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Thuma TBT, Procopio RA, Jimenez HJ, Gunton KB, Pulido JS. Hypomorphic variants in inherited retinal and ocular diseases: A review of the literature with clinical cases. Surv Ophthalmol 2024; 69:337-348. [PMID: 38036193 DOI: 10.1016/j.survophthal.2023.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 11/17/2023] [Accepted: 11/20/2023] [Indexed: 12/02/2023]
Abstract
Hypomorphic variants decrease, but do not eliminate, gene function via a reduction in the amount of mRNA or protein product produced by a gene or by production of a gene product with reduced function. Many hypomorphic variants have been implicated in inherited retinal diseases (IRDs) and other genetic ocular conditions; however, there is heterogeneity in the use of the term "hypomorphic" in the scientific literature. We searched for all hypomorphic variants reported to cause IRDs and ocular disorders. We also discuss the presence of hypomorphic variants in the patient population of our ocular genetics department over the past decade. We propose that standardized criteria should be adopted for use of the term "hypomorphic" to describe gene variants to improve genetic counseling and patient care outcomes.
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Affiliation(s)
- Tobin B T Thuma
- Department of Pediatric Ophthalmology and Strabismus, Wills Eye Hospital, Philadelphia, PA, USA
| | | | - Hiram J Jimenez
- Vickie and Jack Farber Vision Research Center, Wills Eye Hospital, Philadelphia, PA, USA
| | - Kammi B Gunton
- Department of Pediatric Ophthalmology and Strabismus, Wills Eye Hospital, Philadelphia, PA, USA
| | - Jose S Pulido
- Vickie and Jack Farber Vision Research Center, Wills Eye Hospital, Philadelphia, PA, USA; Retina Service, Wills Eye Hospital, Philadelphia, PA, USA.
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2
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Wulff-Fuentes E, Boakye J, Kroenke K, Berendt RR, Martinez-Morant C, Pereckas M, Hanover JA, Olivier-Van Stichelen S. O-GlcNAcylation regulates OTX2's proteostasis. iScience 2023; 26:108184. [PMID: 38026167 PMCID: PMC10661118 DOI: 10.1016/j.isci.2023.108184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 08/28/2023] [Accepted: 10/09/2023] [Indexed: 12/01/2023] Open
Abstract
O-GlcNAcylation is a key post-translational modification, playing a vital role in cell signaling during development, especially in the brain. In this study, we investigated the role of O-GlcNAcylation in regulating the homeobox protein OTX2, which contributes to various brain disorders, such as combined pituitary hormone deficiency, retinopathy, and medulloblastoma. Our research demonstrated that, under normal physiological conditions, the proteasome plays a pivotal role in breaking down endogenous OTX2. However, when the levels of OTX2 rise, it forms oligomers and/or aggregates that require macroautophagy for clearance. Intriguingly, we demonstrated that O-GlcNAcylation enhances the solubility of OTX2, thereby limiting the formation of these aggregates. Additionally, we unveiled an interaction between OTX2 and the chaperone protein CCT5 at the O-GlcNAc sites, suggesting a potential collaborative role in preventing OTX2 aggregation. Finally, our study demonstrated that while OTX2 physiologically promotes cell proliferation, an O-GlcNAc-depleted OTX2 is detrimental to cancer cells.
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Affiliation(s)
| | - Jeffrey Boakye
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0851, USA
| | - Kaeley Kroenke
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Rex R. Berendt
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | | | - Michaela Pereckas
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - John A. Hanover
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0851, USA
| | - Stephanie Olivier-Van Stichelen
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Department of Obstetrics and Gynecology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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3
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Sun C, Chen S. Disease-causing mutations in genes encoding transcription factors critical for photoreceptor development. Front Mol Neurosci 2023; 16:1134839. [PMID: 37181651 PMCID: PMC10172487 DOI: 10.3389/fnmol.2023.1134839] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 04/04/2023] [Indexed: 05/16/2023] Open
Abstract
Photoreceptor development of the vertebrate visual system is controlled by a complex transcription regulatory network. OTX2 is expressed in the mitotic retinal progenitor cells (RPCs) and controls photoreceptor genesis. CRX that is activated by OTX2 is expressed in photoreceptor precursors after cell cycle exit. NEUROD1 is also present in photoreceptor precursors that are ready to specify into rod and cone photoreceptor subtypes. NRL is required for the rod fate and regulates downstream rod-specific genes including the orphan nuclear receptor NR2E3 which further activates rod-specific genes and simultaneously represses cone-specific genes. Cone subtype specification is also regulated by the interplay of several transcription factors such as THRB and RXRG. Mutations in these key transcription factors are responsible for ocular defects at birth such as microphthalmia and inherited photoreceptor diseases such as Leber congenital amaurosis (LCA), retinitis pigmentosa (RP) and allied dystrophies. In particular, many mutations are inherited in an autosomal dominant fashion, including the majority of missense mutations in CRX and NRL. In this review, we describe the spectrum of photoreceptor defects that are associated with mutations in the above-mentioned transcription factors, and summarize the current knowledge of molecular mechanisms underlying the pathogenic mutations. At last, we deliberate the outstanding gaps in our understanding of the genotype-phenotype correlations and outline avenues for future research of the treatment strategies.
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Affiliation(s)
- Chi Sun
- Department of Ophthalmology and Visual Sciences, Washington University in St. Louis, St. Louis, MO, United States
- *Correspondence: Chi Sun,
| | - Shiming Chen
- Department of Ophthalmology and Visual Sciences, Washington University in St. Louis, St. Louis, MO, United States
- Department of Developmental Biology, Washington University in St. Louis, St. Louis, MO, United States
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Fabiani M, Libotte F, Margiotti K, Tannous DKI, Sparacino D, D’Aleo MP, Monaco F, Dello Russo C, Mesoraca A, Giorlandino C. Agnathia-Otocephaly Complex Due to a De Novo Deletion in the OTX2 Gene. Genes (Basel) 2022; 13:genes13122269. [PMID: 36553536 PMCID: PMC9778614 DOI: 10.3390/genes13122269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 12/05/2022] Open
Abstract
Agnathia-otocephaly complex (AOC) is a rare and usually lethal malformation typically characterized by hypoplasia or the absence of the mandible, ventromedial and caudal displacement of the ears with or without the fusion of the ears, a small oral aperture with or without a tongue hypoplasia. Its incidence is reported as 1 in 70,000 births and its etiology has been attributed to both genetic and teratogenic causes. AOC is characterized by a wide severity clinical spectrum even when occurring within the same family, ranging from a mild mandibular defect to an extreme facial aberration incompatible with life. Most AOC cases are due to a de novo sporadic mutation. Given the genetic heterogeneity, many genes have been reported to be implicated in this disease but to date, the link to only two genes has been confirmed in the development of this complex: the orthodenticle homeobox 2 (OTX2) gene and the paired related homeobox 1 (PRRX1) gene. In this article, we report a case of a fetus with severe AOC, diagnosed in routine ultrasound scan in the first trimester of pregnancy. The genetic analysis showed a novel 10 bp deletion mutation c.766_775delTTGGGTTTTA in the OTX2 gene, which has never been reported before, together with a missense variant c.778T>C in cis conformation.
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Affiliation(s)
- Marco Fabiani
- ALTAMEDICA, Human Genetics Laboratory, Viale Liegi 45, 00198 Rome, Italy
| | - Francesco Libotte
- ALTAMEDICA, Human Genetics Laboratory, Viale Liegi 45, 00198 Rome, Italy
| | - Katia Margiotti
- ALTAMEDICA, Human Genetics Laboratory, Viale Liegi 45, 00198 Rome, Italy
- Correspondence: ; Tel.: +39-06-85058961
| | - Dina Khader Issa Tannous
- School of Medicine and Surgery, Department of Obstetrics and Gynecology, UniCamillus-Saint Camillus International University of Health Sciences, Via di Sant’Alessandro, 8, 00131 Rome, Italy
| | - Davide Sparacino
- ALTAMEDICA, Human Genetics Laboratory, Viale Liegi 45, 00198 Rome, Italy
| | - Maria Pia D’Aleo
- ALTAMEDICA, Human Genetics Laboratory, Viale Liegi 45, 00198 Rome, Italy
| | - Francesca Monaco
- ALTAMEDICA, Human Genetics Laboratory, Viale Liegi 45, 00198 Rome, Italy
| | | | - Alvaro Mesoraca
- ALTAMEDICA, Human Genetics Laboratory, Viale Liegi 45, 00198 Rome, Italy
| | - Claudio Giorlandino
- ALTAMEDICA, Human Genetics Laboratory, Viale Liegi 45, 00198 Rome, Italy
- ALTAMEDICA, Department of Prenatal Diagnosis, Fetal-Maternal Medical Centre, Altamedica Viale Liegi 45, 00198 Rome, Italy
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Susaimanickam PJ, Kiral FR, Park IH. Region Specific Brain Organoids to Study Neurodevelopmental Disorders. Int J Stem Cells 2022; 15:26-40. [PMID: 35220290 PMCID: PMC8889336 DOI: 10.15283/ijsc22006] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Accepted: 01/17/2022] [Indexed: 12/03/2022] Open
Abstract
Region specific brain organoids are brain organoids derived by patterning protocols using extrinsic signals as opposed to cerebral organoids obtained by self-patterning. The main focus of this review is to discuss various region-specific brain organoids developed so far and their application in modeling neurodevelopmental disease. We first discuss the principles of neural axis formation by series of growth factors, such as SHH, WNT, BMP signalings, that are critical to generate various region-specific brain organoids. Then we discuss various neurodevelopmental disorders modeled so far with these region-specific brain organoids, and findings made on mechanism and treatment options for neurodevelopmental disorders (NDD).
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Affiliation(s)
- Praveen Joseph Susaimanickam
- Department of Genetics, Yale Stem Cell Center, Yale Child Study Center, Yale School of Medicine, New Haven, CT, USA
| | - Ferdi Ridvan Kiral
- Department of Genetics, Yale Stem Cell Center, Yale Child Study Center, Yale School of Medicine, New Haven, CT, USA
| | - In-Hyun Park
- Department of Genetics, Yale Stem Cell Center, Yale Child Study Center, Yale School of Medicine, New Haven, CT, USA
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Rafati M, Mohamadhashem F, Jalilian K, Hoseininasab F, Fakhri L, Hoseini A, Amiri H, Barati Z, Darzi Ramandi S, Mostofinezhad N, Mahmoudi AH, Ghaffari SR. Identification of a novel de novo variant in OTX2 in a patient with congenital microphthalmia using targeted next-generation sequencing followed by prenatal diagnosis. Ophthalmic Genet 2021; 43:262-267. [PMID: 34791963 DOI: 10.1080/13816810.2021.2002915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
BACKGROUND Next-generation sequencing has been proven to be a reliable method for the detection of genetic causes in heterogeneous ocular disorders. In this report an NGS-based diagnostic approach was taken to uncover the genetic etiology in a patient with coloboma and microphthalmia, a highly heterogeneous disease with intrafamilial phenotypic variability. MATERIALS AND METHODS Next generation sequencing using a targeted panel of 316 genes, was carried out in the proband. Prioritized variants were then identified and confirmed using Sanger sequencing. Prenatal diagnosis of the detected variant was then performed in the family. RESULTS A novel de novo frameshift variant c.157_164delTTCACTCG (p.Phe53fs) in OTX2, leading to a truncated protein, was identified. Prenatal diagnosis identified the same variant in the fetus. CONCLUSIONS This report demonstrates the importance of genetic counseling and underscores the efficiency and effectiveness of targeted NGS as a means of detecting variants in inherited eye disorders.
