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Mullin NP, Varghese J, Colby D, Richardson JM, Findlay GM, Chambers I. Phosphorylation of NANOG by casein kinase I regulates embryonic stem cell self-renewal. FEBS Lett 2021; 595:14-25. [PMID: 33107035 PMCID: PMC7839479 DOI: 10.1002/1873-3468.13969] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 10/13/2020] [Accepted: 10/15/2020] [Indexed: 12/24/2022]
Abstract
The self-renewal efficiency of mouse embryonic stem cells (ESCs) is determined by the concentration of the transcription factor NANOG. While NANOG binds thousands of sites in chromatin, the regulatory systems that control DNA binding are poorly characterised. Here, we show that NANOG is phosphorylated by casein kinase I, and identify target residues. Phosphomimetic substitutions at phosphorylation sites within the homeodomain (S130 and S131) have site-specific functional effects. Phosphomimetic substitution of S130 abolishes DNA binding by NANOG and eliminates LIF-independent self-renewal. In contrast, phosphomimetic substitution of S131 enhances LIF-independent self-renewal, without influencing DNA binding. Modelling the DNA-homeodomain complex explains the disparate effects of these phosphomimetic substitutions. These results indicate how phosphorylation may influence NANOG homeodomain interactions that underpin ESC self-renewal.
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Affiliation(s)
- Nicholas P. Mullin
- Centre for Regenerative MedicineInstitute for Stem Cell ResearchSchool of Biological SciencesUniversity of EdinburghUK
| | - Joby Varghese
- Protein Phosphorylation and Ubiquitylation UnitJames Black CentreSchool of Life SciencesDundeeUK
| | - Douglas Colby
- Centre for Regenerative MedicineInstitute for Stem Cell ResearchSchool of Biological SciencesUniversity of EdinburghUK
| | - Julia M. Richardson
- Institute of Quantitative Biology, Biochemistry and BiotechnologyEdinburghUK
| | - Greg M. Findlay
- Protein Phosphorylation and Ubiquitylation UnitJames Black CentreSchool of Life SciencesDundeeUK
| | - Ian Chambers
- Centre for Regenerative MedicineInstitute for Stem Cell ResearchSchool of Biological SciencesUniversity of EdinburghUK
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2
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Mullin NP, Gagliardi A, Khoa LTP, Colby D, Hall-Ponsele E, Rowe AJ, Chambers I. Distinct Contributions of Tryptophan Residues within the Dimerization Domain to Nanog Function. J Mol Biol 2016; 429:1544-1553. [PMID: 27939294 PMCID: PMC5446312 DOI: 10.1016/j.jmb.2016.12.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 11/18/2016] [Accepted: 12/01/2016] [Indexed: 12/02/2022]
Abstract
The level of the transcription factor Nanog directly determines the efficiency of mouse embryonic stem cell self-renewal. Nanog protein exists as a dimer with the dimerization domain composed of a simple repeat region in which every fifth residue is a tryptophan, the tryptophan repeat (WR). Although WR is necessary to enable Nanog to confer LIF-independent self-renewal, the mechanism of dimerization and the effect of modulating dimerization strength have been unclear. Here we couple mutagenesis with functional and dimerization assays to show that the number of tryptophans within the WR is linked to the strength of homodimerization, Sox2 heterodimerization and self-renewal activity. A reduction in the number of tryptophan residues leads initially to a gradual reduction in activity before a precipitous reduction in activity occurs upon reduction in tryptophan number below eight. Further functional attrition follows subsequent tryptophan number reduction with substitution of all tryptophan residues ablating dimerization and self-renewal function completely. A strong positional influence of tryptophans exists, with residues at the WR termini contributing more to Nanog function, particularly at the N-terminal end. Limited proteolysis demonstrates that a structural core of Nanog encompassing the homeodomain and the tryptophan repeat can support LIF-independent colony formation. These results increase understanding of the molecular interactions occurring between transcription factor subunits at the core of the pluripotency gene regulatory network and will enhance our ability to control pluripotent cell self-renewal and differentiation. The Nanog tryptophan repeat (WR) is required for LIF-independent mouse embryonic stem cell self-renewal. Tryptophans within WR give a graded increase in self-renewal and dimerization. Tryptophans at the WR extremities contribute disproportionally to Nanog function. A structural core of Nanog containing WR can drive LIF-independent self-renewal. Results clarify the contribution of tryptophan residues within WR to Nanog function.
