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Griffin C, Saint-Jeannet JP. In vitro modeling of cranial placode differentiation: Recent advances, challenges, and perspectives. Dev Biol 2024; 506:20-30. [PMID: 38052294 PMCID: PMC10843546 DOI: 10.1016/j.ydbio.2023.11.009] [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: 05/26/2023] [Revised: 11/27/2023] [Accepted: 11/29/2023] [Indexed: 12/07/2023]
Abstract
Cranial placodes are transient ectodermal thickenings that contribute to a diverse array of organs in the vertebrate head. They develop from a common territory, the pre-placodal region that over time segregates along the antero-posterior axis into individual placodal domains: the adenohypophyseal, olfactory, lens, trigeminal, otic, and epibranchial placodes. These placodes terminally differentiate into the anterior pituitary, the lens, and contribute to sensory organs including the olfactory epithelium, and inner ear, as well as several cranial ganglia. To study cranial placodes and their derivatives and generate cells for therapeutic purposes, several groups have turned to in vitro derivation of placodal cells from human embryonic stem cells (hESCs) or induced pluripotent stem cells (hiPSCs). In this review, we summarize the signaling cues and mechanisms involved in cranial placode induction, specification, and differentiation in vivo, and discuss how this knowledge has informed protocols to derive cranial placodes in vitro. We also discuss the benefits and limitations of these protocols, and the potential of in vitro cranial placode modeling in regenerative medicine to treat cranial placode-related pathologies.
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Affiliation(s)
- Casey Griffin
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY, 10010, USA
| | - Jean-Pierre Saint-Jeannet
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY, 10010, USA.
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2
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Fogliano C, Carotenuto R, Rusciano G, Sasso A, Motta CM, Agnisola C, Avallone B. Structural and functional damage to the retina and skeletal muscle in Xenopus laevis embryos exposed to the commonly used psychotropic benzodiazepine delorazepam. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2023; 102:104235. [PMID: 37481049 DOI: 10.1016/j.etap.2023.104235] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 07/03/2023] [Accepted: 07/18/2023] [Indexed: 07/24/2023]
Abstract
Benzodiazepines, psychotropic drugs, are among the most frequently found pharmaceuticals in aquatic matrices. An increasing number of studies are reporting their harmful effects on adults' behaviour and physiology, while little information is available regarding developing organisms exposed since early stages. Improper activation of GABA receptors during embryonic development is likely to induce relevant consequences on the morphogenesis and, at later stages, on behaviour. This study investigated the negative effects of three increasing concentrations of delorazepam on Xenopus laevis retinal and skeletal muscle morphogenesis. Morphological and ultrastructural investigations were correlated with gene expression, while Raman spectroscopy highlighted the main biochemical components affected. Conventional phototactic response and orientation in the magnetic field were assessed as indicators of proper interaction between sensory organs and the nervous system. Results confirm the profound impact of delorazepam on development and return an alarming picture of the amphibians' survival potentialities in a benzodiazepine-contaminated environment.
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Affiliation(s)
- Chiara Fogliano
- Department of Biology, University of Naples Federico II, Naples, Italy
| | - Rosa Carotenuto
- Department of Biology, University of Naples Federico II, Naples, Italy
| | - Giulia Rusciano
- Department of Physics, University of Naples Federico II, Naples, Italy
| | - Antonio Sasso
- Department of Physics, University of Naples Federico II, Naples, Italy
| | | | - Claudio Agnisola
- Department of Biology, University of Naples Federico II, Naples, Italy
| | - Bice Avallone
- Department of Biology, University of Naples Federico II, Naples, Italy
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3
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Swamynathan SK, Swamynathan S. Corneal epithelial development and homeostasis. Differentiation 2023; 132:4-14. [PMID: 36870804 PMCID: PMC10363238 DOI: 10.1016/j.diff.2023.02.002] [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: 10/26/2022] [Revised: 01/27/2023] [Accepted: 02/20/2023] [Indexed: 03/06/2023]
Abstract
The corneal epithelium (CE), the most anterior cellular structure of the eye, is a self-renewing stratified squamous tissue that protects the rest of the eye from external elements. Each cell in this exquisite three-dimensional structure needs to have proper polarity and positional awareness for the CE to serve as a transparent, refractive, and protective tissue. Recent studies have begun to elucidate the molecular and cellular events involved in the embryonic development, post-natal maturation, and homeostasis of the CE, and how they are regulated by a well-coordinated network of transcription factors. This review summarizes the status of related knowledge and aims to provide insight into the pathophysiology of disorders caused by disruption of CE development, and/or homeostasis.
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Affiliation(s)
| | - Sudha Swamynathan
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
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Koontz A, Urrutia HA, Bronner ME. Making a head: Neural crest and ectodermal placodes in cranial sensory development. Semin Cell Dev Biol 2023; 138:15-27. [PMID: 35760729 PMCID: PMC10224775 DOI: 10.1016/j.semcdb.2022.06.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 04/11/2022] [Accepted: 06/19/2022] [Indexed: 01/04/2023]
Abstract
During development of the vertebrate sensory system, many important components like the sense organs and cranial sensory ganglia arise within the head and neck. Two progenitor populations, the neural crest, and cranial ectodermal placodes, contribute to these developing vertebrate peripheral sensory structures. The interactions and contributions of these cell populations to the development of the lens, olfactory, otic, pituitary gland, and cranial ganglia are vital for appropriate peripheral nervous system development. Here, we review the origins of both neural crest and placode cells at the neural plate border of the early vertebrate embryo and investigate the molecular and environmental signals that influence specification of different sensory regions. Finally, we discuss the underlying molecular pathways contributing to the complex vertebrate sensory system from an evolutionary perspective, from basal vertebrates to amniotes.
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Affiliation(s)
- Alison Koontz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Hugo A Urrutia
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Marianne E Bronner
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
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Chang W, Zhao Y, Rayêe D, Xie Q, Suzuki M, Zheng D, Cvekl A. Dynamic changes in whole genome DNA methylation, chromatin and gene expression during mouse lens differentiation. Epigenetics Chromatin 2023; 16:4. [PMID: 36698218 PMCID: PMC9875507 DOI: 10.1186/s13072-023-00478-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 01/17/2023] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Cellular differentiation is marked by temporally and spatially coordinated gene expression regulated at multiple levels. DNA methylation represents a universal mechanism to control chromatin organization and its accessibility. Cytosine methylation of CpG dinucleotides regulates binding of methylation-sensitive DNA-binding transcription factors within regulatory regions of transcription, including promoters and distal enhancers. Ocular lens differentiation represents an advantageous model system to examine these processes as lens comprises only two cell types, the proliferating lens epithelium and postmitotic lens fiber cells all originating from the epithelium. RESULTS Using whole genome bisulfite sequencing (WGBS) and microdissected lenses, we investigated dynamics of DNA methylation and chromatin changes during mouse lens fiber and epithelium differentiation between embryos (E14.5) and newborns (P0.5). Histone H3.3 variant chromatin landscapes were also generated for both P0.5 lens epithelium and fibers by chromatin immunoprecipitation followed by next generation sequencing (ChIP-seq). Tissue-specific features of DNA methylation patterns are demonstrated via comparative studies with embryonic stem (ES) cells and neural progenitor cells (NPCs) at Nanog, Pou5f1, Sox2, Pax6 and Six3 loci. Comparisons with ATAC-seq and RNA-seq data demonstrate that reduced methylation is associated with increased expression of fiber cell abundant genes, including crystallins, intermediate filament (Bfsp1 and Bfsp2) and gap junction proteins (Gja3 and Gja8), marked by high levels of histone H3.3 within their transcribed regions. Interestingly, Pax6-binding sites exhibited predominantly DNA hypomethylation in lens chromatin. In vitro binding of Pax6 proteins showed Pax6's ability to interact with sites containing one or two methylated CpG dinucleotides. CONCLUSIONS Our study has generated the first data on methylation changes between two different stages of mammalian lens development and linked these data with chromatin accessibility maps, presence of histone H3.3 and gene expression. Reduced DNA methylation correlates with expression of important genes involved in lens morphogenesis and lens fiber cell differentiation.
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Affiliation(s)
- William Chang
- Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Yilin Zhao
- Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Danielle Rayêe
- Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Qing Xie
- Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- University of California Santa Cruz, Santa Cruz, CA, 95064, USA
| | - Masako Suzuki
- Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Deyou Zheng
- Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Neurology and Neuroscience, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Ales Cvekl
- Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
- Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
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Tian C, Duan L, Fu C, He J, Dai J, Zhu G. Study on the Correlation Between Iris Characteristics and Schizophrenia. Neuropsychiatr Dis Treat 2022; 18:811-820. [PMID: 35431547 PMCID: PMC9005354 DOI: 10.2147/ndt.s361614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 04/01/2022] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Recently, researchers have conducted many studies on the potential contribution of the retina and other eye structures on schizophrenia. This study aimed to evaluate differences in iris characteristics between patients with schizophrenia and healthy individuals so as to find more easily accessible and easily measurable biomarkers with a view to improving clinical assessments and furthering our understanding of the disease. METHODS Overall, 80 patients with schizophrenia and 52 healthy individuals were included in the case group and the control group, respectively. Iris images were collected from all subjects to compare differences in the structure and color of the iris. The Positive and Negative Symptom Scale (PANSS) and the Modified Overt Aggression Scale (MOAS) were used to evaluate the clinical symptoms and characteristics of 45 first-episode untreated schizophrenics, and analyzed correlations between iris characteristics and schizophrenia symptoms. RESULTS There were significant differences in iris crypts (P<0.05) and pigment spots (P<0.01) between the case and control group, but no significant difference was found in iris wrinkles (P<0.05). The logistic regression analysis demonstrated that the total iris crypts [odds ratio (OR) 1.166, 95% confidence interval (CI) 1.022-1.330] and total iris pigment spots (OR 1.815, 95% CI 1.186-2.775) increased the risk of suffering from schizophrenia. Furthermore, it was demonstrated that the number of iris crypts was positively associated with the MOAS score (r=0.474, P<0.01). Moreover, the number of the iris pigment spots (r=0.395, P<0.01) and wrinkles (r=0.309, P<0.05) were positively correlated with the subjects' negative symptom scores, respectively. CONCLUSION Iris crypts and pigment spots were identified as potential biomarkers for detecting schizophrenia. In patients with first-episode untreated schizophrenia, iris characteristics may help psychiatrists to identify the illness and its severity, and to detect characteristic clinical symptoms.
