoxib A in dogs. Fluorocoxib A, N-[(5-carboxy-X-rhodaminyl)but-4-yl]-2-[1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indol-3-yl]acetamide, selectively binds and inhibits the cyclooxygenase-2 (COX-2) enzyme, which is overexpressed in many cancers. Safety pilot studies were performed in research dogs following intravenous (i.v.) administration of 0.1 and 1 mg/kg fluorocoxib A. Blood and urine samples collected three days after administration of each dose of fluorocoxib A revealed no evidence of toxicity, and no clinically relevant adverse events were noted on physical examination of exposed dogs over that time period. Pharmacokinetic parameters were assessed in additional research dogs from plasma collected at several time points after i.v. administration of fluorocoxib A using high-performance liquid chromatography analysis. The pharmacokinetic studies using 1 mg/kg showed a peak of fluorocoxib A (92±28 ng/ml) in plasma collected at 0.5 h. Tumor specific uptake of fluorocoxib A was demonstrated using a dog diagnosed with colorectal cancer expressing COX-2. Our data support the safe single-dose administration and in vivo efficacy of fluorocoxib A, suggesting a high potential for successful translation to clinical use as an imaging agent for improved tumor detection in humans.
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Affiliation(s)
- Maria Cekanova
- The University of Tennessee, College of Veterinary Medicine, Department of Small Animal Clinical Sciences, Knoxville, Tennessee 37996, USA.
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13
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Abstract
The reactivation of the INK4-ARF locus, which is epigenetically repressed by Polycomb proteins in healthy cells, is a hallmark of senescence. One mechanism of reactivating Polycomb-silenced genes is mediated by the epigenetic factor ZRF1, which associates with ubiquitinated histone H2A. We show that cells undergoing senescence following oncogenic Ras expression have increased ZRF1 levels, and that this binds to the p15INK4b, ARF and p16INK4a promoters. Furthermore, ZRF1 depletion in oncogenic Ras-expressing cells restores proliferation by preventing Arf and p16Ink4a expression, consequently bypassing senescence. Thus, ZRF1 regulates the INK4-ARF locus during cellular proliferation and senescence, and alterations in ZRF1 may contribute to tumorigenesis.
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14
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Feller A, Machemer K, Braun EL, Grotewold E. Evolutionary and comparative analysis of MYB and bHLH plant transcription factors. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2011; 66:94-116. [PMID: 21443626 DOI: 10.1111/j.1365-313x.2010.04459.x] [Citation(s) in RCA: 701] [Impact Index Per Article: 53.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The expansion of gene families encoding regulatory proteins is typically associated with the increase in complexity characteristic of multi-cellular organisms. The MYB and basic helix-loop-helix (bHLH) families provide excellent examples of how gene duplication and divergence within particular groups of transcription factors are associated with, if not driven by, the morphological and metabolic diversity that characterize the higher plants. These gene families expanded dramatically in higher plants; for example, there are approximately 339 and 162 MYB and bHLH genes, respectively, in Arabidopsis, and approximately 230 and 111, respectively, in rice. In contrast, the Chlamydomonas genome has only 38 MYB genes and eight bHLH genes. In this review, we compare the MYB and bHLH gene families from structural, evolutionary and functional perspectives. The knowledge acquired on the role of many of these factors in Arabidopsis provides an excellent reference to explore sequence-function relationships in crops and other plants. The physical interaction and regulatory synergy between particular sub-classes of MYB and bHLH factors is perhaps one of the best examples of combinatorial plant gene regulation. However, members of the MYB and bHLH families also interact with a number of other regulatory proteins, forming complexes that either activate or repress the expression of sets of target genes that are increasingly being identified through a diversity of high-throughput genomic approaches. The next few years are likely to witness an increasing understanding of the extent to which conserved transcription factors participate at similar positions in gene regulatory networks across plant species.
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Affiliation(s)
- Antje Feller
- Plant Biotechnology Center and Department of Molecular Genetics, Ohio State University, Columbus, OH 43210, USA
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15
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Abstract
Mammalian ribosome-associated complex (mRAC), consisting of the J-domain protein MPP11 and the atypical Hsp70 homolog (70-homolog) Hsp70L1, can partly complement the function of RAC, which is the homologous complex from Saccharomyces cerevisiae. RAC is the J-domain partner exclusively of the 70-homolog Ssb, which directly and independently of RAC binds to the ribosome. We here show that growth defects due to mRAC depletion in HeLa cells resemble those of yeast strains lacking RAC. Functional conservation, however, did not extend to the 70-homolog partner of mRAC. None of the major human 70-homologs was able to complement the growth defects of yeast strains lacking Ssb or was bound to ribosomes in an Ssb-like manner. Instead, our data suggest that mRAC was a specific partner of human Hsp70 but not of its close homolog Hsc70. On a mechanistic level, ATP binding, but not ATP hydrolysis, by Hsp70L1 affected mRAC's function as a J-domain partner of Hsp70. The combined data indicate that, while functionally conserved, yeast and mammalian cells have evolved distinct solutions to ensure that Hsp70-type chaperones can efficiently assist the biogenesis of newly synthesized polypeptide chains.
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16
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Pappas V, Miller SM. Functional analysis of the Volvox carteri asymmetric division protein GlsA. Mech Dev 2009; 126:842-51. [PMID: 19646527 DOI: 10.1016/j.mod.2009.07.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2008] [Revised: 07/17/2009] [Accepted: 07/23/2009] [Indexed: 12/19/2022]
Abstract
The Zuotin-family J protein chaperone GlsA is essential for the asymmetric divisions that establish germ and somatic cell initials during embryogenesis in the green alga Volvox carteri, but it is not known on what cellular process GlsA acts to carry out this function. Most GlsA protein is nuclear, and GlsA possesses two SANT domains, suggesting that GlsA may function as a transcriptional regulator. On the other hand, close homologs from yeast and mice are ribosome-associated factors that regulate translation fidelity, implying GlsA might also regulate translation. Here we set out to gain additional evidence regarding the function of GlsA, specifically with respect to its possible involvement in transcription and translation. We found that like zuotin mutants, glsA mutants are ultrasensitive to both cold and to the ribosome-binding aminoglycoside antibiotic paromomycin, so some fraction of GlsA is likely to be ribosome associated. We also found that GlsA co-immunoprecipitates with histones and that this interaction is dependent on the presence of intact SANT domains. Through rescue experiments using transgenes that encode GlsA variants, we determined that the growth and asymmetric division defects of the glsA mutant are separable-a GlsA variant that rescued the growth defects did not completely rescue the asymmetric division phenotype. Considered in total, our results suggest that GlsA acts both at the level of translation and transcription, but the function that is essential for tolerance to paromomycin and cold is not sufficient for asymmetric cell division.
