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Daruich A, Duncan M, Robert MP, Lagali N, Semina EV, Aberdam D, Ferrari S, Romano V, des Roziers CB, Benkortebi R, De Vergnes N, Polak M, Chiambaretta F, Nischal KK, Behar-Cohen F, Valleix S, Bremond-Gignac D. Congenital aniridia beyond black eyes: From phenotype and novel genetic mechanisms to innovative therapeutic approaches. Prog Retin Eye Res 2023; 95:101133. [PMID: 36280537 PMCID: PMC11062406 DOI: 10.1016/j.preteyeres.2022.101133] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 09/27/2022] [Accepted: 10/03/2022] [Indexed: 11/05/2022]
Abstract
Congenital PAX6-aniridia, initially characterized by the absence of the iris, has progressively been shown to be associated with other developmental ocular abnormalities and systemic features making congenital aniridia a complex syndromic disorder rather than a simple isolated disease of the iris. Moreover, foveal hypoplasia is now recognized as a more frequent feature than complete iris hypoplasia and a major visual prognosis determinant, reversing the classical clinical picture of this disease. Conversely, iris malformation is also a feature of various anterior segment dysgenesis disorders caused by PAX6-related developmental genes, adding a level of genetic complexity for accurate molecular diagnosis of aniridia. Therefore, the clinical recognition and differential genetic diagnosis of PAX6-related aniridia has been revealed to be much more challenging than initially thought, and still remains under-investigated. Here, we update specific clinical features of aniridia, with emphasis on their genotype correlations, as well as provide new knowledge regarding the PAX6 gene and its mutational spectrum, and highlight the beneficial utility of clinically implementing targeted Next-Generation Sequencing combined with Whole-Genome Sequencing to increase the genetic diagnostic yield of aniridia. We also present new molecular mechanisms underlying aniridia and aniridia-like phenotypes. Finally, we discuss the appropriate medical and surgical management of aniridic eyes, as well as innovative therapeutic options. Altogether, these combined clinical-genetic approaches will help to accelerate time to diagnosis, provide better determination of the disease prognosis and management, and confirm eligibility for future clinical trials or genetic-specific therapies.
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Affiliation(s)
- Alejandra Daruich
- Ophthalmology Department, Necker-Enfants Malades University Hospital, AP-HP, Paris Cité University, Paris, France; INSERM, UMRS1138, Team 17, From Physiopathology of Ocular Diseases to Clinical Development, Sorbonne Paris Cité University, Centre de Recherche des Cordeliers, Paris, France
| | - Melinda Duncan
- Department of Biological Sciences, University of Delaware, Newark, DE, USA
| | - Matthieu P Robert
- Ophthalmology Department, Necker-Enfants Malades University Hospital, AP-HP, Paris Cité University, Paris, France; Borelli Centre, UMR 9010, CNRS-SSA-ENS Paris Saclay-Paris Cité University, Paris, France
| | - Neil Lagali
- Division of Ophthalmology, Department of Biomedical and Clinical Sciences, Faculty of Medicine, Linköping University, 581 83, Linköping, Sweden; Department of Ophthalmology, Sørlandet Hospital Arendal, Arendal, Norway
| | - Elena V Semina
- Department of Pediatrics, Children's Research Institute at the Medical College of Wisconsin and Children's Hospital of Wisconsin, Milwaukee, WI, 53226, USA
| | - Daniel Aberdam
- INSERM, UMRS1138, Team 17, From Physiopathology of Ocular Diseases to Clinical Development, Sorbonne Paris Cité University, Centre de Recherche des Cordeliers, Paris, France
| | - Stefano Ferrari
- Fondazione Banca degli Occhi del Veneto, Via Paccagnella 11, Venice, Italy
| | - Vito Romano
- Department of Medical and Surgical Specialties, Radiolological Sciences, and Public Health, Ophthalmology Clinic, University of Brescia, Italy
| | - Cyril Burin des Roziers
- INSERM, UMRS1138, Team 17, From Physiopathology of Ocular Diseases to Clinical Development, Sorbonne Paris Cité University, Centre de Recherche des Cordeliers, Paris, France; Service de Médecine Génomique des Maladies de Système et d'Organe, APHP. Centre Université de Paris, Fédération de Génétique et de Médecine Génomique Hôpital Cochin, 27 rue du Fbg St-Jacques, 75679, Paris Cedex 14, France
| | - Rabia Benkortebi
- Ophthalmology Department, Necker-Enfants Malades University Hospital, AP-HP, Paris Cité University, Paris, France
| | - Nathalie De Vergnes
- Ophthalmology Department, Necker-Enfants Malades University Hospital, AP-HP, Paris Cité University, Paris, France
| | - Michel Polak
- Pediatric Endocrinology, Gynecology and Diabetology, Hôpital Universitaire Necker Enfants Malades, AP-HP, Paris Cité University, INSERM U1016, Institut IMAGINE, France
| | | | - Ken K Nischal
- Division of Pediatric Ophthalmology, Strabismus, and Adult Motility, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, USA; UPMC Eye Center, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Francine Behar-Cohen
- INSERM, UMRS1138, Team 17, From Physiopathology of Ocular Diseases to Clinical Development, Sorbonne Paris Cité University, Centre de Recherche des Cordeliers, Paris, France
| | - Sophie Valleix
- INSERM, UMRS1138, Team 17, From Physiopathology of Ocular Diseases to Clinical Development, Sorbonne Paris Cité University, Centre de Recherche des Cordeliers, Paris, France; Service de Médecine Génomique des Maladies de Système et d'Organe, APHP. Centre Université de Paris, Fédération de Génétique et de Médecine Génomique Hôpital Cochin, 27 rue du Fbg St-Jacques, 75679, Paris Cedex 14, France
| | - Dominique Bremond-Gignac
- Ophthalmology Department, Necker-Enfants Malades University Hospital, AP-HP, Paris Cité University, Paris, France; INSERM, UMRS1138, Team 17, From Physiopathology of Ocular Diseases to Clinical Development, Sorbonne Paris Cité University, Centre de Recherche des Cordeliers, Paris, France.
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2
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Pan Q, Lu K, Luo J, Jiang Y, Xia B, Chen L, Wang M, Dai R, Chen T. Japanese medaka Olpax6.1 mutant as a potential model for spondylo-ocular syndrome. Funct Integr Genomics 2023; 23:168. [PMID: 37204625 DOI: 10.1007/s10142-023-01090-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 05/03/2023] [Accepted: 05/05/2023] [Indexed: 05/20/2023]
Abstract
pax6 is a canonic master gene for eye formation. Knockout of pax6 affects the development of craniofacial skeleton and eye in mice. Whether pax6 affects the development of spinal bone has not been reported yet. In the present study, we used CRISPR/Cas9 system to generate Olpax6.1 mutant in Japanese medaka. Phenotype analysis showed that ocular mutation caused by the Olpax6.1 mutation occurred in the homozygous mutant. The phenotype of heterozygotes is not significantly different from that of wild-type. In addition, knockout Olpax6.1 resulted in severe curvature of the spine in the homozygous F2 generation. Comparative transcriptome analysis and qRT-PCR revealed that the defective Olpax6.1 protein caused a decrease in the expression level of sp7, col10a1a, and bglap, while the expression level of xylt2 did not change significantly. The functional enrichment of differentially expressed genes (DEGs) using the Kyoto Encyclopedia of Genes and Genomes database showed that the DEGs between Olpax6.1 mutation and wild-type were enriched in p53 signaling pathway, extracellular matrix (ECM) -receptor interaction, et al. Our results indicated that the defective Olpax6.1 protein results in the reduction of sp7 expression level and the activation of p53 signaling pathway, which leads to a decrease in the expression of genes encoding ECM protein, such as collagen protein family and bone gamma-carboxyglutamate protein, which further inhibits bone development. Based on the phenotype and molecular mechanism of ocular mutation and spinal curvature induced by Olpax6.1 knockout, we believe that the Olpax6.1-/- mutant could be a potential model for the study of spondylo-ocular syndrome.
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Affiliation(s)
- Qihua Pan
- Fisheries College of Jimei University, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture and Rural Affairs, Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, Xiamen, 361021, Fujian, China
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Ke Lu
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Junzhi Luo
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Yuewen Jiang
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Bilin Xia
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Lei Chen
- Fisheries College of Jimei University, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture and Rural Affairs, Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, Xiamen, 361021, Fujian, China
| | - Mengyang Wang
- Fisheries College of Jimei University, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture and Rural Affairs, Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, Xiamen, 361021, Fujian, China
| | - Ronggui Dai
- Fisheries College of Jimei University, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture and Rural Affairs, Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, Xiamen, 361021, Fujian, China
| | - Tiansheng Chen
- Fisheries College of Jimei University, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture and Rural Affairs, Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, Xiamen, 361021, Fujian, China.
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.
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Lu K, Wu J, Tang S, Jia X, Liang XF. Knockout of sws2a and sws2b in Medaka ( Oryzias latipes) Reveals Their Roles in Regulating Vision-Guided Behavior and Eye Development. Int J Mol Sci 2023; 24:ijms24108786. [PMID: 37240129 DOI: 10.3390/ijms24108786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 04/20/2023] [Accepted: 04/28/2023] [Indexed: 05/28/2023] Open
Abstract
The medaka (Oryzias latipes) is an excellent vertebrate model for studying the development of the retina. Its genome database is complete, and the number of opsin genes is relatively small compared to zebrafish. Short wavelength sensitive 2 (sws2), a G-protein-coupled receptor expressed in the retina, has been lost in mammals, but its role in eye development in fish is still poorly understood. In this study, we established a sws2a and sws2b knockout medaka model by CRISPR/Cas9 technology. We discovered that medaka sws2a and sws2b are mainly expressed in the eyes and may be regulated by growth differentiation factor 6a (gdf6a). Compared with the WT, sws2a-/- and sws2b-/- mutant larvae displayed an increase in swimming speed during the changes from light to dark. We also observed that sws2a-/- and sws2b-/- larvae both swam faster than WT in the first 10 s of the 2 min light period. The enhanced vision-guided behavior in sws2a-/- and sws2b-/- medaka larvae may be related to the upregulation of phototransduction-related genes. Additionally, we also found that sws2b affects the expression of eye development genes, while sws2a is unaffected. Together, these findings indicate that sws2a and sws2b knockouts increase vision-guided behavior and phototransduction, but on the other hand, sws2b plays an important role in regulating eye development genes. This study provides data for further understanding of the role of sws2a and sws2b in medaka retina development.
