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Wang Z, Zhu T, Ma W, Fan E, Lu N, Ouyang F, Wang N, Yang G, Kong L, Qu G, Zhang S, Wang J. Potential function of CbuSPL and gene encoding its interacting protein during flowering in Catalpa bungei. BMC PLANT BIOLOGY 2020; 20:105. [PMID: 32143577 PMCID: PMC7060540 DOI: 10.1186/s12870-020-2303-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Accepted: 02/24/2020] [Indexed: 05/27/2023]
Abstract
BACKGROUND "Bairihua", a variety of the Catalpa bungei, has a large amount of flowers and a long flowering period which make it an excellent material for flowering researches in trees. SPL is one of the hub genes that regulate both flowering transition and development. RESULTS SPL homologues CbuSPL9 was cloned using degenerate primers with RACE. Expression studies during flowering transition in "Bairihua" and ectopic expression in Arabidopsis showed that CbuSPL9 was functional similarly with its Arabidopsis homologues. In the next step, we used Y2H to identify the proteins that could interact with CbuSPL9. HMGA, an architectural transcriptional factor, was identified and cloned for further research. BiFC and BLI showed that CbuSPL9 could form a heterodimer with CbuHMGA in the nucleus. The expression analysis showed that CbuHMGA had a similar expression trend to that of CbuSPL9 during flowering in "Bairihua". Intriguingly, ectopic expression of CbuHMGA in Arabidopsis would lead to aberrant flowers, but did not effect flowering time. CONCLUSIONS Our results implied a novel pathway that CbuSPL9 regulated flowering development, but not flowering transition, with the participation of CbuHMGA. Further investments need to be done to verify the details of this pathway.
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Affiliation(s)
- Zhi Wang
- Present address: State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091 People’s Republic of China
| | - Tianqing Zhu
- Present address: State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091 People’s Republic of China
| | - Wenjun Ma
- Present address: State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091 People’s Republic of China
| | - Erqin Fan
- Present address: State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091 People’s Republic of China
- Present address: State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, 26 Hexing Road, Harbin, 150040 People’s Republic of China
| | - Nan Lu
- Present address: State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091 People’s Republic of China
| | - Fangqun Ouyang
- Present address: State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091 People’s Republic of China
| | - Nan Wang
- Present address: State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091 People’s Republic of China
| | - Guijuan Yang
- Present address: State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091 People’s Republic of China
| | - Lisheng Kong
- Present address: Department of Biology Centre for Forest Biology, University of Victoria, Victoria 11, BC Canada
| | - Guanzheng Qu
- Present address: State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, 26 Hexing Road, Harbin, 150040 People’s Republic of China
| | - Shougong Zhang
- Present address: State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091 People’s Republic of China
| | - Junhui Wang
- Present address: State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091 People’s Republic of China
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Resar L, Chia L, Xian L. Lessons from the Crypt: HMGA1-Amping up Wnt for Stem Cells and Tumor Progression. Cancer Res 2018; 78:1890-1897. [PMID: 29618461 DOI: 10.1158/0008-5472.can-17-3045] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 12/05/2017] [Accepted: 01/31/2018] [Indexed: 11/16/2022]
Abstract
High mobility group A1 (HMGA1) chromatin remodeling proteins are enriched in aggressive cancers and stem cells, although their common function in these settings has remained elusive until now. Recent work in murine intestinal stem cells (ISC) revealed a novel role for Hmga1 in enhancing self-renewal by amplifying Wnt signaling, both by inducing genes expressing Wnt agonist receptors and Wnt effectors. Surprisingly, Hmga1 also "builds" a stem cell niche by upregulating Sox9, a factor required for differentiation to Paneth cells; these cells constitute an epithelial niche by secreting Wnt and other factors to support ISCs. HMGA1 is also highly upregulated in colon cancer compared with nonmalignant epithelium and SOX9 becomes overexpressed during colon carcinogenesis. Intriguingly, HMGA1 is overexpressed in diverse cancers with poor outcomes, where it regulates developmental genes. Similarly, HMGA1 induces genes responsible for pluripotency and self-renewal in embryonic stem cells. These findings demonstrate that HMGA1 maintains Wnt and other developmental transcriptional networks and suggest that HMGA1 overexpression fosters carcinogenesis and tumor progression through dysregulation of these pathways. Studies are now needed to determine more precisely how HMGA1 modulates chromatin structure to amplify developmental genes and how to disrupt this process in cancer therapy. Cancer Res; 78(8); 1890-7. ©2018 AACR.