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Affiliation(s)
- Valeria Pappas
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD 21250, USA
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17
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Rajan VBV, D'Silva P. Arabidopsis thaliana J-class heat shock proteins: cellular stress sensors. Funct Integr Genomics 2009; 9:433-46. [PMID: 19633874 DOI: 10.1007/s10142-009-0132-0] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2009] [Revised: 07/06/2009] [Accepted: 07/06/2009] [Indexed: 12/22/2022]
Abstract
Plants are sessile organisms that have evolved a variety of mechanisms to maintain their cellular homeostasis under stressful environmental conditions. Survival of plants under abiotic stress conditions requires specialized group of heat shock protein machinery, belonging to Hsp70:J-protein family. These heat shock proteins are most ubiquitous types of chaperone machineries involved in diverse cellular processes including protein folding, translocation across cell membranes, and protein degradation. They play a crucial role in maintaining the protein homeostasis by reestablishing functional native conformations under environmental stress conditions, thus providing protection to the cell. J-proteins are co-chaperones of Hsp70 machine, which play a critical role by stimulating Hsp70s ATPase activity, thereby stabilizing its interaction with client proteins. Using genome-wide analysis of Arabidopsis thaliana, here we have outlined identification and systematic classification of J-protein co-chaperones which are key regulators of Hsp70s function. In comparison with Saccharomyces cerevisiae model system, a comprehensive domain structural organization, cellular localization, and functional diversity of A. thaliana J-proteins have also been summarized.
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18
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Chen L, Qiu J, Yang C, Yang X, Chen X, Jiang J, Luo X. Identification of a novel estrogen receptor β1 binding partner, inhibitor of differentiation-1, and role of ERβ1 in human breast cancer cells. Cancer Lett 2009; 278:210-219. [DOI: 10.1016/j.canlet.2009.01.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Revised: 12/26/2008] [Accepted: 01/06/2009] [Indexed: 02/07/2023]
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19
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Greiner J, Bullinger L, Guinn BA, Döhner H, Schmitt M. Leukemia-associated antigens are critical for the proliferation of acute myeloid leukemia cells. Clin Cancer Res 2008; 14:7161-6. [PMID: 19010831 DOI: 10.1158/1078-0432.ccr-08-1102] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Acute myeloid leukemia (AML) is the most common acute leukemia in adults. With intensive induction therapy, most patients younger than 60 years achieve complete remission. However, even if these younger patients were treated intensively, more than 50% will relapse. Clinical results of patients older than 60 years are more unfavorable. Therefore, in all patients with AML, the overall survival is still low. In the past decade, several leukemia-associated antigens (LAA) have been identified in patients with acute myeloid leukemia. BAGE, BCL-2, OFA-iLRP, FLT3-ITD, G250, hTERT, PRAME, proteinase 3, RHAMM, survivin, and WT-1 are all LAAs that have been shown to induce CD8+ T-cell recognition and for some antigens also humoral immune responses. Interestingly, most of these LAAs are linked to cell cycle or proliferation. This article discusses the balance between LAA-driven leukemia cell expansion and the elimination of these cells through attacks on LAAs by the immune system. Current knowledge of the function and CD8+ T-cell recognition of LAAs is reviewed and an outlook is given on how to improve T-cell responses to LAAs in acute myeloid leukemia cells.
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Affiliation(s)
- Jochen Greiner
- Department of Internal Medicine III, University of Ulm, Ulm, Germany.
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20
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Abstract
Asymmetric cell division and apoptosis (programmed cell death) are two fundamental processes that are important for the development and function of multicellular organisms. We have found that the processes of asymmetric cell division and apoptosis can be functionally linked. Specifically, we show that asymmetric cell division in the nematode Caenorhabditis elegans is mediated by a pathway involving three genes, dnj-11 MIDA1, ces-2 HLF, and ces-1 Snail, that directly control the enzymatic machinery responsible for apoptosis. Interestingly, the MIDA1-like protein GlsA of the alga Volvox carteri, as well as the Snail-related proteins Snail, Escargot, and Worniu of Drosophila melanogaster, have previously been implicated in asymmetric cell division. Therefore, C. elegans dnj-11 MIDA1, ces-2 HLF, and ces-1 Snail may be components of a pathway involved in asymmetric cell division that is conserved throughout the plant and animal kingdoms. Furthermore, based on our results, we propose that this pathway directly controls the apoptotic fate in C. elegans, and possibly other animals as well. Asymmetric cell division and apoptosis (programmed cell death) are two fundamental processes that are important for the development and function of multicellular organisms. Asymmetric cell division creates daughter cells of different fates, and this is critical for the generation of cellular diversity. Apoptosis eliminates superfluous cells from the organism, which is critical for cellular homeostasis. We found that the processes of asymmetric cell division and apoptosis can be functionally linked. Specifically, we show that asymmetric cell division in the nematode Caenorhabditis elegans is mediated by a pathway involving three genes, dnj-11 MIDA1, ces-2 HLF, and ces-1 Snail, that directly control the enzymatic machinery responsible for apoptosis. Interestingly, the role of this pathway in asymmetric cell division and the control of apoptosis might be evolutionarily conserved. Furthermore, it might have an unexpected role in stem cell biology: the process of asymmetric cell division plays an essential role in the ability of stem cells to self-renew, and the mammalian counterparts of two components of the dnj-11 MIDA1, ces-2 HLF, ces-1 Snail pathway have recently been implicated in stem cell function. For this reason, we speculate that a dnj-11 MIDA1, ces-2 HLF, ces-1 Snail–like pathway might function in stem cells to coordinate self-renewal and apoptosis and, hence, the number of stem cells. A pathway involved in asymmetric cell division in the nematode Caenorhabditis elegans, the dnj-11 MIDA1, ces-2 HLF, ces-1 Snail pathway, directly controls the enzymatic machinery responsible for apoptosis.
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Affiliation(s)
- Julia Hatzold
- Department of Genetics, Norris Cotton Cancer Center, Dartmouth Medical School, Hanover, New Hampshire, United States of America
- Max Planck Institute of Neurobiology, Planegg-Martinsried, Germany
| | - Barbara Conradt
- Department of Genetics, Norris Cotton Cancer Center, Dartmouth Medical School, Hanover, New Hampshire, United States of America
- * To whom correspondence should be addressed. E-mail:
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Vasudevaraju P, Bharathi, Garruto R, Sambamurti K, Rao K. Role of DNA dynamics in Alzheimer's disease. ACTA ACUST UNITED AC 2008; 58:136-48. [DOI: 10.1016/j.brainresrev.2008.01.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2007] [Revised: 01/14/2008] [Accepted: 01/15/2008] [Indexed: 10/22/2022]
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22
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Wang C, Chen X, Wang Y, Gong J, Hu G. C/EBPalphap30 plays transcriptional regulatory roles distinct from C/EBPalphap42. Cell Res 2007; 17:374-83. [PMID: 17242690 DOI: 10.1038/sj.cr.7310121] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
CCAAT/enhancer binding protein alpha (C/EBPalpha) is a transcriptional regulatory factor that inhibits cell proliferation, and alternative translational initiation produces two polypeptides, C/EBPalphap30 and C/EBPalphap42. By expression profiling, it was revealed that C/EBPalphap30 specifically inhibited a unique set of genes, including MPP11, p84N5 and SMYD2, which were not affected by C/EBPalphap42 in both QSG-7701 hepatocyte cell line and QGY-7703 hepatoma cells. Semi-quantitative RT-PCR analysis independently confirmed these results. Chromatin immunoprecipitation assay showed that C/EBPalphap30 bound to the promoters of these genes more strongly than C/EBPalphap42. In clinical hepatoma samples in which C/EBPalpha was downregulated, all three genes specifically inhibited by C/EBPalphap30 were upregulated. However, repression of MPP11, p84N5 and SMYD2 genes might not be directly involved in C/EBPalphap30-mediated growth inhibition. Our data suggest that C/EBPalphap30 regulates a unique set of target genes and is more than a dominant-negative regulator of C/EBPalphap42.