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Affiliation(s)
- Ke Lu
- College of Fisheries, Chinese Perch Research Center, Huazhong Agricultural University, Wuhan 430070, China
- Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, Wuhan 430070, China
| | - Jiaqi Wu
- College of Fisheries, Chinese Perch Research Center, Huazhong Agricultural University, Wuhan 430070, China
- Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, Wuhan 430070, China
| | - Shulin Tang
- College of Fisheries, Chinese Perch Research Center, Huazhong Agricultural University, Wuhan 430070, China
- Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, Wuhan 430070, China
| | - Xiaodan Jia
- College of Fisheries, Chinese Perch Research Center, Huazhong Agricultural University, Wuhan 430070, China
- Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, Wuhan 430070, China
| | - Xu-Fang Liang
- College of Fisheries, Chinese Perch Research Center, Huazhong Agricultural University, Wuhan 430070, China
- Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, Wuhan 430070, China
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Dong Z, He W, Lin G, Chen X, Cao S, Guan T, Sun Y, Zhang Y, Qi M, Guo B, Zhou Z, Zhuo R, Wu R, Liu M, Liu Y. Histone acetyltransferase KAT2A modulates neural stem cell differentiation and proliferation by inducing degradation of the transcription factor PAX6. J Biol Chem 2023; 299:103020. [PMID: 36791914 PMCID: PMC10011063 DOI: 10.1016/j.jbc.2023.103020] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 01/31/2023] [Accepted: 02/02/2023] [Indexed: 02/15/2023] Open
Abstract
Neural stem cells (NSCs) proliferation and differentiation rely on proper expression and post-translational modification of transcription factors involved in the determination of cell fate. Further characterization is needed to connect modifying enzymes with their transcription factor substrates in the regulation of these processes. Here, we demonstrated that the inhibition of KAT2A, a histone acetyltransferase, leads to a phenotype of small eyes in the developing embryo of zebrafish, which is associated with enhanced proliferation and apoptosis of NSCs in zebrafish eyes. We confirmed that this phenotype is mediated by the evaluated level of PAX6 protein. We further verified that KAT2A negatively regulates PAX6 at the protein level in cultured neural stem cells of rat cerebral cortex. We revealed that PAX6 is a novel acetylation substrate of KAT2A, and the acetylation of PAX6 promotes its ubiquitination mediated by the E3 ligase RNF8 that facilitated PAX6 degradation. Our study proposes that KAT2A inhibition results in accelerated proliferation, delayed differentiation, or apoptosis, depending on the context of PAX6 dosage. Thus, the KAT2A/PAX6 axis plays an essential role to keep a balance between the self-renewal and differentiation of NSCs.
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Affiliation(s)
- Zhangji Dong
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, China
| | - Wei He
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, China
| | - Ge Lin
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, China
| | - Xu Chen
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, China
| | - Sixian Cao
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, China
| | - Tuchen Guan
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, China
| | - Ying Sun
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, China
| | - Yufang Zhang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, China
| | - Mengwei Qi
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, China
| | - Beibei Guo
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, China
| | - Zhihao Zhou
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, China
| | - Run Zhuo
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, China
| | - Ronghua Wu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, China
| | - Mei Liu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, China.
| | - Yan Liu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, China.
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5
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Abdolkarimi D, Cunha DL, Lahne1 M, Moosajee M. PAX6 disease models for aniridia. Indian J Ophthalmol 2022; 70:4119-4129. [PMID: 36453299 PMCID: PMC9940591 DOI: 10.4103/ijo.ijo_316_22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/01/2022] [Accepted: 08/10/2022] [Indexed: 12/12/2022] Open
Abstract
Aniridia is a pan-ocular genetic developmental eye disorder characterized by complete or partial iris and foveal hypoplasia, for which there is no treatment currently. Progressive sight loss can arise from cataracts, glaucoma, and aniridia-related keratopathy, which can be managed conservatively or through surgical intervention. The vast majority of patients harbor heterozygous mutations involving the PAX6 gene, which is considered the master transcription factor of early eye development. Over the past decades, several disease models have been investigated to gain a better understanding of the molecular pathophysiology, including several mouse and zebrafish strains and, more recently, human-induced pluripotent stem cells (hiPSCs) derived from aniridia patients. The latter provides a more faithful cellular system to study early human eye development. This review outlines the main aniridia-related animal and cellular models used to study aniridia and highlights the key discoveries that are bringing us closer to a therapy for patients.
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Affiliation(s)
| | - Dulce Lima Cunha
- UCL Institute of Ophthalmology, London, UK
- Radboud Institute for Molecular Life Sciences, Radboud University, Nijmegen, Netherlands
| | | | - Mariya Moosajee
- UCL Institute of Ophthalmology, London, UK
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
- The Francis Crick Institute, London, UK
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6
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Nieves-Moreno M, Noval S, Peralta J, Palomares-Bralo M, del Pozo A, Garcia-Miñaur S, Santos-Simarro F, Vallespin E. Expanding the Phenotypic Spectrum of PAX6 Mutations: From Congenital Cataracts to Nystagmus. Genes (Basel) 2021; 12:genes12050707. [PMID: 34065151 PMCID: PMC8151272 DOI: 10.3390/genes12050707] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Revised: 05/04/2021] [Accepted: 05/05/2021] [Indexed: 12/15/2022] Open
Abstract
Background: Congenital aniridia is a complex ocular disorder, usually associated with severe visual impairment, generally caused by mutations on the PAX6 gene. The clinical phenotype of PAX6 mutations is highly variable, making the genotype–phenotype correlations difficult to establish. Methods: we describe the phenotype of eight patients from seven unrelated families with confirmed mutations in PAX6, and very different clinical manifestations. Results: Only two patients had the classical aniridia phenotype while the other two presented with aniridia-related manifestations, such as aniridia-related keratopathy or partial aniridia. Congenital cataracts were the main manifestation in three of the patients in this series. All the patients had nystagmus and low visual acuity. Conclusions: The diagnosis of mild forms of aniridia is challenging, but these patients have a potentially blinding hereditary disease that might present with a more severe phenotype in future generations. Clinicians should be aware of the mild aniridia phenotype and request genetic testing to perform an accurate diagnosis.
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Affiliation(s)
- Maria Nieves-Moreno
- Department of Ophthalmology, Hospital Universitario La Paz, 28046 Madrid, Spain; (S.N.); (J.P.)
- Correspondence:
| | - Susana Noval
- Department of Ophthalmology, Hospital Universitario La Paz, 28046 Madrid, Spain; (S.N.); (J.P.)
| | - Jesus Peralta
- Department of Ophthalmology, Hospital Universitario La Paz, 28046 Madrid, Spain; (S.N.); (J.P.)
| | - María Palomares-Bralo
- Department of Molecular Developmental Disorders, Medical and Molecular Genetics Institue (INGEMM) IdiPaz, CIBERER, Hospital Universitario La Paz, 28046 Madrid, Spain;
| | - Angela del Pozo
- Department of Bioinformatics, Medical and Molecular Genetics Institue (INGEMM) IdiPaz, CIBERER, Hospital Universitario La Paz, 28046 Madrid, Spain;
| | - Sixto Garcia-Miñaur
- Department of Clinical Genetics, Medical and Molecular Genetics Institue (INGEMM) IdiPaz, CIBERER, Hospital Universitario La Paz, 28046 Madrid, Spain; (S.G.-M.); (F.S.-S.)
| | - Fernando Santos-Simarro
- Department of Clinical Genetics, Medical and Molecular Genetics Institue (INGEMM) IdiPaz, CIBERER, Hospital Universitario La Paz, 28046 Madrid, Spain; (S.G.-M.); (F.S.-S.)
| | - Elena Vallespin
- Department of Molecular Ophthalmology, Medical and Molecular Genetics Institue (INGEMM) IdiPaz, CIBERER, Hospital Universitario La Paz, 28046 Madrid, Spain;
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7
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Chhabra NF, Amarie OV, Wu M, Amend AL, Rubey M, Gradinger D, Irmler M, Beckers J, Rathkolb B, Wolf E, Feuchtinger A, Huypens P, Teperino R, Rozman J, Przemeck GKH, Hrabě de Angelis M. PAX6 mutation alters circadian rhythm and β cell function in mice without affecting glucose tolerance. Commun Biol 2020; 3:628. [PMID: 33127955 PMCID: PMC7599253 DOI: 10.1038/s42003-020-01337-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 09/25/2020] [Indexed: 11/09/2022] Open
Abstract
The transcription factor PAX6 is involved in the development of the eye and pancreatic islets, besides being associated with sleep–wake cycles. Here, we investigated a point mutation in the RED subdomain of PAX6, previously described in a human patient, to present a comprehensive study of a homozygous Pax6 mutation in the context of adult mammalian metabolism and circadian rhythm. Pax6Leca2 mice lack appropriate retinal structures for light perception and do not display normal daily rhythmic changes in energy metabolism. Despite β cell dysfunction and decreased insulin secretion, mutant mice have normal glucose tolerance. This is associated with reduced hepatic glucose production possibly due to altered circadian variation in expression of clock and metabolic genes, thereby evading hyperglycemia. Hence, our findings show that while the RED subdomain is important for β cell functional maturity, the Leca2 mutation impacts peripheral metabolism via loss of circadian rhythm, thus revealing pleiotropic effects of PAX6. Nirav Chhabra et al. characterize adult mice carrying a homozygous mutation in Pax6 that was identified in a patient with foveal hypoplasia. They find that the Pax6 point mutation has pleiotropic effects, including defects in the mouse retinal structures, loss of the optic nerve, changes in energy metabolism and circadian rhythms, and dysregulation of genes expressed in the pancreas.