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Affiliation(s)
- Nicholas P Mullin
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, 5 Little France Drive, Edinburgh EH16 4UU, UK.
| | - Alessia Gagliardi
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, 675 West 10th Avenue, Vancouver, BC, Canada V5Z 1L3
| | - Le Tran Phuc Khoa
- Department of Anatomy and Embryology, PhD Program in Human Biology, School of Integrative and Global Majors, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Douglas Colby
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, 5 Little France Drive, Edinburgh EH16 4UU, UK
| | - Elisa Hall-Ponsele
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, 5 Little France Drive, Edinburgh EH16 4UU, UK
| | - Arthur J Rowe
- NCMH Business Centre, School of Biosciences, University of Nottingham, Sutton Bonington, Leicestershire LE12 5RD, UK
| | - Ian Chambers
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, 5 Little France Drive, Edinburgh EH16 4UU, UK.
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Yang F, Zhang J, Liu Y, Cheng D, Wang H. Structure and functional evaluation of porcine NANOG that is a single-exon gene and has two pseudogenes. Int J Biochem Cell Biol 2015; 59:142-52. [DOI: 10.1016/j.biocel.2014.12.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 12/11/2014] [Accepted: 12/15/2014] [Indexed: 12/25/2022]
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Lineage-restricted function of the pluripotency factor NANOG in stratified epithelia. Nat Commun 2014; 5:4226. [PMID: 24979572 DOI: 10.1038/ncomms5226] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 05/23/2014] [Indexed: 12/22/2022] Open
Abstract
NANOG is a pluripotency transcription factor in embryonic stem cells; however, its role in adult tissues remains largely unexplored. Here we show that mouse NANOG is selectively expressed in stratified epithelia, most notably in the oesophagus where the Nanog promoter is hypomethylated. Interestingly, inducible ubiquitous overexpression of NANOG in mice causes hyperplasia selectively in the oesophagus, in association with increased cell proliferation. NANOG transcriptionally activates the mitotic programme, including Aurora A kinase (Aurka), in stratified epithelia, and endogenous NANOG directly binds to the Aurka promoter in primary keratinocytes. Interestingly, overexpression of Nanog or Aurka in mice increased proliferation and aneuploidy in the oesophageal basal epithelium. Finally, inactivation of NANOG in cell lines from oesophageal or head and neck squamous cell carcinomas (ESCCs or HNSCCs, respectively) results in lower levels of AURKA and decreased proliferation, and NANOG and AURKA expression are positively correlated in HNSCCs. Together, these results indicate that NANOG has a lineage-restricted mitogenic function in stratified epithelia.
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Saunders A, Faiola F, Wang J. Concise review: pursuing self-renewal and pluripotency with the stem cell factor Nanog. Stem Cells 2014; 31:1227-36. [PMID: 23653415 DOI: 10.1002/stem.1384] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 03/04/2013] [Indexed: 01/06/2023]
Abstract
Pluripotent embryonic stem cells and induced pluripotent stem cells hold great promise for future use in tissue replacement therapies due to their ability to self-renew indefinitely and to differentiate into all adult cell types. Harnessing this therapeutic potential efficiently requires a much deeper understanding of the molecular processes at work within the pluripotency network. The transcription factors Nanog, Oct4, and Sox2 reside at the core of this network, where they interact and regulate their own expression as well as that of numerous other pluripotency factors. Of these core factors, Nanog is critical for blocking the differentiation of pluripotent cells, and more importantly, for establishing the pluripotent ground state during somatic cell reprogramming. Both mouse and human Nanog are able to form dimers in vivo, allowing them to preferentially interact with certain factors and perform unique functions. Recent studies have identified an evolutionary functional conservation among vertebrate Nanog orthologs from chick, zebrafish, and the axolotl salamander, adding an additional layer of complexity to Nanog function. Here, we present a detailed overview of published work focusing on Nanog structure, function, dimerization, and regulation at the genetic and post-translational levels with regard to the establishment and maintenance of pluripotency. The full spectrum of Nanog function in pluripotent stem cells and in cancer is only beginning to be revealed. We therefore use this evidence to advocate for more comprehensive analysis of Nanog in the context of disease, development, and regeneration.