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Affiliation(s)
- Chunxi Wang
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai 200031, China
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23
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Ikematsu K, Tsuda R, Tsuruya S, Kubo SI, Nakasono I. Toluene inhalation induced changes of gene expression in rat brain: Fluorescence differential display PCR analysis. Leg Med (Tokyo) 2007; 9:265-9. [PMID: 17584516 DOI: 10.1016/j.legalmed.2007.03.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2006] [Revised: 02/26/2007] [Accepted: 03/11/2007] [Indexed: 10/23/2022]
Abstract
Toluene, an abused substance in Japan, is well known as a neurotoxic chemical and has been shown to have neurobehavioral and electrophysiological effects. We used a fluorescence differential display PCR technique to analyze the genes expressed in the brain by toluene inhalation. We found 20 genes that were differentially expressed by toluene exposure. We confirmed by re-amplified PCR, nucleotide sequence and quantitative real-time PCR that of the 20 cDNAs, only 10 showed reproducible expression patterns by toluene inhalation. Of these genes, four had high homology with known genes (MIDA1, PEBP2 beta, phosphatidylserine synthase 2 and SKAP55) and six fragments were new sequence tags of unknown genes. This result may contribute to reveal the patho-physiological effects of toluene inhalation on rat brain.
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Affiliation(s)
- Kazuya Ikematsu
- Department of Forensic Pathology and Science, Unit of Social Medicine, Course of Medical and Dental Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki City, Nagasaki 852-8523, Japan.
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24
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Nishiyama K, Takaji K, Uchijima Y, Kurihara Y, Asano T, Yoshimura M, Ogawa H, Kurihara H. Protein kinase A-regulated nucleocytoplasmic shuttling of Id1 during angiogenesis. J Biol Chem 2007; 282:17200-9. [PMID: 17412691 DOI: 10.1074/jbc.m611609200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Id1, an inhibitory partner of basic-helix-loop-helix transcriptional factors, has recently been recognized as a potent contributor to angiogenesis. However, the molecular mechanism underlying its role in angiogenesis remains essentially unknown. Herein we demonstrate the subcellular localization of Id1 to be altered depending on the cellular context of vascular endothelial cells. Id1 was localized in the nuclei of human umbilical vein endothelial cells (HUVECs) cultured on uncoated plates, whereas it was translocated to the cytoplasm in HUVECs on Matrigel along with the formation of capillary-like structures. Treatment with the nuclear export inhibitor leptomycin B and mutagenesis analysis using green fluorescent protein-fused Id1 revealed CRM1/exportin-dependent nuclear export of Id1 in HUVECs on Matrigel. This nuclear export of Id1 was inhibited by protein kinase A (PKA) activation by dibutyryl cyclic AMP and forskolin but was promoted by PKA inactivation by H-89 and MDL-12,330A. Mutagenesis analysis of Id1 showed the phosphorylation of Ser-5 to possibly mediate the effect of PKA. These results suggest the function of Id1 as a transcriptional factor to be controlled by nucleocytoplasmic shuttling during angiogenesis and that PKA might be involved in this process. This may serve as a novel mechanism regulating angiogenesis and as a possible target for therapeutic vascular regeneration.
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Affiliation(s)
- Koichi Nishiyama
- Department of Physiological Chemistry and Metabolism, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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25
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Mark EB, Jonsson M, Asp J, Wennberg AM, Mölne L, Lindahl A. Expression of genes involved in the regulation of p16 in psoriatic involved skin. Arch Dermatol Res 2006; 297:459-67. [PMID: 16552541 DOI: 10.1007/s00403-006-0649-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2005] [Revised: 10/12/2005] [Accepted: 02/13/2006] [Indexed: 01/03/2023]
Abstract
It has been suggested that the up-regulation of the tumour suppressor p16 gene and induction of senescence protect the phenotype of psoriatic involved skin from malignant transformation. On the other hand, Id1, which is inversely correlated with p16 has been shown to be up-regulated in psoriatic involved skin. To test the hypothesis that there may be an altered regulation of p16 in psoriatic involved skin, we have measured genes involved in the Igf-1 receptor signalling through the Ras/MAPK cascade. Igf-1R, IGFBP3, hRas, Ets2, JunB, Egr-1, Id1, MIDA1 and p16 gene expressions were measured using quantitative real-time PCR in total RNA isolated from punch biopsies from psoriatic involved (n = 9) and uninvolved skin (n = 9) and from cutaneous squamous cell cancer (SCC) involved (n = 8) and uninvolved skin (n = 8). The IGFBP3, hRas, JunB, Egr-1, Id1 and MIDA1 genes were up-regulated in psoriatic involved skin compared with uninvolved skin. The p16, JunB and MIDA1 genes were up-regulated in SCC involved skin compared with uninvolved skin. Our results indicate that there may be a balance between the proliferation and induction of senescence in psoriasis. This balance may vary and the psoriatic involved skin represented in this study appears to be in a proliferative state rather than senescence. Furthermore, we suggest that the noted up-regulation of JunB, which has been shown to up-regulate p16, in combination with the previously reported elevation of p16 expression in psoriatic involved skin, may indicate activation of a pathway by which JunB may protect the psoriatic plaque by inducing p16 in an event of malignant stress.
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Affiliation(s)
- Elisabeth Björntorp Mark
- Department of Dermatology, Sahlgrenska University Hospital, Göteborg University, 413 45, Göteborg, Sweden.