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Affiliation(s)
- Maryam Rafati
- Comprehensive Genetic Center, Hope Generation Foundation, Tehran, Iran.,Reproductive Biotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran.,Department of Genomics Gene Clinic, Tehran, Iran
| | - Faezeh Mohamadhashem
- Reproductive Biotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran
| | - Koosha Jalilian
- Department of Cell and Molecular Biology, Faculty of Biological Sciences, Kharazmi University, Tehran, Iran
| | - Fatemeh Hoseininasab
- Reproductive Biotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran
| | - Laya Fakhri
- Reproductive Biotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran
| | - Azadeh Hoseini
- Comprehensive Genetic Center, Hope Generation Foundation, Tehran, Iran
| | - Hosna Amiri
- Comprehensive Genetic Center, Hope Generation Foundation, Tehran, Iran
| | - Zeinab Barati
- Comprehensive Genetic Center, Hope Generation Foundation, Tehran, Iran
| | | | | | | | - Saeed Reza Ghaffari
- Comprehensive Genetic Center, Hope Generation Foundation, Tehran, Iran.,Reproductive Biotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran.,Department of Genomics Gene Clinic, Tehran, Iran
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Photoreceptor cKO of OTX2 Enhances OTX2 Intercellular Transfer in the Retina and Causes Photophobia. eNeuro 2021; 8:ENEURO.0229-21.2021. [PMID: 34475267 PMCID: PMC8496205 DOI: 10.1523/eneuro.0229-21.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/26/2021] [Accepted: 08/03/2021] [Indexed: 11/21/2022] Open
Abstract
In the mature mouse retina, Otx2 is expressed in both retinal pigmented epithelium (RPE) and photoreceptor (PR) cells, and Otx2 knock-out (KO) in the RPE alone results in PR degeneration. To study the cell-autonomous function of OTX2 in PRs, we performed PR-specific Otx2 KO (cKO) in adults. As expected, the protein disappears completely from PR nuclei but is still observed in PR inner and outer segments while its level concomitantly decreases in the RPE, suggesting a transfer of OTX2 from RPE to PRs in response to Otx2 ablation in PRs. The ability of OTX2 to transfer from RPE to PRs was verified by viral expression of tagged-OTX2 in the RPE. Transferred OTX2 distributed across the PR cytoplasm, suggesting functions distinct from nuclear transcription regulation. PR-specific Otx2 cKO did not alter the structure of the retina but impaired the translocation of PR arrestin-1 on illumination changes, making mice photophobic. RNA-seq analyses following Otx2 KO revealed downregulation of genes involved in the cytoskeleton that might account for the arrestin-1 translocation defect, and of genes involved in extracellular matrix (ECM) and signaling factors that may participate in the enhanced transfer of OTX2. Interestingly, several RPE-specific OTX2 target genes involved in melanogenesis were downregulated, lending weight to a decrease of OTX2 levels in the RPE following PR-specific Otx2 cKO. Our study reveals a new role of endogenous OTX2 in PR light adaptation and demonstrates the existence of OTX2 transfer from RPE to PR cells, which is increased on PR-specific Otx2 ablation and might participate in PR neuroprotection.
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Gregory LC, Gergics P, Nakaguma M, Bando H, Patti G, McCabe MJ, Fang Q, Ma Q, Ozel AB, Li JZ, Poina MM, Jorge AAL, Benedetti AFF, Lerario AM, Arnhold IJP, Mendonca BB, Maghnie M, Camper SA, Carvalho LRS, Dattani MT. The phenotypic spectrum associated with OTX2 mutations in humans. Eur J Endocrinol 2021; 185:121-135. [PMID: 33950863 PMCID: PMC8437083 DOI: 10.1530/eje-20-1453] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 05/05/2021] [Indexed: 11/25/2022]
Abstract
Objective The transcription factor OTX2 is implicated in ocular, craniofacial, and pituitary development. Design We aimed to establish the contribution of OTX2 mutations in congenital hypopituitarism patients with/without eye abnormalities, study functional consequences, and establish OTX2 expression in the human brain, with a view to investigate the mechanism of action. Methods We screened patients from the UK (n = 103), international centres (n = 24), and Brazil (n = 282); 145 were within the septo-optic dysplasia spectrum, and 264 had no eye phenotype. Transactivation ability of OTX2 variants was analysed in murine hypothalamic GT1-7 neurons. In situ hybridization was performed on human embryonic brain sections. Genetically engineered mice were generated with a series of C-terminal OTX2 variants. Results Two chromosomal deletions and six haploinsufficient mutations were identified in individuals with eye abnormalities; an affected relative of one patient harboured the same mutation without an ocular phenotype. OTX2 truncations led to significant transactivation reduction. A missense variant was identified in another patient without eye abnormalities; however, studies revealed it was most likely not causative. In the mouse, truncations proximal to aa219 caused anophthalmia, while distal truncations and the missense variant were tolerated. During human embryogenesis, OTX2 was expressed in the posterior pituitary, retina, ear, thalamus, choroid plexus, and partially in the hypothalamus, but not in the anterior pituitary. Conclusions OTX2 mutations are rarely associated with hypopituitarism in isolation without eye abnormalities, and may be variably penetrant, even within the same pedigree. Our data suggest that the endocrine phenotypes in patients with OTX2 mutations are of hypothalamic origin.
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Affiliation(s)
- Louise C Gregory
- Section of Molecular Basis of Rare Disease, Genetics and Genomic Medicine Research & Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Peter Gergics
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA
| | - Marilena Nakaguma
- Developmental Endocrinology Unit, Hospital das Clinicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Hironori Bando
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA
| | - Giuseppa Patti
- Section of Molecular Basis of Rare Disease, Genetics and Genomic Medicine Research & Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK
- Department of Pediatrics, IRCCS Istituto Giannina Gaslini
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Genova, Italy
| | - Mark J McCabe
- Section of Molecular Basis of Rare Disease, Genetics and Genomic Medicine Research & Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Qing Fang
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA
| | - Qianyi Ma
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA
| | - Ayse Bilge Ozel
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA
| | - Jun Z Li
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA
| | - Michele Moreira Poina
- Developmental Endocrinology Unit, Hospital das Clinicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Alexander A L Jorge
- Developmental Endocrinology Unit, Hospital das Clinicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Anna F Figueredo Benedetti
- Developmental Endocrinology Unit, Hospital das Clinicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Antonio M Lerario
- Developmental Endocrinology Unit, Hospital das Clinicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Ivo J P Arnhold
- Developmental Endocrinology Unit, Hospital das Clinicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Berenice B Mendonca
- Developmental Endocrinology Unit, Hospital das Clinicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Mohamad Maghnie
- Department of Pediatrics, IRCCS Istituto Giannina Gaslini
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Genova, Italy
| | - Sally A Camper
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA
| | - Luciani R S Carvalho
- Developmental Endocrinology Unit, Hospital das Clinicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Mehul T Dattani
- Section of Molecular Basis of Rare Disease, Genetics and Genomic Medicine Research & Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK
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Kano M, Suga H, Arima H. Induction of Functional Hypothalamus and Pituitary Tissues From Pluripotent Stem Cells for Regenerative Medicine. J Endocr Soc 2020; 5:bvaa188. [PMID: 33604493 PMCID: PMC7880040 DOI: 10.1210/jendso/bvaa188] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Indexed: 12/22/2022] Open
Abstract
The hypothalamus and pituitary have been identified to play essential roles in maintaining homeostasis. Various diseases can disrupt the functions of these systems, which can often result in serious lifelong symptoms. The current treatment for hypopituitarism involves hormone replacement therapy. However, exogenous drug administration cannot mimic the physiological changes that are a result of hormone requirements. Therefore, patients are at a high risk of severe hormone deficiency, including adrenal crisis. Pluripotent stem cells (PSCs) self-proliferate and differentiate into all types of cells. The generation of endocrine tissues from PSCs has been considered as another new treatment for hypopituitarism. Our colleagues established a 3-dimensional (3D) culture method for embryonic stem cells (ESCs). In this culture, the ESC-derived aggregates exhibit self-organization and spontaneous formation of highly ordered patterning. Recent results have shown that strict removal of exogenous patterning factors during early differentiation efficiently induces rostral hypothalamic progenitors from mouse ESCs. These hypothalamic progenitors generate vasopressinergic neurons, which release neuropeptides upon exogenous stimulation. Subsequently, we reported adenohypophysis tissue self-formation in 3D cultures of mouse ESCs. The ESCs were found to differentiate into both nonneural oral ectoderm and hypothalamic neuroectoderm in adjacent layers. Interactions between the 2 tissues appear to be critically important for in vitro induction of a Rathke’s pouch-like developing embryo. Various endocrine cells were differentiated from nonneural ectoderm. The induced corticotrophs efficiently secreted adrenocorticotropic hormone when engrafted in vivo, which rescued hypopituitary hosts. For future regenerative medicine, generation of hypothalamic and pituitary tissues from human PSCs is necessary. We and other groups succeeded in establishing a differentiation method with the use of human PSCs. Researchers could use these methods for models of human diseases to elucidate disease pathology or screen potential therapeutics.
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Affiliation(s)
- Mayuko Kano
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, Japan
| | - Hidetaka Suga
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, Japan
| | - Hiroshi Arima
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, Japan
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Apulei J, Kim N, Testa D, Ribot J, Morizet D, Bernard C, Jourdren L, Blugeon C, Di Nardo AA, Prochiantz A. Non-cell Autonomous OTX2 Homeoprotein Regulates Visual Cortex Plasticity Through Gadd45b/g. Cereb Cortex 2020; 29:2384-2395. [PMID: 29771284 DOI: 10.1093/cercor/bhy108] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 04/19/2018] [Indexed: 11/14/2022] Open
Abstract
The non-cell autonomous transfer of OTX2 homeoprotein transcription factor into juvenile mouse cerebral cortex regulates parvalbumin interneuron maturation and critical period timing. By analyzing gene expression in primary visual cortex of wild-type and Otx2+/GFP mice at plastic and nonplastic ages, we identified several putative genes implicated in Otx2-dependent visual cortex plasticity for ocular dominance. Cortical OTX2 infusion in juvenile mice induced Gadd45b/g expression through direct regulation of transcription. Intriguingly, a reverse effect was found in the adult, where reducing cortical OTX2 resulted in Gadd45b/g upregulation. Viral expression of Gadd45b in adult visual cortex directly induced ocular dominance plasticity with concomitant changes in MeCP2 foci within parvalbumin interneurons and in methylation states of several plasticity gene promoters, suggesting epigenetic regulation. This interaction provides a molecular mechanism for OTX2 to trigger critical period plasticity yet suppress adult plasticity.
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Affiliation(s)
- Jessica Apulei
- Centre for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS UMR 7241, INSERM U1050, PSL University, Labex MemoLife, Paris, France
| | - Namsuk Kim
- Centre for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS UMR 7241, INSERM U1050, PSL University, Labex MemoLife, Paris, France
| | - Damien Testa
- Centre for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS UMR 7241, INSERM U1050, PSL University, Labex MemoLife, Paris, France
| | - Jérôme Ribot
- Centre for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS UMR 7241, INSERM U1050, PSL University, Labex MemoLife, Paris, France
| | - David Morizet
- Centre for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS UMR 7241, INSERM U1050, PSL University, Labex MemoLife, Paris, France
| | - Clémence Bernard
- Centre for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS UMR 7241, INSERM U1050, PSL University, Labex MemoLife, Paris, France
| | - Laurent Jourdren
- Genomic Core Facility, Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL University, Paris, France
| | - Corinne Blugeon
- Genomic Core Facility, Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL University, Paris, France
| | - Ariel A Di Nardo
- Centre for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS UMR 7241, INSERM U1050, PSL University, Labex MemoLife, Paris, France
| | - Alain Prochiantz
- Centre for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS UMR 7241, INSERM U1050, PSL University, Labex MemoLife, Paris, France
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11
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Matsumoto R, Suga H, Aoi T, Bando H, Fukuoka H, Iguchi G, Narumi S, Hasegawa T, Muguruma K, Ogawa W, Takahashi Y. Congenital pituitary hypoplasia model demonstrates hypothalamic OTX2 regulation of pituitary progenitor cells. J Clin Invest 2020; 130:641-654. [PMID: 31845906 DOI: 10.1172/jci127378] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 10/15/2019] [Indexed: 12/15/2022] Open
Abstract
Pituitary develops from oral ectoderm in contact with adjacent ventral hypothalamus. Impairment in this process results in congenital pituitary hypoplasia (CPH); however, there have been no human disease models for CPH thus far, prohibiting the elucidation of the underlying mechanisms. In this study, we established a disease model of CPH using patient-derived induced pluripotent stem cells (iPSCs) and 3D organoid technique, in which oral ectoderm and hypothalamus develop simultaneously. Interestingly, patient iPSCs with a heterozygous mutation in the orthodenticle homeobox 2 (OTX2) gene showed increased apoptosis in the pituitary progenitor cells, and the differentiation into pituitary hormone-producing cells was severely impaired. As an underlying mechanism, OTX2 in hypothalamus, not in oral ectoderm, was essential for progenitor cell maintenance by regulating LHX3 expression in oral ectoderm via FGF10 expression in the hypothalamus. Convincingly, the phenotype was reversed by the correction of the mutation, and the haploinsufficiency of OTX2 in control iPSCs revealed a similar phenotype, demonstrating that this mutation was responsible. Thus, we established an iPSC-based congenital pituitary disease model, which recapitulated interaction between hypothalamus and oral ectoderm and demonstrated the essential role of hypothalamic OTX2.