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Affiliation(s)
- Linda Resar
- Department of Medicine, Division of Hematology, The Johns Hopkins University School of Medicine, Baltimore, Maryland. .,Departments of Oncology, Pathology and Institute of Cellular Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland.,Pathobiology Graduate Program, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Lionel Chia
- Pathobiology Graduate Program, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Lingling Xian
- Department of Medicine, Division of Hematology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
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Sumter TF, Xian L, Huso T, Koo M, Chang YT, Almasri TN, Chia L, Inglis C, Reid D, Resar LMS. The High Mobility Group A1 (HMGA1) Transcriptome in Cancer and Development. Curr Mol Med 2016; 16:353-93. [PMID: 26980699 DOI: 10.2174/1566524016666160316152147] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 02/15/2016] [Accepted: 03/10/2016] [Indexed: 01/19/2023]
Abstract
BACKGROUND & OBJECTIVES Chromatin structure is the single most important feature that distinguishes a cancer cell from a normal cell histologically. Chromatin remodeling proteins regulate chromatin structure and high mobility group A (HMGA1) proteins are among the most abundant, nonhistone chromatin remodeling proteins found in cancer cells. These proteins include HMGA1a/HMGA1b isoforms, which result from alternatively spliced mRNA. The HMGA1 gene is overexpressed in cancer and high levels portend a poor prognosis in diverse tumors. HMGA1 is also highly expressed during embryogenesis and postnatally in adult stem cells. Overexpression of HMGA1 drives neoplastic transformation in cultured cells, while inhibiting HMGA1 blocks oncogenic and cancer stem cell properties. Hmga1 transgenic mice succumb to aggressive tumors, demonstrating that dysregulated expression of HMGA1 causes cancer in vivo. HMGA1 is also required for reprogramming somatic cells into induced pluripotent stem cells. HMGA1 proteins function as ancillary transcription factors that bend chromatin and recruit other transcription factors to DNA. They induce oncogenic transformation by activating or repressing specific genes involved in this process and an HMGA1 "transcriptome" is emerging. Although prior studies reveal potent oncogenic properties of HMGA1, we are only beginning to understand the molecular mechanisms through which HMGA1 functions. In this review, we summarize the list of putative downstream transcriptional targets regulated by HMGA1. We also briefly discuss studies linking HMGA1 to Alzheimer's disease and type-2 diabetes. CONCLUSION Further elucidation of HMGA1 function should lead to novel therapeutic strategies for cancer and possibly for other diseases associated with aberrant HMGA1 expression.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - L M S Resar
- Department of Medicine, Faculty of the Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross Research Building, Room 1025, Baltimore, MD 21205-2109, USA.
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Abstract
The high mobility group protein A1 (HMGA1) is a master regulator of chromatin structure mediating its major gene regulatory activity by direct interactions with A/T-rich DNA sequences located in the promoter and enhancer regions of a large variety of genes. HMGA1 DNA-binding through three AT-hook motifs results in an open chromatin structure and subsequently leads to changes in gene expression. Apart from its significant expression during development, HMGA1 is over-expressed in virtually every cancer, where HMGA1 expression levels correlate with tumor malignancy. The exogenous overexpression of HMGA1 can lead to malignant cell transformation, assigning the protein a key role during cancerogenesis. Recent studies have unveiled highly specific competitive interactions of HMGA1 with cellular and viral RNAs also through an AT-hook domain of the protein, significantly impacting the HMGA1-dependent gene expression. In this review, we discuss the structure and function of HMGA1-RNA complexes during transcription and epigenomic regulation and their implications in HMGA1-related diseases.