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Affiliation(s)
- Chunsheng Tian
- Department of Psychiatry, The First Affiliated Hospital of China Medical University, Shenyang, 110001, People's Republic of China.,Shenyang Mental Health Center, Shenyang, 110168, People's Republic of China
| | - Li Duan
- Department of Psychiatry, The First Affiliated Hospital of China Medical University, Shenyang, 110001, People's Republic of China.,School of Nursing, Chengde Medical University, Chengde, 067000, People's Republic of China
| | - Chunfeng Fu
- Department of Psychiatry, The First Affiliated Hospital of China Medical University, Shenyang, 110001, People's Republic of China
| | - Juan He
- Department of Psychiatry, The First Affiliated Hospital of China Medical University, Shenyang, 110001, People's Republic of China
| | - Jiali Dai
- Department of Psychiatry, The First Affiliated Hospital of China Medical University, Shenyang, 110001, People's Republic of China
| | - Gang Zhu
- Department of Psychiatry, The First Affiliated Hospital of China Medical University, Shenyang, 110001, People's Republic of China
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Meurer L, Ferdman L, Belcher B, Camarata T. The SIX Family of Transcription Factors: Common Themes Integrating Developmental and Cancer Biology. Front Cell Dev Biol 2021; 9:707854. [PMID: 34490256 PMCID: PMC8417317 DOI: 10.3389/fcell.2021.707854] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 06/28/2021] [Indexed: 01/19/2023] Open
Abstract
The sine oculis (SIX) family of transcription factors are key regulators of developmental processes during embryogenesis. Members of this family control gene expression to promote self-renewal of progenitor cell populations and govern mechanisms of cell differentiation. When the function of SIX genes becomes disrupted, distinct congenital defects develops both in animal models and humans. In addition to the embryonic setting, members of the SIX family have been found to be critical regulators of tumorigenesis, promoting cell proliferation, epithelial-to-mesenchymal transition, and metastasis. Research in both the fields of developmental biology and cancer research have provided an extensive understanding of SIX family transcription factor functions. Here we review recent progress in elucidating the role of SIX family genes in congenital disease as well as in the promotion of cancer. Common themes arise when comparing SIX transcription factor function during embryonic and cancer development. We highlight the complementary nature of these two fields and how knowledge in one area can open new aspects of experimentation in the other.
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Affiliation(s)
- Logan Meurer
- Department of Basic Sciences, NYIT College of Osteopathic Medicine at Arkansas State University, Jonesboro, AR, United States
| | - Leonard Ferdman
- Department of Basic Sciences, NYIT College of Osteopathic Medicine at Arkansas State University, Jonesboro, AR, United States
| | - Beau Belcher
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR, United States
| | - Troy Camarata
- Department of Basic Sciences, NYIT College of Osteopathic Medicine at Arkansas State University, Jonesboro, AR, United States
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8
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Lima Cunha D, Arno G, Corton M, Moosajee M. The Spectrum of PAX6 Mutations and Genotype-Phenotype Correlations in the Eye. Genes (Basel) 2019; 10:genes10121050. [PMID: 31861090 PMCID: PMC6947179 DOI: 10.3390/genes10121050] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 12/09/2019] [Accepted: 12/12/2019] [Indexed: 12/13/2022] Open
Abstract
The transcription factor PAX6 is essential in ocular development in vertebrates, being considered the master regulator of the eye. During eye development, it is essential for the correct patterning and formation of the multi-layered optic cup and it is involved in the developing lens and corneal epithelium. In adulthood, it is mostly expressed in cornea, iris, and lens. PAX6 is a dosage-sensitive gene and it is highly regulated by several elements located upstream, downstream, and within the gene. There are more than 500 different mutations described to affect PAX6 and its regulatory regions, the majority of which lead to PAX6 haploinsufficiency, causing several ocular and systemic abnormalities. Aniridia is an autosomal dominant disorder that is marked by the complete or partial absence of the iris, foveal hypoplasia, and nystagmus, and is caused by heterozygous PAX6 mutations. Other ocular abnormalities have also been associated with PAX6 changes, and genotype-phenotype correlations are emerging. This review will cover recent advancements in PAX6 regulation, particularly the role of several enhancers that are known to regulate PAX6 during eye development and disease. We will also present an updated overview of the mutation spectrum, where an increasing number of mutations in the non-coding regions have been reported. Novel genotype-phenotype correlations will also be discussed.
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Affiliation(s)
| | - Gavin Arno
- Institute of Ophthalmology, UCL, London EC1V 9EL, UK
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
| | - Marta Corton
- Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital—Universidad Autónoma de Madrid (IIS-FJD, UAM), 28040 Madrid, Spain
- Centre for Biomedical Network Research on Rare Diseases (CIBERER), 28029 Madrid, Spain
| | - Mariya Moosajee
- Institute of Ophthalmology, UCL, London EC1V 9EL, UK
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
- Correspondence:
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9
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The genetic architecture of aniridia and Gillespie syndrome. Hum Genet 2018; 138:881-898. [PMID: 30242502 PMCID: PMC6710220 DOI: 10.1007/s00439-018-1934-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Accepted: 09/06/2018] [Indexed: 12/13/2022]
Abstract
Absence of part or all of the iris, aniridia, is a feature of several genetically distinct conditions. This review focuses on iris development and then the clinical features and molecular genetics of these iris malformations. Classical aniridia, a panocular eye malformation including foveal hypoplasia, is the archetypal phenotype associated with heterozygous PAX6 loss-of-function mutations. Since this was identified in 1991, many genetic mechanisms of PAX6 inactivation have been elucidated, the commonest alleles being intragenic mutations causing premature stop codons, followed by those causing C-terminal extensions. Rarely, aniridia cases are associated with FOXC1, PITX2 and/or their regulatory regions. Aniridia can also occur as a component of many severe global eye malformations. Gillespie syndrome—a triad of partial aniridia, non-progressive cerebellar ataxia and intellectual disability—is phenotypically and genotypically distinct from classical aniridia. The causative gene has recently been identified as ITPR1. The same characteristic Gillespie syndrome-like iris, with aplasia of the pupillary sphincter and a scalloped margin, is seen in ACTA2-related multisystemic smooth muscle dysfunction syndrome. WAGR syndrome (Wilms tumour, aniridia, genitourinary anomalies and mental retardation/intellectual disability), is caused by contiguous deletion of PAX6 and WT1 on chromosome 11p. Deletions encompassing BDNF have been causally implicated in the obesity and intellectual disability associated with the condition. Lastly, we outline a genetic investigation strategy for aniridia in light of recent developments, suggesting an approach based principally on chromosomal array and gene panel testing. This strategy aims to test all known aniridia loci—including the rarer, life-limiting causes—whilst remaining simple and practical.
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Kinare V, Shetty AS, Suresh A, Tole S. PAX6 can substitute for LHX2 and override NFIA-induced astrogliogenesis in developing hippocampus in vivo. J Biosci 2018; 43:75-83. [PMID: 29485116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In the developing central nervous system, transcription factors play a crucial role in the regulation of cell fate. Previously we demonstrated that LHX2 is a critical regulator of the neuron-glia cell fate switch in the developing mouse hippocampus. Here, we test LHX2 target gene Pax6 for a role in this process. We report that Pax6 overexpression is able to suppress the enhanced astrogliogenesis arising due to loss of functional LHX2. Furthermore, we show that like Lhx2, Pax6 is also able to suppress induced astrogliogenesis caused by overexpression of progliogenic factor Nfia. This demonstrates that overexpression of Pax6 can substitute for Lhx2 in the regulation of the neuronal versus glial cell fate in the developing hippocampus, and therefore, supports a role for PAX6 as a mediator of LHX2 function in this process.
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Affiliation(s)
- Veena Kinare
- Department of Life Sciences, Sophia College for Women, Mumbai, India
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11
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Kinare V, Shetty AS, Suresh A, Tole S. PAX6 can substitute for LHX2 and override NFIA-induced astrogliogenesis in developing hippocampus in vivo. J Biosci 2018. [DOI: 10.1007/s12038-018-9731-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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12
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The Gene Regulatory Network of Lens Induction Is Wired through Meis-Dependent Shadow Enhancers of Pax6. PLoS Genet 2016; 12:e1006441. [PMID: 27918583 PMCID: PMC5137874 DOI: 10.1371/journal.pgen.1006441] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 10/21/2016] [Indexed: 01/03/2023] Open
Abstract
Lens induction is a classical developmental model allowing investigation of cell specification, spatiotemporal control of gene expression, as well as how transcription factors are integrated into highly complex gene regulatory networks (GRNs). Pax6 represents a key node in the gene regulatory network governing mammalian lens induction. Meis1 and Meis2 homeoproteins are considered as essential upstream regulators of Pax6 during lens morphogenesis based on their interaction with the ectoderm enhancer (EE) located upstream of Pax6 transcription start site. Despite this generally accepted regulatory pathway, Meis1-, Meis2- and EE-deficient mice have surprisingly mild eye phenotypes at placodal stage of lens development. Here, we show that simultaneous deletion of Meis1 and Meis2 in presumptive lens ectoderm results in arrested lens development in the pre-placodal stage, and neither lens placode nor lens is formed. We found that in the presumptive lens ectoderm of Meis1/Meis2 deficient embryos Pax6 expression is absent. We demonstrate using chromatin immunoprecipitation (ChIP) that in addition to EE, Meis homeoproteins bind to a remote, ultraconserved SIMO enhancer of Pax6. We further show, using in vivo gene reporter analyses, that the lens-specific activity of SIMO enhancer is dependent on the presence of three Meis binding sites, phylogenetically conserved from man to zebrafish. Genetic ablation of EE and SIMO enhancers demostrates their requirement for lens induction and uncovers an apparent redundancy at early stages of lens development. These findings identify a genetic requirement for Meis1 and Meis2 during the early steps of mammalian eye development. Moreover, they reveal an apparent robustness in the gene regulatory mechanism whereby two independent "shadow enhancers" maintain critical levels of a dosage-sensitive gene, Pax6, during lens induction.