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Affiliation(s)
- Arven Saunders
- Department of Developmental and Regenerative Biology, Black Family Stem Cell Institute, New York, NY, USA
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Scerbo P, Markov GV, Vivien C, Kodjabachian L, Demeneix B, Coen L, Girardot F. On the origin and evolutionary history of NANOG. PLoS One 2014; 9:e85104. [PMID: 24465486 PMCID: PMC3894937 DOI: 10.1371/journal.pone.0085104] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 11/22/2013] [Indexed: 11/27/2022] Open
Abstract
Though pluripotency is well characterized in mammals, many questions remain to be resolved regarding its evolutionary history. A necessary prerequisite for addressing this issue is to determine the phylogenetic distributions and orthology relationships of the transcription factor families sustaining or modulating this property. In mammals, the NANOG homeodomain transcription factor is one of the core players in the pluripotency network. However, its evolutionary history has not been thoroughly studied, hindering the interpretation of comparative studies. To date, the NANOG family was thought to be monogenic, with numerous pseudogenes described in mammals, including a tandem duplicate in Hominidae. By examining a wide-array of craniate genomes, we provide evidence that the NANOG family arose at the latest in the most recent common ancestor of osteichthyans and that NANOG genes are frequently found as tandem duplicates in sarcopterygians and as a single gene in actinopterygians. Their phylogenetic distribution is thus reminiscent of that recently shown for Class V POU paralogues, another key family of pluripotency-controlling factors. However, while a single ancestral duplication has been reported for the Class V POU family, we suggest that multiple independent duplication events took place during evolution of the NANOG family. These multiple duplications could have contributed to create a layer of complexity in the control of cell competence and pluripotency, which could explain the discrepancies relative to the functional evolution of this important gene family. Further, our analysis does not support the hypothesis that loss of NANOG and emergence of the preformation mode of primordial germ cell specification are causally linked. Our study therefore argues for the need of further functional comparisons between NANOG paralogues, notably regarding the novel duplicates identified in sauropsids and non-eutherian mammals.
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Affiliation(s)
- Pierluigi Scerbo
- Département Régulations, Développement et Diversité Moléculaire, Muséum National d'Histoire Naturelle, Centre National de la Recherche Scientifique, Paris, France
- Institut de Biologie du Développement de Marseille, Aix-Marseille Université, Centre National de la Recherche Scientifique, Marseille, France
| | - Gabriel V. Markov
- Département Régulations, Développement et Diversité Moléculaire, Muséum National d'Histoire Naturelle, Centre National de la Recherche Scientifique, Paris, France
- Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, Ecole Normale Supérieure de Lyon, Centre National de la Recherche Scientifique, Lyon, France
- Department for Evolutionary Biology, Max-Planck-Institute for Developmental Biology, Tuebingen, Germany
| | - Céline Vivien
- Département Régulations, Développement et Diversité Moléculaire, Muséum National d'Histoire Naturelle, Centre National de la Recherche Scientifique, Paris, France
- WatchFrog S.A., Evry, France
| | - Laurent Kodjabachian
- Institut de Biologie du Développement de Marseille, Aix-Marseille Université, Centre National de la Recherche Scientifique, Marseille, France
| | - Barbara Demeneix
- Département Régulations, Développement et Diversité Moléculaire, Muséum National d'Histoire Naturelle, Centre National de la Recherche Scientifique, Paris, France
| | - Laurent Coen
- Département Régulations, Développement et Diversité Moléculaire, Muséum National d'Histoire Naturelle, Centre National de la Recherche Scientifique, Paris, France
| | - Fabrice Girardot
- Département Régulations, Développement et Diversité Moléculaire, Muséum National d'Histoire Naturelle, Centre National de la Recherche Scientifique, Paris, France
- * E-mail:
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Shin M, Alev C, Wu Y, Nagai H, Sheng G. Activin/TGF-beta signaling regulates Nanog expression in the epiblast during gastrulation. Mech Dev 2011; 128:268-78. [PMID: 21402155 DOI: 10.1016/j.mod.2011.03.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Revised: 03/03/2011] [Accepted: 03/07/2011] [Indexed: 01/26/2023]
Abstract
Nanog is required for the maintenance of cellular pluripotency during normal development and in cultured embryonic stem cells. A number of signaling pathways have been implicated in regulating Nanog gene expression in vitro. Using the chick model, we provide in vivo evidence for the involvement of the Activin/TGF-beta signaling pathway in regulating Nanog expression in epiblast cells during gastrulation. Nanog expression in primordial germ cells is not regulated by this pathway, indicating that these two cell types employ different mechanisms for maintaining pluripotency in early development. Furthermore, our data suggest that the bHLH factor E2A plays a role in negatively regulating Nanog expression in vivo. Overall, our data support a direct and positive role of the Smad2/3 mediated TGF-beta signaling pathway in inducing/maintaining Nanog expression.