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Huso TH, Resar LMS. The high mobility group A1 molecular switch: turning on cancer - can we turn it off? Expert Opin Ther Targets 2014; 18:541-53. [PMID: 24684280 DOI: 10.1517/14728222.2014.900045] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Emerging evidence demonstrates that the high mobility group A1 (HMGA1) chromatin remodeling protein is a key molecular switch required by cancer cells for tumor progression and a poorly differentiated, stem-like state. Because the HMGA1 gene and proteins are expressed at high levels in all aggressive tumors studied to date, research is needed to determine how to 'turn off' this master regulatory switch in cancer. AREAS COVERED In this review, we describe prior studies that underscore the central role of HMGA1 in refractory cancers and we discuss approaches to target HMGA1 in cancer therapy. EXPERT OPINION Given the widespread overexpression of HMGA1 in diverse, aggressive tumors, further research to develop technology to target HMGA1 holds immense promise as potent anticancer therapy. Previous work in preclinical models indicates that delivery of short hairpin RNA or interfering RNA molecules to 'switch off' HMGA1 expression dramatically impairs cancer cell growth and tumor progression. The advent of nanoparticle technology to systemically deliver DNA or RNA molecules to tumors brings this approach even closer to clinical applications, although further efforts are needed to translate these advances into therapies for cancer patients.
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Affiliation(s)
- Tait H Huso
- The Johns Hopkins University School of Medicine, Hematology Division , Ross Research Building, Room 1015, 720 Rutland Avenue, Baltimore MD 21205 , USA
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The maize HMGA protein is localized to the nucleolus and can be acetylated in vitro at its globular domain, and phosphorylation by CDK reduces its binding activity to AT-rich DNA. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2009; 1789:751-7. [DOI: 10.1016/j.bbagrm.2009.09.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Accepted: 09/16/2009] [Indexed: 11/23/2022]
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Functional equivalence of HMGA- and histone H1-like domains in a bacterial transcriptional factor. Proc Natl Acad Sci U S A 2009; 106:13546-51. [PMID: 19666574 DOI: 10.1073/pnas.0902233106] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Histone H1 and high-mobility group A (HMGA) proteins compete dynamically to modulate chromatin structure and regulate DNA transactions in eukaryotes. In prokaryotes, HMGA-like domains are known only in Myxococcus xanthus CarD and its Stigmatella aurantiaca ortholog. These have an N-terminal module absent in HMGA that interacts with CarG (a zinc-associated factor that does not bind DNA) to form a stable complex essential in regulating multicellular development, light-induced carotenogenesis, and other cellular processes. An analogous pair, CarD(Ad) and CarG(Ad), exists in another myxobacterium, Anaeromyxobacter dehalogenans. Intriguingly, the CarD(Ad) C terminus lacks the hallmark HMGA DNA-binding AT-hooks and instead resembles the C-terminal region (CTR) of histone H1. We find that CarD(Ad) alone could not replace CarD in M. xanthus. By contrast, when introduced with CarG(Ad), CarD(Ad) functionally replaced CarD in regulating not just 1 but 3 distinct processes in M. xanthus, despite the lower DNA-binding affinity of CarD(Ad) versus CarD in vitro. The ability of the cognate CarD(Ad)-CarG(Ad) pair to interact, but not the noncognate CarD(Ad)-CarG, rationalizes these data. Thus, in chimeras that conserve CarD-CarG interactions, the H1-like CTR of CarD(Ad) could replace the CarD HMGA AT-hooks with no loss of function in vivo. More tellingly, even chimeras with the CarD AT-hook region substituted by human histone H1 CTR or full-length H1 functioned in M. xanthus. Our domain-swap analyses showing functional equivalence of HMGA AT-hooks and H1 CTR in prokaryotic transcriptional regulation provide molecular insights into possible modes of action underlying their biological roles.
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Klosterman SJ, Choi JJ, Hadwiger LA. Analysis of pea HMG-I/Y expression suggests a role in defence gene regulation. MOLECULAR PLANT PATHOLOGY 2003; 4:249-58. [PMID: 20569385 DOI: 10.1046/j.1364-3703.2003.00171.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
SUMMARY HMG-I/Y proteins are characterized by the presence of AT-hook motifs, DNA binding domains that recognize AT-rich tracts of DNA. By facilitating protein:protein and protein:DNA interactions in the vicinity of these AT-rich binding sites, HMG-I/Y positively or negatively regulates gene expression. Several pea defence gene promoters have AT-rich tracts of DNA that are potential targets for modulation via HMG-I/Y. In this study, a comparison of the expression of a pea defence gene (DRR206) mRNA relative to the expression of HMG-I/Y mRNA was monitored by Northern analysis following the inoculation of a fungal pathogen, Fusarium solani or treatment with chitosan and a F. solani DNase (Fsph DNase). In pea pod endocarp tissue, HMG-I/Y expression was observed at high levels in untreated tissue and at lower levels 6 h following inoculation or wounding of the tissue. Western blots with an antipea HMG-I/Y polyclonal antibody also revealed that pea HMG-I/Y is expressed at decreased levels 6 h following inoculation or elicitor treatment. HMG-I/Y extracted from pea caused alterations in the gel migration of radio-labelled AT-rich sequences from the pea DRR206 promoter, suggesting that similar interactions could exist in vivo. Agroinfiltration was utilized to express the pea HMG-I/Y gene in tobacco containing a chimeric gene fusion of a promoter from the PR gene, DRR206, and the beta-glucuronidase (GUS) reporter gene. Transient expression of pea HMG-I/Y led to a decrease in GUS reporter gene activity in the heterologous tobacco system. These data implicate pea HMG-I/Y abundance in the down-regulation of DRR206 gene expression, and possibly HMG-I/Y depletion in the expression of defence genes in pea.