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13
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Cvekl A, Callaerts P. PAX6: 25th anniversary and more to learn. Exp Eye Res 2016; 156:10-21. [PMID: 27126352 DOI: 10.1016/j.exer.2016.04.017] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 04/12/2016] [Accepted: 04/22/2016] [Indexed: 01/29/2023]
Abstract
The DNA-binding transcription factor PAX6 was cloned 25 years ago by multiple teams pursuing identification of human and mouse eye disease causing genes, cloning vertebrate homologues of pattern-forming regulatory genes identified in Drosophila, or abundant eye-specific transcripts. Since its discovery in 1991, genetic, cellular, molecular and evolutionary studies on Pax6 mushroomed in the mid 1990s leading to the transformative thinking regarding the genetic program orchestrating both early and late stages of eye morphogenesis as well as the origin and evolution of diverse visual systems. Since Pax6 is also expressed outside of the eye, namely in the central nervous system and pancreas, a number of important insights into the development and function of these organs have been amassed. In most recent years, genome-wide technologies utilizing massively parallel DNA sequencing have begun to provide unbiased insights into the regulatory hierarchies of specification, determination and differentiation of ocular cells and neurogenesis in general. This review is focused on major advancements in studies on mammalian eye development driven by studies of Pax6 genes in model organisms and future challenges to harness the technology-driven opportunities to reconstruct, step-by-step, the transition from naïve ectoderm, neuroepithelium and periocular mesenchyme/neural crest cells into the three-dimensional architecture of the eye.
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Affiliation(s)
- Ales Cvekl
- The Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; The Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
| | - Patrick Callaerts
- Laboratory of Behavioral and Developmental Genetics, K.U. Leuven, VIB, 3000, Leuven, Belgium.
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Beccari L, Marco-Ferreres R, Tabanera N, Manfredi A, Souren M, Wittbrodt B, Conte I, Wittbrodt J, Bovolenta P. A trans-Regulatory Code for the Forebrain Expression of Six3.2 in the Medaka Fish. J Biol Chem 2015; 290:26927-26942. [PMID: 26378230 PMCID: PMC4646366 DOI: 10.1074/jbc.m115.681254] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 09/11/2015] [Indexed: 12/16/2022] Open
Abstract
A well integrated and hierarchically organized gene regulatory network is responsible for the progressive specification of the forebrain. The transcription factor Six3 is one of the central components of this network. As such, Six3 regulates several components of the network, but its upstream regulators are still poorly characterized. Here we have systematically identified such regulators, taking advantage of the detailed functional characterization of the regulatory region of the medaka fish Six3.2 ortholog and of a time/cost-effective trans-regulatory screening, which complemented and overcame the limitations of in silico prediction approaches. The candidates resulting from this search were validated with dose-response luciferase assays and expression pattern criteria. Reconfirmed candidates with a matching expression pattern were also tested with chromatin immunoprecipitation and functional studies. Our results confirm the previously proposed direct regulation of Pax6 and further demonstrate that Msx2 and Pbx1 are bona fide direct regulators of early Six3.2 distribution in distinct domains of the medaka fish forebrain. They also point to other transcription factors, including Tcf3, as additional regulators of different spatial-temporal domains of Six3.2 expression. The activity of these regulators is discussed in the context of the gene regulatory network proposed for the specification of the forebrain.
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Affiliation(s)
- Leonardo Beccari
- Centro de Biología Molecular "Severo Ochoa," Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, c/ Nicolas Cabrera 1, Madrid 28049, Spain,; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), c/ Nicolas Cabrera 1, Madrid 28049, Spain; Instituto Cajal, Consejo Superior de Investigaciones Científicas, Avda. Dr. Arce 37, Madrid, 28002, Spain,.
| | - Raquel Marco-Ferreres
- Centro de Biología Molecular "Severo Ochoa," Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, c/ Nicolas Cabrera 1, Madrid 28049, Spain,; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), c/ Nicolas Cabrera 1, Madrid 28049, Spain; Instituto Cajal, Consejo Superior de Investigaciones Científicas, Avda. Dr. Arce 37, Madrid, 28002, Spain
| | - Noemi Tabanera
- Centro de Biología Molecular "Severo Ochoa," Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, c/ Nicolas Cabrera 1, Madrid 28049, Spain,; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), c/ Nicolas Cabrera 1, Madrid 28049, Spain; Instituto Cajal, Consejo Superior de Investigaciones Científicas, Avda. Dr. Arce 37, Madrid, 28002, Spain
| | - Anna Manfredi
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, Avda. Dr. Arce 37, Madrid, 28002, Spain
| | - Marcel Souren
- the Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Beate Wittbrodt
- the Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Ivan Conte
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, Avda. Dr. Arce 37, Madrid, 28002, Spain,; the Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, Pozzuoli, Naples, 80078, Italy
| | - Jochen Wittbrodt
- the Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Paola Bovolenta
- Centro de Biología Molecular "Severo Ochoa," Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, c/ Nicolas Cabrera 1, Madrid 28049, Spain,; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), c/ Nicolas Cabrera 1, Madrid 28049, Spain; Instituto Cajal, Consejo Superior de Investigaciones Científicas, Avda. Dr. Arce 37, Madrid, 28002, Spain,.
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Lens Development and Crystallin Gene Expression. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 134:129-67. [DOI: 10.1016/bs.pmbts.2015.05.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Anchan RM, Lachke SA, Gerami-Naini B, Lindsey J, Ng N, Naber C, Nickerson M, Cavallesco R, Rowan S, Eaton JL, Xi Q, Maas RL. Pax6- and Six3-mediated induction of lens cell fate in mouse and human ES cells. PLoS One 2014; 9:e115106. [PMID: 25517354 PMCID: PMC4269389 DOI: 10.1371/journal.pone.0115106] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 11/18/2014] [Indexed: 11/19/2022] Open
Abstract
Embryonic stem (ES) cells provide a potentially useful in vitro model for the study of in vivo tissue differentiation. We used mouse and human ES cells to investigate whether the lens regulatory genes Pax6 and Six3 could induce lens cell fate in vitro. To help assess the onset of lens differentiation, we derived a new mES cell line (Pax6-GFP mES) that expresses a GFP reporter under the control of the Pax6 P0 promoter and lens ectoderm enhancer. Pax6 or Six3 expression vectors were introduced into mES or hES cells by transfection or lentiviral infection and the differentiating ES cells analyzed for lens marker expression. Transfection of mES cells with Pax6 or Six3 but not with other genes induced the expression of lens cell markers and up-regulated GFP reporter expression in Pax6-GFP mES cells by 3 days post-transfection. By 7 days post-transfection, mES cell cultures exhibited a>10-fold increase over controls in the number of colonies expressing γA-crystallin, a lens fiber cell differentiation marker. RT-PCR and immunostaining revealed induction of additional lens epithelial or fiber cell differentiation markers including Foxe3, Prox1, α- and β-crystallins, and Tdrd7. Moreover, γA-crystallin- or Prox1-expressing lentoid bodies formed by 30 days in culture. In hES cells, Pax6 or Six3 lentiviral vectors also induced lens marker expression. mES cells that express lens markers reside close to but are distinct from the Pax6 or Six3 transduced cells, suggesting that the latter induce nearby undifferentiated ES cells to adopt a lens fate by non-cell autonomous mechanisms. In sum, we describe a novel mES cell GFP reporter line that is useful for monitoring induction of lens fate, and demonstrate that Pax6 or Six3 is sufficient to induce ES cells to adopt a lens fate, potentially via non-cell autonomous mechanisms. These findings should facilitate investigations of lens development.
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Affiliation(s)
- Raymond M. Anchan
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, 02115, United States of America
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics, Gynecology and Reproductive Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, 02115, United States of America
| | - Salil A. Lachke
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, 02115, United States of America
- Department of Biological Sciences, Center for Bioinformatics and Computational Biology, University of Delaware, Newark, Delaware, 9716, United States of America
| | - Behzad Gerami-Naini
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, 02115, United States of America
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics, Gynecology and Reproductive Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, 02115, United States of America
| | - Jennifer Lindsey
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics, Gynecology and Reproductive Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, 02115, United States of America
| | - Nicholas Ng
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics, Gynecology and Reproductive Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, 02115, United States of America
| | - Catherine Naber
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, 02115, United States of America
| | - Michael Nickerson
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics, Gynecology and Reproductive Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, 02115, United States of America
| | - Resy Cavallesco
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, 02115, United States of America
| | - Sheldon Rowan
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, 02115, United States of America
| | - Jennifer L. Eaton
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, 02115, United States of America
| | - Qiongchao Xi
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, 02115, United States of America
| | - Richard L. Maas
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, 02115, United States of America
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Cvekl A, Ashery-Padan R. The cellular and molecular mechanisms of vertebrate lens development. Development 2014; 141:4432-47. [PMID: 25406393 PMCID: PMC4302924 DOI: 10.1242/dev.107953] [Citation(s) in RCA: 158] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The ocular lens is a model system for understanding important aspects of embryonic development, such as cell specification and the spatiotemporally controlled formation of a three-dimensional structure. The lens, which is characterized by transparency, refraction and elasticity, is composed of a bulk mass of fiber cells attached to a sheet of lens epithelium. Although lens induction has been studied for over 100 years, recent findings have revealed a myriad of extracellular signaling pathways and gene regulatory networks, integrated and executed by the transcription factor Pax6, that are required for lens formation in vertebrates. This Review summarizes recent progress in the field, emphasizing the interplay between the diverse regulatory mechanisms employed to form lens progenitor and precursor cells and highlighting novel opportunities to fill gaps in our understanding of lens tissue morphogenesis.