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Affiliation(s)
- Nirav Florian Chhabra
- Helmholtz Zentrum München, Institute of Experimental Genetics and German Mouse Clinic, Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Oana Veronica Amarie
- Helmholtz Zentrum München, Institute of Experimental Genetics and German Mouse Clinic, Neuherberg, Germany
| | - Moya Wu
- Helmholtz Zentrum München, Institute of Experimental Genetics and German Mouse Clinic, Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Anna-Lena Amend
- Helmholtz Zentrum München, Institute of Experimental Genetics and German Mouse Clinic, Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Marina Rubey
- Helmholtz Zentrum München, Institute of Experimental Genetics and German Mouse Clinic, Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Daniel Gradinger
- Helmholtz Zentrum München, Institute of Experimental Genetics and German Mouse Clinic, Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Martin Irmler
- Helmholtz Zentrum München, Institute of Experimental Genetics and German Mouse Clinic, Neuherberg, Germany
| | - Johannes Beckers
- Helmholtz Zentrum München, Institute of Experimental Genetics and German Mouse Clinic, Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany.,Chair of Experimental Genetics, Center of Life and Food Sciences, Weihenstephan, Technische Universität München, Freising, Germany
| | - Birgit Rathkolb
- Helmholtz Zentrum München, Institute of Experimental Genetics and German Mouse Clinic, Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany.,Ludwig-Maximilians-Universität München, Gene Center, Chair for Molecular Animal Breeding and Biotechnology, Munich, Germany
| | - Eckhard Wolf
- German Center for Diabetes Research (DZD), Neuherberg, Germany.,Ludwig-Maximilians-Universität München, Gene Center, Chair for Molecular Animal Breeding and Biotechnology, Munich, Germany
| | - Annette Feuchtinger
- Helmholtz Zentrum München, Research Unit Analytical Pathology, Neuherberg, Germany
| | - Peter Huypens
- Helmholtz Zentrum München, Institute of Experimental Genetics and German Mouse Clinic, Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Raffaele Teperino
- Helmholtz Zentrum München, Institute of Experimental Genetics and German Mouse Clinic, Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Jan Rozman
- Helmholtz Zentrum München, Institute of Experimental Genetics and German Mouse Clinic, Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Gerhard K H Przemeck
- Helmholtz Zentrum München, Institute of Experimental Genetics and German Mouse Clinic, Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Martin Hrabě de Angelis
- Helmholtz Zentrum München, Institute of Experimental Genetics and German Mouse Clinic, Neuherberg, Germany. .,German Center for Diabetes Research (DZD), Neuherberg, Germany. .,Chair of Experimental Genetics, Center of Life and Food Sciences, Weihenstephan, Technische Universität München, Freising, Germany.
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8
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Takamiya M, Stegmaier J, Kobitski AY, Schott B, Weger BD, Margariti D, Cereceda Delgado AR, Gourain V, Scherr T, Yang L, Sorge S, Otte JC, Hartmann V, van Wezel J, Stotzka R, Reinhard T, Schlunck G, Dickmeis T, Rastegar S, Mikut R, Nienhaus GU, Strähle U. Pax6 organizes the anterior eye segment by guiding two distinct neural crest waves. PLoS Genet 2020; 16:e1008774. [PMID: 32555736 PMCID: PMC7323998 DOI: 10.1371/journal.pgen.1008774] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 06/29/2020] [Accepted: 04/09/2020] [Indexed: 01/11/2023] Open
Abstract
Cranial neural crest (NC) contributes to the developing vertebrate eye. By multidimensional, quantitative imaging, we traced the origin of the ocular NC cells to two distinct NC populations that differ in the maintenance of sox10 expression, Wnt signalling, origin, route, mode and destination of migration. The first NC population migrates to the proximal and the second NC cell group populates the distal (anterior) part of the eye. By analysing zebrafish pax6a/b compound mutants presenting anterior segment dysgenesis, we demonstrate that Pax6a/b guide the two NC populations to distinct proximodistal locations. We further provide evidence that the lens whose formation is pax6a/b-dependent and lens-derived TGFβ signals contribute to the building of the anterior segment. Taken together, our results reveal multiple roles of Pax6a/b in the control of NC cells during development of the anterior segment.
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Affiliation(s)
- Masanari Takamiya
- Institute of Biological and Chemical Systems - Biological Information Processing, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Johannes Stegmaier
- Institute for Automation and Applied Informatics, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Andrei Yu Kobitski
- Institute of Biological and Chemical Systems - Biological Information Processing, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Institute of Applied Physics, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Benjamin Schott
- Institute for Automation and Applied Informatics, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Benjamin D. Weger
- Institute of Biological and Chemical Systems - Biological Information Processing, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Dimitra Margariti
- Institute of Biological and Chemical Systems - Biological Information Processing, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Angel R. Cereceda Delgado
- Institute of Biological and Chemical Systems - Biological Information Processing, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Victor Gourain
- Institute of Biological and Chemical Systems - Biological Information Processing, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Tim Scherr
- Institute for Automation and Applied Informatics, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Lixin Yang
- Institute of Biological and Chemical Systems - Biological Information Processing, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Sebastian Sorge
- Institute of Biological and Chemical Systems - Biological Information Processing, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Jens C. Otte
- Institute of Biological and Chemical Systems - Biological Information Processing, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Volker Hartmann
- Institute for Data Processing and Electronics, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Jos van Wezel
- Steinbuch Centre for Computing, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Rainer Stotzka
- Institute for Data Processing and Electronics, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Thomas Reinhard
- Eye Center, Freiburg University Medical Center, Freiburg, Germany
| | - Günther Schlunck
- Eye Center, Freiburg University Medical Center, Freiburg, Germany
| | - Thomas Dickmeis
- Institute of Biological and Chemical Systems - Biological Information Processing, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Sepand Rastegar
- Institute of Biological and Chemical Systems - Biological Information Processing, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Ralf Mikut
- Institute for Automation and Applied Informatics, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Gerd Ulrich Nienhaus
- Institute of Biological and Chemical Systems - Biological Information Processing, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Institute of Applied Physics, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Uwe Strähle
- Institute of Biological and Chemical Systems - Biological Information Processing, Karlsruhe Institute of Technology, Karlsruhe, Germany
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9
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Markitantova Y, Simirskii V. Inherited Eye Diseases with Retinal Manifestations through the Eyes of Homeobox Genes. Int J Mol Sci 2020; 21:E1602. [PMID: 32111086 PMCID: PMC7084737 DOI: 10.3390/ijms21051602] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/21/2020] [Accepted: 02/24/2020] [Indexed: 12/14/2022] Open
Abstract
Retinal development is under the coordinated control of overlapping networks of signaling pathways and transcription factors. The paper was conceived as a review of the data and ideas that have been formed to date on homeobox genes mutations that lead to the disruption of eye organogenesis and result in inherited eye/retinal diseases. Many of these diseases are part of the same clinical spectrum and have high genetic heterogeneity with already identified associated genes. We summarize the known key regulators of eye development, with a focus on the homeobox genes associated with monogenic eye diseases showing retinal manifestations. Recent advances in the field of genetics and high-throughput next-generation sequencing technologies, including single-cell transcriptome analysis have allowed for deepening of knowledge of the genetic basis of inherited retinal diseases (IRDs), as well as improve their diagnostics. We highlight some promising avenues of research involving molecular-genetic and cell-technology approaches that can be effective for IRDs therapy. The most promising neuroprotective strategies are aimed at mobilizing the endogenous cellular reserve of the retina.
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10
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Vetrivel S, Tiso N, Kügler A, Irmler M, Horsch M, Beckers J, Hladik D, Giesert F, Gailus-Durner V, Fuchs H, Sabrautzki S, Hrabě de Angelis M, Graw J. Mutation in the mouse histone gene Hist2h3c1 leads to degeneration of the lens vesicle and severe microphthalmia. Exp Eye Res 2019; 188:107632. [PMID: 30991053 PMCID: PMC6876282 DOI: 10.1016/j.exer.2019.03.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 03/20/2019] [Accepted: 03/30/2019] [Indexed: 12/21/2022]
Abstract
During an ENU (N-ethyl-N-nitrosourea) mutagenesis screen, we observed a dominant small-eye mutant mouse with viable homozygotes. A corresponding mutant line was established and referred to as Aey69 (abnormality of the eye #69). Comprehensive phenotyping of the homozygous Aey69 mutants in the German Mouse Clinic revealed only a subset of statistically significant alterations between wild types and homozygous mutants. The mutation causes microphthalmia without a lens but with retinal hyperproliferation. Linkage was demonstrated to mouse chromosome 3 between the markers D3Mit188 and D3Mit11. Sequencing revealed a 358 A-> C mutation (Ile120Leu) in the Hist2h3c1 gene and a 71 T-> C (Val24Ala) mutation in the Gja8 gene. Detailed analysis of eye development in the homozygous mutant mice documented a perturbed lens development starting from the lens vesicle stage including decreasing expression of crystallins as well as of lens-specific transcription factors like PITX3 and FOXE3. In contrast, we observed an early expression of retinal progenitor cells characterized by several markers including BRN3 (retinal ganglion cells) and OTX2 (cone photoreceptors). The changes in the retina at the early embryonic stages of E11.5-E15.5 happen in parallel with apoptotic processes in the lens at the respective stages. The excessive retinal hyperproliferation is characterized by an increased level of Ki67. The hyperproliferation, however, does not disrupt the differentiation and appearance of the principal retinal cell types at postnatal stages, even if the overgrowing retina covers finally the entire bulbus of the eye. Morpholino-mediated knock-down of the hist2h3ca1 gene in zebrafish leads to a specific perturbation of lens development. When injected into zebrafish zygotes, only the mutant mouse mRNA leads to severe malformations, ranging from cyclopia to severe microphthalmia. The wild-type Hist2h3c1 mRNA can rescue the morpholino-induced defects corroborating its specific function in lens development. Based upon these data, it is concluded that the ocular function of the Hist2h3c1 gene (encoding a canonical H3.2 variant) is conserved throughout evolution. Moreover, the data highlight also the importance of Hist2h3c1 in the coordinated formation of lens and retina during eye development. A dominant small-eye mutant mouse is caused by a mutation in the histone gene Hist2H3c1. Morpholino-mediated knock-down of hist2h3ca1 in the zebrafish validated this finding. The mutation leads to degeneration of the lens vesicle and retina hyperproliferation.
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Affiliation(s)
- Sharmilee Vetrivel
- Helmholtz Center Munich, German Research Center for Environmental Health, Institute of Developmental Genetics, D-85764 Neuherberg, Germany
| | - Natascia Tiso
- Department of Biology, University of Padova, I-35131 Padova, Italy.
| | - Andrea Kügler
- Helmholtz Center Munich, German Research Center for Environmental Health, Institute of Developmental Genetics, D-85764 Neuherberg, Germany
| | - Martin Irmler
- Helmholtz Center Munich, German Research Center for Environmental Health, Institute of Experimental Genetics, D-85764 Neuherberg, Germany
| | - Marion Horsch
- Helmholtz Center Munich, German Research Center for Environmental Health, Institute of Experimental Genetics, D-85764 Neuherberg, Germany
| | - Johannes Beckers
- Helmholtz Center Munich, German Research Center for Environmental Health, Institute of Experimental Genetics, D-85764 Neuherberg, Germany; Chair of Experimental Genetics, School of Life Science Weihenstephan, Technische Universität München, D-85354 Freising, Germany; German Center for Diabetes Research (DZD), D-85764 Neuherberg, Germany
| | - Daniela Hladik
- Helmholtz Center Munich, German Research Center for Environmental Health, Institute of Developmental Genetics, D-85764 Neuherberg, Germany
| | - Florian Giesert
- Helmholtz Center Munich, German Research Center for Environmental Health, Institute of Developmental Genetics, D-85764 Neuherberg, Germany
| | - Valerie Gailus-Durner
- Helmholtz Center Munich, German Research Center for Environmental Health, Institute of Experimental Genetics, D-85764 Neuherberg, Germany
| | - Helmut Fuchs
- Helmholtz Center Munich, German Research Center for Environmental Health, Institute of Experimental Genetics, D-85764 Neuherberg, Germany
| | - Sibylle Sabrautzki
- Helmholtz Center Munich, German Research Center for Environmental Health, Institute of Experimental Genetics, D-85764 Neuherberg, Germany; Helmholtz Center Munich, German Research Center for Environmental Health, Research Unit Comparative Medicine, D-85764 Neuherberg, Germany
| | - Martin Hrabě de Angelis
- Helmholtz Center Munich, German Research Center for Environmental Health, Institute of Experimental Genetics, D-85764 Neuherberg, Germany; Chair of Experimental Genetics, School of Life Science Weihenstephan, Technische Universität München, D-85354 Freising, Germany; German Center for Diabetes Research (DZD), D-85764 Neuherberg, Germany
| | - Jochen Graw
- Helmholtz Center Munich, German Research Center for Environmental Health, Institute of Developmental Genetics, D-85764 Neuherberg, Germany.