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Affiliation(s)
- Steven J Klosterman
- Department of Plant Pathology, Washington State University, Pullman, WA 99164-6430, USA
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Zhang W, Wu Q, Pwee KH, Manjunatha Kini R. Interaction of wheat high-mobility-group proteins with four-way-junction DNA and characterization of the structure and expression of HMGA gene. Arch Biochem Biophys 2003; 409:357-66. [PMID: 12504903 DOI: 10.1016/s0003-9861(02)00630-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Plant high-mobility-group (HMG) chromosomal proteins are the most abundant and ubiquitous nonhistone proteins found in the nuclei of higher eukaryotes. There are only two families of HMG proteins, namely, HMGA and HMGB in plants. The cDNA encoding wheat HMGa protein was isolated and characterized. Wheat HMGA cDNA encodes a protein of 189 amino acid residues. At its N terminus, there is a histone H1-like structure, which is a common feature of plant HMGA proteins, followed by four AT-hook motifs. Polymerase chain reaction results show that the gene contains a single intron of 134 bp. All four AT-hook motifs are encoded by the second exon. Northern blot results show that the expression of HMGA gene is much higher in organs undergoing active cell proliferation. Gel retardation analysis show that wheat HMGa, b, c and histone H1 bind to four-way-junction DNA with high binding affinity, but affinity is dramatically reduced with increasing Mg(2+) and Na(+) ion concentration. Competition binding studies show that proteins share overlapping binding sites on four-way-junction DNA. HMGd does not bind to four-way-junction DNA.
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Affiliation(s)
- Wensheng Zhang
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 10 Kent Ridge Crescent, 117543, Singapore, Singapore
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Lichota J, Grasser KD. Differential chromatin association and nucleosome binding of the maize HMGA, HMGB, and SSRP1 proteins. Biochemistry 2001; 40:7860-7. [PMID: 11425313 DOI: 10.1021/bi010548y] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In plants, chromosomal high mobility group (HMG) proteins have been identified in the HMGA family, containing A/T-hook DNA binding motifs, and in the HMGB family, containing an HMG-box DNA binding domain, that are considered architectural factors in chromatin. We have characterized the association of the HMGA protein, five different HMGB proteins, and the structure-specific recognition protein 1 (SSRP1) with maize chromatin by extraction experiments using NaCl, ethidium bromide, spermine, and distamycin A. The difference in the release of the proteins from chromatin by these reagents indicates that they are differentially associated with chromatin. This was confirmed by treatment of chromatin with micrococcal nuclease, demonstrating that the HMGA, HMGB2/3, and SSRP1 proteins are enriched in the highly nuclease-sensitive fraction of chromatin, which is likely to be transcriptionally competent. As examined by electrophoretic mobility shift analyses, the HMGA protein and the proteins containing an HMG domain (HMGB proteins and SSRP1) bind specifically to purified maize mononucleosomes that contain a histone octamer and approximately 165 bp of DNA. The mode of interaction with the nucleosomes differs for HMGA and HMGB proteins. In the case of the HMGB1 protein, the full-length protein is required for specific nucleosome binding, as the individual HMG-box DNA binding domain (which is sufficient for DNA interactions) interacts nonspecifically with the nucleosomes. Collectively, these findings indicate that HMGA, the various HMGB proteins, and SSPR1 are differentially associated with plant chromatin and may act as architectural factors in different nucleoprotein structures.