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Affiliation(s)
- Aleš Cvekl
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Ruth Ashery-Padan
- Sackler School of Medicine and Sagol School of Neuroscience, Tel-Aviv University, 69978 Ramat Aviv, Tel Aviv, Israel
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Mochizuki T, Masai I. The lens equator: a platform for molecular machinery that regulates the switch from cell proliferation to differentiation in the vertebrate lens. Dev Growth Differ 2014; 56:387-401. [PMID: 24720470 DOI: 10.1111/dgd.12128] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 02/20/2014] [Accepted: 02/21/2014] [Indexed: 01/17/2023]
Abstract
The vertebrate lens is a transparent, spheroidal tissue, located in the anterior region of the eye that focuses visual images on the retina. During development, surface ectoderm associated with the neural retina invaginates to form the lens vesicle. Cells in the posterior half of the lens vesicle differentiate into primary lens fiber cells, which form the lens fiber core, while cells in the anterior half maintain a proliferative state as a monolayer lens epithelium. After formation of the primary fiber core, lens epithelial cells start to differentiate into lens fiber cells at the interface between the lens epithelium and the primary lens fiber core, which is called the equator. Differentiating lens fiber cells elongate and cover the old lens fiber core, resulting in growth of the lens during development. Thus, lens fiber differentiation is spatially regulated and the equator functions as a platform that regulates the switch from cell proliferation to cell differentiation. Since the 1970s, the mechanism underlying lens fiber cell differentiation has been intensively studied, and several regulatory factors that regulate lens fiber cell differentiation have been identified. In this review, we focus on the lens equator, where these regulatory factors crosstalk and cooperate to regulate lens fiber differentiation. Normally, lens epithelial cells must pass through the equator to start lens fiber differentiation. However, there are reports that when the lens epithelium structure is collapsed, lens fiber cell differentiation occurs without passing the equator. We also discuss a possible mechanism that represses lens fiber cell differentiation in lens epithelium.
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Affiliation(s)
- Toshiaki Mochizuki
- Developmental Neurobiology Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa, 904-0495, Japan
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Ocular surface development and gene expression. J Ophthalmol 2013; 2013:103947. [PMID: 23533700 PMCID: PMC3595720 DOI: 10.1155/2013/103947] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Accepted: 01/16/2013] [Indexed: 01/10/2023] Open
Abstract
The ocular surface-a continuous epithelial surface with regional specializations including the surface and glandular epithelia of the cornea, conjunctiva, and lacrimal and meibomian glands connected by the overlying tear film-plays a central role in vision. Molecular and cellular events involved in embryonic development, postnatal maturation, and maintenance of the ocular surface are precisely regulated at the level of gene expression by a well-coordinated network of transcription factors. A thorough appreciation of the biological characteristics of the ocular surface in terms of its gene expression profiles and their regulation provides us with a valuable insight into the pathophysiology of various blinding disorders that disrupt the normal development, maturation, and/or maintenance of the ocular surface. This paper summarizes the current status of our knowledge related to the ocular surface development and gene expression and the contribution of different transcription factors to this process.
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Ozturk F, Li Y, Zhu X, Guda C, Nawshad A. Systematic analysis of palatal transcriptome to identify cleft palate genes within TGFβ3-knockout mice alleles: RNA-Seq analysis of TGFβ3 Mice. BMC Genomics 2013; 14:113. [PMID: 23421592 PMCID: PMC3618314 DOI: 10.1186/1471-2164-14-113] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 02/13/2013] [Indexed: 12/19/2022] Open
Abstract
Background In humans, cleft palate (CP) accounts for one of the largest number of birth defects with a complex genetic and environmental etiology. TGFβ3 has been established as an important regulator of palatal fusion in mice and it has been shown that TGFβ3-null mice exhibit CP without any other major deformities. However, the genes that regulate cellular decisions and molecular mechanisms maintained by the TGFβ3 pathway throughout palatogenesis are predominantly unexplored. Our objective in this study was to analyze global transcriptome changes within the palate during different gestational ages within TGFβ3 knockout mice to identify TGFβ3-associated genes previously unknown to be associated with the development of cleft palate. We used deep sequencing technology, RNA-Seq, to analyze the transcriptome of TGFβ3 knockout mice at crucial stages of palatogenesis, including palatal growth (E14.5), adhesion (E15.5), and fusion (E16.5). Results The overall transcriptome analysis of TGFβ3 wildtype mice (C57BL/6) reveals that almost 6000 genes were upregulated during the transition from E14.5 to E15.5 and more than 2000 were downregulated from E15.5 to E16.5. Using bioinformatics tools and databases, we identified the most comprehensive list of CP genes (n = 322) in which mutations cause CP either in humans or mice, and analyzed their expression patterns. The expression motifs of CP genes between TGFβ3+/− and TGFβ3−/− were not significantly different from each other, and the expression of the majority of CP genes remained unchanged from E14.5 to E16.5. Using these patterns, we identified 8 unique genes within TGFβ3−/− mice (Chrng, Foxc2, H19, Kcnj13, Lhx8, Meox2, Shh, and Six3), which may function as the primary contributors to the development of cleft palate in TGFβ3−/− mice. When the significantly altered CP genes were overlaid with TGFβ signaling, all of these genes followed the Smad-dependent pathway. Conclusions Our study represents the first analysis of the palatal transcriptome of the mouse, as well as TGFβ3 knockout mice, using deep sequencing methods. In this study, we characterized the critical regulation of palatal transcripts that may play key regulatory roles through crucial stages of palatal development. We identified potential causative CP genes in a TGFβ3 knockout model, which may lead to a better understanding of the genetic mechanisms of palatogenesis and provide novel potential targets for gene therapy approaches to treat cleft palate.
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Affiliation(s)
- Ferhat Ozturk
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, 40th and Holdrege St, Lincoln, NE 68583, USA
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Grigoryan EN, Markitantova YV, Avdonin PP, Radugina EA. Study of regeneration in amphibians in age of molecular-genetic approaches and methods. RUSS J GENET+ 2013. [DOI: 10.1134/s1022795413010043] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Abstract
Despite its complexity in the adult, during development the inner ear arises from a simple epithelium, the otic placode. Placode specification is a multistep process that involves the integration of various signalling pathways and downstream transcription factors in time and space. Here we review the molecular events that successively commit multipotent ectodermal precursors to the otic lineage. The first step in this hierarchy is the specification of sensory progenitor cells, which can contribute to all sensory placodes, followed by the induction of a common otic-epibranchial field and finally the establishment the otic territory. In recent years, some of the molecular components that control this process have been identified, and begin to reveal complex interactions. Future studies will need to unravel how this information is integrated and encoded in the genome. This will form the blueprint for stem cell differentiation towards otic fates and generate a predictive gene regulatory network that models the earliest steps of otic specification.
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Affiliation(s)
- Jingchen Chen
- Department of Craniofacial Development and Stem Cell Biology, King's College London, Guy's Tower Wing, Floor 27, London SE1 9RT, UK
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Medio M, Yeh E, Popelut A, Babajko S, Berdal A, Helms JA. Wnt/β-catenin signaling and Msx1 promote outgrowth of the maxillary prominences. Front Physiol 2012; 3:375. [PMID: 23055979 PMCID: PMC3457051 DOI: 10.3389/fphys.2012.00375] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2012] [Accepted: 09/02/2012] [Indexed: 01/02/2023] Open
Abstract
Facial morphogenesis requires a series of precisely orchestrated molecular events to promote the growth and fusion of the facial prominences. Cleft palate (CP) results from perturbations in this process. The transcriptional repressor Msx1 is a key participant in these molecular events, as demonstrated by the palatal clefting phenotype observed in Msx1−/− embryos. Here, we exploited the high degree of conservation that exists in the gene regulatory networks that shape the faces of birds and mice, to gain a deeper understanding of Msx1 function in CP. Histomorphometric analyses indicated that facial development was disrupted as early as E12.5 in Msx1−/− embryos, long before the palatal shelves have formed. By mapping the expression domain of Msx1 in E11.5 and E12.5 embryos, we found the structures most affected by loss of Msx1 function were the maxillary prominences. Maxillary growth retardation was accompanied by perturbations in angiogenesis that preceded the CP phenotype. Experimental chick manipulations and in vitro assays showed that the regulation of Msx1 expression by the Wnt/β-catenin pathway is highly specific. Our data in mice and chicks indicate a conserved role for Msx1 in regulating the outgrowth of the maxillary prominences, and underscore how imbalances in Msx1 function can lead of growth disruptions that manifest as CP.
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Affiliation(s)
- Marie Medio
- Department of Orthodontics, Service of Odontology, Pitié-Salpêtrière Hospital, AP-HP, Paris 7 - Denis Diderot University, U.F.R. of Odontology Paris, France
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Iwanaga R, Wang CA, Micalizzi DS, Harrell JC, Jedlicka P, Sartorius CA, Kabos P, Farabaugh SM, Bradford AP, Ford HL. Expression of Six1 in luminal breast cancers predicts poor prognosis and promotes increases in tumor initiating cells by activation of extracellular signal-regulated kinase and transforming growth factor-beta signaling pathways. Breast Cancer Res 2012; 14:R100. [PMID: 22765220 PMCID: PMC3680936 DOI: 10.1186/bcr3219] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2012] [Accepted: 07/05/2012] [Indexed: 12/16/2022] Open
Abstract
Introduction Mammary-specific overexpression of Six1 in mice induces tumors that resemble human breast cancer, some having undergone epithelial to mesenchymal transition (EMT) and exhibiting stem/progenitor cell features. Six1 overexpression in human breast cancer cells promotes EMT and metastatic dissemination. We hypothesized that Six1 plays a role in the tumor initiating cell (TIC) population specifically in certain subtypes of breast cancer, and that by understanding its mechanism of action, we could potentially develop new means to target TICs. Methods We examined gene expression datasets to determine the breast cancer subtypes with Six1 overexpression, and then examined its expression in the CD24low/CD44+ putative TIC population in human luminal breast cancers xenografted through mice and in luminal breast cancer cell lines. Six1 overexpression, or knockdown, was performed in different systems to examine how Six1 levels affect TIC characteristics, using gene expression and flow cytometric analysis, tumorsphere assays, and in vivo TIC assays in immunocompromised and immune-competent mice. We examined the molecular pathways by which Six1 influences TICs using genetic/inhibitor approaches in vitro and in vivo. Finally, we examined the expression of Six1 and phosphorylated extracellular signal-regulated kinase (p-ERK) in human breast cancers. Results High levels of Six1 are associated with adverse outcomes in luminal breast cancers, particularly the luminal B subtype. Six1 levels are enriched in the CD24low/CD44+ TIC population in human luminal breast cancers xenografted through mice, and in tumorsphere cultures in MCF7 and T47D luminal breast cancer cells. When overexpressed in MCF7 cells, Six1expands the TIC population through activation of transforming growth factor-beta (TGF-β) and mitogen activated protein kinase (MEK)/ERK signaling. Inhibition of ERK signaling in MCF7-Six1 cells with MEK1/2 inhibitors, U0126 and AZD6244, restores the TIC population of luminal breast cancer cells back to that observed in control cells. Administration of AZD6244 dramatically inhibits tumor formation efficiency and metastasis in cells that express high levels of Six1 ectopically or endogenously. Finally, we demonstrate that Six1 significantly correlates with phosphorylated ERK in human breast cancers. Conclusions Six1 plays an important role in the TIC population in luminal breast cancers and induces a TIC phenotype by enhancing both TGF-β and ERK signaling. MEK1/2 kinase inhibitors are potential candidates for targeting TICs in breast tumors.