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11
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Roux LN, Petit I, Domart R, Concordet JP, Qu J, Zhou H, Joliot A, Ferrigno O, Aberdam D. Modeling of Aniridia-Related Keratopathy by CRISPR/Cas9 Genome Editing of Human Limbal Epithelial Cells and Rescue by Recombinant PAX6 Protein. Stem Cells 2018; 36:1421-1429. [PMID: 29808941 DOI: 10.1002/stem.2858] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 05/08/2018] [Accepted: 05/14/2018] [Indexed: 12/24/2022]
Abstract
Heterozygous PAX6 gene mutations leading to haploinsufficiency are the main cause of congenital aniridia, a rare and progressive panocular disease characterized by reduced visual acuity. Up to 90% of patients suffer from aniridia-related keratopathy (ARK), caused by a combination of factors including limbal epithelial stem cell (LSC) deficiency, impaired healing response and abnormal differentiation of the corneal epithelium. It usually begins in the first decade of life, resulting in recurrent corneal erosions, sub-epithelial fibrosis, and corneal opacification. Unfortunately, there are currently no efficient treatments available for these patients and no in vitro model for this pathology. We used CRISPR/Cas9 technology to introduce into the PAX6 gene of LSCs a heterozygous nonsense mutation found in ARK patients. Nine clones carrying a p.E109X mutation on one allele were obtained with no off-target mutations. Compared with the parental LSCs, heterozygous mutant LSCs displayed reduced expression of PAX6 and marked slow-down of cell proliferation, migration and detachment. Moreover, addition to the culture medium of recombinant PAX6 protein fused to a cell penetrating peptide was able to activate the endogenous PAX6 gene and to rescue phenotypic defects of mutant LSCs, suggesting that administration of such recombinant PAX6 protein could be a promising therapeutic approach for aniridia-related keratopathy. More generally, our results demonstrate that introduction of disease mutations into LSCs by CRISPR/Cas9 genome editing allows the creation of relevant cellular models of ocular disease that should greatly facilitate screening of novel therapeutic approaches. Stem Cells 2018;36:1421-1429.
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Affiliation(s)
- Lauriane N Roux
- INSERM U976, Hôpital Saint-Louis, Paris, France.,Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
| | - Isabelle Petit
- INSERM U976, Hôpital Saint-Louis, Paris, France.,Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
| | - Romain Domart
- INSERM U1154, CNRS UMR 7196, Museum National d'Histoire Naturelle, Paris, France
| | - Jean-Paul Concordet
- INSERM U1154, CNRS UMR 7196, Museum National d'Histoire Naturelle, Paris, France
| | - Jieqiong Qu
- Department of Human Developmental biology, Radboud University, Nijmegen, The Netherlands.,Faculty of Sciences, Department of Human Genetics, Radboud University Nijmegen, The Netherlands
| | - Huiqing Zhou
- Department of Human Developmental biology, Radboud University, Nijmegen, The Netherlands.,Faculty of Sciences, Department of Human Genetics, Radboud University Nijmegen, The Netherlands
| | - Alain Joliot
- Collège de France CNRS/UMR 7241 - INSERM U1050, Paris, France
| | | | - Daniel Aberdam
- INSERM U976, Hôpital Saint-Louis, Paris, France.,Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
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12
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Functional non-coding polymorphism in an EPHA2 promoter PAX2 binding site modifies expression and alters the MAPK and AKT pathways. Sci Rep 2017; 7:9992. [PMID: 28855599 PMCID: PMC5577203 DOI: 10.1038/s41598-017-10117-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 08/04/2017] [Indexed: 01/11/2023] Open
Abstract
To identify possible genetic variants influencing expression of EPHA2 (Ephrin-receptor Type-A2), a tyrosine kinase receptor that has been shown to be important for lens development and to contribute to both congenital and age related cataract when mutated, the extended promoter region of EPHA2 was screened for variants. SNP rs6603883 lies in a PAX2 binding site in the EPHA2 promoter region. The C (minor) allele decreased EPHA2 transcriptional activity relative to the T allele by reducing the binding affinity of PAX2. Knockdown of PAX2 in human lens epithelial (HLE) cells decreased endogenous expression of EPHA2. Whole RNA sequencing showed that extracellular matrix (ECM), MAPK-AKT signaling pathways and cytoskeleton related genes were dysregulated in EPHA2 knockdown HLE cells. Taken together, these results indicate a functional non-coding SNP in EPHA2 promoter affects PAX2 binding and reduces EPHA2 expression. They further suggest that decreasing EPHA2 levels alters MAPK, AKT signaling pathways and ECM and cytoskeletal genes in lens cells that could contribute to cataract. These results demonstrate a direct role for PAX2 in EPHA2 expression and help delineate the role of EPHA2 in development and homeostasis required for lens transparency.
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13
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Wang X, Gregory-Evans K, Wasan KM, Sivak O, Shan X, Gregory-Evans CY. Efficacy of Postnatal In Vivo Nonsense Suppression Therapy in a Pax6 Mouse Model of Aniridia. MOLECULAR THERAPY. NUCLEIC ACIDS 2017. [PMID: 28624217 PMCID: PMC5440746 DOI: 10.1016/j.omtn.2017.05.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Nonsense mutations leading to premature stop codons are common occurring in approximately 12% of all human genetic diseases. Thus, pharmacological nonsense mutation suppression strategies would be beneficial to a large number of patients if the drugs could be targeted to the affected tissues at the appropriate time. Here, we used nonsense suppression to manipulate Pax6 dosage at different developmental times in the eye of the small eye (Pax6Sey/+; G194X) mouse model of aniridia. Efficacy was assessed by functional assays for visual capacity, including electroretinography and optokinetic tracking (OKT), in addition to histological and biochemical studies. Malformation defects in the Pax6Sey/+ postnatal eye responded to topically delivered nonsense suppression in a dose- and time-dependent manner. Elevated levels of Mmp9, a direct downstream target of Pax6 in the cornea, were observed with the different treatment regimens. The lens capsule was particularly sensitive to Pax6 dosage, revealing a potential new role for Pax6 in lens capsule maintenance and development. The remarkable capacity of malformed ocular tissue to respond postnatally to Pax6 dosage in vivo demonstrates that the use of nonsense suppression could be a valuable therapeutic approach for blinding diseases caused by nonsense mutations.
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Affiliation(s)
- Xia Wang
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, BC V5Z 3N9, Canada
| | - Kevin Gregory-Evans
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, BC V5Z 3N9, Canada
| | - Kishor M Wasan
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK S7N 5A2, Canada
| | - Olena Sivak
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, BC V5Z 3N9, Canada
| | - Xianghong Shan
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, BC V5Z 3N9, Canada
| | - Cheryl Y Gregory-Evans
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, BC V5Z 3N9, Canada.
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14
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Yasue A, Kono H, Habuta M, Bando T, Sato K, Inoue J, Oyadomari S, Noji S, Tanaka E, Ohuchi H. Relationship between somatic mosaicism of Pax6 mutation and variable developmental eye abnormalities-an analysis of CRISPR genome-edited mouse embryos. Sci Rep 2017; 7:53. [PMID: 28246397 PMCID: PMC5428340 DOI: 10.1038/s41598-017-00088-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 01/31/2017] [Indexed: 12/25/2022] Open
Abstract
The clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein (Cas) system is a rapid gene-targeting technology that does not require embryonic stem cells. To demonstrate dosage effects of the Pax6 gene on eye formation, we generated Pax6-deficient mice with the CRISPR/Cas system. Eyes of founder embryos at embryonic day (E) 16.5 were examined and categorized according to macroscopic phenotype as class 1 (small eye with distinct pigmentation), class 2 (pigmentation without eye globes), or class 3 (no pigmentation and no eyes). Histologically, class 1 eyes were abnormally small in size with lens still attached to the cornea at E16.5. Class 2 eyes had no lens and distorted convoluted retinas. Class 3 eyes had only rudimentary optic vesicle-like tissues or histological anophthalmia. Genotyping of neck tissue cells from the founder embryos revealed somatic mosaicism and allelic complexity for Pax6. Relationships between eye phenotype and genotype were developed. The present results demonstrated that development of the lens from the surface ectoderm requires a higher gene dose of Pax6 than development of the retina from the optic vesicle. We further anticipate that mice with somatic mosaicism in a targeted gene generated by CRISPR/Cas-mediated genome editing will give some insights for understanding the complexity in human congenital diseases that occur in mosaic form.
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Affiliation(s)
- Akihiro Yasue
- Department of Orthodontics Dentofacial Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-cho, Tokushima, 770-8504, Japan.
| | - Hitomi Kono
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan
| | - Munenori Habuta
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan
| | - Tetsuya Bando
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan
| | - Keita Sato
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan
| | - Junji Inoue
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan
| | - Seiichi Oyadomari
- Division of Molecular Biology, Institute for Advanced Enzyme Research, Tokushima University, 3-18-15 Kuramoto-cho, Tokushima, 770-8503, Japan
| | - Sumihare Noji
- Tokushima University, 2-24 Shinkura-cho, Tokushima, 770-8501, Japan
| | - Eiji Tanaka
- Department of Orthodontics Dentofacial Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-cho, Tokushima, 770-8504, Japan
| | - Hideyo Ohuchi
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan.