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Affiliation(s)
- Ryusaku Matsumoto
- Division of Diabetes and Endocrinology, Department of Internal Medicine, and.,Department of iPS cell Applications, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.,Department of Advanced Medical Science, Kobe University Graduate School of Science, Technology, and Innovation, Kobe, Hyogo, Japan
| | - Hidetaka Suga
- Department of Diabetes and Endocrinology, Nagoya University Hospital, Nagoya, Aichi, Japan
| | - Takashi Aoi
- Department of iPS cell Applications, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.,Department of Advanced Medical Science, Kobe University Graduate School of Science, Technology, and Innovation, Kobe, Hyogo, Japan
| | - Hironori Bando
- Division of Diabetes and Endocrinology, Department of Internal Medicine, and
| | - Hidenori Fukuoka
- Department of Diabetes and Endocrinology, Kobe University Hospital, Kobe, Hyogo, Japan
| | - Genzo Iguchi
- Department of Diabetes and Endocrinology, Kobe University Hospital, Kobe, Hyogo, Japan.,Medical Center for Student Health, Kobe University, Kobe, Hyogo, Japan.,Department of Biosignal Pathophysiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Satoshi Narumi
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, Japan.,Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
| | - Tomonobu Hasegawa
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
| | - Keiko Muguruma
- Laboratory for Cell Asymmetry, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo, Japan.,Department of iPS Cell Applied Medicine, Graduate School of Medicine, Kansai Medical University, Hirakata, Osaka, Japan
| | - Wataru Ogawa
- Division of Diabetes and Endocrinology, Department of Internal Medicine, and
| | - Yutaka Takahashi
- Division of Diabetes and Endocrinology, Department of Internal Medicine, and
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12
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Hughes AEO, Myers CA, Corbo JC. A massively parallel reporter assay reveals context-dependent activity of homeodomain binding sites in vivo. Genome Res 2018; 28:1520-1531. [PMID: 30158147 PMCID: PMC6169884 DOI: 10.1101/gr.231886.117] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 08/27/2018] [Indexed: 12/20/2022]
Abstract
Cone-rod homeobox (CRX) is a paired-like homeodomain transcription factor (TF) and a master regulator of photoreceptor development in vertebrates. The in vitro DNA binding preferences of CRX have been described in detail, but the degree to which in vitro binding affinity is correlated with in vivo enhancer activity is not known. In addition, paired-class homeodomain TFs can bind DNA cooperatively as both homodimers and heterodimers at inverted TAAT half-sites separated by 2 or 3 nucleotides. This dimeric configuration is thought to mediate target specificity, but whether monomeric and dimeric sites encode distinct levels of activity is not known. Here, we used a massively parallel reporter assay to determine how local sequence context shapes the regulatory activity of CRX binding sites in mouse photoreceptors. We assayed inactivating mutations in more than 1700 TF binding sites and found that dimeric CRX binding sites act as stronger enhancers than monomeric CRX binding sites. Furthermore, the activity of dimeric half-sites is cooperative, dependent on a strict 3-bp spacing, and tuned by the identity of the spacer nucleotides. Saturating single-nucleotide mutagenesis of 195 CRX binding sites showed that, on average, changes in TF binding site affinity are correlated with changes in regulatory activity, but this relationship is obscured when considering mutations across multiple cis-regulatory elements (CREs). Taken together, these results demonstrate that the activity of CRX binding sites is highly dependent on sequence context, providing insight into photoreceptor gene regulation and illustrating functional principles of homeodomain binding sites that may be conserved in other cell types.
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Affiliation(s)
- Andrew E O Hughes
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | - Connie A Myers
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | - Joseph C Corbo
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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13
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A Simple Grammar Defines Activating and Repressing cis-Regulatory Elements in Photoreceptors. Cell Rep 2017; 17:1247-1254. [PMID: 27783940 DOI: 10.1016/j.celrep.2016.09.066] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 08/06/2016] [Accepted: 09/20/2016] [Indexed: 12/22/2022] Open
Abstract
Transcription factors often activate and repress different target genes in the same cell. How activation and repression are encoded by different arrangements of transcription factor binding sites in cis-regulatory elements is poorly understood. We investigated how sites for the transcription factor CRX encode both activation and repression in photoreceptors by assaying thousands of genomic and synthetic cis-regulatory elements in wild-type and Crx-/- retinas. We found that sequences with high affinity for CRX repress transcription, whereas sequences with lower affinity activate. This rule is modified by a cooperative interaction between CRX sites and sites for the transcription factor NRL, which overrides the repressive effect of high affinity for CRX. Our results show how simple rearrangements of transcription factor binding sites encode qualitatively different responses to a single transcription factor and explain how CRX plays multiple cis-regulatory roles in the same cell.
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14
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Sakai A, Nakato R, Ling Y, Hou X, Hara N, Iijima T, Yanagawa Y, Kuwano R, Okuda S, Shirahige K, Sugiyama S. Genome-Wide Target Analyses of Otx2 Homeoprotein in Postnatal Cortex. Front Neurosci 2017; 11:307. [PMID: 28620275 PMCID: PMC5450002 DOI: 10.3389/fnins.2017.00307] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 05/16/2017] [Indexed: 11/13/2022] Open
Abstract
Juvenile brain has a unique time window, or critical period, in which neuronal circuits are remodeled by experience. Mounting evidence indicates the importance of neuronal circuit rewiring in various neurodevelopmental disorders of human cognition. We previously showed that Otx2 homeoprotein, essential for brain formation, is recaptured during postnatal maturation of parvalbumin-positive interneurons (PV cells) to activate the critical period in mouse visual cortex. Cortical Otx2 is the only interneuron-enriched transcription factor known to regulate the critical period, but its downstream targets remain unknown. Here, we used ChIP-seq (chromatin immunoprecipitation sequencing) to identify genome-wide binding sites of Otx2 in juvenile mouse cortex, and interneuron-specific RNA-seq to explore the Otx2-dependent transcriptome. Otx2-bound genes were associated with human diseases such as schizophrenia as well as critical periods. Of these genes, expression of neuronal factors involved in transcription, signal transduction and mitochondrial function was moderately and broadly affected in Otx2-deficient interneurons. In contrast to reported binding sites in the embryo, genes encoding potassium ion transporters such as KV3.1 had juvenile cortex-specific binding sites, suggesting that Otx2 is involved in regulating fast-spiking properties during PV cell maturation. Moreover, transcripts of oxidative resistance-1 (Oxr1), whose promoter has Otx2 binding sites, were markedly downregulated in Otx2-deficient interneurons. Therefore, an important role of Otx2 may be to protect the cells from the increased oxidative stress in fast-spiking PV cells. Our results suggest that coordinated expression of Otx2 targets promotes PV cell maturation and maintains its function in neuronal plasticity and disease.
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Affiliation(s)
- Akiko Sakai
- Laboratory of Neuronal Development, Graduate School of Medical and Dental Sciences, Niigata UniversityNiigata, Japan
| | - Ryuichiro Nakato
- Research Center for Epigenetic Disease, Institute of Molecular and Cellular Biosciences, University of TokyoTokyo, Japan
| | - Yiwei Ling
- Bioinformatics Laboratory, Graduate School of Medical and Dental Sciences, Niigata UniversityNiigata, Japan
| | - Xubin Hou
- Laboratory of Neuronal Development, Graduate School of Medical and Dental Sciences, Niigata UniversityNiigata, Japan
| | - Norikazu Hara
- Department of Molecular Genetics, Center for Bioresources, Brain Research Institute, Niigata UniversityNiigata, Japan
| | - Tomoya Iijima
- Laboratory of Neuronal Development, Graduate School of Medical and Dental Sciences, Niigata UniversityNiigata, Japan
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Graduate School of Medicine, Gunma UniversityGunma, Japan
| | - Ryozo Kuwano
- Department of Molecular Genetics, Center for Bioresources, Brain Research Institute, Niigata UniversityNiigata, Japan
| | - Shujiro Okuda
- Bioinformatics Laboratory, Graduate School of Medical and Dental Sciences, Niigata UniversityNiigata, Japan
| | - Katsuhiko Shirahige
- Research Center for Epigenetic Disease, Institute of Molecular and Cellular Biosciences, University of TokyoTokyo, Japan
| | - Sayaka Sugiyama
- Laboratory of Neuronal Development, Graduate School of Medical and Dental Sciences, Niigata UniversityNiigata, Japan
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15
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Fant B, Samuel A, Audebert S, Couzon A, El Nagar S, Billon N, Lamonerie T. Comprehensive interactome of Otx2 in the adult mouse neural retina. Genesis 2015; 53:685-94. [PMID: 26426291 DOI: 10.1002/dvg.22903] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 09/28/2015] [Accepted: 09/29/2015] [Indexed: 11/10/2022]
Abstract
The Otx2 homeodomain transcription factor exerts multiple functions in specific developmental contexts, probably through the regulation of different sets of genes. Protein partners of Otx2 have been shown to modulate its activity. Therefore, the Otx2 interactome may play a key role in selecting a precise target-gene repertoire, hence determining its function in a specific tissue. To address the nature of Otx2 interactome, we generated a new recombinant Otx2(CTAP-tag) mouse line, designed for protein complexes purification. We validated this mouse line by establishing the Otx2 interactome in the adult neural retina. In this tissue, Otx2 is thought to have overlapping function with its paralog Crx. Our analysis revealed that, in contrary to Crx, Otx2 did not develop interactions with proteins that are known to regulate phototransduction genes but showed specific partnership with factors associated with retinal development. The relationship between Otx2 and Crx in the neural retina should therefore be considered as complementarity rather than redundancy. Furthermore, study of the Otx2 interactome revealed strong associations with RNA processing and translation machineries, suggesting unexpected roles for Otx2 in the regulation of selected target genes all along the transcription/translation pathway. The Otx2(CTAP-tag) line, therefore, appears suitable for a systematic approach to Otx2 protein-protein interactions. genesis 53:685-694, 2015. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Bruno Fant
- Institut De Biologie Valrose, University of Nice Sophia Antipolis, UFR Sciences, CNRS, UMR7277, Inserm, U1091, Nice, F-06108, France
| | - Alexander Samuel
- Institut De Biologie Valrose, University of Nice Sophia Antipolis, UFR Sciences, CNRS, UMR7277, Inserm, U1091, Nice, F-06108, France
| | - Stéphane Audebert
- Centre De Recherche En Cancérologie De Marseille, INSERM U1068/Institut Paoli-Calmettes, 13273 Marseille CEDEX 9, France
| | - Agnès Couzon
- AniRA-PBES, SFR BioSciences Gerland, UMS3444/US8, ENS De Lyon, Lyon, 69007, France
| | - Salsabiel El Nagar
- Institut De Biologie Valrose, University of Nice Sophia Antipolis, UFR Sciences, CNRS, UMR7277, Inserm, U1091, Nice, F-06108, France
| | - Nathalie Billon
- Institut De Biologie Valrose, University of Nice Sophia Antipolis, UFR Sciences, CNRS, UMR7277, Inserm, U1091, Nice, F-06108, France
| | - Thomas Lamonerie
- Institut De Biologie Valrose, University of Nice Sophia Antipolis, UFR Sciences, CNRS, UMR7277, Inserm, U1091, Nice, F-06108, France
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16
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Sergouniotis PI, Urquhart JE, Williams SG, Bhaskar SS, Black GC, Lovell SC, Whitby DJ, Newman WG, Clayton-Smith J. Agnathia-otocephaly complex and asymmetric velopharyngeal insufficiency due to an in-frame duplication in OTX2. J Hum Genet 2015; 60:199-202. [PMID: 25589041 DOI: 10.1038/jhg.2014.122] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 12/03/2014] [Accepted: 12/05/2014] [Indexed: 02/05/2023]
Abstract
Agnathia-otocephaly complex is a malformation characterized by absent/hypoplastic mandible and abnormally positioned ears. Mutations in two genes, PRRX1 and OTX2, have been described in a small number of families with this disorder. We performed clinical and genetic testing in an additional family. The proband is a healthy female with a complicated pregnancy history that includes two offspring diagnosed with agnathia-otocephaly during prenatal ultrasound scans. Exome sequencing was performed in fetal DNA from one of these two offspring revealing a heterozygous duplication in OTX2: c.271_273dupCAG, p.(Gln91dup). This change leads to the insertion of a glutamine within the OTX2 homeodomain region, and is predicted to alter this signaling molecule's ability to interact with DNA. The same variant was also identified in the proband's clinically unaffected 38-year-old husband and their 9-year-old daughter, who presented with a small mandible, normal ears and velopharyngeal insufficiency due to a short hemi-palate. This unusual presentation of OTX2-related disease suggests that OTX2 might have a role in palatal hypoplasia cases. A previously unreported OTX2 variant associated with extreme intrafamilial variability is described and the utility of exome sequencing as a tool to confirm the diagnosis of agnathia-otocephaly and to inform the reproductive decisions of affected families is highlighted.