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Shaham O, Menuchin Y, Farhy C, Ashery-Padan R. Pax6: a multi-level regulator of ocular development. Prog Retin Eye Res 2012; 31:351-76. [PMID: 22561546 DOI: 10.1016/j.preteyeres.2012.04.002] [Citation(s) in RCA: 165] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Revised: 04/19/2012] [Accepted: 04/24/2012] [Indexed: 02/08/2023]
Abstract
Eye development has been a paradigm for the study of organogenesis, from the demonstration of lens induction through epithelial tissue morphogenesis, to neuronal specification and differentiation. The transcription factor Pax6 has been shown to play a key role in each of these processes. Pax6 is required for initiation of developmental pathways, patterning of epithelial tissues, activation of tissue-specific genes and interaction with other regulatory pathways. Herein we examine the data accumulated over the last few decades from extensive analyses of biochemical modules and genetic manipulation of the Pax6 gene. Specifically, we describe the regulation of Pax6's expression pattern, the protein's DNA-binding properties, and its specific roles and mechanisms of action at all stages of lens and retinal development. Pax6 functions at multiple levels to integrate extracellular information and execute cell-intrinsic differentiation programs that culminate in the specification and differentiation of a distinct ocular lineage.
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Affiliation(s)
- Ohad Shaham
- Sackler Faculty of Medicine, Department of Human Molecular Genetics and Biochemistry, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
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Ogino H, Ochi H, Reza HM, Yasuda K. Transcription factors involved in lens development from the preplacodal ectoderm. Dev Biol 2012; 363:333-47. [PMID: 22269169 DOI: 10.1016/j.ydbio.2012.01.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Revised: 12/14/2011] [Accepted: 01/09/2012] [Indexed: 12/14/2022]
Abstract
Lens development is a stepwise process accompanied by the sequential activation of transcription factors. Transcription factor genes can be classified into three groups according to their functions: the first group comprises preplacodal genes, which are implicated in the formation of the preplacodal ectoderm that serves as a common primordium for cranial sensory tissues, including the lens. The second group comprises lens-specification genes, which establish the lens-field within the preplacodal ectoderm. The third group comprises lens-differentiation genes, which promote lens morphogenesis after the optic vesicle makes contact with the presumptive lens ectoderm. Analyses of the regulatory interactions between these genes have provided an overview of lens development, highlighting crucial roles for positive cross-regulation in fate specification and for feed-forward regulation in the execution of terminal differentiation. This overview also sheds light upon the mechanisms of how preplacodal gene activities lead to the activation of genes involved in lens-specification.
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Affiliation(s)
- Hajime Ogino
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5, Takayama, Ikoma, Nara, 630-0192, Japan.
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Posnien N, Koniszewski NDB, Hein HJ, Bucher G. Candidate gene screen in the red flour beetle Tribolium reveals six3 as ancient regulator of anterior median head and central complex development. PLoS Genet 2011; 7:e1002416. [PMID: 22216011 PMCID: PMC3245309 DOI: 10.1371/journal.pgen.1002416] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Accepted: 10/13/2011] [Indexed: 11/19/2022] Open
Abstract
Several highly conserved genes play a role in anterior neural plate patterning of vertebrates and in head and brain patterning of insects. However, head involution in Drosophila has impeded a systematic identification of genes required for insect head formation. Therefore, we use the red flour beetle Tribolium castaneum in order to comprehensively test the function of orthologs of vertebrate neural plate patterning genes for a function in insect head development. RNAi analysis reveals that most of these genes are indeed required for insect head capsule patterning, and we also identified several genes that had not been implicated in this process before. Furthermore, we show that Tc-six3/optix acts upstream of Tc-wingless, Tc-orthodenticle1, and Tc-eyeless to control anterior median development. Finally, we demonstrate that Tc-six3/optix is the first gene known to be required for the embryonic formation of the central complex, a midline-spanning brain part connected to the neuroendocrine pars intercerebralis. These functions are very likely conserved among bilaterians since vertebrate six3 is required for neuroendocrine and median brain development with certain mutations leading to holoprosencephaly.
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Affiliation(s)
- Nico Posnien
- Center for Molecular Physiology of the Brain (CMPB), Göttingen Center of Molecular Biology, Caspari-Haus, Georg-August-University Göttingen, Göttingen, Germany
- School of Life Sciences, Oxford Brookes University, Oxford, United Kingdom
| | - Nikolaus Dieter Bernhard Koniszewski
- Center for Molecular Physiology of the Brain (CMPB), Göttingen Center of Molecular Biology, Caspari-Haus, Georg-August-University Göttingen, Göttingen, Germany
| | | | - Gregor Bucher
- Center for Molecular Physiology of the Brain (CMPB), Göttingen Center of Molecular Biology, Caspari-Haus, Georg-August-University Göttingen, Göttingen, Germany
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Lachke SA, Maas RL. Building the developmental oculome: systems biology in vertebrate eye development and disease. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2011; 2:305-323. [PMID: 20836031 DOI: 10.1002/wsbm.59] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The vertebrate eye is a sophisticated multicomponent organ that has been actively studied for over a century, resulting in the identification of the major embryonic and molecular events involved in its complex developmental program. Data gathered so far provides sufficient information to construct a rudimentary network of the various signaling molecules, transcription factors, and their targets for several key stages of this process. With the advent of genomic technologies, there has been a rapid expansion in our ability to collect and process biological information, and the use of systems-level approaches to study specific aspects of vertebrate eye development has already commenced. This is beginning to result in the definition of the dynamic developmental networks that operate in ocular tissues, and the interactions of such networks between coordinately developing ocular tissues. Such an integrative understanding of the eye by a comprehensive systems-level analysis can be termed the 'oculome', and that of serial developmental stages of the eye as it transits from its initiation to a fully formed functional organ represents the 'developmental oculome'. Construction of the developmental oculome will allow novel mechanistic insights that are essential for organ regeneration-based therapeutic applications, and the generation of computational models for eye disease states to predict the effects of drugs. This review discusses our present understanding of two of the individual components of the developing vertebrate eye--the lens and retina--at both the molecular and systems levels, and outlines the directions and tools required for construction of the developmental oculome.
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Affiliation(s)
- Salil A Lachke
- Division of Genetics, Brigham & Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Richard L Maas
- Division of Genetics, Brigham & Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
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van Leeuwen S, Mikkers H. Long non-coding RNAs: Guardians of development. Differentiation 2010; 80:175-83. [PMID: 20705382 DOI: 10.1016/j.diff.2010.07.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 07/09/2010] [Accepted: 07/24/2010] [Indexed: 01/16/2023]
Abstract
Two decades ago, the existence of long non-coding RNAs (lncRNAs) was discovered. In the following genomics era more transcribed non-coding genomic regions were identified. These were initially regarded as transcriptional noise and did not receive a lot of attention. Emerging data on several of these long non-coding transcripts have refuted this hypothesis by demonstrating that non-coding RNAs (ncRNAs) are important for regulating transcription and cell signaling. A special subset of the lncRNAs affecting gene transcription appears to orchestrate major developmental programs. Here, we discuss the mechanisms by which lncRNAs regulate transcription, and review the evidence that links this class of lncRNAs to a role in development.
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Affiliation(s)
- Selina van Leeuwen
- Department of Molecular Cell Biology, Regenerative Medicine Program, Leiden University Medical Center, Postal zone S1P, P.O. Box 9600, 2300RC Leiden, The Netherlands
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Andréasson U, Edén P, Peterson C, Högerkorp CM, Jerkeman M, Andersen N, Berglund M, Sundström C, Rosenquist R, Borrebaeck CAK, Ek S. Identification of uniquely expressed transcription factors in highly purified B-cell lymphoma samples. Am J Hematol 2010; 85:418-25. [PMID: 20513119 DOI: 10.1002/ajh.21701] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Transcription factors (TFs) are critical for B-cell differentiation, affecting gene expression both by repression and transcriptional activation. Still, this information is not used for classification of B-cell lymphomas (BCLs). Traditionally, BCLs are diagnosed based on a phenotypic resemblance to normal B-cells; assessed by immunohistochemistry or flow cytometry, by using a handful of phenotypic markers. In the last decade, diagnostic and prognostic evaluation has been facilitated by global gene expression profiling (GEP), providing a new powerful means for the classification, prediction of survival, and response to treatment of lymphomas. However, most GEP studies have typically been performed on whole tissue samples, containing varying degrees of tumor cell content, which results in uncertainties in data analysis. In this study, global GEP analyses were performed on highly purified, flow-cytometry sorted tumor-cells from eight subgroups of BCLs. This enabled identification of TFs that can be uniquely associated to the tumor cells of chronic lymphocytic leukemia (CLL), diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), hairy cell leukemia (HCL), and mantle cell lymphoma (MCL). The identified transcription factors influence both the global and specific gene expression of the BCLs and have possible implications for diagnosis and treatment.