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26
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Ding B, Liu CJ, Huang Y, Yu J, Kong W, Lengyel P. p204 protein overcomes the inhibition of the differentiation of P19 murine embryonal carcinoma cells to beating cardiac myocytes by Id proteins. J Biol Chem 2006; 281:14893-906. [PMID: 16556596 DOI: 10.1074/jbc.m511748200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We reported in the accompanying article (Ding, B., Liu, C., Huang, Y., Hickey, R. P., Yu, J., Kong, W., and Lengyel, P. (2006) J. Biol. Chem. 281, 14882-14892) that (i) the p204 protein is required for the differentiation of murine P19 embryonal carcinoma stem cells to beating cardiac myocytes, and (ii) the expression of p204 in the differentiating P19 cells is synergistically transactivated by the cardiac transcription factors Gata4, Nkx2.5, and Tbx5. Here we report that endogenous or ectopic inhibitor of differentiation (Id) proteins inhibited the differentiation of P19 cells to myocytes. This was in consequence of the binding of Id1, Id2, or Id3 protein to the Gata4 and Nkx2.5 proteins and the resulting inhibitions (i) of the binding of these transcription factors to each other and to DNA and (ii) of their synergistic transactivation of the expression of various genes, including atrial natriuretic factor and Ifi204 (encoding p204). p204 overcame this inhibition by Id proteins in consequence of (i) binding and sequestering Id proteins, (ii) accelerating their ubiquitination and degradation by proteasomes, and (iii) decreasing the level of Id proteins in the nucleus by increasing their translocation from the nucleus to the cytoplasm. Points (ii) and (iii) depended on the presence of the nuclear export signal in p204. In the course of the differentiation, Gata4, Nkx2.5, and p204 were components of a positive feedback loop. This loop arose in consequence of it that p204 overcame the inhibition of the synergistic activity of Gata4 and Nkx2.5 by the Id proteins.
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Affiliation(s)
- Bo Ding
- Department of Molecular Biophysics and Biochemistry, Yale University, 333 Cedar Street, New Haven, CT 06520-8024, USA
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27
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Cheng Q, Pappas V, Hallmann A, Miller SM. Hsp70A and GlsA interact as partner chaperones to regulate asymmetric division in Volvox. Dev Biol 2005; 286:537-48. [PMID: 16168403 DOI: 10.1016/j.ydbio.2005.08.028] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2005] [Revised: 08/15/2005] [Accepted: 08/16/2005] [Indexed: 11/26/2022]
Abstract
GlsA, a J-protein chaperone, is required for the asymmetric divisions that set aside germ and somatic cell precursors during embryogenesis in Volvox carteri, and previous evidence indicated that this function requires an intact Hsp70-binding site. To determine if Hsp70A, the only known cytoplasmic Hsp70 in V. carteri, is the chaperone partner of GlsA, we investigated the localization of the two proteins during critical stages of embryogenesis and tested their capacity to interact. We found that a substantial fraction of Hsp70A co-localizes with GlsA, both in interphase and mitotic blastomeres. In addition, Hsp70A coimmunoprecipitated with GlsA, and co-expression of GlsA and Hsp70A variants partially rescued the Gls phenotype of a glsA mutant, whereas neither variant by itself rescued the mutant phenotype. Immunofluorescence analysis demonstrated that GlsA is about equally abundant in all blastomeres at all cleavage stages examined but that Hsp70A is more abundant in anterior (asymmetrically dividing) blastomeres than in posterior (symmetrically dividing) blastomeres during the period of asymmetric division. We conclude that Hsp70A and GlsA function as chaperone partners that regulate asymmetric division and that the relative abundance of Hsp70A in asymmetrically dividing embryos may determine which blastomeres divide asymmetrically and which do not.
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Affiliation(s)
- Qian Cheng
- Department of Biological Sciences, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
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28
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Wu J, Lim RW. Regulation of inhibitor of differentiation gene 3 (Id3) expression by Sp2-motif binding factor in myogenic C2C12 cells: Downregulation of DNA binding activity following skeletal muscle differentiation. ACTA ACUST UNITED AC 2005; 1731:13-22. [PMID: 16216350 DOI: 10.1016/j.bbaexp.2005.08.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2005] [Revised: 08/23/2005] [Accepted: 08/24/2005] [Indexed: 10/25/2022]
Abstract
Id3 is a member of the Id family of transcriptional regulators that have been implicated in the development of multiple tissues. Altered expression of the Id genes and proteins contribute to carcinogenesis and atherosclerosis. Id3 is highly expressed in proliferating skeletal muscle cells but becomes downregulated upon terminal differentiation. We have identified several DNase I protected footprints within a proximal region of the mouse Id3 promoter that has been shown previously to support high levels of transcriptional activity in proliferating skeletal muscle cells. Two of these sites interacted, respectively, in vitro with Sp2 and Egr-1 proteins present in muscle cell nuclear extracts. Mutation analysis revealed that the Sp2 site accounted for a major part of the Id3 promoter activity in proliferating muscle cells whereas the Egr-1 site was dispensable. Consistent with the previously observed downregulation of the endogenous Id3 gene, protein binding to the Sp2 site was substantially reduced with extracts from differentiated muscle cells. Our results reveal Id3 as a potential target for Sp2 and raise the possibility that acute activation and the chronic and maintained expression of Id3 gene might be regulated by different mechanisms.
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Affiliation(s)
- Jinmei Wu
- Department of Medical Pharmacology and Physiology and Molecular Biology Program, University of Missouri-Columbia, Columbia, MO 65201, USA
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29
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Otto H, Conz C, Maier P, Wölfle T, Suzuki CK, Jenö P, Rücknagel P, Stahl J, Rospert S. The chaperones MPP11 and Hsp70L1 form the mammalian ribosome-associated complex. Proc Natl Acad Sci U S A 2005; 102:10064-9. [PMID: 16002468 PMCID: PMC1177401 DOI: 10.1073/pnas.0504400102] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Soluble Hsp70 homologs cotranslationally interact with nascent polypeptides in all kingdoms of life. In addition, fungi possess a specialized Hsp70 system attached to ribosomes, which in Saccharomyces cerevisiae consists of the Hsp70 homologs Ssb1/2p, Ssz1p, and the Hsp40 homolog zuotin. Ssz1p and zuotin are assembled into a unique heterodimeric complex termed ribosome-associated complex. So far, no such specialized chaperones have been identified on ribosomes of higher eukaryotes. However, a family of proteins characterized by an N-terminal zuotin-homology domain fused to a C-terminal two-repeat Myb domain is present in animals and plants. Members of this family, like human MPP11 and mouse MIDA1, have been implicated in the regulation of cell growth. Specific targets of MPP11/MIDA1, however, have remained elusive. Here, we report that MPP11 is localized to the cytosol and associates with ribosomes. Purification of MPP11 revealed that it forms a stable complex with Hsp70L1, a distantly related homolog of Ssz1p. Complementation experiments indicate that mammalian ribosome-associated complex is functional in yeast. We conclude that despite a low degree of homology on the amino acid level cooperation of ribosome-associated chaperones with the translational apparatus is well conserved in eukaryotic cells.