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Affiliation(s)
- Panagiotis I Sergouniotis
- 1] Institute of Human Development, University of Manchester, Manchester, UK [2] Manchester Royal Eye Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
| | - Jill E Urquhart
- 1] Institute of Human Development, University of Manchester, Manchester, UK [2] Manchester Centre for Genomic Medicine, St Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
| | - Simon G Williams
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
| | - Sanjeev S Bhaskar
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
| | - Graeme C Black
- 1] Institute of Human Development, University of Manchester, Manchester, UK [2] Manchester Centre for Genomic Medicine, St Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
| | - Simon C Lovell
- Department of Computational and Evolutionary Biology, Faculty of Life Sciences, University of Manchester, Manchester, UK
| | - David J Whitby
- North West, Isle of Man and North Wales Cleft Lip and Palate Network, Royal Manchester Children's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
| | - William G Newman
- 1] Institute of Human Development, University of Manchester, Manchester, UK [2] Manchester Centre for Genomic Medicine, St Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
| | - Jill Clayton-Smith
- 1] Institute of Human Development, University of Manchester, Manchester, UK [2] Manchester Centre for Genomic Medicine, St Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
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17
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Ip CK, Fossat N, Jones V, Lamonerie T, Tam PPL. Head formation: OTX2 regulates Dkk1 and Lhx1 activity in the anterior mesendoderm. Development 2014; 141:3859-67. [DOI: 10.1242/dev.114900] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The Otx2 gene encodes a paired-type homeobox transcription factor that is essential for the induction and the patterning of the anterior structures in the mouse embryo. Otx2 knockout embryos fail to form a head. Whereas previous studies have shown that Otx2 is required in the anterior visceral endoderm and the anterior neuroectoderm for head formation, its role in the anterior mesendoderm (AME) has not been assessed specifically. Here, we show that tissue-specific ablation of Otx2 in the AME phenocopies the truncation of the embryonic head of the Otx2 null mutant. Expression of Dkk1 and Lhx1, two genes that are also essential for head formation, is disrupted in the AME of the conditional Otx2-deficient embryos. Consistent with the fact that Dkk1 is a direct target of OTX2, we showed that OTX2 can interact with the H1 regulatory region of Dkk1 to activate its expression. Cross-species comparative analysis, RT-qPCR, ChIP-qPCR and luciferase assays have revealed two conserved regions in the Lhx1 locus to which OTX2 can bind to activate Lhx1 expression. Abnormal development of the embryonic head in Otx2;Lhx1 and Otx2;Dkk1 compound mutant embryos highlights the functional intersection of Otx2, Dkk1 and Lhx1 in the AME for head formation.
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Affiliation(s)
- Chi Kin Ip
- Embryology Unit, Children's Medical Research Institute, Locked Bag 23, Wentworthville, New South Wales 2145, Australia
- Discipline of Medicine, Sydney Medical School, University of Sydney, New South Wales 2006, Australia
| | - Nicolas Fossat
- Embryology Unit, Children's Medical Research Institute, Locked Bag 23, Wentworthville, New South Wales 2145, Australia
- Discipline of Medicine, Sydney Medical School, University of Sydney, New South Wales 2006, Australia
| | - Vanessa Jones
- Embryology Unit, Children's Medical Research Institute, Locked Bag 23, Wentworthville, New South Wales 2145, Australia
| | - Thomas Lamonerie
- Equipe Neurodéveloppement, Institut de Biologie Valrose, UMR UNS/CNRS 7277/INSERM 1091, Université Nice Sophia Antipolis, Parc Valrose, 06108 Nice cedex 2, France
| | - Patrick P. L. Tam
- Embryology Unit, Children's Medical Research Institute, Locked Bag 23, Wentworthville, New South Wales 2145, Australia
- Discipline of Medicine, Sydney Medical School, University of Sydney, New South Wales 2006, Australia
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18
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Yang SH, Kalkan T, Morissroe C, Marks H, Stunnenberg H, Smith A, Sharrocks A. Otx2 and Oct4 drive early enhancer activation during embryonic stem cell transition from naive pluripotency. Cell Rep 2014; 7:1968-81. [PMID: 24931607 PMCID: PMC4074343 DOI: 10.1016/j.celrep.2014.05.037] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 04/11/2014] [Accepted: 05/19/2014] [Indexed: 02/02/2023] Open
Abstract
Embryonic stem cells (ESCs) are unique in that they have the capacity to differentiate into all of the cell types in the body. We know a lot about the complex transcriptional control circuits that maintain the naive pluripotent state under self-renewing conditions but comparatively less about how cells exit from this state in response to differentiation stimuli. Here, we examined the role of Otx2 in this process in mouse ESCs and demonstrate that it plays a leading role in remodeling the gene regulatory networks as cells exit from ground state pluripotency. Otx2 drives enhancer activation through affecting chromatin marks and the activity of associated genes. Mechanistically, Oct4 is required for Otx2 expression, and reciprocally, Otx2 is required for efficient Oct4 recruitment to many enhancer regions. Therefore, the Oct4-Otx2 regulatory axis actively establishes a new regulatory chromatin landscape during the early events that accompany exit from ground state pluripotency.
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Affiliation(s)
- Shen-Hsi Yang
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK
| | - Tüzer Kalkan
- Wellcome Trust-Medical Research Council Stem Cell Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QR, UK
| | - Claire Morissroe
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK
| | - Hendrik Marks
- Department of Molecular Biology, Faculty of Science, Raboud Institute for Molecular Life Sciences, Radboud University, 6525GA Nijmegen, the Netherlands
| | - Hendrik Stunnenberg
- Department of Molecular Biology, Faculty of Science, Raboud Institute for Molecular Life Sciences, Radboud University, 6525GA Nijmegen, the Netherlands
| | - Austin Smith
- Wellcome Trust-Medical Research Council Stem Cell Institute and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QR, UK
| | - Andrew D. Sharrocks
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK,Corresponding author
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19
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Samuel A, Housset M, Fant B, Lamonerie T. Otx2 ChIP-seq reveals unique and redundant functions in the mature mouse retina. PLoS One 2014; 9:e89110. [PMID: 24558479 PMCID: PMC3928427 DOI: 10.1371/journal.pone.0089110] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 01/17/2014] [Indexed: 11/18/2022] Open
Abstract
During mouse retinal development and into adulthood, the transcription factor Otx2 is expressed in pigment epithelium, photoreceptors and bipolar cells. In the mature retina, Otx2 ablation causes photoreceptor degeneration through a non-cell-autonomous mechanism involving Otx2 function in the supporting RPE. Surprisingly, photoreceptor survival does not require Otx2 expression in the neural retina, where the related Crx homeobox gene, a major regulator of photoreceptor development, is also expressed. To get a deeper view of mouse Otx2 activities in the neural retina, we performed chromatin-immunoprecipitation followed by massively parallel sequencing (ChIP-seq) on Otx2. Using two independent ChIP-seq assays, we identified consistent sets of Otx2-bound cis-regulatory elements. Comparison with our previous RPE-specific Otx2 ChIP-seq data shows that Otx2 occupies different functional domains of the genome in RPE cells and in neural retina cells and regulates mostly different sets of genes. To assess the potential redundancy of Otx2 and Crx, we compared our data with Crx ChIP-seq data. While Crx genome occupancy markedly differs from Otx2 genome occupancy in the RPE, it largely overlaps that of Otx2 in the neural retina. Thus, in accordance with its essential role in the RPE and its non-essential role in the neural retina, Otx2 regulates different gene sets in the RPE and the neural retina, and shares an important part of its repertoire with Crx in the neural retina. Overall, this study provides a better understanding of gene-regulatory networks controlling photoreceptor homeostasis and disease.
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Affiliation(s)
- Alexander Samuel
- Institut de Biologie Valrose, University of Nice Sophia Antipolis, CNRS UMR7277, Inserm U1091, Nice, France
| | - Michael Housset
- Institut de Biologie Valrose, University of Nice Sophia Antipolis, CNRS UMR7277, Inserm U1091, Nice, France
| | - Bruno Fant
- Institut de Biologie Valrose, University of Nice Sophia Antipolis, CNRS UMR7277, Inserm U1091, Nice, France
| | - Thomas Lamonerie
- Institut de Biologie Valrose, University of Nice Sophia Antipolis, CNRS UMR7277, Inserm U1091, Nice, France
- * E-mail:
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20
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Bernard C, Kim HT, Torero Ibad R, Lee EJ, Simonutti M, Picaud S, Acampora D, Simeone A, Di Nardo AA, Prochiantz A, Moya KL, Kim JW. Graded Otx2 activities demonstrate dose-sensitive eye and retina phenotypes. Hum Mol Genet 2013; 23:1742-53. [PMID: 24234651 DOI: 10.1093/hmg/ddt562] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In the human, mutations of OTX2 (Orthodenticle homeobox 2 transcription factor) translate into eye malformations of variable expressivity (even between the two eyes of the same individual) and incomplete penetrance, suggesting the existence of subtle thresholds in OTX2 activity. We have addressed this issue by analyzing retinal structure and function in six mutant mice with graded Otx2 activity: Otx2(+/+), Otx2(+/AA), Otx2(+/GFP), Otx2(AA/AA), Otx2(AA/GFP) and Otx2(GFP/GFP). Null mice (Otx2(GFP/GFP)) fail to develop the head and are embryonic lethal, and compound heterozygous Otx2(AA/GFP) mice show a truncated head and die at birth. All other genotypes develop until adulthood. We analyzed eye structure and visual physiology in the genotypes that develop until adulthood and report that phenotype severity parallels Otx2 activity. Otx2(+/AA) are only mildly affected whereas Otx2(+/GFP) are more affected than Otx2(+/AA) but less than Otx2(AA/AA) mice. Otx2(AA/AA) mice later manifest the most severe defects, with variable expressivity. Electrophysiological and histological analyses of the mouse retina revealed progressive death of bipolar cells and cone photoreceptors that is both Otx2 activity- and age-dependent with the same ranking of phenotypic severity. This study demonstrates the importance of gene dosage in the development of age-dependent pathologies and underscores the fact that small gene dosage differences can cause significant pathological states.