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Shyr CR, Tsai MY, Yeh S, Kang HY, Chang YC, Wong PL, Huang CC, Huang KE, Chang C. Tumor suppressor PAX6 functions as androgen receptor co-repressor to inhibit prostate cancer growth. Prostate 2010; 70:190-9. [PMID: 19790232 PMCID: PMC3729259 DOI: 10.1002/pros.21052] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND PAX6, a transcription factor, has currently been suggested to function as a tumor suppressor in glioblastoma and to act as an early differentiation marker for neuroendocrine cells. The androgen receptor (AR) plays a pivotal role in prostate cancer development and progression due to its transcriptional activity in regulating genes involved in cell growth, differentiation, and apoptosis. To determine the role of PAX6 in prostate cancer, we investigated whether PAX6 interacts with AR to affect prostate cancer development. METHODS We used immunostaining, RT-PCR, and Western blotting assays to show the expression status of PAX6 in prostate tissue and human prostate cancer cell lines. The role of PAX6 in cell growth and colony regeneration potential of LNCaP cells were evaluated by MTT assay and soft agar assay with PAX6-overexpressed LNCaP cells. Mammalian two-hybrid and co-immunoprecipitation (Co-IP) assays were used to demonstrate the interaction between PAX6 and AR. Reporter gene and Q-RT-PCR assays were performed to determine the effects of PAX6 on the function of AR. RESULTS In prostate cancer tissues, PAX6 expression was stronger in normal epithelial cells than cancer cells, and decreased in LNCaP cells compared to that of DU145 and PC3 cells. Enforced expression of PAX6 suppressed the cell growth of LNCaP cells and also inhibited the colony formation of LNCaP cells. PAX 6 interacted with AR and repressed its transcriptional activity. PAX6 overexpression decreased the expression of androgen target gene PSA in LNCaP cells. CONCLUSIONS In this study, we found that PAX6 may act as a prostate cancer repressor by interacting with AR and repressing the transcriptional activity and target gene expression of AR to regulate cell growth and regeneration.
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Affiliation(s)
- Chih-Rong Shyr
- Department of Laboratory Medicine & Biotechnology, Tzu-Chi University, Hualien, Taiwan
- The Center for Menopause and Reproductive Medicine Research, Chang Gung University/Memorial Hospital, Kaohsiung, Taiwan
| | - Meng-Yin Tsai
- Graduate Institute of Clinical Medicine, Kaohsiung Division, Chang Gung University, Kaohsiung, Taiwan
- The Center for Menopause and Reproductive Medicine Research, Chang Gung University/Memorial Hospital, Kaohsiung, Taiwan
| | - Shuyuan Yeh
- George Whipple Laboratory for Cancer Research, Department of Urology, Pathology, Radiation Oncology, and the Cancer Center, University of Rochester Medical Center, Rochester, NY
| | - Hong-Yo Kang
- Graduate Institute of Clinical Medicine, Kaohsiung Division, Chang Gung University, Kaohsiung, Taiwan
- The Center for Menopause and Reproductive Medicine Research, Chang Gung University/Memorial Hospital, Kaohsiung, Taiwan
| | - Yun-Chao Chang
- The Center for Menopause and Reproductive Medicine Research, Chang Gung University/Memorial Hospital, Kaohsiung, Taiwan
| | - Pei-Ling Wong
- The Center for Menopause and Reproductive Medicine Research, Chang Gung University/Memorial Hospital, Kaohsiung, Taiwan
| | - Chao-Cheng Huang
- Graduate Institute of Clinical Medicine, Kaohsiung Division, Chang Gung University, Kaohsiung, Taiwan
| | - Ko-En Huang
- The Center for Menopause and Reproductive Medicine Research, Chang Gung University/Memorial Hospital, Kaohsiung, Taiwan
- Correspondence to: Chawnshang Chang, PhD, George Whipple Laboratory for Cancer Research, Department of Urology, Pathology, Radiation Oncology, and the Cancer Center, University of Rochester Medical Center, Rochester, NY. Ko-En Huang, MD, The Center for Menopause and Reproductive Medicine Research, Chang Gung University/Memorial Hospital, Kaohsiung, Taiwan.
| | - Chawnshang Chang
- George Whipple Laboratory for Cancer Research, Department of Urology, Pathology, Radiation Oncology, and the Cancer Center, University of Rochester Medical Center, Rochester, NY
- Correspondence to: Chawnshang Chang, PhD, George Whipple Laboratory for Cancer Research, Department of Urology, Pathology, Radiation Oncology, and the Cancer Center, University of Rochester Medical Center, Rochester, NY. Ko-En Huang, MD, The Center for Menopause and Reproductive Medicine Research, Chang Gung University/Memorial Hospital, Kaohsiung, Taiwan.
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Ramaesh T, Williams SE, Paul C, Ramaesh K, Dhillon B, West JD. Histopathological characterisation of effects of the mouse Pax6Leca4 missense mutation on eye development. Exp Eye Res 2009; 89:263-73. [DOI: 10.1016/j.exer.2009.03.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Revised: 02/06/2009] [Accepted: 03/23/2009] [Indexed: 02/02/2023]
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Christensen KL, Patrick AN, McCoy EL, Ford HL. The six family of homeobox genes in development and cancer. Adv Cancer Res 2009; 101:93-126. [PMID: 19055944 DOI: 10.1016/s0065-230x(08)00405-3] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The homeobox gene superfamily encodes transcription factors that act as master regulators of development through their ability to activate or repress a diverse range of downstream target genes. Numerous families exist within the homeobox gene superfamily, and are classified on the basis of conservation of their homeodomains as well as additional motifs that contribute to DNA binding and to interactions with other proteins. Members of one such family, the Six family, form a transcriptional complex with Eya and Dach proteins, and together these proteins make up part of the retinal determination network first identified in Drosophila. This network is highly conserved in both invertebrate and vertebrate species, where it influences the development of numerous organs in addition to the eye, primarily through regulation of cell proliferation, survival, migration, and invasion. Mutations in Six, Eya, and Dach genes have been identified in a variety of human genetic disorders, demonstrating their critical role in human development. In addition, aberrant expression of Six, Eya, and Dach occurs in numerous human tumors, and Six1, in particular, plays a causal role both in tumor initiation and in metastasis. Emerging evidence for the importance of Six family members and their cofactors in numerous human tumors suggests that targeting of this complex may be a novel and powerful means to inhibit both tumor growth and progression.
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Affiliation(s)
- Kimberly L Christensen
- Program in Molecular Biology, University of Colorado School of Medicine, Denver, Colorado, USA
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35
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Avdonin PP, Markitantova YV, Zinovieva RD, Mitashov VI. Expression of regulatory genes Px6, Otx2, Six3, and FGF2 during newt retina regeneration. BIOL BULL+ 2008. [DOI: 10.1134/s1062359008040043] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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36
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Firsova NV, Zinovieva RD. Molecular genetic aspects of human eye development. BIOL BULL+ 2008. [DOI: 10.1134/s106235900804002x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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37
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Manuel M, Pratt T, Liu M, Jeffery G, Price DJ. Overexpression of Pax6 results in microphthalmia, retinal dysplasia and defective retinal ganglion cell axon guidance. BMC DEVELOPMENTAL BIOLOGY 2008; 8:59. [PMID: 18507827 PMCID: PMC2422841 DOI: 10.1186/1471-213x-8-59] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2007] [Accepted: 05/28/2008] [Indexed: 11/17/2022]
Abstract
Background The transcription factor Pax6 is expressed by many cell types in the developing eye. Eyes do not form in homozygous loss-of-function mouse mutants (Pax6Sey/Sey) and are abnormally small in Pax6Sey/+ mutants. Eyes are also abnormally small in PAX77 mice expressing multiple copies of human PAX6 in addition to endogenous Pax6; protein sequences are identical in the two species. The developmental events that lead to microphthalmia in PAX77 mice are not well-characterised, so it is not clear whether over- and under-expression of Pax6/PAX6 cause microphthalmia through similar mechanisms. Here, we examined the consequences of over-expression for the eye and its axonal connections. Results Eyes form in PAX77+/+ embryos but subsequently degenerate. At E12.5, we found no abnormalities in ocular morphology, retinal cell cycle parameters and the incidence of retinal cell death. From E14.5 on, we observed malformations of the optic disc. From E16.5 into postnatal life there is progressively more severe retinal dysplasia and microphthalmia. Analyses of patterns of gene expression indicated that PAX77+/+ retinae produce a normal range of cell types, including retinal ganglion cells (RGCs). At E14.5 and E16.5, quantitative RT-PCR with probes for a range of molecules associated with retinal development showed only one significant change: a slight reduction in levels of mRNA encoding the secreted morphogen Shh at E16.5. At E16.5, tract-tracing with carbocyanine dyes in PAX77+/+ embryos revealed errors in intraretinal navigation by RGC axons, a decrease in the number of RGC axons reaching the thalamus and an increase in the proportion of ipsilateral projections among those RGC axons that do reach the thalamus. A survey of embryos with different Pax6/PAX6 gene dosage (Pax6Sey/+, Pax6+/+, PAX77+ and PAX77+/+) showed that (1) the total number of RGC axons projected by the retina and (2) the proportions that are sorted into the ipsilateral and contralateral optic tracts at the optic chiasm vary differently with gene dosage. Increasing dosage increases the proportion projecting ipsilaterally regardless of the size of the total projection. Conclusion Pax6 overexpression does not obviously impair the initial formation of the eye and its major cell-types but prevents normal development of the retina from about E14.5, leading eventually to severe retinal degeneration in postnatal life. This sequence is different to that underlying microphthalmia in Pax6+/- heterozygotes, which is due primarily to defects in the initial stages of lens formation. Before the onset of severe retinal dysplasia, Pax6 overexpression causes defects of retinal axons, preventing their normal growth and navigation through the optic chiasm.
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Affiliation(s)
- Martine Manuel
- Genes and Development Group, Centres for Integrative Physiology and Neuroscience Research, Hugh Robson Building, George Square, University of Edinburgh, Edinburgh EH8 9XD, UK.