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15
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Wang X, Shan X, Gregory-Evans CY. A mouse model of aniridia reveals the in vivo downstream targets of Pax6 driving iris and ciliary body development in the eye. Biochim Biophys Acta Mol Basis Dis 2017; 1863:60-67. [DOI: 10.1016/j.bbadis.2016.10.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 10/13/2016] [Accepted: 10/18/2016] [Indexed: 11/28/2022]
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16
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Fang Q, George AS, Brinkmeier ML, Mortensen AH, Gergics P, Cheung LYM, Daly AZ, Ajmal A, Pérez Millán MI, Ozel AB, Kitzman JO, Mills RE, Li JZ, Camper SA. Genetics of Combined Pituitary Hormone Deficiency: Roadmap into the Genome Era. Endocr Rev 2016; 37:636-675. [PMID: 27828722 PMCID: PMC5155665 DOI: 10.1210/er.2016-1101] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 10/31/2016] [Indexed: 02/08/2023]
Abstract
The genetic basis for combined pituitary hormone deficiency (CPHD) is complex, involving 30 genes in a variety of syndromic and nonsyndromic presentations. Molecular diagnosis of this disorder is valuable for predicting disease progression, avoiding unnecessary surgery, and family planning. We expect that the application of high throughput sequencing will uncover additional contributing genes and eventually become a valuable tool for molecular diagnosis. For example, in the last 3 years, six new genes have been implicated in CPHD using whole-exome sequencing. In this review, we present a historical perspective on gene discovery for CPHD and predict approaches that may facilitate future gene identification projects conducted by clinicians and basic scientists. Guidelines for systematic reporting of genetic variants and assigning causality are emerging. We apply these guidelines retrospectively to reports of the genetic basis of CPHD and summarize modes of inheritance and penetrance for each of the known genes. In recent years, there have been great improvements in databases of genetic information for diverse populations. Some issues remain that make molecular diagnosis challenging in some cases. These include the inherent genetic complexity of this disorder, technical challenges like uneven coverage, differing results from variant calling and interpretation pipelines, the number of tolerated genetic alterations, and imperfect methods for predicting pathogenicity. We discuss approaches for future research in the genetics of CPHD.
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Affiliation(s)
- Qing Fang
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Akima S George
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Michelle L Brinkmeier
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Amanda H Mortensen
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Peter Gergics
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Leonard Y M Cheung
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Alexandre Z Daly
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Adnan Ajmal
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - María Ines Pérez Millán
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - A Bilge Ozel
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Jacob O Kitzman
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Ryan E Mills
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Jun Z Li
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Sally A Camper
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
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Analysis of compound heterozygotes reveals that the mouse floxed Pax6 (tm1Ued) allele produces abnormal eye phenotypes. Transgenic Res 2016; 25:679-92. [PMID: 27240603 PMCID: PMC5023747 DOI: 10.1007/s11248-016-9962-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 05/13/2016] [Indexed: 01/27/2023]
Abstract
Analysis of abnormal phenotypes produced by different types of mutations has been crucial for our understanding of gene function. Some floxed alleles that retain a neomycin-resistance selection cassette (neo cassette) are not equivalent to wild-type alleles and provide useful experimental resources. Pax6 is an important developmental gene and the aim of this study was to determine whether the floxed Pax6tm1Ued (Pax6fl) allele, which has a retained neo cassette, produced any abnormal eye phenotypes that would imply that it differs from the wild-type allele. Homozygous Pax6fl/fl and heterozygous Pax6fl/+ mice had no overt qualitative eye abnormalities but morphometric analysis showed that Pax6fl/fl corneas tended be thicker and smaller in diameter. To aid identification of weak effects, we produced compound heterozygotes with the Pax6Sey-Neu (Pax6−) null allele. Pax6fl/− compound heterozygotes had more severe eye abnormalities than Pax6+/− heterozygotes, implying that Pax6fl differs from the wild-type Pax6+ allele. Immunohistochemistry showed that the Pax6fl/− corneal epithelium was positive for keratin 19 and negative for keratin 12, indicating that it was abnormally differentiated. This Pax6fl allele provides a useful addition to the existing Pax6 allelic series and this study demonstrates the utility of using compound heterozygotes with null alleles to unmask cryptic effects of floxed alleles.
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18
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Berthoud VM, Minogue PJ, Snabb JI, Dzhashiashvili Y, Novak LA, Zoltoski RK, Popko B, Beyer EC. Connexin23 deletion does not affect lens transparency. Exp Eye Res 2016; 146:283-288. [PMID: 27038752 DOI: 10.1016/j.exer.2016.03.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 03/24/2016] [Accepted: 03/28/2016] [Indexed: 11/25/2022]
Abstract
While connexin46 (Cx46) and connexin50 (Cx50) are crucial for maintaining lens transparency and growth, the contributions of a more recently identified lens fiber connexin, Cx23, are poorly understood. Therefore, we studied the consequences of absence of Cx23 in mouse lenses. Cx23-null mice were generated by homologous Cre recombination. Cx23 mRNA was abundantly expressed in wild type lenses, but not in Cx23-null lenses. The transparency and refractive properties of Cx23-null lenses were similar to wild type lenses when examined by darkfield microscopy. Neither the focusing ability nor the light scattering was altered in the Cx23-null lenses. While both Cx46 and Cx50 localized to appositional fiber cell membranes (as in wild type lenses), their levels were consistently (but not significantly) decreased in homozygous Cx23-null lenses. These results suggest that although Cx23 expression can influence the abundance of the co-expressed lens fiber connexins, heterozygous or homozygous expression of a Cx23-null allele does not alter lens transparency.
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Affiliation(s)
| | - Peter J Minogue
- Department of Pediatrics, University of Chicago, Chicago, IL, USA
| | - Joseph I Snabb
- Department of Pediatrics, University of Chicago, Chicago, IL, USA
| | | | | | | | - Brian Popko
- Department of Neurology, University of Chicago, Chicago, IL, USA
| | - Eric C Beyer
- Department of Pediatrics, University of Chicago, Chicago, IL, USA
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19
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Pax6 in Collembola: Adaptive Evolution of Eye Regression. Sci Rep 2016; 6:20800. [PMID: 26856893 PMCID: PMC4746759 DOI: 10.1038/srep20800] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 01/12/2016] [Indexed: 11/12/2022] Open
Abstract
Unlike the compound eyes in insects, collembolan eyes are comparatively simple: some species have eyes with different numbers of ocelli (1 + 1 to 8 + 8), and some species have no apparent eye structures. Pax6 is a universal master control gene for eye morphogenesis. In this study, full-length Pax6 cDNAs, Fc-Pax6 and Cd-Pax6, were cloned from an eyeless collembolan (Folsomia candida, soil-dwelling) and an eyed one (Ceratophysella denticulata, surface-dwelling), respectively. Their phylogenetic positions are between the two Pax6 paralogs in insects, eyeless (ey) and twin of eyeless (toy), and their protein sequences are more similar to Ey than to Toy. Both Fc-Pax6 and Cd-Pax6 could induce ectopic eyes in Drosophila, while Fc-Pax6 exhibited much weaker transactivation ability than Cd-Pax6. The C-terminus of collembolan Pax6 is indispensable for its transactivation ability, and determines the differences of transactivation ability between Fc-Pax6 and Cd-Pax6. One of the possible reasons is that Fc-Pax6 accumulated more mutations at some key functional sites of C-terminus under a lower selection pressure on eye development due to the dark habitats of F. candida. The composite data provide a first molecular evidence for the monophyletic origin of collembolan eyes, and indicate the eye degeneration of collembolans is caused by adaptive evolution.
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20
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Abstract
Age-related cataracts are frequently associated with degenerative changes in the ocular lens including the aggregation of proteins - mainly crystallins, but also other proteins including amyloids (Aβ) leading to the hypothesis that cataracts could be used as "biomarkers" for Alzheimer disease. Even if this hypothesis was rejected by David Beebe's last paper (Bei et al., Exp. Eye Res., 2015), it is a fascinating aspect to look for commonalities between eye diseases and neurological disorders. In this review, I discuss such commonalities between eye and brain mainly from a developmental point of view. The finding of the functional homology of the Drosophila eyeless gene with the mammalian Pax6 gene marks a first highlight in the developmental genetics of the eye - this result destroyed the "dogma" of the different evolutionary routes of eye development in flies and mammals. The second highlight was the finding that Pax6 is also involved in the development of the forebrain supporting the pleiotropic role of many genes. These findings opened a new avenue for research showing that a broad variety of transcription factors, but also structural proteins are involved both, in eye and brain development as well as into the maintenance of the functional integrity of the corresponding tissue(s). In this review recent findings are summarized demonstrating that genes whose mutations have been identified first to be causative for congenital or juvenile eye disorders are also involved in regenerative processes and neurogenesis (Pax6), but also in neurodegenerative diseases like Parkinson (e.g. Pitx3) or in neurological disorders like Schizophrenia (e.g. Crybb1, Crybb2).
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Affiliation(s)
- Jochen Graw
- Helmholtz Zentrum München, Institute of Developmental Genetics, Ingolstaedter Landstr, 1, D-85764 Neuherberg, Germany.
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21
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Nakayama T, Fisher M, Nakajima K, Odeleye AO, Zimmerman KB, Fish MB, Yaoita Y, Chojnowski JL, Lauderdale JD, Netland PA, Grainger RM. Xenopus pax6 mutants affect eye development and other organ systems, and have phenotypic similarities to human aniridia patients. Dev Biol 2015; 408:328-44. [PMID: 25724657 DOI: 10.1016/j.ydbio.2015.02.012] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 02/13/2015] [Accepted: 02/16/2015] [Indexed: 02/06/2023]
Abstract
Mutations in the Pax6 gene cause ocular defects in both vertebrate and invertebrate animal species, and the disease aniridia in humans. Despite extensive experimentation on this gene in multiple species, including humans, we still do not understand the earliest effects on development mediated by this gene. This prompted us to develop pax6 mutant lines in Xenopus tropicalis taking advantage of the utility of the Xenopus system for examining early development and in addition to establish a model for studying the human disease aniridia in an accessible lower vertebrate. We have generated mutants in pax6 by using Transcription Activator-Like Effector Nuclease (TALEN) constructs for gene editing in X. tropicalis. Embryos with putative null mutations show severe eye abnormalities and changes in brain development, as assessed by changes in morphology and gene expression. One gene that we found is downregulated very early in development in these pax6 mutants is myc, a gene involved in pluripotency and progenitor cell maintenance and likely a mediator of some key pax6 functions in the embryo. Changes in gene expression in the developing brain and pancreas reflect other important functions of pax6 during development. In mutations with partial loss of pax6 function eye development is initially relatively normal but froglets show an underdeveloped iris, similar to the classic phenotype (aniridia) seen in human patients with PAX6 mutations. Other eye abnormalities observed in these froglets, including cataracts and corneal defects, are also common in human aniridia. The frog model thus allows us to examine the earliest deficits in eye formation as a result of pax6 lesions, and provides a useful model for understanding the developmental basis for the aniridia phenotype seen in humans.