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Affiliation(s)
- Clémence Bernard
- Collège de France, Center for Interdisciplinary Research in Biology, UMR CNRS 7241/INSERM U1050, 11 place Marcelin Berthelot, Paris 75005, France
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21
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Loss of Otx2 in the adult retina disrupts retinal pigment epithelium function, causing photoreceptor degeneration. J Neurosci 2013; 33:9890-904. [PMID: 23761884 DOI: 10.1523/jneurosci.1099-13.2013] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Photoreceptors are specialized neurons of the retina that receive nursing from the adjacent retinal pigment epithelium (RPE). Frequent in the elderly, photoreceptor loss can originate from primary dysfunction of either cell type. Despite intense interest in the etiology of these diseases, early molecular actors of late-onset photoreceptor degeneration remain elusive, mostly because of the lack of dedicated models. Conditional Otx2 ablation in the adult mouse retina elicits photoreceptor degeneration, providing a new model of late-onset neuronal disease. Here, we use this model to identify the earliest events after Otx2 ablation. Electroretinography and gene expression analyses suggest a nonautonomous, RPE-dependent origin for photoreceptor degeneration. This is confirmed by RPE-specific ablation of Otx2, which results in similar photoreceptor degeneration. In contrast, constitutive Otx2 expression in RPE cells prevents degeneration of photoreceptors in Otx2-ablated retinas. We use chromatin immunoprecipitation followed by massive sequencing (ChIP-seq) analysis to identify the molecular network controlled in vivo by Otx2 in RPE cells. We uncover four RPE-specific functions coordinated by Otx2 that underpin the cognate photoreceptor degeneration. Many direct Otx2 target genes are associated with human retinopathies, emphasizing the significance of the model. Importantly, we report a secondary genetic response after Otx2 ablation, which largely precedes apoptosis of photoreceptors, involving inflammation and stress genes. These findings thus provide novel general markers for clinical detection and prevention of neuronal cell death.
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22
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Beby F, Lamonerie T. The homeobox gene Otx2 in development and disease. Exp Eye Res 2013; 111:9-16. [DOI: 10.1016/j.exer.2013.03.007] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 03/07/2013] [Accepted: 03/11/2013] [Indexed: 01/04/2023]
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Tajima T, Ishizu K, Nakamura A. Molecular and Clinical Findings in Patients with LHX4 and OTX2 Mutations. Clin Pediatr Endocrinol 2013; 22:15-23. [PMID: 23990694 DOI: 10.1292/cpe.22.15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 12/28/2012] [Indexed: 11/22/2022] Open
Abstract
The pituitary gland produces hormones that play important roles in both the development and homeostasis of the body. Ontogeny of the anterior and posterior pituitary is orchestrated by inputs from neighboring tissues, cellular signaling molecules and transcription factors. Disruption of expression or function of these factors has been implicated in the etiology of combined pituitary hormone deficiency (CPHD). These include the transcription factors HESX1, PROP1, POU1F1, LHX3, LHX4, OTX2, SOX2, SOX3 and GLI2. This review focuses on summarizing most recent mutations in LHX4 and OTX2 responsible for pituitary hormone deficiency. In both genetic defects of LHX4 and OTX2, there is high variability in clinical manifestations even in the same family. In addition, there is no clear phenotype-genotype correlation. These findings indicate that the other genetic and/or environmental factors influence the phenotype. In addition, the variability might reflect a plasticity during pituitary development and maintenance. Over the past two decades, a genetic basis for pituitary hormone deficiency and the mechanism of pituitary development have been clarified. It should be kept in mind that this review is not comprehensive, and defects of other transcriptional factors have been described in patients with CPHD. Furthermore, the causes in many patients with CPHD have not yet been determined. Therefore, continuing efforts for the clarification of the etiology are necessary.
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Affiliation(s)
- Toshihiro Tajima
- Department of Pediatrics, Hokkaido University School of Medicine, Hokkaido, Japan
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Abstract
The pituitary gland produces hormones that play
important roles in both the development and homeostasis of the body. Ontogeny of the
anterior and posterior pituitary is orchestrated by inputs from neighboring tissues,
cellular signaling molecules and transcription factors. Disruption of expression or
function of these factors has been implicated in the etiology of combined pituitary
hormone deficiency (CPHD). These include the transcription factors HESX1, PROP1, POU1F1,
LHX3, LHX4, OTX2, SOX2, SOX3 and GLI2. This review focuses on summarizing most recent
mutations in LHX4 and OTX2 responsible for pituitary
hormone deficiency. In both genetic defects of LHX4 and
OTX2, there is high variability in clinical manifestations even in the
same family. In addition, there is no clear phenotype-genotype correlation. These findings
indicate that the other genetic and/or environmental factors influence the phenotype. In
addition, the variability might reflect a plasticity during pituitary development and
maintenance. Over the past two decades, a genetic basis for pituitary hormone deficiency
and the mechanism of pituitary development have been clarified. It should be kept in mind
that this review is not comprehensive, and defects of other transcriptional factors have
been described in patients with CPHD. Furthermore, the causes in many patients with CPHD
have not yet been determined. Therefore, continuing efforts for the clarification of the
etiology are necessary.
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Affiliation(s)
- Toshihiro Tajima
- Department of Pediatrics, Hokkaido University School of Medicine, Hokkaido, Japan
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Liu Z, Chi L, Fang Y, Liu L, Zhang X. Specific expression pattern of a novel Otx2 splicing variant during neural differentiation. Gene 2013; 523:33-8. [PMID: 23566845 DOI: 10.1016/j.gene.2013.03.114] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 03/20/2013] [Accepted: 03/25/2013] [Indexed: 01/30/2023]
Abstract
We cloned a new splicing variant of Otx2 gene, Otx2c. Otx2c lacks entire exon 4, most of the region encoding the homeodomain. More importantly, Otx2c harbors an early premature stop codon and bioinformatics analysis prefers it to be a non-protein coding RNA. In addition, this splicing variant is not simply a noise during mRNA processing, since it is mainly expressed in undifferentiated human embryonic stem cells but gradually decreased during differentiation. Therefore, we report here that a single pre-mRNA can generate both coding and non-coding RNAs through alternative splicing and this splicing activity is tightly regulated in different cell contexts.
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Affiliation(s)
- Zhongliang Liu
- Shanghai Tenth People's Hospital and Department of Regenerative Medicine, Tongji University School of Medicine, Shanghai 200092, China
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Bai RY, Staedtke V, Lidov HG, Eberhart CG, Riggins GJ. OTX2 represses myogenic and neuronal differentiation in medulloblastoma cells. Cancer Res 2012; 72:5988-6001. [PMID: 22986744 DOI: 10.1158/0008-5472.can-12-0614] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The brain development transcription factor OTX2 is overexpressed and/or genomically amplified in most medulloblastomas, but the mechanistic basis for its contributions in this setting are not understood. In this study, we identified OTX2 as a transcriptional repressor and a gatekeeper of myogenic and neuronal differentiation in medulloblastoma cells. OTX2 binds to the MyoD1 core enhancer through its homeobox domain, and the remarkable repressor activity exhibited by the homeobox domain renders OTX2 transcriptionally repressive. RNA interference-mediated attenuation of OTX2 expression triggered myogenic and neuronal differentiation in vitro and prolonged the survival in an orthotopic medulloblastoma mouse model. Conversely, inducing myogenic conversion of medulloblastoma cells led to the loss of OTX2 expression. In medullomyoblastoma, a medulloblastoma subtype containing muscle elements, myogenic cells share cytogenetic signatures with the primitive tumor cells and OTX2 expression was lost in the differentiated myogenic cells. Thus, OTX2 functions via its homeobox domain as a suppressor of differentiation, and the loss of OTX2 expression is linked to the myogenesis in medullomyoblastoma. Together, our findings illustrate the origin of muscle cells in medullomyoblastomas and the oncogenic mechanism of OTX2 as a repressor of diverse differentiating potential.
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Affiliation(s)
- Ren-Yuan Bai
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, USA.
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27
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Gorbenko Del Blanco D, Romero CJ, Diaczok D, de Graaff LCG, Radovick S, Hokken-Koelega ACS. A novel OTX2 mutation in a patient with combined pituitary hormone deficiency, pituitary malformation, and an underdeveloped left optic nerve. Eur J Endocrinol 2012; 167:441-52. [PMID: 22715480 DOI: 10.1530/eje-12-0333] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Orthodenticle homolog 2 (OTX2) is a homeobox family transcription factor required for brain and eye formation. Various genetic alterations in OTX2 have been described, mostly in patients with severe ocular malformations. In order to expand the knowledge of the spectrum of OTX2 mutation, we performed OTX2 mutation screening in 92 patients with combined pituitary hormone deficiency (CPHD). We directly sequenced the coding regions and exon-intron boundaries of OTX2 in 92 CPHD patients from the Dutch HYPOPIT study in whom mutations in the classical CPHD genes PROP1, POU1F1, HESX1, LHX3, and LHX4 had been ruled out. Among 92 CPHD patients, we identified a novel heterozygous missense mutation c.401C>G (p.Pro134Arg) in a patient with CPHD, pituitary malformation, and an underdeveloped left optic nerve. Binding of both the wild-type and mutant OTX2 proteins to bicoid binding sites was equivalent; however, the mutant OTX2 exhibited decreased transactivation. We describe a novel missense heterozygous OTX2 mutation that acts as a dominant negative inhibitor of target gene expression in a patient with CPHD, pituitary malformation, and optic nerve hypoplasia. We provide an overview of all OTX2 mutations described till date, which show that OTX2 is a promising candidate gene for genetic screening of patients with CPHD or isolated GH deficiency (IGHD). As the majority of the OTX2 mutations found in patients with CPHD, IGHD, or short stature have been found in exon 5, we recommend starting mutational screening in those patients in exon 5 of the gene.
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Prasov L, Masud T, Khaliq S, Mehdi SQ, Abid A, Oliver ER, Silva ED, Lewanda A, Brodsky MC, Borchert M, Kelberman D, Sowden JC, Dattani MT, Glaser T. ATOH7 mutations cause autosomal recessive persistent hyperplasia of the primary vitreous. Hum Mol Genet 2012; 21:3681-94. [PMID: 22645276 DOI: 10.1093/hmg/dds197] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The vertebrate basic helix-loop-helix (bHLH) transcription factor ATOH7 (Math5) is specifically expressed in the embryonic neural retina and is required for the genesis of retinal ganglion cells (RGCs) and optic nerves. In Atoh7 mutant mice, the absence of trophic factors secreted by RGCs prevents the development of the intrinsic retinal vasculature and the regression of fetal blood vessels, causing persistent hyperplasia of the primary vitreous (PHPV). We therefore screened patients with hereditary PHPV, as well as bilateral optic nerve aplasia (ONA) or hypoplasia (ONH), for mutations in ATOH7. We identified a homozygous ATOH7 mutation (N46H) in a large family with an autosomal recessive PHPV disease trait linked to 10q21, and a heterozygous variant (R65G, p.Arg65Gly) in one of five sporadic ONA patients. High-density single-nucleotide polymorphism analysis also revealed a CNTN4 duplication and an OTX2 deletion in the ONA cohort. Functional analysis of ATOH7 bHLH domain substitutions, by electrophoretic mobility shift and luciferase cotransfection assays, revealed that the N46H variant cannot bind DNA or activate transcription, consistent with structural modeling. The N46H variant also failed to rescue RGC development in mouse Atoh7-/- retinal explants. The R65G variant retains all of these activities, similar to wild-type human ATOH7. Our results strongly suggest that autosomal recessive persistent hyperplastic primary vitreous is caused by N46H and is etiologically related to nonsyndromic congenital retinal nonattachment. The R65G allele, however, cannot explain the ONA phenotype. Our study firmly establishes ATOH7 as a retinal disease gene and provides a functional basis to analyze new coding variants.