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Affiliation(s)
- Masahiro Shin
- Laboratory for Early Embryogenesis, RIKEN Center for Developmental Biology, Kobe, Japan
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Lee SH, Jeyapalan JN, Appleby V, Mohamed Noor DA, Sottile V, Scotting PJ. Dynamic methylation and expression of Oct4 in early neural stem cells. J Anat 2010; 217:203-13. [PMID: 20646110 DOI: 10.1111/j.1469-7580.2010.01269.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Neural stem cells are a multipotent population of tissue-specific stem cells with a broad but limited differentiation potential. However, recent studies have shown that over-expression of the pluripotency gene, Oct4, alone is sufficient to initiate a process by which these can form 'induced pluripotent stem cells' (iPS cells) with the same broad potential as embryonic stem cells. This led us to examine the expression of Oct4 in endogenous neural stem cells, as data regarding its expression in neural stem cells in vivo are contradictory and incomplete. In this study we have therefore analysed the expression of Oct4 and other genes associated with pluripotency throughout development of the mouse CNS and in neural stem cells grown in vitro. We find that Oct4 is still expressed in the CNS by E8.5, but that this expression declines rapidly until it is undetectable by E15.5. This decline is coincident with the gradual methylation of the Oct4 promoter and proximal enhancer. Immunostaining suggests that the Oct4 protein is predominantly cytoplasmic in location. We also found that neural stem cells from all ages expressed the pluripotency associated genes, Sox2, c-Myc, Klf4 and Nanog. These data provide an explanation for the varying behaviour of cells from the early neuroepithelium at different stages of development. The expression of these genes also provides an indication of why Oct4 alone is sufficient to induce iPS formation in neural stem cells at later stages.
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Affiliation(s)
- Shih-Han Lee
- Children's Brain Tumour Research Centre, Institute of Genetics, University of Nottingham, Queen's Medical Centre, Nottingham, UK
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Kuijk EW, de Gier J, Lopes SMCDS, Chambers I, van Pelt AMM, Colenbrander B, Roelen BAJ. A distinct expression pattern in mammalian testes indicates a conserved role for NANOG in spermatogenesis. PLoS One 2010; 5:e10987. [PMID: 20539761 PMCID: PMC2881870 DOI: 10.1371/journal.pone.0010987] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2010] [Accepted: 05/14/2010] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND NANOG is a key player in pluripotency and its expression is restricted to pluripotent cells of the inner cell mass, the epiblast and to primordial germ cells. Spermatogenesis is closely associated with pluripotency, because through this process highly specialized sperm cells are produced that contribute to the formation of totipotent zygotes. Nevertheless, it is unknown if NANOG plays a role in this process. METHODOLOGY/PRINCIPAL FINDINGS In the current study, NANOG expression was examined in testes of various mammals, including mouse and human. Nanog mRNA and NANOG protein were detected by RT-PCR, immunohistochemistry, and western blotting. Furthermore, eGFP expression was detected in the testis of a transgenic Nanog eGFP-reporter mouse. Surprisingly, although NANOG expression has previously been associated with undifferentiated cells with stem cell potential, expression in the testis was observed in pachytene spermatocytes and in the first steps of haploid germ cell maturation (spermiogenesis). Weak expression in type A spermatogonia was also observed. CONCLUSIONS The findings of the current study strongly suggest a conserved role for NANOG in meiotic and post-meiotic stages of male germ cell development.
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Affiliation(s)
- Ewart W Kuijk
- Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
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Liedtke S, Enczmann J, Waclawczyk S, Wernet P, Kögler G. Oct4 and its pseudogenes confuse stem cell research. Cell Stem Cell 2008; 1:364-6. [PMID: 18371374 DOI: 10.1016/j.stem.2007.09.003] [Citation(s) in RCA: 182] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Revised: 08/29/2007] [Accepted: 09/13/2007] [Indexed: 11/30/2022]
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Abstract
The defining activity of the homeodomain protein Nanog is the ability to confer cytokine-independent self-renewal upon ES (embryonic stem) cells in which it is overexpressed. However, the biochemical basis by which Nanog achieves this function remains unknown. In the present study, we show that Nanog dimerizes through a functionally critical domain. Co-immunoprecipitation of Nanog molecules tagged with distinct epitopes demonstrates that Nanog self-associates through a region in which every fifth residue is tryptophan. In vitro binding experiments establish that this region participates directly in self-association. Moreover, analytical ultracentrifugation indicates that, in solution, Nanog is in equilibrium between monomeric and dimeric forms with a K(d) of 3 muM. The functional importance of Nanog dimerization is established by ES cell colony-forming assays in which deletion of the tryptophan-repeat region eliminates the capacity of Nanog to direct LIF (leukaemia inhibitory factor)-independent self-renewal.
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Nanog safeguards pluripotency and mediates germline development. Nature 2007; 450:1230-4. [DOI: 10.1038/nature06403] [Citation(s) in RCA: 1204] [Impact Index Per Article: 70.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2007] [Accepted: 10/22/2007] [Indexed: 01/04/2023]
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