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Affiliation(s)
- J Lichota
- Department of Life Science, Aalborg University, Sohngaardsholmsvej 49, DK-9000 Aalborg, Denmark
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Reeves R, Beckerbauer L. HMGI/Y proteins: flexible regulators of transcription and chromatin structure. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1519:13-29. [PMID: 11406267 DOI: 10.1016/s0167-4781(01)00215-9] [Citation(s) in RCA: 285] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The mammalian HMGI/Y (HMGA) non-histone proteins participate in a wide variety of cellular processes including regulation of inducible gene transcription, integration of retroviruses into chromosomes and the induction of neoplastic transformation and promotion of metastatic progression of cancer cells. Recent advances have contributed greatly to our understanding of how the HMGI/Y proteins participate in the molecular mechanisms underlying these biological events. All members of the HMGI/Y family of 'high mobility group' proteins are characterized by the presence of multiple copies of a conserved DNA-binding peptide motif called the 'AT hook' that preferentially binds to the narrow minor groove of stretches of AT-rich sequence. The mammalian HMGI/Y proteins have little, if any, secondary structure in solution but assume distinct conformations when bound to substrates such as DNA or other proteins. Their intrinsic flexibility allows the HMGI/Y proteins to participate in specific protein-DNA and protein-protein interactions that induce both structural changes in chromatin substrates and the formation of stereospecific complexes called 'enhanceosomes' on the promoter/enhancer regions of genes whose transcription they regulate. The formation of such regulatory complexes is characterized by reciprocal inductions of conformational changes in both the HMGI/Y proteins themselves and in their interacting substrates. It may well be that the inherent flexibility of the HMGI/Y proteins, combined with their ability to undergo reversible disordered-to-ordered structural transitions, has been a significant factor in the evolutionary selection of these proteins for their functional role(s) in cells.
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Affiliation(s)
- R Reeves
- Department of Biochemistry/Biophysics, School of Molecular Biosciences, Washington State University, Pullman, WA 99164-4660, USA.
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Forzani C, Loulergue C, Lobréaux S, Briat JF, Lebrun M. Nickel resistance and chromatin condensation in Saccharomyces cerevisiae expressing a maize high mobility group I/Y protein. J Biol Chem 2001; 276:16731-8. [PMID: 11278346 DOI: 10.1074/jbc.m007462200] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Expression of a maize cDNA encoding a high mobility group (HMG) I/Y protein enables growth of transformed yeast on a medium containing toxic nickel concentrations. No difference in the nickel content was measured between yeast cells expressing either the empty vector or the ZmHMG I/Y2 cDNA. The ZmHMG I/Y2 protein contains four AT hook motifs known to be involved in binding to the minor groove of AT-rich DNA regions. HMG I/Y proteins may act as architectural elements modifying chromatin structure. Indeed, a ZmHMG I/Y2-green fluorescent protein fusion protein was observed in yeast nuclei. Nickel toxicity has been suggested to occur through an epigenetic mechanism related to chromatin condensation and DNA methylation, leading to the silencing of neighboring genes. Therefore, the ZmHMG I/Y2 protein could prevent nickel toxicity by interfering with chromatin structure. Yeast cell growth in the presence of nickel and yeast cells expressing the ZmHMG I/Y2 cDNA increased telomeric URA3 gene silencing. Furthermore, ZmHMG I/Y2 restored a wild-type level of nickel sensitivity to the yeast (Delta)rpd3 mutant. Therefore, nickel resistance of yeast cells expressing the ZmHMG I/Y2 cDNA is likely achieved by chromatin structure modification, restricting nickel accessibility to DNA.
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Affiliation(s)
- C Forzani
- Biochimie et Physiologie Moléculaire des Plantes, CNRS Unité Mixte de Recherche 5004, Université Montpellier 2, Institut National de la Recherche Agronomique, Ecole Nationale Supérieure d'Agronomie, 2 place Viala, F-34060 Montpellier Cedex 1, France
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Zhao J, Grafi G. The High Mobility Group I/Y Protein Is Hypophosphorylated in Endoreduplicating Maize Endosperm Cells and Is Involved in Alleviating Histone H1-mediated Transcriptional Repression. J Biol Chem 2000. [DOI: 10.1016/s0021-9258(19)61535-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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