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Affiliation(s)
- Hendrik Otto
- Institut für Biochemie und Molekularbiologie, and Fakultät für Biologie, University of Freiburg, D-79104 Freiburg, Germany
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30
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Chang MS, Chen BC, Yu MT, Sheu JR, Chen TF, Lin CH. Phorbol 12-myristate 13-acetate upregulates cyclooxygenase-2 expression in human pulmonary epithelial cells via Ras, Raf-1, ERK, and NF-κB, but not p38 MAPK, pathways. Cell Signal 2005; 17:299-310. [PMID: 15567061 DOI: 10.1016/j.cellsig.2004.07.008] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2004] [Accepted: 07/23/2004] [Indexed: 12/21/2022]
Abstract
In this study, we investigated the signaling pathway involved in cyclooxygenase-2 (COX-2) expression and prostaglandin E2 (PGE2) release by phorbol 12-myristate 13-acetate (PMA), a protein kinase C (PKC) activator, in human pulmonary epithelial cells (A549). PMA-induced COX-2 expression was attenuated by PKC inhibitors (Go 6976 and Ro 31-8220), a Ras inhibitor (manumycin A), a Raf-1 inhibitor (GW 5074), a MEK inhibitor (PD 098059), and an NF-kappaB inhibitor (PDTC), but not by a tyrosine kinase inhibitor (genistein) or a p38 MAPK inhibitor (SB 203580). PMA also caused the activation of Ras, Raf-1, and ERK1/2. PMA-induced activation of Ras and Raf-1 was inhibited by Ro 31-8220 and manumycin A. PMA-mediated activation of ERK1/2 was inhibited by Ro 31-8220, manumycin A, GW 5074, and PD 098059. Stimulation of cells with PMA caused IkappaBalpha phosphorylation, IkappaBalpha degradation, and the formation of a NF-kappaB-specific DNA-protein complex. The PMA-mediated increase in kappaB-luciferase activity was inhibited by Ro 31-8220, manumycin A, GW5074, PD 098059, and PDTC. Taken together, these results indicate that PMA might activate PKC to elicit activation of the Ras/Raf-1/ERK1/2 pathway, which in turn initiates NF-kappaB activation, and finally induces COX-2 expression and PGE2 release in A549 cells.
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Affiliation(s)
- Ming-Shyan Chang
- Graduate Institute of Biomedical Technology, Taipei Medical University, Taipei, Taiwan
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31
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Buitenhuis M, van Deutekom HWM, Verhagen LP, Castor A, Jacobsen SEW, Lammers JWJ, Koenderman L, Coffer PJ. Differential regulation of granulopoiesis by the basic helix-loop-helix transcriptional inhibitors Id1 and Id2. Blood 2005; 105:4272-81. [PMID: 15701714 DOI: 10.1182/blood-2004-12-4883] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Inhibitor of DNA binding (Id) proteins function as inhibitors of members of the basic helix-loop-helix family of transcription factors and have been demonstrated to play an important role in regulating lymphopoiesis. However, the role of these proteins in regulation of myelopoiesis is currently unclear. In this study, we have investigated the role of Id1 and Id2 in the regulation of granulopoiesis. Id1 expression was initially up-regulated during early granulopoiesis, which was then followed by a decrease in expression during final maturation. In contrast, Id2 expression was up-regulated in terminally differentiated granulocytes. In order to determine whether Id expression plays a critical role in regulating granulopoiesis, Id1 and Id2 were ectopically expressed in CD34(+) cells by retroviral transduction. Our experiments demonstrate that constitutive expression of Id1 inhibits eosinophil development, whereas in contrast neutrophil differentiation was modestly enhanced. Constitutive Id2 expression accelerates final maturation of both eosinophils and neutrophils, whereas inhibition of Id2 expression blocks differentiation of both lineages. Transplantation of beta2-microglobulin(-/-) nonobese diabetic severe combined immunodeficient (NOD/SCID) mice with CD34(+) cells ectopically expressing Id1 resulted in enhanced neutrophil development, whereas ectopic expression of Id2 induced both eosinophil and neutrophil development. These data demonstrate that both Id1 and Id2 play a critical, although differential role in granulopoiesis.
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Affiliation(s)
- Miranda Buitenhuis
- Department of Pulmonary Diseases, University Medical Center, Utrecht, The Netherlands
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32
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de Candia P, Benera R, Solit DB. A role for Id proteins in mammary gland physiology and tumorigenesis. Adv Cancer Res 2004; 92:81-94. [PMID: 15530557 DOI: 10.1016/s0065-230x(04)92004-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Id helix-loop-helix (HLH) proteins are regulators of cell growth and differentiation in embryonic and adult tissues. They are members of the basic HLH family of transcription factors but lack a DNA binding domain. By binding to basic HLH transcription factors, Id proteins regulate gene expression. Id1 and Id3 have extensive sequence homology and similar patterns of expression during embryogenesis and in adult tissues. They are also expressed at high levels in the endothelial cells of tumor-infiltrating blood vessels, and breast tumors spontaneously arising in MMTV-neu mice demonstrate impaired angiogenesis when growing in an Id1- and/or Id3-deficient background. These lesions are typically cystic with a small rim of viable tumor cells surrounding an acellular necrotic core. Id2 plays a critical role in breast differentiation and lactation. Id4 regulates BRCA1 expression and may be involved in hormone-dependent regulation of BRCA1 homeostasis. Thus, all four members of the Id protein family play pivotal roles in distinct aspects of normal and malignant breast biology, the subject of this review.
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Affiliation(s)
- Paola de Candia
- Memorial Sloan-Kettering Cancer Center, Program in Cell Biology and Department of Medicine, New York, New York 10021, USA
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33
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Yoshida M, Inoue T, Shoji W, Ikawa S, Obinata M. Reporter gene stimulation by MIDA1 through its DnaJ homology region. Biochem Biophys Res Commun 2004; 324:326-32. [PMID: 15465022 DOI: 10.1016/j.bbrc.2004.09.059] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2004] [Indexed: 11/29/2022]
Abstract
MIDA1 was reported as a protein that can associate with Id1. Its N-terminus has homology to Z-DNA binding protein, Zuotin, that contains DnaJ motif, considered to interact with Hsp70s, and Id binding domain. In the present study, we found that MIDA1 stimulates the transcription of the co-transfected genes. This stimulation was independent of promoter specificity because it was observed in various transfected genes. MIDA1 enhanced formation of DNA-protein complexes with E-box or TATA box without its direct binding to DNA. Analysis with deletion mutants of MIDA1 showed that the short protein fragment containing DnaJ motif within Zuotin homology region is sufficient for the stimulation of transcription and we demonstrated that MIDA1 associates with Hsp70. These data suggest involvement of MIDA1 in the stimulation of transcription in concert with Hsp70/Hsc70 molecular chaperones, thus providing a link between Hsp70/Hsc70 molecular chaperones and components of the transcriptional machinery.
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Affiliation(s)
- Masayoshi Yoshida
- Department of Cell Biology, Institute of Development, Aging and Cancer, Tohoku University, 4-1, Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8575, Japan
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34
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Forrest S, McNamara C. Id family of transcription factors and vascular lesion formation. Arterioscler Thromb Vasc Biol 2004; 24:2014-20. [PMID: 15345510 DOI: 10.1161/01.atv.0000143932.03151.ad] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Vascular smooth muscle cell (VSMC) modulation to a de-differentiated phenotype and proliferation are key components of vascular lesion formation. Understanding how these processes are regulated is essential to understanding the progression of vascular diseases such as atherosclerosis and in-stent restenosis. The Id family of helix-loop-helix (HLH) transcription factors has emerged as important regulators of cellular growth and differentiation. Recent published findings have implicated the Id proteins as important regulators of growth and phenotypic modulation in VSMC and in the vascular response to injury. In this review, we summarize what is known regarding how the Id proteins function to control cellular growth and differentiation and their role in vascular lesion formation.