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Affiliation(s)
- Lev Prasov
- Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA
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Slavotinek AM. Eye development genes and known syndromes. Mol Genet Metab 2011; 104:448-56. [PMID: 22005280 PMCID: PMC3224152 DOI: 10.1016/j.ymgme.2011.09.029] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 09/21/2011] [Accepted: 09/21/2011] [Indexed: 11/22/2022]
Abstract
Anophthalmia and microphthalmia (A/M) are significant eye defects because they can have profound effects on visual acuity. A/M is associated with non-ocular abnormalities in an estimated 33-95% of cases and around 25% of patients have an underlying genetic syndrome that is diagnosable. Syndrome recognition is important for targeted molecular genetic testing, prognosis and for counseling regarding recurrence risks. This review provides clinical and molecular information for several of the commonest syndromes associated with A/M: Anophthalmia-Esophageal-Genital syndrome, caused by SOX2 mutations, Anophthalmia and pituitary abnormalities caused by OTX2 mutations, Matthew-Wood syndrome caused by STRA6 mutations, oculofaciocardiodental syndrome and Lenz microphthalmia caused by BCOR mutations, Microphthalmia Linear Skin pigmentation syndrome caused by HCCS mutations, Anophthalmia, pituitary abnormalities, polysyndactyly caused by BMP4 mutations and Waardenburg anophthalmia caused by mutations in SMOC1. In addition, we briefly discuss the ocular and extraocular phenotypes associated with several other important eye developmental genes, including GDF6, VSX2, RAX, SHH, SIX6 and PAX6.
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Affiliation(s)
- Anne M Slavotinek
- Department of Pediatrics, Division of Genetics, University of California, San Francisco, San Francisco, CA 94143-0748, USA.
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Bunt J, Hasselt NE, Zwijnenburg DA, Koster J, Versteeg R, Kool M. Joint binding of OTX2 and MYC in promotor regions is associated with high gene expression in medulloblastoma. PLoS One 2011; 6:e26058. [PMID: 22016811 PMCID: PMC3189962 DOI: 10.1371/journal.pone.0026058] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 09/16/2011] [Indexed: 01/19/2023] Open
Abstract
Both OTX2 and MYC are important oncogenes in medulloblastoma, the most common malignant brain tumor in childhood. Much is known about MYC binding to promoter regions, but OTX2 binding is hardly investigated. We used ChIP-on-chip data to analyze the binding patterns of both transcription factors in D425 medulloblastoma cells. When combining the data for all promoter regions in the genome, OTX2 binding showed a remarkable bi-modal distribution pattern with peaks around −250 bp upstream and +650 bp downstream of the transcription start sites (TSSs). Indeed, 40.2% of all OTX2-bound TSSs had more than one significant OTX2-binding peak. This OTX2-binding pattern was very different from the TSS-centered single peak binding pattern observed for MYC and other known transcription factors. However, in individual promoter regions, OTX2 and MYC have a strong tendency to bind in proximity of each other. OTX2-binding sequences are depleted near TSSs in the genome, providing an explanation for the observed bi-modal distribution of OTX2 binding. This contrasts to the enrichment of E-box sequences at TSSs. Both OTX2 and MYC binding independently correlated with higher gene expression. Interestingly, genes of promoter regions with multiple OTX2 binding as well as MYC binding showed the highest expression levels in D425 cells and in primary medulloblastomas. Genes within this class of promoter regions were enriched for medulloblastoma and stem cell specific genes. Our data suggest an important functional interaction between OTX2 and MYC in regulating gene expression in medulloblastoma.
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Affiliation(s)
- Jens Bunt
- Department of Oncogenomics, Academic Medical Center, Amsterdam, The Netherlands
| | - Nancy E. Hasselt
- Department of Oncogenomics, Academic Medical Center, Amsterdam, The Netherlands
| | | | - Jan Koster
- Department of Oncogenomics, Academic Medical Center, Amsterdam, The Netherlands
| | - Rogier Versteeg
- Department of Oncogenomics, Academic Medical Center, Amsterdam, The Netherlands
| | - Marcel Kool
- Department of Oncogenomics, Academic Medical Center, Amsterdam, The Netherlands
- * E-mail:
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31
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Montana CL, Lawrence KA, Williams NL, Tran NM, Peng GH, Chen S, Corbo JC. Transcriptional regulation of neural retina leucine zipper (Nrl), a photoreceptor cell fate determinant. J Biol Chem 2011; 286:36921-31. [PMID: 21865162 DOI: 10.1074/jbc.m111.279026] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The transcription factor neural retina leucine zipper (Nrl) is a critical determinant of rod photoreceptor cell fate and a key regulator of rod differentiation. Nrl(-/-) rod precursors fail to turn on rod genes and instead differentiate as cones. Furthermore, NRL mutations in humans cause retinitis pigmentosa. Despite the developmental and clinical significance of this gene, little is known about the transcriptional regulation of Nrl itself. In this study, we sought to define the cis- and trans-acting factors responsible for initiation and maintenance of Nrl transcription in the mouse retina. Utilizing a quantitative mouse retinal explant electroporation assay, we discovered a phylogenetically conserved, 30-base pair region immediately upstream of the transcription start site that is required for Nrl promoter activity. This region contains binding sites for the retinal transcription factors CRX, OTX2, and RORβ, and point mutations in these sites completely abolish promoter activity in living retinas. Gel-shift experiments show that CRX, OTX2, and RORβ can bind to the critical region in vitro, whereas ChIP experiments demonstrate binding of CRX and OTX2 to the critical region in vivo. Thus, our results indicate that CRX, OTX2, and RORβ directly regulate Nrl transcription by binding to critical sites within the Nrl promoter. We propose a model in which Nrl expression is primarily initiated by OTX2 and RORβ and later maintained at high levels by CRX and RORβ.
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Affiliation(s)
- Cynthia L Montana
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Schilter KF, Schneider A, Bardakjian T, Soucy JF, Tyler RC, Reis LM, Semina EV. OTX2 microphthalmia syndrome: four novel mutations and delineation of a phenotype. Clin Genet 2011; 79:158-68. [PMID: 20486942 DOI: 10.1111/j.1399-0004.2010.01450.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The OTX2 homeobox-containing transcription factor gene was shown to play a key role in the development of head structures in vertebrates. In humans, OTX2 mutations result in anophthalmia/microphthalmia (A/M) often associated with systemic anomalies. We screened 52 unrelated individuals affected with A/M and identified disease-causing variants in four families (8%), a higher frequency than previously reported. All four mutations are predicted to result in truncation of normal OTX2 protein sequence, consistent with previously reported mechanisms; three changes occurred de novo and one mutation was inherited from an affected parent. Four of the five OTX2-positive patients in our study displayed additional systemic findings, including two novel features, Wolf-Parkinson-White syndrome and an anteriorly placed anus. Analysis of the phenotypic features of OTX2-positive A/M patients in this study and those previously reported suggests the presence of pituitary anomalies and lack of genitourinary and gastrointestinal manifestations as potential distinguishing characteristics from SOX2 anophthalmia syndrome. Interestingly, pituitary anomalies seem to be more strongly associated with mutations that occur in the second half of OTX2, after the homeodomain and SGQFTP motif. OTX2 patients also show a high rate of inherited mutations (35%), often from mildly or unaffected parents, emphasizing the importance of careful parental examination/testing.
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Affiliation(s)
- K F Schilter
- Department of Pediatrics and Children's Research Institute, Medical College of Wisconsin and Children's Hospital of Wisconsin, Milwaukee, WI 53226-0509, USA
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Corbo JC, Lawrence KA, Karlstetter M, Myers CA, Abdelaziz M, Dirkes W, Weigelt K, Seifert M, Benes V, Fritsche LG, Weber BH, Langmann T. CRX ChIP-seq reveals the cis-regulatory architecture of mouse photoreceptors. Genome Res 2010; 20:1512-25. [PMID: 20693478 PMCID: PMC2963815 DOI: 10.1101/gr.109405.110] [Citation(s) in RCA: 165] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Accepted: 08/05/2010] [Indexed: 01/28/2023]
Abstract
Approximately 98% of mammalian DNA is noncoding, yet we understand relatively little about the function of this enigmatic portion of the genome. The cis-regulatory elements that control gene expression reside in noncoding regions and can be identified by mapping the binding sites of tissue-specific transcription factors. Cone-rod homeobox (CRX) is a key transcription factor in photoreceptor differentiation and survival, but its in vivo targets are largely unknown. Here, we used chromatin immunoprecipitation with massively parallel sequencing (ChIP-seq) on CRX to identify thousands of cis-regulatory regions around photoreceptor genes in adult mouse retina. CRX directly regulates downstream photoreceptor transcription factors and their target genes via a network of spatially distributed regulatory elements around each locus. CRX-bound regions act in a synergistic fashion to activate transcription and contain multiple CRX binding sites which interact in a spacing- and orientation-dependent manner to fine-tune transcript levels. CRX ChIP-seq was also performed on Nrl(-/-) retinas, which represent an enriched source of cone photoreceptors. Comparison with the wild-type ChIP-seq data set identified numerous rod- and cone-specific CRX-bound regions as well as many shared elements. Thus, CRX combinatorially orchestrates the transcriptional networks of both rods and cones by coordinating the expression of photoreceptor genes including most retinal disease genes. In addition, this study pinpoints thousands of noncoding regions of relevance to both Mendelian and complex retinal disease.
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Affiliation(s)
- Joseph C. Corbo
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110-1024, USA
| | - Karen A. Lawrence
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110-1024, USA
| | | | - Connie A. Myers
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110-1024, USA
| | - Musa Abdelaziz
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110-1024, USA
| | - William Dirkes
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110-1024, USA
| | - Karin Weigelt
- Department of Immunology, Erasmus Medical Center, Rotterdam 3015 GE, The Netherlands
| | | | - Vladimir Benes
- European Molecular Biology Laboratory, Heidelberg 69117, Germany
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McDonald EC, Xie B, Workman M, Charlton-Perkins M, Terrell DA, Reischl J, Wimmer EA, Gebelein BA, Cook TA. Separable transcriptional regulatory domains within Otd control photoreceptor terminal differentiation events. Dev Biol 2010; 347:122-32. [PMID: 20732315 DOI: 10.1016/j.ydbio.2010.08.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Revised: 08/13/2010] [Accepted: 08/16/2010] [Indexed: 10/19/2022]
Abstract
Orthodenticle (Otd)-related transcription factors are essential for anterior patterning and brain morphogenesis from Cnidaria to Mammals, and genetically underlie several human retinal pathologies. Despite their key developmental functions, relatively little is known regarding the molecular basis of how these factors regulate downstream effectors in a cell- or tissue-specific manner. Many invertebrate and vertebrate species encode two to three Otd proteins, whereas Drosophila encodes a single Otd protein. In the fly retina, Otd controls rhabdomere morphogenesis of all photoreceptors and regulates distinct Rhodopsin-encoding genes in a photoreceptor subtype-specific manner. Here, we performed a structure-function analysis of Otd during Drosophila eye development using in vivo rescue experiments and in vitro transcriptional regulatory assays. Our findings indicate that Otd requires at least three distinct transcriptional regulatory domains to control photoreceptor-specific rhodopsin gene expression and photoreceptor morphogenesis. Our results also uncover a previously unknown role for Otd in preventing co-expression of sensory receptors in blue vs. green-sensitive R8 photoreceptors. Sequence analysis indicates that many of the transcriptional regulatory domains identified here are conserved in multiple Diptera Otd-related proteins. Thus, these studies provide a basis for identifying shared molecular pathways involved in a wide range of developmental processes.