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Zhao H, Yang T, Madakashira BP, Thiels CA, Bechtle CA, Garcia CM, Zhang H, Yu K, Ornitz DM, Beebe DC, Robinson ML. Fibroblast growth factor receptor signaling is essential for lens fiber cell differentiation. Dev Biol 2008; 318:276-88. [PMID: 18455718 DOI: 10.1016/j.ydbio.2008.03.028] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2007] [Revised: 03/14/2008] [Accepted: 03/17/2008] [Indexed: 11/19/2022]
Abstract
The vertebrate lens provides an excellent model to study the mechanisms that regulate terminal differentiation. Although fibroblast growth factors (FGFs) are thought to be important for lens cell differentiation, it is unclear which FGF receptors mediate these processes during different stages of lens development. Deletion of three FGF receptors (Fgfr1-3) early in lens development demonstrated that expression of only a single allele of Fgfr2 or Fgfr3 was sufficient for grossly normal lens development, while mice possessing only a single Fgfr1 allele developed cataracts and microphthalmia. Profound defects were observed in lenses lacking all three Fgfrs. These included lack of fiber cell elongation, abnormal proliferation in prospective lens fiber cells, reduced expression of the cell cycle inhibitors p27(kip1) and p57(kip2), increased apoptosis and aberrant or reduced expression of Prox1, Pax6, c-Maf, E-cadherin and alpha-, beta- and gamma-crystallins. Therefore, while signaling by FGF receptors is essential for lens fiber differentiation, different FGF receptors function redundantly.
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MESH Headings
- Animals
- Cell Differentiation
- Cell Enlargement
- Cyclin-Dependent Kinase Inhibitor p27/metabolism
- Cyclin-Dependent Kinase Inhibitor p57/metabolism
- Eye Abnormalities/embryology
- Fibroblast Growth Factors/metabolism
- Gene Targeting
- Homeodomain Proteins/metabolism
- Lens, Crystalline/cytology
- Lens, Crystalline/embryology
- Mice
- Mutation
- Proto-Oncogene Proteins c-maf/metabolism
- Receptor, Fibroblast Growth Factor, Type 1/genetics
- Receptor, Fibroblast Growth Factor, Type 1/metabolism
- Receptor, Fibroblast Growth Factor, Type 2/genetics
- Receptor, Fibroblast Growth Factor, Type 2/metabolism
- Receptor, Fibroblast Growth Factor, Type 3/genetics
- Receptor, Fibroblast Growth Factor, Type 3/metabolism
- Signal Transduction
- Tumor Suppressor Proteins/metabolism
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Affiliation(s)
- Haotian Zhao
- Graduate Program in Molecular, Cellular and Developmental Biology, College of Biological Sciences, The Ohio State University, Columbus, OH 43210, USA
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Appolloni I, Calzolari F, Corte G, Perris R, Malatesta P. Six3 controls the neural progenitor status in the murine CNS. Cereb Cortex 2008; 18:553-62. [PMID: 17576749 DOI: 10.1093/cercor/bhm092] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Six3, a homeodomain-containing transcriptional regulator belonging to the Six/so family, shows a defined spatiotemporal expression pattern in the developing murine telencephalon, suggesting that it may control the development of specific subsets of neural progenitors. We find that retrovirus-mediated misexpression of Six3 causes clonal expansion of isolated cortical progenitor cells by shortening their cell cycle and by prolonging their amplification period, while maintaining them in an immature precursor state. Our results show that the observed effects exerted by Six3 overexpression in mammalian brain depend strictly on the integrity of its DNA-binding domain, suggesting that Six3 action likely relies exclusively on its transcriptional activity. In vivo upregulation of Six3 expression in single progenitor cells of the embryonic telencephalon keeps them in an undifferentiated state. Our observations point to a role of Six3 in the control of the subtle equilibrium between proliferation and differentiation of defined precursor populations during mammalian neurogenesis.
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Affiliation(s)
- Irene Appolloni
- Istituto Nazionale per la Ricerca sul Cancro (IST), Largo Rosanna Benzi 10, 16132 Genoa, Italy
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40
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Cvekl A, Duncan MK. Genetic and epigenetic mechanisms of gene regulation during lens development. Prog Retin Eye Res 2007; 26:555-97. [PMID: 17905638 PMCID: PMC2136409 DOI: 10.1016/j.preteyeres.2007.07.002] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Recent studies demonstrated a number of links between chromatin structure, gene expression, extracellular signaling and cellular differentiation during lens development. Lens progenitor cells originate from a pool of common progenitor cells, the pre-placodal region (PPR) which is formed from a combination of extracellular signaling between the neural plate, naïve ectoderm and mesendoderm. A specific commitment to the lens program over alternate choices such as the formation of olfactory epithelium or the anterior pituitary is manifested by the formation of a thickened surface ectoderm, the lens placode. Mouse lens progenitor cells are characterized by the expression of a complement of lens lineage-specific transcription factors including Pax6, Six3 and Sox2, controlled by FGF and BMP signaling, followed later by c-Maf, Mab21like1, Prox1 and FoxE3. Proliferation of lens progenitors together with their morphogenetic movements results in the formation of the lens vesicle. This transient structure, comprised of lens precursor cells, is polarized with its anterior cells retaining their epithelial morphology and proliferative capacity, whereas the posterior lens precursor cells initiate terminal differentiation forming the primary lens fibers. Lens differentiation is marked by expression and accumulation of crystallins and other structural proteins. The transcriptional control of crystallin genes is characterized by the reiterative use of transcription factors required for the establishment of lens precursors in combination with more ubiquitously expressed factors (e.g. AP-1, AP-2alpha, CREB and USF) and recruitment of histone acetyltransferases (HATs) CBP and p300, and chromatin remodeling complexes SWI/SNF and ISWI. These studies have poised the study of lens development at the forefront of efforts to understand the connections between development, cell signaling, gene transcription and chromatin remodeling.
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Affiliation(s)
- Ales Cvekl
- Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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41
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Buckingham M, Relaix F. The role of Pax genes in the development of tissues and organs: Pax3 and Pax7 regulate muscle progenitor cell functions. Annu Rev Cell Dev Biol 2007; 23:645-73. [PMID: 17506689 DOI: 10.1146/annurev.cellbio.23.090506.123438] [Citation(s) in RCA: 328] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Pax genes play key roles in the formation of tissues and organs during embryogenesis. Pax3 and Pax7 mark myogenic progenitor cells and regulate their behavior and their entry into the program of skeletal muscle differentiation. Recent results have underlined the importance of the Pax3/7 population of cells for skeletal muscle development and regeneration. We present our current understanding of different aspects of Pax3/7 function in myogenesis, focusing on the mouse model. This is compared with that of other Pax proteins in the emergence of tissue specific lineages and their differentiation as well as in cell survival, proliferation, and migration. Finally, we consider the molecular mechanisms that underlie the function of Pax transcription factors, including the cofactors and regulatory networks with which they interact.
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Affiliation(s)
- Margaret Buckingham
- Department of Developmental Biology, CNRS URA 2578, Pasteur Institute, 75015 Paris, France.
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42
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Blixt A, Landgren H, Johansson BR, Carlsson P. Foxe3 is required for morphogenesis and differentiation of the anterior segment of the eye and is sensitive to Pax6 gene dosage. Dev Biol 2007; 302:218-29. [PMID: 17064680 DOI: 10.1016/j.ydbio.2006.09.021] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2006] [Revised: 09/08/2006] [Accepted: 09/11/2006] [Indexed: 11/19/2022]
Abstract
The dysgenetic lens (dyl) mouse mutant has mutations in Foxe3, which inactivate DNA binding by the encoded forkhead transcription factor. Here we confirm, by targeted inactivation, that Foxe3 mutations are responsible for the dyl phenotype, which include loss of lens epithelium; a small, cataractic lens; and failure of the lens to detach from the surface ectoderm. In contrast to a recent report of targeted Foxe3, we found no phenotypic difference between dyl and Foxe3(-/-) mutants when congenic strains were compared, and thus nothing that argues against Foxe3(dyl) being a null allele. In addition to the lens, most tissues of the anterior segment-iris, cornea, ciliary body and trabecular meshwork-are malformed or show differentiation defects. Many of these abnormalities, such as irido-corneal and irido-lenticular adherences, are present in a less severe form in mice heterozygous for the Foxe3 mutation, in spite of these having an intact lens epithelium. Early Foxe3 expression is highly sensitive to a halved Pax6 gene dosage and there is a striking phenotypic similarity between Pax6 and Foxe3 mutants. We therefore propose that many of the ocular malformations associated with Pax6 haploinsufficiency are consequences of a reduced expression of Foxe3.
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Affiliation(s)
- Asa Blixt
- Dept of Cell and Molecular Biology, Göteborg University, 405 30 Göteborg, Sweden
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Liu W, Lagutin OV, Mende M, Streit A, Oliver G. Six3 activation of Pax6 expression is essential for mammalian lens induction and specification. EMBO J 2006; 25:5383-95. [PMID: 17066077 PMCID: PMC1636621 DOI: 10.1038/sj.emboj.7601398] [Citation(s) in RCA: 131] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2006] [Accepted: 09/26/2006] [Indexed: 01/31/2023] Open
Abstract
The homeobox gene Six3 regulates forebrain development. Here we show that Six3 is also crucial for lens formation. Conditional deletion of mouse Six3 in the presumptive lens ectoderm (PLE) disrupted lens formation. In the most severe cases, lens induction and specification were defective, and the lens placode and lens were absent. In Six3-mutant embryos, Pax6 was downregulated, and Sox2 was absent in the lens preplacodal ectoderm. Using ChIP, electrophoretic mobility shift assay, and luciferase reporter assays, we determined that Six3 activates Pax6 and Sox2 expression. Misexpression of mouse Six3 into chick embryos promoted the ectopic expansion of the ectodermal Pax6 expression domain. Our results position Six3 at the top of the regulatory pathway leading to lens formation. We conclude that Six3 directly activates Pax6 and probably also Sox2 in the PLE and regulates cell autonomously the earliest stages of mammalian lens induction.
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Affiliation(s)
- Wei Liu
- Department of Genetics and Tumor Cell Biology, St Jude Children's Research Hospital, Memphis, TN, USA
| | - Oleg V Lagutin
- Department of Genetics and Tumor Cell Biology, St Jude Children's Research Hospital, Memphis, TN, USA
| | - Michael Mende
- Department of Craniofacial Development, King's College London, London, UK
| | - Andrea Streit
- Department of Craniofacial Development, King's College London, London, UK
| | - Guillermo Oliver
- Department of Genetics and Tumor Cell Biology, St Jude Children's Research Hospital, Memphis, TN, USA
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44
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Abstract
The newt is one of the few organisms that is able to undergo lens regeneration as an adult. This review will examine the signaling pathways that are involved in this amazing phenomenon. In addition to outlining the current research involved in elucidating the key signaling molecules in lens regeneration, we will also highlight some of the similarities and differences between lens regeneration and development.