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Affiliation(s)
- Scott Forrest
- Cardiovascular Division, Department of Internal Medicine and the Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22901, USA
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35
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Kroczynska B, Evangelista CM, Samant SS, Elguindi EC, Blond SY. The SANT2 domain of the murine tumor cell DnaJ-like protein 1 human homologue interacts with alpha1-antichymotrypsin and kinetically interferes with its serpin inhibitory activity. J Biol Chem 2004; 279:11432-43. [PMID: 14668352 PMCID: PMC1553221 DOI: 10.1074/jbc.m310903200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The murine tumor cell DnaJ-like protein 1 or MTJ1/ERdj1 is a membrane J-domain protein enriched in microsomal and nuclear fractions. We previously showed that its lumenal J-domain stimulates the ATPase activity of the molecular chaperone BiP/GRP78 (Chevalier, M., Rhee, H., Elguindi, E. C., and Blond, S. Y. (2000) J. Biol. Chem. 275, 19620-19627). MTJ1/ERdj1 also contains a large carboxyl-terminal cytosolic extension composed of two tryptophan-mediated repeats or SANT domains for which the function(s) is unknown. Here we describe the cloning of the human homologue HTJ1 and its interaction with alpha(1)-antichymotrypsin (ACT), a member of the serine proteinase inhibitor (serpin) family. The interaction was initially identified in a two-hybrid screening and further confirmed in vitro by dot blots, native electrophoresis, and fluorescence studies. The second SANT domain of HTJ1 (SANT2) was found to be sufficient for binding to ACT, both in yeast and in vitro. Single tryptophan-alanine substitutions at two strictly conserved residues significantly (Trp-497) or totally (Trp-520) abolished the interaction with ACT. SANT2 binds to human ACT with an intrinsic affinity equal to 0.5 nm. Preincubation of ACT with nearly stoichiometric concentrations of SANT2 wild-type but not SANT2: W520A results in an apparent loss of ACT inhibitory activity toward chymotrypsin. Kinetic analysis indicates that the formation of the covalent inhibitory complex ACT-chymotrypsin is significantly delayed in the presence of SANT2 with no change on the catalytic efficiency of the enzyme. This work demonstrates for the first time that the SANT2 domain of MTJ1/HTJ1/ERdj1 mediates stable and high affinity protein-protein interactions.
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Affiliation(s)
- Barbara Kroczynska
- Center for Pharmaceutical Biotechnology, College of Pharmacy, Department of Medicinal Chemistry and Pharmacognosy, University of Illinois, Chicago, Illinois 60607-7173, USA
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36
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Greiner J, Ringhoffer M, Taniguchi M, Li L, Schmitt A, Shiku H, Döhner H, Schmitt M. mRNA expression of leukemia-associated antigens in patients with acute myeloid leukemia for the development of specific immunotherapies. Int J Cancer 2003; 108:704-11. [PMID: 14696097 DOI: 10.1002/ijc.11623] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Specific immunotherapies for patients with acute myeloid leukemia (AML) using leukemia-associated antigens (LAA) as target structures might be a therapeutic option to enhance the graft-vs.-leukemia effect observed after allogeneic stem cell transplantation or to prolong a complete remission (CR) achieved by chemotherapy. Significant mRNA expression of LAA is a prerequisite for such immunotherapies. Here, previously characterized antigens associated with solid tumors (TAA) and newly characterized LAA were investigated for their expression in up to 60 AML patients and in leukemia cell lines. To investigate their specificity for leukemic blasts, the mRNA expression was also characterized in PBMN and CD34 positive cells of healthy volunteers and in a panel of normal tissues. The following antigens showed high mRNA expression in AML patients: MPP11 was detected in 43/50 (86%), RHAMM in 35/50 (70%), WT1 in 40/60 (67%), PRAME in 32/50 (64%), G250 in 18/35 (51%), hTERT in 7/25 (28%) and BAGE in 8/30 (27%) of AML patients. Real-time RT-PCR showed a tumor-specific expression of the antigens BAGE, G250 and hTERT, as well as highly tumor-restricted expression for RHAMM, PRAME and WT1. The antigen MPP11 was overexpressed. These antigens might be candidates for immunotherapies of leukemia patients and, because of their simultaneous expression, also for polyvalent vaccines.
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Affiliation(s)
- Jochen Greiner
- Third Department of Medicine, University of Ulm, Ulm, Germany
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37
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Greiner J, Ringhoffer M, Taniguchi M, Hauser T, Schmitt A, Döhner H, Schmitt M. Characterization of several leukemia-associated antigens inducing humoral immune responses in acute and chronic myeloid leukemia. Int J Cancer 2003; 106:224-31. [PMID: 12800198 DOI: 10.1002/ijc.11200] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
To design a specific immunotherapy for leukemia patients, the identification of leukemia-associated antigens (LAAs) is a pivotal step. Antileukemic effects after hematopoetic stem cell transplantation for myeloid leukemias are observed and might be related to the recognition of LAAs. Using the serological screening of an expression library (SEREX) of K562 cells, we identified 16 different clones encoding LAAs eliciting a humoral immune response, among them the heat shock proteins HSJ2 and HSP70, the M-phase phosphoprotein 11 (MPP11), the BRCA1-associated protein (BRAP), the Jkappa recombination binding protein (RBPJkappa) and the receptor for hyaluronic acid mediated motility (RHAMM). Serological responses to MPP11 were observed in 7/19 (37%) of patients with acute myeloid leukemia (AML) and 6/16 (38%) of patients with chronic myeloid leukemia (CML), but not in healthy volunteers (0/20). IgG antibodies directed against MPP11 were also detected in 25-50% of the sera of patients with solid tumors such as melanoma, renal cell, ovarian and breast carcinoma. mRNA expression of MPP11 was detected in 20/20 AML patients and 7/10 patients with CML. In normal tissues, strong mRNA expression of MPP11 was only detected in testis. By real-time PCR, we detected upregulation of MPP11 in leukemic blasts. Simultaneous humoral immune responses to 2 or more of the 16 LAAs identified here was observed, suggesting the feasibility of a polyvalent vaccination as an option for immunotherapies in leukemia patients.