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Affiliation(s)
- Elizabeth C McDonald
- Molecular and Developmental Biology Graduate Program, Division of Developmental Biology and Department of Pediatric Ophthalmology, Cincinnati Children's Hospital Medical Center, USA
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Béby F, Housset M, Fossat N, Le Greneur C, Flamant F, Godement P, Lamonerie T. Otx2 gene deletion in adult mouse retina induces rapid RPE dystrophy and slow photoreceptor degeneration. PLoS One 2010; 5:e11673. [PMID: 20657788 PMCID: PMC2908139 DOI: 10.1371/journal.pone.0011673] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Accepted: 06/16/2010] [Indexed: 11/23/2022] Open
Abstract
Background Many developmental genes are still active in specific tissues after development is completed. This is the case for the homeobox gene Otx2, an essential actor of forebrain and head development. In adult mouse, Otx2 is strongly expressed in the retina. Mutations of this gene in humans have been linked to severe ocular malformation and retinal diseases. It is, therefore, important to explore its post-developmental functions. In the mature retina, Otx2 is expressed in three cell types: bipolar and photoreceptor cells that belong to the neural retina and retinal pigment epithelium (RPE), a neighbour structure that forms a tightly interdependent functional unit together with photoreceptor cells. Methodology/Principal Findings Conditional self-knockout was used to address the late functions of Otx2 gene in adult mice. This strategy is based on the combination of a knock-in CreERT2 allele and a floxed allele at the Otx2 locus. Time-controlled injection of tamoxifen activates the recombinase only in Otx2 expressing cells, resulting in selective ablation of the gene in its entire domain of expression. In the adult retina, loss of Otx2 protein causes slow degeneration of photoreceptor cells. By contrast, dramatic changes of RPE activity rapidly occur, which may represent a primary cause of photoreceptor disease. Conclusions Our novel mouse model uncovers new Otx2 functions in adult retina. We show that this transcription factor is necessary for long-term maintenance of photoreceptors, likely through the control of specific activities of the RPE.
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Affiliation(s)
- Francis Béby
- Institut de Génomique Fonctionnelle de Lyon, Centre National de la Recherche Scientifique, Ecole Normale Supérieure de Lyon, Institut National de la Recherche Agronomique, Université de Lyon, Lyon, France
| | - Michael Housset
- Institut de Biologie du Développement et Cancer, Centre National de la Recherche Scientifique, Université de Nice Sophia-Antipolis, Nice, France
| | - Nicolas Fossat
- Embryology Unit, Children's Medical Research Institute, Sydney Medical School, University of Sydney, Wentworthville, Australia
| | - Coralie Le Greneur
- Institut de Génomique Fonctionnelle de Lyon, Centre National de la Recherche Scientifique, Ecole Normale Supérieure de Lyon, Institut National de la Recherche Agronomique, Université de Lyon, Lyon, France
- Institut de Biologie du Développement et Cancer, Centre National de la Recherche Scientifique, Université de Nice Sophia-Antipolis, Nice, France
| | - Frédéric Flamant
- Institut de Génomique Fonctionnelle de Lyon, Centre National de la Recherche Scientifique, Ecole Normale Supérieure de Lyon, Institut National de la Recherche Agronomique, Université de Lyon, Lyon, France
| | - Pierre Godement
- Institut de Génomique Fonctionnelle de Lyon, Centre National de la Recherche Scientifique, Ecole Normale Supérieure de Lyon, Institut National de la Recherche Agronomique, Université de Lyon, Lyon, France
| | - Thomas Lamonerie
- Institut de Génomique Fonctionnelle de Lyon, Centre National de la Recherche Scientifique, Ecole Normale Supérieure de Lyon, Institut National de la Recherche Agronomique, Université de Lyon, Lyon, France
- Institut de Biologie du Développement et Cancer, Centre National de la Recherche Scientifique, Université de Nice Sophia-Antipolis, Nice, France
- * E-mail:
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Quantitative fine-tuning of photoreceptor cis-regulatory elements through affinity modulation of transcription factor binding sites. Gene Ther 2010; 17:1390-9. [PMID: 20463752 DOI: 10.1038/gt.2010.77] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Given the remarkable recent progress in gene therapy-based treatments for retinal disease, there is an urgent need for the development of new approaches to quantitative design and analysis of photoreceptor-specific promoters. In this study, we determined the relative binding affinity of all single-nucleotide variants of the consensus binding site of the mammalian photoreceptor transcription factor, Crx. We then showed that it is possible to use these data to accurately predict the relative binding affinity of Crx for all possible 8 bp sequences. By rationally adjusting the binding affinity of three Crx sites, we were able to fine-tune the expression of the rod-specific Rhodopsin promoter over a 225-fold range in living retinas. In addition, we showed that it is possible to fine-tune the activity of the rod-specific Gnat1 promoter over ∼275-fold range by modulating the affinity of a single Crx-binding site. We found that the action of individual binding sites depends on the precise promoter context of the site and that increasing binding affinity does not always equate with increased promoter output. Despite these caveats, this tuning approach permits quantitative engineering of photoreceptor-specific cis-regulatory elements, which can be used as drivers in gene therapy vectors for the treatment of blindness.
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Ashkenazi-Hoffnung L, Lebenthal Y, Wyatt AW, Ragge NK, Dateki S, Fukami M, Ogata T, Phillip M, Gat-Yablonski G. A novel loss-of-function mutation in OTX2 in a patient with anophthalmia and isolated growth hormone deficiency. Hum Genet 2010; 127:721-9. [PMID: 20396904 DOI: 10.1007/s00439-010-0820-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Accepted: 03/29/2010] [Indexed: 11/30/2022]
Abstract
Heterozygous mutations of the gene encoding transcription factor OTX2 were recently shown to be responsible for ocular as well as pituitary abnormalities. Here, we describe a patient with unilateral anophthalmia and short stature. Endocrine evaluation of the hypothalamic-pituitary axis revealed isolated growth hormone deficiency (IGHD) with small anterior pituitary gland, invisible stalk, ectopic posterior lobe, and right anophthalmia on brain magnetic resonance imaging. DNA was analyzed for mutations in the HESX1, SOX2, and OTX2 genes. Molecular analysis yielded a novel heterozygous OTX2 mutation (c.270A>T, p.R90S) within the homeodomain. Functional analysis revealed that the mutation inhibited both the DNA binding and transactivation activities of the protein. This novel loss-of-function mutation is associated with anophthalmia and IGHD in a patient of Sephardic Jewish descent. We recommend that patients with GH deficiency and ocular malformation in whom genetic analysis for classic transcription factor genes (PROP1, POU1F1, HESX1, and LHX4) failed to identify alterations should be checked for the presence of mutations in the OTX2 gene.
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Affiliation(s)
- Liat Ashkenazi-Hoffnung
- The Jesse Z and Sara Lea Shafer Institute of Endocrinology and Diabetes, National Center for Childhood Diabetes, Schneider Children's Medical Center of Israel, 14 Kaplan Street, 49202 Petach Tikva, Israel
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Dateki S, Kosaka K, Hasegawa K, Tanaka H, Azuma N, Yokoya S, Muroya K, Adachi M, Tajima T, Motomura K, Kinoshita E, Moriuchi H, Sato N, Fukami M, Ogata T. Heterozygous orthodenticle homeobox 2 mutations are associated with variable pituitary phenotype. J Clin Endocrinol Metab 2010; 95:756-64. [PMID: 19965921 DOI: 10.1210/jc.2009-1334] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
CONTEXT Although recent studies have suggested a positive role of OTX2 in pituitary as well as ocular development and function, detailed pituitary phenotypes in OTX2 mutations and OTX2 target genes for pituitary function other than HESX1 and POU1F1 remain to be determined. OBJECTIVE We aimed to examine such unresolved issues. SUBJECTS We studied 94 Japanese patients with various ocular or pituitary abnormalities. RESULTS We identified heterozygous p.K74fsX103 in case 1, p.A72fsX86 in case 2, p.G188X in two unrelated cases (3 and 4), and a 2,860,561-bp microdeletion involving OTX2 in case 5. Clinical studies revealed isolated GH deficiency in cases 1 and 5; combined pituitary hormone deficiency in case 3; abnormal pituitary structures in cases 1, 3, and 5; and apparently normal pituitary function in cases 2 and 4, together with ocular anomalies in cases 1-5. The wild-type Orthodenticle homeobox 2 (OTX2) protein transactivated the GNRH1 promoter as well as the HESX1, POU1F1, and IRBP (interstitial retinoid-binding protein) promoters, whereas the p.K74fsX103-OTX2 and p.A72fsX86-OTX2 proteins had no transactivation functions and the p.G188X-OTX2 protein had reduced ( approximately 50%) transactivation functions for the four promoters, with no dominant-negative effect. cDNA screening identified positive OTX2 expression in the hypothalamus. CONCLUSIONS The results imply that OTX2 mutations are associated with variable pituitary phenotype, with no genotype-phenotype correlations, and that OTX2 can transactivate GNRH1 as well as HESX1 and POU1F1.
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Affiliation(s)
- Sumito Dateki
- Department of Endocrinology and Metabolism, National Research Institute for Child Health and Development, 2-10-1 Ohkura, Setagaya, Tokyo 157-8535, Japan
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Bellipanni G, Murakami T, Weinberg ES. Molecular dissection of Otx1 functional domains in the zebrafish embryo. J Cell Physiol 2010; 222:286-93. [DOI: 10.1002/jcp.21944] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Kelberman D, Rizzoti K, Lovell-Badge R, Robinson ICAF, Dattani MT. Genetic regulation of pituitary gland development in human and mouse. Endocr Rev 2009; 30:790-829. [PMID: 19837867 PMCID: PMC2806371 DOI: 10.1210/er.2009-0008] [Citation(s) in RCA: 273] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Normal hypothalamopituitary development is closely related to that of the forebrain and is dependent upon a complex genetic cascade of transcription factors and signaling molecules that may be either intrinsic or extrinsic to the developing Rathke's pouch. These factors dictate organ commitment, cell differentiation, and cell proliferation within the anterior pituitary. Abnormalities in these processes are associated with congenital hypopituitarism, a spectrum of disorders that includes syndromic disorders such as septo-optic dysplasia, combined pituitary hormone deficiencies, and isolated hormone deficiencies, of which the commonest is GH deficiency. The highly variable clinical phenotypes can now in part be explained due to research performed over the last 20 yr, based mainly on naturally occurring and transgenic animal models. Mutations in genes encoding both signaling molecules and transcription factors have been implicated in the etiology of hypopituitarism, with or without other syndromic features, in mice and humans. To date, mutations in known genes account for a small proportion of cases of hypopituitarism in humans. However, these mutations have led to a greater understanding of the genetic interactions that lead to normal pituitary development. This review attempts to describe the complexity of pituitary development in the rodent, with particular emphasis on those factors that, when mutated, are associated with hypopituitarism in humans.
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Affiliation(s)
- Daniel Kelberman
- Developmental Endocrinology Research Group, Clinical and Molecular Genetics Unit, Institute of Child Health, 30 Guilford Street, London WC1N 1EH, United Kingdom
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Romero CJ, Nesi-França S, Radovick S. The molecular basis of hypopituitarism. Trends Endocrinol Metab 2009; 20:506-16. [PMID: 19854060 PMCID: PMC2787976 DOI: 10.1016/j.tem.2009.06.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2009] [Revised: 06/26/2009] [Accepted: 06/30/2009] [Indexed: 01/31/2023]
Abstract
Hypopituitarism is defined as the deficiency of one or more of the hormones secreted by the pituitary gland. Several developmental factors necessary for pituitary embryogenesis and hormone secretion have been described, and mutations of these genes in humans provide a molecular understanding of hypopituitarism. Genetic studies of affected patients and their families provide insights into possible mechanisms of abnormal pituitary development; however, mutations are rare. This review characterizes several of these developmental proteins and their role in the pathogenesis of hypopituitarism. Continuing research is required to better understand the complexities and interplay between these pituitary factors and to make improvements in genetic diagnosis that can lead to early detection and provide a future cure.