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Affiliation(s)
- Matthew W Grogg
- Laboratory of Molecular Biology, Department of Biology, University of Dayton, Dayton, OH 45469-2320, USA
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45
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Elkins MB, Henry JJ. Isolation and characterization of a novel gene, xMADML, involved in Xenopus laevis eye development. Dev Dyn 2006; 235:1845-57. [PMID: 16607642 DOI: 10.1002/dvdy.20824] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
We have identified Xenopus MADM-like (xMADML), a Xenopus laevis gene related to the murine MADM and the human NRBP genes. xMADML is expressed throughout early development and is expressed most strongly in the developing lens and more weakly in the retina and other anterior tissues. We demonstrate that disruption of xMADML translation by means of morpholino injection results in impaired retina and lens development. Reciprocal transplantation of the presumptive lens ectoderm between morpholino-injected embryos and those injected solely with a dextran lineage tracer demonstrates that xMADML is necessary in both the lens and the retina for correct development of these eye tissues. Analysis of gene expression after knockdown of xMADML revealed significant alterations in the expression of some genes, including Pax6, xSix3, Sox2, and Sox3, suggesting that xMADML plays a role in regulating gene expression during development of the eye. This investigation is the first in vivo study examining the developmental role of this novel gene and reveals an important role of xMADML in eye tissue development and differentiation.
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Affiliation(s)
- Matthew B Elkins
- Department of Cell and Developmental Biology and College of Medicine, University of Illinois, Urbana, Illinois, USA
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46
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Valleix S, Niel F, Nedelec B, Algros MP, Schwartz C, Delbosc B, Delpech M, Kantelip B. Homozygous nonsense mutation in the FOXE3 gene as a cause of congenital primary aphakia in humans. Am J Hum Genet 2006; 79:358-64. [PMID: 16826526 PMCID: PMC1559477 DOI: 10.1086/505654] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2006] [Accepted: 04/21/2006] [Indexed: 11/03/2022] Open
Abstract
Congenital primary aphakia (CPA) is a rare developmental disorder characterized by the absence of lens, the development of which is normally induced during the 4th-5th wk of human embryogenesis. This original failure leads, in turn, to complete aplasia of the anterior segment of the eye, which is the diagnostic histological criterion for CPA. So far, the genetic basis for this human condition has remained unclear. Here, we present the analysis of a consanguineous family with three siblings who had bilateral aphakia, microphthalmia, and complete agenesis of the ocular anterior segment. We show that a null mutation in the FOXE3 gene segregates and, in the homozygous state, produces the mutant phenotype in this family. Therefore, this study identifies--to our knowledge, for the first time--a causative gene for CPA in humans. Furthermore, it indicates a possible critical role for FOXE3 very early in the lens developmental program, perhaps earlier than any role recognized elsewhere for this gene.
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Affiliation(s)
- Sophie Valleix
- Laboratoire de Biochimie et Genetique Moleculaire, Hopital Cochin, 123 Boulevard de Port-Royal, 75014 Paris, France.
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47
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Zhao H, Yang Y, Partanen J, Ciruna BG, Rossant J, Robinson ML. Fibroblast growth factor receptor 1 (Fgfr1) is not essential for lens fiber differentiation in mice. Mol Vis 2006; 12:15-25. [PMID: 16446698 PMCID: PMC4280232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023] Open
Abstract
PURPOSE The developing lens expresses at least three different FGF receptor genes (Fgfr1, Fgfr2, Fgfr3). Furthermore, FGFs have been shown to induce lens epithelial cells to differentiate into fiber cells both in vitro and in vivo. While the loss of Fgfr2 alone does not prevent fiber differentiation and the loss of Fgfr3 alone does not appear to affect lens development, the independent role of Fgfr1 in lens development has not been reported. These experiments were conducted to determine if Fgfr1 plays an independent, essential role in lens development. METHODS To address this question, we took two complementary approaches. First, we employed the aphakia (ak) lens complementation system to show that Fgfr1 deficient embryonic stem (ES) cells were able to form a normal embryonic lens that maintains a normal pattern of crystallin gene expression. Second, we employed the Cre-loxP system to achieve lens-specific inactivation of Fgfr1. RESULTS Fgfr1 null embryonic stem cells were able to rescue normal embryonic lens development in chimeric combination with aphakia mutant embryos. In addition, conditional deletion of Fgfr1 does not compromise lens development either before or after birth. CONCLUSIONS The results of both approaches suggest that lens epithelial cell integrity, cell cycle regulation and lens fiber differentiation are intact in the Fgfr1 deficient lens. Overall, our results demonstrate that Fgfr1 is not cell autonomously essential for lens development and suggests functional redundancy among different FGF receptor genes with respect to lens fiber differentiation.
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MESH Headings
- Alleles
- Animals
- Animals, Newborn
- Aphakia/genetics
- Chimera
- Embryonic Development/physiology
- Fluorescent Antibody Technique
- Genotype
- In Situ Hybridization
- Lens, Crystalline/embryology
- Lens, Crystalline/growth & development
- Lens, Crystalline/metabolism
- Lens, Crystalline/pathology
- Mice
- Mice, Mutant Strains
- Mice, Transgenic
- Mutation
- Receptor, Fibroblast Growth Factor, Type 1/genetics
- Receptor, Fibroblast Growth Factor, Type 1/metabolism
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Affiliation(s)
- Haotian Zhao
- Center for Human and Molecular Genetics, Columbus Children's Research Institute, Columbus, OH, USA.
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48
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Khosrowshahian F, Wolanski M, Chang WY, Fujiki K, Jacobs L, Crawford MJ. Lens and retina formation require expression of Pitx3 in Xenopus pre-lens ectoderm. Dev Dyn 2006; 234:577-89. [PMID: 16170783 DOI: 10.1002/dvdy.20540] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Pitx3 is expressed in tissues fated to contribute to eye development, namely, neurula stage ectoderm and pre-chordal mesoderm, then presumptive lens ectoderm, placode, and finally lens. Pitx3 overexpression alters lens, optic cup, optic nerve, and diencephalon development. Many of the induced anomalies are attributable to midline deficits; however, as assessed by molecular markers, ectopic Pitx3 appears to temporarily enlarge the lens field. These changes are usually insufficient to generate either ectopic lenses to enlarge the eye that eventually differentiates. Conversely, use of a repressor chimera or of antisense morpholinos alters early expression of marker genes, and later inhibits lens development, thereby abrogating retinal induction. Reciprocal grafting experiments using wild-type and morpholino-treated tissues demonstrate that Pitx3 expression in the presumptive lens ectoderm is required for lens formation. Contradictory to recent assertions that retina can form in the absence of a lens, the expression of Pitx3 in the presumptive lens ectoderm is critical for retina development.
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49
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Purcell P, Oliver G, Mardon G, Donner AL, Maas RL. Pax6-dependence of Six3, Eya1 and Dach1 expression during lens and nasal placode induction. Gene Expr Patterns 2005; 6:110-8. [PMID: 16024294 DOI: 10.1016/j.modgep.2005.04.010] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2005] [Revised: 04/15/2005] [Accepted: 04/18/2005] [Indexed: 11/17/2022]
Abstract
The Drosophila eyeless gene plays a central role in fly eye development and controls a subordinate regulatory network consisting of the so, eya and dac genes. All three genes have highly conserved mammalian homologs, suggesting possible conservation of this eye forming regulatory network. sine oculis (so) belongs to the so/Six gene family, and Six3 is prominently expressed in the developing mammalian eye. Eya1 and Dach1 are mammalian homologs of eya and dac, respectively, and although neither Eya1 nor Dach1 knockout mice express prenatal eye defects, possibilities exist for postnatal ocular phenotypes or for functional redundancy between related family members. To examine whether expression relationships analogous to those between ey, so, eya and dac exist in early mammalian oculogenesis, we investigated Pax6, Six3, Eya1 and Dach1 protein expression in murine lens and nasal placode development. Six3 expression in the pre-placode lens ectoderm is initially Pax6-independent, but subsequently both its expression and nuclear localization become Pax6-dependent. Six3, Dach1 and Eya1 nasal expression in pre-placode ectoderm are also initially Pax6-independent, but thereafter become Pax6-dependent. Pax6, Six3, Dach1 and Eya1 are all co-expressed in the developing ciliary marginal zone, a source of retinal stem cells in some vertebrates. An in vitro protein-protein interaction is detected between Six3 and Eya1. Collectively, these findings suggest that the Pax-Eya-Six-Dach network is at best only partly conserved during lens and nasal placode development. However, the findings do not rule out the possibility that such a regulatory network acts at later stages of oculogenesis.
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Affiliation(s)
- Patricia Purcell
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard, Medical School, New Research Building, Rm. 458H, 77, Avenue Louis Pasteur, Boston, MA 02115, USA
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50
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Lengler J, Bittner T, Münster D, Gawad AEDA, Graw J. Agonistic and antagonistic action of AP2, Msx2, Pax6, Prox1 AND Six3 in the regulation of Sox2 expression. Ophthalmic Res 2005; 37:301-9. [PMID: 16118513 DOI: 10.1159/000087774] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2004] [Accepted: 04/18/2005] [Indexed: 01/02/2023]
Abstract
Sox2 transcription factor is expressed in neural tissues and sensory epithelia from the early stages of development. Particularly, it is known to activate crystallin gene expression and to be involved in differentiation of lens and neural tissues. However, its place in the signaling cascade is not well understood. Here, we report about the response of its promoter to the presence of other transcription factors, AP2alpha, Msx2, Pax6, Prox1 and Six3, in a transient reporter gene assay using HEK293 cells as recipient cells. Taking our data together, AP2, Pax6 and PROX1 can activate the Sox2 promoter. Msx2 has an inhibitory effect, whereas Six3 does not affect the Sox2 promoter. These data indicate a common activating cascade at least for AP2, Pax6, Prox1 and Sox2.
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