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MESH Headings
- Acute Disease
- Antibodies, Neoplasm/blood
- Antigens, Neoplasm/analysis
- Breast Neoplasms/genetics
- Breast Neoplasms/immunology
- Carcinoma, Renal Cell/genetics
- Carcinoma, Renal Cell/immunology
- DNA-Binding Proteins/genetics
- Female
- Gene Expression
- Humans
- K562 Cells
- Kidney Neoplasms/genetics
- Kidney Neoplasms/immunology
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/immunology
- Molecular Chaperones
- Neoplasm Proteins/analysis
- Oncogene Proteins/genetics
- RNA, Messenger/metabolism
- RNA-Binding Proteins
- Reverse Transcriptase Polymerase Chain Reaction
- Skin Neoplasms/genetics
- Skin Neoplasms/immunology
- Skin Neoplasms/secondary
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Affiliation(s)
- Jochen Greiner
- Third Department of Internal Medicine, University of Ulm, Ulm, Germany
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38
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Abstract
Id proteins are important parts of signaling pathways involved in development, cell cycle and tumorigenesis. They were first shown to act as dominant negative antagonists of the basic helix-loop-helix family of transcription factors, which positively regulate differentiation in many cell lineages. The Id proteins do this by associating with the ubiquitous E proteins and preventing them from binding DNA or other transcription factors. Id proteins also associate with Ets transcription factors and the Rb family of tumor suppressor proteins, and are downstream targets of transforming growth factor beta and bone morphogenic protein signaling. Thus, the Id proteins have become important molecules for understanding basic biological processes as well as targets for potential therapeutic intervention in human disease.
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Affiliation(s)
- Marianna B Ruzinova
- Department of Cell Biology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue Box 241, New York, NY 10021, USA
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39
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Cheng Q, Fowler R, Tam LW, Edwards L, Miller SM. The role of GlsA in the evolution of asymmetric cell division in the green alga Volvox carteri. Dev Genes Evol 2003; 213:328-35. [PMID: 12743823 DOI: 10.1007/s00427-003-0332-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2003] [Accepted: 03/07/2003] [Indexed: 10/26/2022]
Abstract
Volvox carteri, a green alga in the order Volvocales, contains two completely differentiated cell types, small motile somatic cells and large reproductive cells called gonidia, that are set apart from each other during embryogenesis by a series of visibly asymmetric cell divisions. Mutational analysis has revealed a class of genes (gonidialess, gls) that are required specifically for asymmetric divisions in V. carteri, but that are dispensable for symmetric divisions. Previously we cloned one of these genes, glsA, and showed that it encodes a chaperone-like protein (GlsA) that has close orthologs in a diverse set of eukaryotes, ranging from fungi to vertebrates and higher plants. In the present study we set out to explore the role of glsA in the evolution of asymmetric division in the volvocine algae by cloning and characterizing a glsA ortholog from one of the simplest members of the group, Chlamydomonas reinhardtii, which does not undergo asymmetric divisions. This ortholog (which we have named gar1, for glsA related) is predicted to encode a protein that is 70% identical to GlsA overall, and that is most closely related to GlsA in the same domains that are most highly conserved between GlsA and its other known orthologs. We report that a gar1 transgene fully complements the glsA mutation in V. carteri, a result that suggests that asymmetric division probably arose through the modification of a gene whose product interacts with GlsA, but not through a modification of glsA itself.
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Affiliation(s)
- Qian Cheng
- Department of Biological Sciences, University of Maryland, 1000 Hilltop Circle, Baltimore County, Baltimore, MD 21250, USA
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40
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Mori T, Kuroiwa H, Higashiyama T, Kuroiwa T. Identification of higher plant GlsA, a putative morphogenesis factor of gametic cells. Biochem Biophys Res Commun 2003; 306:564-9. [PMID: 12804602 DOI: 10.1016/s0006-291x(03)01005-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
GlsA has been identified in an asexual-reproductive-cell (gonidia)-deficient mutant of Volvox as a chaperone-like protein essential for gonidia production. In this study, we isolated an angiosperm glsA (LlglsA) gene expressed during Lilium longiflorum pollen development. Immunoblot analyses showed that the strong LlGlsA expression occurred in the generative cell and its pattern during pollen development corresponded to that of alpha-tubulin. Morphological analyses succeeded in visualizing the dispersion of the strong LlGlsA signal in developing generative cells. In addition, multiple-immunofluorescence staining of LlGlsA and alpha-tubulin revealed that some of the dot-like LlGlsA signals were co-localized with microtubule filaments. From those results, we suggest that angiosperm GlsA functions as a chaperone modifying various structures during male gametic cell formation.
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Affiliation(s)
- Toshiyuki Mori
- Department of Life Science, College of Science, Rikkyo (St. Paul's) University, 3-34-1, Nishi-Ikebukuro, Toshima-ku, 171-8501, Tokyo, Japan.
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41
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Craig EA, Eisenman HC, Hundley HA. Ribosome-tethered molecular chaperones: the first line of defense against protein misfolding? Curr Opin Microbiol 2003; 6:157-62. [PMID: 12732306 DOI: 10.1016/s1369-5274(03)00030-4] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Folding of many cellular proteins is facilitated by molecular chaperones. Analysis of both prokaryotic and lower eukaryotic model systems has revealed the presence of ribosome-associated molecular chaperones, thought to be the first line of defense against protein aggregation as translating polypeptides emerge from the ribosome. However, structurally unrelated chaperones have evolved to carry out these functions in different microbes. In the yeast Saccharomyces cerevisiae, an unusual complex of Hsp70 and J-type chaperones associates with ribosome-bound nascent chains, whereas in Escherichia coli the ribosome-associated peptidyl-prolyl-cis-trans isomerase, trigger factor, plays a predominant role.
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Affiliation(s)
- Elizabeth A Craig
- Department of Biochemistry, 433 Babcock Drive, University of Wisconsin-Madison, Madison, WI 53706, USA.
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42
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Abstract
Id proteins function as negative regulators of bHLH transcription factors by disrupting the homo- and/or hetero-dimerization of bHLH-bHLH transcription factors. Recent data from in vitro and in vivo studies have revealed the complex biological functions of Id proteins in the regulation of cell differentiation, the cell cycle, and cell survival. Several advances in the understanding of Id-regulated neurogenesis have been made. Basically, Id proteins are positive regulators of neural cell proliferation, are required for neural cell cycle progression, and also play a role in the timing of oligodendroglial differentiation. Here we summarize recent findings regarding the regulation of Id proteins in neural cells and discuss the possible mechanisms of Id-regulated neurogenesis.
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Affiliation(s)
- Shun-Fen Tzeng
- Department of Biology, National Cheng Kung University, #1 Ta-Hsiueh Road, Tainan City, Taiwan 70101.
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43
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Galego L, Almeida J. Role of DIVARICATA in the control of dorsoventral asymmetry in Antirrhinum flowers. Genes Dev 2002; 16:880-91. [PMID: 11937495 PMCID: PMC186332 DOI: 10.1101/gad.221002] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Dorsoventral asymmetry of the Antirrhinum corolla depends on expression of the CYC and DICH genes in dorsal petals. One role of these genes is to inhibit DIVARICATA (DIV), a determinant of ventral identity. Therefore, in cyc;dich double mutants ventral identity spreads all around the flower. We show that DIV encodes a protein belonging to the MYB family of transcription factors. Early on in corolla development, DIV affects specifically the growth of ventral and lateral petals but is transcribed in all petals. Analysis of a closely related gene suggests that the lack of effect on dorsal petals is not due to redundancy. More likely, therefore, DIV is regulated posttranscriptionally through a mechanism that depends on CYC and DICH. Later on, DIV affects growth and cell types and is transcribed mostly in a single layer of cells of ventral and lateral petals. This late pattern may itself depend on DIV activity because it fails to be established in a transcribed but inactive div mutant and, conversely, spreads all around the flower in cyc;dich double mutants.