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Affiliation(s)
- Christopher J Romero
- Department of Pediatrics, The Johns Hopkins University School of Medicine, CMSC 4-106, Baltimore, MD 21208, USA
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Larder R, Mellon PL. Otx2 induction of the gonadotropin-releasing hormone promoter is modulated by direct interactions with Grg co-repressors. J Biol Chem 2009; 284:16966-16978. [PMID: 19401468 PMCID: PMC2719334 DOI: 10.1074/jbc.m109.002485] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Hormonal communication between the hypothalamus, pituitary, and gonads orchestrates the development and regulation of mammalian reproductive function. In mice, gonadotropin-releasing hormone (GnRH) expression is limited to approximately 1000 neurons that originate in the olfactory placode then migrate to specific positions scattered throughout the hypothalamus. Coordination of the hypothalamic-pituitary-gonadal axis is dependent upon correct migration of GnRH neurons into the hypothalamus followed by the appropriate synthesis and pulsatile secretion of GnRH. Defects in any one of these processes can cause infertility. Recently, substantial progress has been made in identifying transcription factors, and their cofactors, that regulate not only adult expression of GnRH, but also the maturation of GnRH neurons. Here, we show that expression of Otx2, a homeodomain protein required for the formation of the forebrain, is dramatically up-regulated during GnRH neuronal maturation and that overexpression of Otx2 increases GnRH promoter activity in GnRH neuronal cell lines. Furthermore, Otx2 transcriptional activity is modulated by Grg4, a member of the Groucho-related-gene (Grg) family. Using mutational analysis, we show that a WRPW peptide motif within the Otx2 protein is required for physical interaction between Otx2 and Grg4. Without this physical interaction, Grg4 cannot repress Otx2-dependent activation of GnRH gene transcription. Taken together, these data show that Otx2 is important for GnRH expression and that direct interaction between Otx2 and Grg co-repressors regulates GnRH gene expression in hypothalamic neurons.
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Affiliation(s)
- Rachel Larder
- From the Department of Reproductive Medicine and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California 92093-0674
| | - Pamela L Mellon
- From the Department of Reproductive Medicine and Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California 92093-0674.
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Tajima T, Ohtake A, Hoshino M, Amemiya S, Sasaki N, Ishizu K, Fujieda K. OTX2 loss of function mutation causes anophthalmia and combined pituitary hormone deficiency with a small anterior and ectopic posterior pituitary. J Clin Endocrinol Metab 2009; 94:314-9. [PMID: 18854396 DOI: 10.1210/jc.2008-1219] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
CONTEXT Orthodenticle homeobox 2 (OTX2) is a transcription factor necessary for ocular and forebrain development. In humans, heterozygous mutations of OTX2 cause severe ocular malformations. However, whether mutations of OTX2 cause pituitary structural abnormalities or combined pituitary hormone deficiency (CPHD) has not been clarified. OBJECTIVES We surveyed the functional consequences of a novel OTX2 mutation that was detected in a patient with anophthalmia and CPHD. PATIENT We examined a Japanese patient with growth disturbance, anophthalamia, and severe developmental delay. He showed deficiencies in GH, TSH, LH, FSH, and ACTH. Brain magnetic resonance imaging revealed a small anterior pituitary gland, invisible stalk, ectopic posterior lobe, and Chiari malformation. RESULTS Sequence analysis of OTX2 demonstrated a heterozygous two bases insertion [S136fsX178 (c.576-577insCT)] in exon 3. The mutant Otx2 protein localized to the nucleus, but did not activate the promoter of the HESX1 and POU1F1 gene, indicating a loss of function mutation. No dominant negative effect in the presence of wild-type Otx2 was observed. CONCLUSION This case indicates that the OTX2 mutation is a cause of CPHD. Further study of more patients with OTX2 defects is necessary to clarify the clinical phenotypes and endocrine defects caused by OTX2 mutations.
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Affiliation(s)
- Toshihiro Tajima
- Department of Pediatrics, Hokkaido University School of Medicine, N15, W7, Sapporo, Japan 060-0835.
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Dateki S, Fukami M, Sato N, Muroya K, Adachi M, Ogata T. OTX2 mutation in a patient with anophthalmia, short stature, and partial growth hormone deficiency: functional studies using the IRBP, HESX1, and POU1F1 promoters. J Clin Endocrinol Metab 2008; 93:3697-702. [PMID: 18628516 DOI: 10.1210/jc.2008-0720] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
CONTEXT OTX2 is a transcription factor gene essential for eye development. Although recent studies suggest the involvement of OTX2 in pituitary function, there is no report demonstrating a positive role of OTX2 in the pituitary function. OBJECTIVE The objective of the study was to report the results of functional studies indicating the relevance of OTX2 to pituitary function. PATIENT A Japanese female patient with bilateral anophthalmia was found to have short stature (height, -3.3 sd) and isolated partial GH deficiency (peak serum GH 3.1 and 9.7 mug/liter after insulin and arginine stimulations, respectively; serum IGF-I 37 ng/ml) at 3 yr 9 months of age. Magnetic resonance imaging delineated apparently normal pituitary gland. RESULTS Mutation analysis showed a de novo heterozygous frameshift mutation (c.402insC) that is predicted to retain the homeodomain but lose the transactivation domain. Functional studies revealed that the wild-type and mutant OTX2 proteins localized to the nucleus and bound to the target sequences within the IRBP (interstitial retinoid-binding protein), HESX1 (HESX homeobox 1), and POU1F1 promoters. Furthermore, the wild-type OTX2 protein markedly transactivated the promoters of IRBP ( approximately 27-fold), HESX1 ( approximately 4.5-fold), and POU1F1 ( approximately 19-fold), whereas the mutant OTX2 protein barely retained the transactivation activities and had no dominant-negative effects. CONCLUSIONS The results provide direct evidence for OTX2 being involved in the pituitary function. It is likely that the heterozygous severe OTX2 loss-of-function mutation caused GH deficiency and short stature, primarily because of decreased transactivation function for HESX1 and POU1F1.
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Affiliation(s)
- Sumito Dateki
- Department of Endocrinology and Metabolism, National Research Institute for Child Health and Development, 2-10-1 Ohkura, Setagaya, Tokyo 157-8535, Japan
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A new GFP-tagged line reveals unexpected Otx2 protein localization in retinal photoreceptors. BMC DEVELOPMENTAL BIOLOGY 2007; 7:122. [PMID: 17980036 PMCID: PMC2204009 DOI: 10.1186/1471-213x-7-122] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2007] [Accepted: 11/02/2007] [Indexed: 12/03/2022]
Abstract
Background Dynamic monitoring of protein expression and localization is fundamental to the understanding of biological processes. The paired-class homeodomain-containing transcription factor Otx2 is essential for normal head and brain development in vertebrates. Recent conditional knockout studies have pointed to multiple roles of this protein during late development and post-natal life. Yet, later expression and functions remain poorly characterized as specific reagents to detect the protein at any stage of development are still missing. Results We generated a new mouse line harbouring an insertion of the GFP gene within the Otx2 coding sequence to monitor the gene activity while preserving most of its functions. Our results demonstrate that this line represents a convenient tool to capture the dynamics of Otx2 gene expression from early embryonic stages to adulthood. In addition, we could visualize the intracellular location of Otx2 protein. In the retina, we reinterpret the former view of protein distribution and show a further level of regulation of intranuclear protein localization, which depends on the cell type. Conclusion The GFP-tagged Otx2 mouse line fully recapitulates previously known expression patterns and brings additional accuracy and easiness of detection of Otx2 gene activity. This opens up the way to live imaging of a highly dynamic actor of brain development and can be adapted to any mutant background to probe for genetic interaction between Otx2 and the mutated gene.
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Nishio SI, Kakizawa T, Chatelain G, Triqueneaux G, Brunet F, Rambaud J, Lamonerie T, Laudet V. OTX5 regulates pineal expression of the zebrafish REV-ERB alpha through a new DNA binding site. Mol Endocrinol 2007; 22:23-32. [PMID: 17872382 PMCID: PMC5419633 DOI: 10.1210/me.2007-0170] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The pineal gland plays a central role in the photoneuroendocrine system and acts as a photosensory organ in lower vertebrates. The orphan nuclear receptor Rev-erbalpha (NR1D1) has previously been shown to be expressed in the pineal and to be regulated with a robust circadian rhythm during zebrafish embryogenesis. This early pineal expression is under the control of the transcription factor Orthodenticle homeobox 5 (Otx5). In this paper, we show that Otx5 regulates the second zfRev-erbalpha promoter, ZfP2. Despite the absence of a classical Otx-binding site within ZfP2, this regulation depends on the integrity of the Otx5 homeodomain. Mapping experiments as well as EMSAs show that this interaction between Otx5 and ZfP2 depends on a noncanonical bipartite Otx-binding site (GANNCTTA and TAAA) that we called pineal expression related element (PERE). We showed that PERE is necessary for pineal expression in vivo by injecting zebrafish embryos with wild type and mutated versions of zfRev-erbalpha promoter fused to green fluorescent protein. Interestingly, PERE is found upstream of other genes expressed in the pineal gland, suggesting that it may play an important role in governing pineal expression. Our data establish that PERE is a novel cis-acting element contributing to pineal-specific gene expression and to Otx target gene regulation.
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Affiliation(s)
- Shin-Ichi Nishio
- Université de Lyon, Institut de Génomique Fonctionnelle de Lyon, Unité Mixte de Recherche 5242 du Centre National de la Recherche Scientifique, 69364 Lyon Cedex 07, France
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Hennig AK, Peng GH, Chen S. Regulation of photoreceptor gene expression by Crx-associated transcription factor network. Brain Res 2007; 1192:114-33. [PMID: 17662965 PMCID: PMC2266892 DOI: 10.1016/j.brainres.2007.06.036] [Citation(s) in RCA: 165] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2007] [Revised: 06/13/2007] [Accepted: 06/20/2007] [Indexed: 01/31/2023]
Abstract
Rod and cone photoreceptors in the mammalian retina are special types of neurons that are responsible for phototransduction, the first step of vision. Development and maintenance of photoreceptors require precisely regulated gene expression. This regulation is mediated by a network of photoreceptor transcription factors centered on Crx, an Otx-like homeodomain transcription factor. The cell type (subtype) specificity of this network is governed by factors that are preferentially expressed by rods or cones or both, including the rod-determining factors neural retina leucine zipper protein (Nrl) and the orphan nuclear receptor Nr2e3; and cone-determining factors, mostly nuclear receptor family members. The best-documented of these include thyroid hormone receptor beta2 (Tr beta2), retinoid related orphan receptor Ror beta, and retinoid X receptor Rxr gamma. The appropriate function of this network also depends on general transcription factors and cofactors that are ubiquitously expressed, such as the Sp zinc finger transcription factors and STAGA co-activator complexes. These cell type-specific and general transcription regulators form complex interactomes; mutations that interfere with any of the interactions can cause photoreceptor development defects or degeneration. In this manuscript, we review recent progress on the roles of various photoreceptor transcription factors and interactions in photoreceptor subtype development. We also provide evidence of auto-, para-, and feedback regulation among these factors at the transcriptional level. These protein-protein and protein-promoter interactions provide precision and specificity in controlling photoreceptor subtype-specific gene expression, development, and survival. Understanding these interactions may provide insights to more effective therapeutic interventions for photoreceptor diseases.
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Affiliation(s)
- Anne K. Hennig
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110
| | - Guang-Hua Peng
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110
| | - Shiming Chen
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110
- Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St. Louis, MO 63110
- Corresponding Author: Shiming Chen, Ph.D., Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8096, St. Louis, MO 63110. Phone: (314) 747−4350; Fax: (314) 747−4211;
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