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Affiliation(s)
- Takuya Nakayama
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Marilyn Fisher
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Keisuke Nakajima
- Division of Embryology and Genetics, Institute for Amphibian Biology, Hiroshima University, Higashihiroshima 739-8526, Japan
| | - Akinleye O Odeleye
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Keith B Zimmerman
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Margaret B Fish
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Yoshio Yaoita
- Division of Embryology and Genetics, Institute for Amphibian Biology, Hiroshima University, Higashihiroshima 739-8526, Japan
| | - Jena L Chojnowski
- Department of Cellular Biology, University of Georgia, Athens, GA, 30602, USA
| | - James D Lauderdale
- Department of Cellular Biology, University of Georgia, Athens, GA, 30602, USA
| | - Peter A Netland
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Robert M Grainger
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA; Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
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22
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Novel small-eye allele in paired box gene 6 (Pax6) is caused by a point mutation in intron 7 and creates a new exon. Mol Vis 2013; 19:877-84. [PMID: 23592925 PMCID: PMC3626302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 04/10/2013] [Indexed: 10/28/2022] Open
Abstract
PURPOSE Within a mutagenesis screen, we identified the new mouse mutant Aey80 with small eyes; homozygous mutants were not obtained. The aim of the study was its molecular characterization. METHODS We analyzed the offspring of paternally N-ethyl-N-nitrosourea (ENU)-treated C3HeB/FeJ mice for dysmorphology parameters, which can be observed with the naked eye. The Aey80 mutant (abnormality of the eye) was further characterized with laser interference biometry, Scheimpflug imaging, and optical coherence tomography. Linkage analysis of the Aey80 mutant was performed using a panel of single nucleotide polymorphisms different among C3HeB/FeJ and C57BL/6J mice. The Aey80 mutation was identified with sequence analysis of the positional candidate gene. RESULTS We identified a new mutant characterized by an obvious small-eye phenotype; homozygotes are not viable after birth. Embryos at embryonic day 15.5 demonstrate a clear gene-dosage effect: Heterozygotes have small eyes, whereas homozygous mutants do not have eyes. In adult mice, the lenses and the entire eyes of the heterozygous mutants were significantly smaller than those of the wild-types (p<0.01). No other ocular phenotypes were observed; the lenses were fully transparent, and no adhesion to the cornea was observed. The mutation was mapped to chromosome 2; markers between 70.8 MB and 129.5 MB showed significant linkage to the mutation resulting in paired box gene 6 (Pax6) as an excellent candidate gene. We amplified cDNAs from the embryonic eyes and observed an additional band while amplifying the region corresponding to exons 7 and 8. The additional band included an alternative exon of 141 bp, which was associated with a G->A exchange four bases downstream of the end of the alternative exon. The alternative exon in the mutants is predicted to encode 30 novel amino acids and three stop codons. This alternative exon kept the paired domain intact but led to a loss of the homeodomain and the C-terminal proline-serine-threonine (PST) domain. The mutation cosegregated in the mutant line, since all five additional small-eyed mice from this line showed the same mutation. A general polymorphism at the mutated site was excluded with sequence analysis of seven other wild-type mouse strains different from C3HeB/FeJ. CONCLUSIONS These findings demonstrate a novel allele of the paired box gene 6 (Pax6) that affects lens development in a semidominant manner leading to a classical small-eye phenotype. However, the site of the mutation more than 1 kb downstream of exon 7 and resulting in an alternative exon is quite unusual. It indicates the importance of sequence analysis of cDNA for mutation detection; mutations like this are unlikely to be identified by analyzing genomic sequences only. Moreover, this particular mutation demonstrates how a novel exon can be created by only a single base-pair exchange.
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23
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Viczian AS. Advances in retinal stem cell biology. J Ophthalmic Vis Res 2013; 8:147-59. [PMID: 23943690 PMCID: PMC3740467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2013] [Accepted: 03/14/2013] [Indexed: 11/21/2022] Open
Abstract
Tremendous progress has been made in recent years to generate retinal cells from pluripotent cell sources. These advances provide hope for those suffering from blindness due to lost retinal cells. Understanding the intrinsic genetic network in model organisms, like fly and frog, has led to a better understanding of the extrinsic signaling pathways necessary for retinal progenitor cell formation in mouse and human cell cultures. This review focuses on the culture methods used by different groups, which has culminated in the generation of laminated retinal tissue from both embryonic and induced pluripotent cells. The review also briefly describes advances made in transplantation studies using donor retinal progenitor and cultured retinal cells.
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Affiliation(s)
- Andrea S. Viczian
- Correspondence to: Andrea S. Viczian, PhD. Department of Ophthalmology, Center for Vision Research, SUNY Eye Institute, Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210, USA;
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24
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Beccari L, Marco-Ferreres R, Bovolenta P. The logic of gene regulatory networks in early vertebrate forebrain patterning. Mech Dev 2012; 130:95-111. [PMID: 23111324 DOI: 10.1016/j.mod.2012.10.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Accepted: 10/09/2012] [Indexed: 01/19/2023]
Abstract
The vertebrate forebrain or prosencephalon is patterned at the beginning of neurulation into four major domains: the telencephalic, hypothalamic, retinal and diencephalic anlagen. These domains will then give rise to the majority of the brain structures involved in sensory integration and the control of higher intellectual and homeostatic functions. Understanding how forebrain pattering arises has thus attracted the interest of developmental neurobiologists for decades. As a result, most of its regulators have been identified and their hierarchical relationship is now the object of active investigation. Here, we summarize the main morphogenetic pathways and transcription factors involved in forebrain specification and propose the backbone of a possible gene regulatory network (GRN) governing its specification, taking advantage of the GRN principles elaborated by pioneer studies in simpler organisms. We will also discuss this GRN and its operational logic in the context of the remarkable morphological and functional diversification that the forebrain has undergone during evolution.
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Affiliation(s)
- Leonardo Beccari
- Centro de Biología Molecular "Severo Ochoa", CSIC-UAM, c/Nicolas Cabrera, 1, Madrid 28049, Spain
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25
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Dai L, Li Y, Du CY, Gong LM, Han CC, Li XG, Fan P, Fu SB. Ten SNPs of PAX6, Lumican, and MYOC genes are not associated with high myopia in Han Chinese. Ophthalmic Genet 2012; 33:171-8. [PMID: 22809227 DOI: 10.3109/13816810.2012.675397] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To investigate whether the PAX6, Lumican, and MYOC genes are related to high myopia in Han Chinese since the association between these genes and high myopia is unclear in this patient population. METHODS Peripheral venous blood samples were collected for DNA extraction from 220 subjects with high myopia (refractive error ≤-10.00 D) vs. normal controls among the Han Chinese of Northeastern China. Mass spectrometry was applied to detect 10 SNP loci of the PAX6, Lumican, and MYOC genes. The candidate region was analyzed using case-control correlation analysis. The χ(2) test was used to analyze the allele and genotype frequencies in the myopic group vs. the control group. Haploview software was used for haplotype analysis. RESULTS The χ(2) test was used to compare the allele and genotype frequencies of SNPs in patients and control subjects and the results showed that ten SNPs of the PAX6, Lumican, and MYOC genes were not significantly associated with high myopia. CONCLUSIONS Our results confirm that the PAX6, Lumican, and MYOC genes were not associated with high myopia in the Han Chinese in Northeastern China.
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Affiliation(s)
- Lili Dai
- Department of Ophthalmology, Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
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26
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Shaham O, Menuchin Y, Farhy C, Ashery-Padan R. Pax6: a multi-level regulator of ocular development. Prog Retin Eye Res 2012; 31:351-76. [PMID: 22561546 DOI: 10.1016/j.preteyeres.2012.04.002] [Citation(s) in RCA: 160] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Revised: 04/19/2012] [Accepted: 04/24/2012] [Indexed: 02/08/2023]
Abstract
Eye development has been a paradigm for the study of organogenesis, from the demonstration of lens induction through epithelial tissue morphogenesis, to neuronal specification and differentiation. The transcription factor Pax6 has been shown to play a key role in each of these processes. Pax6 is required for initiation of developmental pathways, patterning of epithelial tissues, activation of tissue-specific genes and interaction with other regulatory pathways. Herein we examine the data accumulated over the last few decades from extensive analyses of biochemical modules and genetic manipulation of the Pax6 gene. Specifically, we describe the regulation of Pax6's expression pattern, the protein's DNA-binding properties, and its specific roles and mechanisms of action at all stages of lens and retinal development. Pax6 functions at multiple levels to integrate extracellular information and execute cell-intrinsic differentiation programs that culminate in the specification and differentiation of a distinct ocular lineage.
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Affiliation(s)
- Ohad Shaham
- Sackler Faculty of Medicine, Department of Human Molecular Genetics and Biochemistry, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
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27
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Mungall CJ, Torniai C, Gkoutos GV, Lewis SE, Haendel MA. Uberon, an integrative multi-species anatomy ontology. Genome Biol 2012; 13:R5. [PMID: 22293552 PMCID: PMC3334586 DOI: 10.1186/gb-2012-13-1-r5] [Citation(s) in RCA: 409] [Impact Index Per Article: 34.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 01/31/2012] [Indexed: 01/20/2023] Open
Abstract
We present Uberon, an integrated cross-species ontology consisting of over 6,500 classes representing a variety of anatomical entities, organized according to traditional anatomical classification criteria. The ontology represents structures in a species-neutral way and includes extensive associations to existing species-centric anatomical ontologies, allowing integration of model organism and human data. Uberon provides a necessary bridge between anatomical structures in different taxa for cross-species inference. It uses novel methods for representing taxonomic variation, and has proved to be essential for translational phenotype analyses. Uberon is available at http://uberon.org
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Affiliation(s)
- Christopher J Mungall
- Genomics Division, Lawrence Berkeley National Laboratory, 1 Cycltotron Road MS 64-121, Berkeley, CA 94720, USA.