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Affiliation(s)
- Lisete Galego
- Instituto de Tecnologia Química e Biológica, 2780 Oeiras, Portugal
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44
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Abstract
Id proteins (inhibitors of DNA binding/differentiation) are negative regulators of basic helix-loop-helix (bHLH) type transcription factors, which promote the differentiation of various cell types. In addition to their "classical" ability to inhibit cell differentiation, they are able to stimulate cell cycle progression. These facts suggest that Id proteins play a role in keeping precursor cells immature and in expanding the cell population size during development. In vitro as well as in vivo analyses in the last several years have shown that Id proteins have more complex activities; they induce apoptosis or function as survival factors, depending on the cell context. Furthermore, dysregulated expression of Id proteins has been reported in several human tumors and seems to be related to the malignant character of tumors. Here, we summarize and discuss the biological activities of Id proteins from the standpoint of cell growth control.
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Affiliation(s)
- Yoshifumi Yokota
- Department of Biochemistry, Fukui Medical University, 23-3 Shimoaizuki, Matsuoka, Fukui 910-1193, Japan.
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45
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Abstract
The Id family of helix-loop-helix (HLH) proteins are thought to affect the balance between cell growth and differentiation by negatively regulating the function of basic-helix-loop-helix (bHLH) transcription factors. Although it has been suggested for some time that Id is involved in cell cycle regulation, little is known about the molecular mechanism of this control. Recent studies, however, have revealed that Id binds to important cell cycle regulatory proteins other than bHLH proteins. Two such proteins, pRB (retinoblastoma tumour suppressor protein) family proteins and Ets-family transcription factors are known to play key roles in cell cycle regulation, transformation and tumour suppression. Through the characterization of these pathways we will begin to understand the mechanisms by which Id controls normal and abnormal cell cycle progression.
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Affiliation(s)
- Z Zebedee
- CRC Cell Cycle Group, Paterson Institute for Cancer Research, Christie Hospital NHS Trust, Wilmslow Road, Manchester M20 4BX, UK
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46
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Abstract
Since the identification of the Id proteins over a decade ago, a great many cell cycle and cell fate decisions have been shown to be under the control of these proteins as described in other sections of this review issue. Perhaps the most unsuspected activity of this class of proteins has been their essential role in angiogenesis, both in the forebrain during development and during the growth and metastasis of tumors in adults. This section of the review issue will focus on the key observations which have led to these conclusions, speculations about potential mechanisms and the outlook for potential therapeutic interventions.
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Affiliation(s)
- R Benezra
- Department of Cell Biology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA.
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47
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Abstract
During development, it is obvious that enormous multiplication and diversification of cells is required to build a body plan from a single fertilized egg and that these two processes, proliferation and differentiation, must be coordinated properly. Id proteins, negative regulators of basic helix-loop-helix transcription factors, possess the ability to inhibit differentiation and to stimulate proliferation, and are useful molecules for investigating the mechanisms regulating development. In the past few years, our understanding of the roles of Id proteins has been substantially enhanced by the detailed investigation of genetically modified animals. The data have indicated that the functions of Id proteins in vivo are functionally related to those revealed by earlier work in cell culture systems. However, unexpected organs and cell types have also been found to require Id proteins for their normal development. This review looks at the advances made in our understanding of the in vivo functions of Id proteins. The topics discussed include neurogenesis, natural killer cell development, lymphoid organogenesis, mammary gland development and spermatogenesis.
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Affiliation(s)
- Y Yokota
- Department of Biochemistry, Fukui Medical University, Shimoaizuki 23-3, Matsuoka, Fukui 910-1193, Japan.
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48
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Kratz CP, Emerling BM, Donovan S, Laig-Webster M, Taylor BR, Thompson P, Jensen S, Banerjee A, Bonifas J, Makalowski W, Green ED, Le Beau MM, Shannon KM. Candidate gene isolation and comparative analysis of a commonly deleted segment of 7q22 implicated in myeloid malignancies. Genomics 2001; 77:171-80. [PMID: 11597142 DOI: 10.1006/geno.2001.6636] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Monosomy 7 and deletion of 7q are recurring abnormalities in malignant myeloid diseases. Here we extensively characterize an approximately 2-Mb commonly deleted segment (CDS) of 7q22 bounded by D7S1503 and D7S1841. Approximately 1.8 Mb of sequence have been generated from this interval, facilitating the construction of a transcript map that includes large numbers of genes and ESTs. The intron/exon organization of seven genes and expression patterns of three genes were determined, and leukemia samples were screened for mutations in five genes. We have used polymorphic markers from this region to examine leukemia cells for allelic loss within 7q22. Finally, we isolated mouse genomic clones orthologous to several of the characterized human genes. Fluorescence in situ hybridization studies using these clones indicate that a region of orthologous synteny lies on proximal mouse chromosome 5. These resources should greatly accelerate the pace of candidate gene discovery in this region.
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Affiliation(s)
- C P Kratz
- Department of Pediatrics, University of California, San Francisco, California 94143, USA
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49
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Benezra R. The Id proteins: targets for inhibiting tumor cells and their blood supply. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1551:F39-47. [PMID: 11591449 DOI: 10.1016/s0304-419x(01)00028-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- R Benezra
- Cell Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
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50
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Braun EL, Grotewold E. Fungal Zuotin proteins evolved from MIDA1-like factors by lineage-specific loss of MYB domains. Mol Biol Evol 2001; 18:1401-12. [PMID: 11420378 DOI: 10.1093/oxfordjournals.molbev.a003924] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Proteins are often characterized by the presence of multiple domains, which make specific contributions to their cellular function. While the gain of domains in proteins by duplication and shuffling is well established, domain loss is poorly documented. Here, we provide evidence that domain loss has played an important role in the evolution of protein architecture and function by demonstrating that fungal Zuotin proteins evolved from MIDA1-like proteins, present in animals and plants, by complete loss of the carboxyl-terminal MYB domains. Phylogenetic analyses of the DnaJ motif (the J domain) present in both Zuotin and MIDA1 proteins were complicated by the limited length and profound differences in evolutionary rates exhibited by this domain. To rigorously examine J domain phylogeny, we combined the nonparametric bootstrap with Monte Carlo simulation. This method, which we have designated the resampled parametric bootstrap, allowed us to assess type I and type II error associated with these analyses. These results revealed significant support for domain loss rather than domain gain or gene loss involving paralogs. The absence of sequences related to the MIDA1 MYB domains in Saccharomyces cerevisiae further indicates that the domains have been completely lost, consistent with known functional differences between Zuotin and MIDA1 proteins. These analyses suggest that the description of additional examples of complete domain loss may provide a method to identify orthologous proteins exhibiting functional differences using genomic sequence data.
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Affiliation(s)
- E L Braun
- Department of Plant Biology and Plant Biotechnology Center, Ohio State University, Columbus, 43210, USA.
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