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28
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Mort RL, Bentley AJ, Martin FL, Collinson JM, Douvaras P, Hill RE, Morley SD, Fullwood NJ, West JD. Effects of aberrant Pax6 gene dosage on mouse corneal pathophysiology and corneal epithelial homeostasis. PLoS One 2011; 6:e28895. [PMID: 22220198 PMCID: PMC3248408 DOI: 10.1371/journal.pone.0028895] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 11/16/2011] [Indexed: 11/18/2022] Open
Abstract
Background Altered dosage of the transcription factor PAX6 causes multiple human eye pathophysiologies. PAX6+/− heterozygotes suffer from aniridia and aniridia-related keratopathy (ARK), a corneal deterioration that probably involves a limbal epithelial stem cell (LESC) deficiency. Heterozygous Pax6+/Sey-Neu (Pax6+/−) mice recapitulate the human disease and are a good model of ARK. Corneal pathologies also occur in other mouse Pax6 mutants and in PAX77Tg/− transgenics, which over-express Pax6 and model human PAX6 duplication. Methodology/Principal Findings We used electron microscopy to investigate ocular defects in Pax6+/− heterozygotes (low Pax6 levels) and PAX77Tg/− transgenics (high Pax6 levels). As well as the well-documented epithelial defects, aberrant Pax6 dosage had profound effects on the corneal stroma and endothelium in both genotypes, including cellular vacuolation, similar to that reported for human macular corneal dystrophy. We used mosaic expression of an X-linked LacZ transgene in X-inactivation mosaic female (XLacZTg/−) mice to investigate corneal epithelial maintenance by LESC clones in Pax6+/− and PAX77Tg/− mosaic mice. PAX77Tg/− mosaics, over-expressing Pax6, produced normal corneal epithelial radial striped patterns (despite other corneal defects), suggesting that centripetal cell movement was unaffected. Moderately disrupted patterns in Pax6+/− mosaics were corrected by introducing the PAX77 transgene (in Pax6+/−, PAX77Tg/− mosaics). Pax6Leca4/+, XLacZTg/− mosaic mice (heterozygous for the Pax6Leca4 missense mutation) showed more severely disrupted mosaic patterns. Corrected corneal epithelial stripe numbers (an indirect estimate of active LESC clone numbers) declined with age (between 15 and 30 weeks) in wild-type XLacZTg/− mosaics. In contrast, corrected stripe numbers were already low at 15 weeks in Pax6+/− and PAX77Tg/− mosaic corneas, suggesting Pax6 under- and over-expression both affect LESC clones. Conclusions/Significance Pax6+/− and PAX77Tg/− genotypes have only relatively minor effects on LESC clone numbers but cause more severe corneal endothelial and stromal defects. This should prompt further investigations of the pathophysiology underlying human aniridia and ARK.
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Affiliation(s)
- Richard L. Mort
- Division of Reproductive and Developmental Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Medical Research Council Human Genetics Unit, Medical Research Council Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Adam J. Bentley
- Division of Biomedical and Life Sciences, Lancaster University, Lancaster, United Kingdom
| | - Francis L. Martin
- Centre for Biophotonics, Lancaster University, Lancaster, United Kingdom
| | - J. Martin Collinson
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Panagiotis Douvaras
- Division of Reproductive and Developmental Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Robert E. Hill
- Medical Research Council Human Genetics Unit, Medical Research Council Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Steven D. Morley
- School of Clinical Sciences & Community Health, University of Edinburgh, Edinburgh, United Kingdom
| | - Nigel J. Fullwood
- Division of Biomedical and Life Sciences, Lancaster University, Lancaster, United Kingdom
| | - John D. West
- Division of Reproductive and Developmental Sciences, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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Churchill A, Graw J. Clinical and experimental advances in congenital and paediatric cataracts. Philos Trans R Soc Lond B Biol Sci 2011; 366:1234-49. [PMID: 21402583 DOI: 10.1098/rstb.2010.0227] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Cataracts (opacities of the lens) are frequent in the elderly, but rare in paediatric practice. Congenital cataracts (in industrialized countries) are mainly caused by mutations affecting lens development. Much of our knowledge about the underlying mechanisms of cataractogenesis has come from the genetic analysis of affected families: there are contributions from genes coding for transcription factors (such as FoxE3, Maf, Pitx3) and structural proteins such as crystallins or connexins. In addition, there are contributions from enzymes affecting sugar pathways (particularly the galactose pathway) and from a quite unexpected area: axon guidance molecules like ephrins and their receptors. Cataractous mouse lenses can be identified easily by visual inspection, and a remarkable number of mutant lines have now been characterized. Generally, most of the mouse mutants show a similar phenotype to their human counterparts; however, there are some remarkable differences. It should be noted that many mutations affect genes that are expressed not only in the lens, but also in tissues and organs outside the eye. There is increasing evidence for pleiotropic effects of these genes, and increasing consideration that cataracts may act as early and readily detectable biomarkers for a number of systemic syndromes.
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Ninkovic J, Pinto L, Petricca S, Lepier A, Sun J, Rieger MA, Schroeder T, Cvekl A, Favor J, Götz M. The transcription factor Pax6 regulates survival of dopaminergic olfactory bulb neurons via crystallin αA. Neuron 2011; 68:682-94. [PMID: 21092858 DOI: 10.1016/j.neuron.2010.09.030] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2010] [Indexed: 10/18/2022]
Abstract
Most neurons in the adult mammalian brain survive for the entire life of an individual. However, it is not known which transcriptional pathways regulate this survival in a healthy brain. Here, we identify a pathway regulating neuronal survival in a highly subtype-specific manner. We show that the transcription factor Pax6 expressed in dopaminergic neurons of the olfactory bulb regulates the survival of these neurons by directly controlling the expression of crystallin αA (CryαA), which blocks apoptosis by inhibition of procaspase-3 activation. Re-expression of CryαA fully rescues survival of Pax6-deficient dopaminergic interneurons in vivo and knockdown of CryαA by shRNA in wild-type mice reduces the number of dopaminergic OB interneurons. Strikingly, Pax6 utilizes different DNA-binding domains for its well-known role in fate specification and this role of regulating the survival of specific neuronal subtypes in the mature, healthy brain.
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Affiliation(s)
- Jovica Ninkovic
- Helmholtz Zentrum München, Institute of Stem Cell Research, Ingolstädter Landstraße 1, D-85764 Neuherberg, Germany
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Kim KC, Go HS, Bak HR, Choi CS, Choi I, Kim P, Han SH, Han SM, Shin CY, Ko KH. Prenatal exposure of ethanol induces increased glutamatergic neuronal differentiation of neural progenitor cells. J Biomed Sci 2010; 17:85. [PMID: 21073715 PMCID: PMC2996361 DOI: 10.1186/1423-0127-17-85] [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: 08/03/2010] [Accepted: 11/12/2010] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Prenatal ethanol exposure during pregnancy induces a spectrum of mental and physical disorders called fetal alcohol spectrum disorder (FASD). The central nervous system is the main organ influenced by FASD, and neurological symptoms include mental retardation, learning abnormalities, hyperactivity and seizure susceptibility in childhood along with the microcephaly. In this study, we examined whether ethanol exposure adversely affects the proliferation of NPC and de-regulates the normal ratio between glutamatergic and GABAergic neuronal differentiation using primary neural progenitor culture (NPC) and in vivo FASD models. METHODS Neural progenitor cells were cultured from E14 embryo brain of Sprague-Dawley rat. Pregnant mice and rats were treated with ethanol (2 or 4 g/kg/day) diluted with normal saline from E7 to E16 for in vivo FASD animal models. Expression level of proteins was investigated by western blot analysis and immunocytochemical assays. MTT was used for cell viability. Proliferative activity of NPCs was identified by BrdU incorporation, immunocytochemistry and FACS analysis. RESULTS Reduced proliferation of NPCs by ethanol was demonstrated using BrdU incorporation, immunocytochemistry and FACS analysis. In addition, ethanol induced the imbalance between glutamatergic and GABAergic neuronal differentiation via transient increase in the expression of Pax6, Ngn2 and NeuroD with concomitant decrease in the expression of Mash1. Similar pattern of expression of those transcription factors was observed using an in vivo model of FASD as well as the increased expression of PSD-95 and decreased expression of GAD67. CONCLUSIONS These results suggest that ethanol induces hyper-differentiation of glutamatergic neuron through Pax6 pathway, which may underlie the hyper-excitability phenotype such as hyperactivity or seizure susceptibility in FASD patients.
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Affiliation(s)
- Ki Chan Kim
- Department of Pharmacology, College of Pharmacy, Seoul National University, Seoul, Korea
| | - Hyo Sang Go
- Department of Pharmacology, College of Pharmacy, Seoul National University, Seoul, Korea
| | - Hae Rang Bak
- Department of Pharmacology, College of Pharmacy, Seoul National University, Seoul, Korea
| | - Chang Soon Choi
- School of Medicine and Center for Neuroscience Research, IBST, Konkuk University, Korea
| | - Inha Choi
- School of Medicine and Center for Neuroscience Research, IBST, Konkuk University, Korea
| | - Pitna Kim
- School of Medicine and Center for Neuroscience Research, IBST, Konkuk University, Korea
| | - Seol-Heui Han
- School of Medicine and Center for Neuroscience Research, IBST, Konkuk University, Korea
| | - So Min Han
- Department of Pharmacology, College of Pharmacy, Seoul National University, Seoul, Korea
| | - Chan Young Shin
- School of Medicine and Center for Neuroscience Research, IBST, Konkuk University, Korea
| | - Kwang Ho Ko
- Department of Pharmacology, College of Pharmacy, Seoul National University, Seoul, Korea
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Dames P, Puff R, Weise M, Parhofer KG, Göke B, Götz M, Graw J, Favor J, Lechner A. Relative roles of the different Pax6 domains for pancreatic alpha cell development. BMC DEVELOPMENTAL BIOLOGY 2010; 10:39. [PMID: 20377917 PMCID: PMC2858030 DOI: 10.1186/1471-213x-10-39] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Accepted: 04/09/2010] [Indexed: 12/04/2022]
Abstract
Background The transcription factor Pax6 functions in the specification and maintenance of the differentiated cell lineages in the endocrine pancreas. It has two DNA binding domains, the paired domain and the homeodomain, in addition to a C-terminal transactivation domain. The phenotype of Pax6-/- knockout mice suggests non-redundant functions of the transcription factor in the development of glucagon-expressing α-cells as this cell type is absent in the mutants. We ask the question of how the differentiation of pancreatic endocrine cells, in particular that of α-cells, is affected by selective inactivation of either one of the three major domains of Pax6. Results The Pax6Aey18 mutant mouse line, in which the paired domain is inactivated, showed a phenotype similar to that of Pax6-/- knockout mice with a near complete absence of glucagon-positive α-cells (0-4 cells/section; ≤1% of wt), reduced β-cell area (74% of wt) and disorganized islets. The proportion of ghrelin-positive ε-cells was expanded. In Pax6Sey-Neu mutants, which lack the transactivation domain, α-and β-cells where reduced to 25 and 40% of wt, respectively. We also studied two mouse lines with mutations in the homeodomain, Pax64Neu and Pax6132-14Neu. Neighboring amino acids are affected in the two lines and both point mutations abolish DNA binding of the classical P3 homeodomain target sequence. The pancreatic phenotype of the two mutants however was divergent. While Pax64Neu homozygotes showed a reduction of α- and β-cells to 59 and 61%, respectively, pancreatic endocrine development was unaltered in the Pax6132-14Neu mutant strain. Conclusions We show that inactivation of the Pax6 paired domain leads to a more severe phenotype with regards to the differentiation of pancreatic α-cells than the loss of the transactivation domain. The analysis of two different homeodomain mutants suggests that the binding of Pax6 to P3 homeodomain consensus sequences is not required for α-cell development. It rather seems that the homeodomain has a modulating role in Pax6 function, possibly by facilitating a PH0-like binding confirmation on paired domain target genes like proglucagon. This function is differentially affected by the two homeodomain mutations analyzed in this study.
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Affiliation(s)
- Petra Dames
- Ludwig-Maximilians-Universität, Klinikum Grosshadern, Medizinische Klinik, München, Germany
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Molecular Genetic and Immunophenotypical Analysis of Pax6 Transcription Factor and Neural Differentiation Markers in Human Fetal Neocortex and Retina In Vivo and In Vitro. Bull Exp Biol Med 2010; 148:697-704. [DOI: 10.1007/s10517-010-0797-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Abstract
The vertebrate eye comprises tissues from different embryonic origins: the lens and the cornea are derived from the surface ectoderm, but the retina and the epithelial layers of the iris and ciliary body are from the anterior neural plate. The timely action of transcription factors and inductive signals ensure the correct development of the different eye components. Establishing the genetic basis of eye defects in zebrafishes, mouse, and human has been an important tool for the detailed analysis of this complex process. A single eye field forms centrally within the anterior neural plate during gastrulation; it is characterized on the molecular level by the expression of "eye-field transcription factors." The single eye field is separated into two, forming the optic vesicle and later (under influence of the lens placode) the optic cup. The lens develops from the lens placode (surface ectoderm) under influence of the underlying optic vesicle. Pax6 acts in this phase as master control gene, and genes encoding cytoskeletal proteins, structural proteins, or membrane proteins become activated. The cornea forms from the surface ectoderm, and cells from the periocular mesenchyme migrate into the cornea giving rise for the future cornea stroma. Similarly, the iris and ciliary body form from the optic cup. The outer layer of the optic cup becomes the retinal pigmented epithelium, and the main part of the inner layer of the optic cup forms later the neural retina with six different types of cells including the photoreceptors. The retinal ganglion cells grow toward the optic stalk forming the optic nerve. This review describes the major molecular players and cellular processes during eye development as they are known from frogs, zebrafish, chick, and mice-showing also differences among species and missing links for future research. The relevance to human disorders is one of the major aspects covered throughout the review.
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Affiliation(s)
- Jochen Graw
- Helmholtz Center Munich-German Research Center for Environmental Health, Institute of Developmental Genetics, Neuherberg, Germany
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Washington NL, Haendel MA, Mungall CJ, Ashburner M, Westerfield M, Lewis SE. Linking human diseases to animal models using ontology-based phenotype annotation. PLoS Biol 2009; 7:e1000247. [PMID: 19956802 PMCID: PMC2774506 DOI: 10.1371/journal.pbio.1000247] [Citation(s) in RCA: 223] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Accepted: 10/13/2009] [Indexed: 11/18/2022] Open
Abstract
A novel method for quantifying the similarity between phenotypes by the use of ontologies can be used to search for candidate genes, pathway members, and human disease models on the basis of phenotypes alone. Scientists and clinicians who study genetic alterations and disease have traditionally described phenotypes in natural language. The considerable variation in these free-text descriptions has posed a hindrance to the important task of identifying candidate genes and models for human diseases and indicates the need for a computationally tractable method to mine data resources for mutant phenotypes. In this study, we tested the hypothesis that ontological annotation of disease phenotypes will facilitate the discovery of new genotype-phenotype relationships within and across species. To describe phenotypes using ontologies, we used an Entity-Quality (EQ) methodology, wherein the affected entity (E) and how it is affected (Q) are recorded using terms from a variety of ontologies. Using this EQ method, we annotated the phenotypes of 11 gene-linked human diseases described in Online Mendelian Inheritance in Man (OMIM). These human annotations were loaded into our Ontology-Based Database (OBD) along with other ontology-based phenotype descriptions of mutants from various model organism databases. Phenotypes recorded with this EQ method can be computationally compared based on the hierarchy of terms in the ontologies and the frequency of annotation. We utilized four similarity metrics to compare phenotypes and developed an ontology of homologous and analogous anatomical structures to compare phenotypes between species. Using these tools, we demonstrate that we can identify, through the similarity of the recorded phenotypes, other alleles of the same gene, other members of a signaling pathway, and orthologous genes and pathway members across species. We conclude that EQ-based annotation of phenotypes, in conjunction with a cross-species ontology, and a variety of similarity metrics can identify biologically meaningful similarities between genes by comparing phenotypes alone. This annotation and search method provides a novel and efficient means to identify gene candidates and animal models of human disease, which may shorten the lengthy path to identification and understanding of the genetic basis of human disease. Model organisms such as fruit flies, mice, and zebrafish are useful for investigating gene function because they are easy to grow, dissect, and genetically manipulate in the laboratory. By examining mutations in these organisms, one can identify candidate genes that cause disease in humans, and develop models to better understand human disease and gene function. A fundamental roadblock for analysis is, however, the lack of a computational method for describing and comparing phenotypes of mutant animals and of human diseases when the genetic basis is unknown. We describe here a novel method using ontologies to record and quantify the similarity between phenotypes. We tested our method by using the annotated mutant phenotype of one member of the Hedgehog signaling pathway in zebrafish to identify other pathway members with similar recorded phenotypes. We also compared human disease phenotypes to those produced by mutation in model organisms, and show that orthologous and biologically relevant genes can be identified by this method. Given that the genetic basis of human disease is often unknown, this method provides a means for identifying candidate genes, pathway members, and disease models by computationally identifying similar phenotypes within and across species.
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Affiliation(s)
- Nicole L Washington
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
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Ng TK, Lam CY, Lam DSC, Chiang SWY, Tam POS, Wang DY, Fan BJ, Yam GHF, Fan DSP, Pang CP. AC and AG dinucleotide repeats in the PAX6 P1 promoter are associated with high myopia. Mol Vis 2009; 15:2239-48. [PMID: 19907666 PMCID: PMC2774452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Accepted: 10/27/2009] [Indexed: 11/03/2022] Open
Abstract
PURPOSE The PAX6 gene, located at the reported myopia locus MYP7 on chromosome 11p13, was postulated to be associated with myopia development. This study investigated the association of PAX6 with high myopia in 379 high myopia patients and 349 controls. METHODS High myopia patients had refractive errors of -6.00 diopters or greater and axial length longer than 26 mm. Control subjects had refractive errors less than -1.00 diopter and axial length shorter than 24 mm. The P1 promoter, all coding sequences, and adjacent splice-site regions of the PAX6 gene were screened in all study subjects by polymerase chain reaction and direct sequencing. PAX6 P1 promoter-luciferase constructs with variable AC and AG repeat lengths were prepared and transfected into human ARPE-19 cells prior to assaying for their transcriptional activities. RESULTS No sequence alterations in the coding or splicing regions showed an association with high myopia. Two dinucleotide repeats, (AC)(m) and (AG)(n), in the P1 promoter region were found to be highly polymorphic and significantly associated with high myopia. Higher repeat numbers were observed in high myopia patients for both (AC)(m) (empirical p = 0.013) and (AG)(n) (empirical p = 0.012) dinucleotide polymorphisms, with a 1.327-fold increased risk associated with the (AG)(n) repeat (empirical p = 0.016; 95% confidence interval: 1.059-1.663). Luciferase-reporter analysis showed elevated transcription activity with increasing individual (AC)(m) and (AG)(n) and combined (AC)(m)(AG)(n) repeat lengths. CONCLUSIONS Our results revealed an association between high myopia and AC and AG dinucleotide repeat lengths in the PAX6 P1 promoter, indicating the involvement of PAX6 in the pathogenesis of high myopia.
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Affiliation(s)
- Tsz Kin Ng
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong S.A.R
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Analysis of Pax6 contiguous gene deletions in the mouse, Mus musculus, identifies regions distinct from Pax6 responsible for extreme small-eye and belly-spotting phenotypes. Genetics 2009; 182:1077-88. [PMID: 19474196 DOI: 10.1534/genetics.109.104562] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In the mouse Pax6 function is critical in a dose-dependent manner for proper eye development. Pax6 contiguous gene deletions were shown to be homozygous lethal at an early embryonic stage. Heterozygotes express belly spotting and extreme microphthalmia. The eye phenotype is more severe than in heterozygous Pax6 intragenic null mutants, raising the possibility that deletions are functionally different from intragenic null mutations or that a region distinct from Pax6 included in the deletions affects eye phenotype. We recovered and identified the exact regions deleted in three new Pax6 deletions. All are homozygous lethal at an early embryonic stage. None express belly spotting. One expresses extreme microphthalmia and two express the milder eye phenotype similar to Pax6 intragenic null mutants. Analysis of Pax6 expression levels and the major isoforms excluded the hypothesis that the deletions expressing extreme microphthalmia are directly due to the action of Pax6 and functionally different from intragenic null mutations. A region distinct from Pax6 containing eight genes was identified for belly spotting. A second region containing one gene (Rcn1) was identified for the extreme microphthalmia phenotype. Rcn1 is a Ca(+2)-binding protein, resident in the endoplasmic reticulum, participates in the secretory pathway and expressed in the eye. Our results suggest that deletion of Rcn1 directly or indirectly contributes to the eye phenotype in Pax6 contiguous gene deletions.
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Brandl C, Florian C, Driemel O, Weber BHF, Morsczeck C. Identification of neural crest-derived stem cell-like cells from the corneal limbus of juvenile mice. Exp Eye Res 2009; 89:209-17. [PMID: 19328783 DOI: 10.1016/j.exer.2009.03.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Revised: 02/25/2009] [Accepted: 03/18/2009] [Indexed: 11/17/2022]
Abstract
The neural crest is a transient embryonic tissue alongside the lateral margins of the neural folds. It contains cells involved in the development of anterior eye segments such as the cornea. Previous studies have revealed the presence of neural crest-derived stem cells in the cornea of the adult murine eye. However, less is known about cell populations of the developing eye. In this study, we have identified neural crest-derived murine corneal cells (MCCs) with stem cell-like properties derived from the corneal limbus of mice between postnatal days 1 and 8. RT-PCR analysis and immunofluorescence staining demonstrate that MCCs express a unique profile of markers including typical neural crest-originated stem cell transcripts like Sca1. MCCs show a limited self-renewing capacity but possess multipotency under in vitro conditions after differentiation into cells with features resembling adipocytes, osteoblasts and neuronal cells. Interestingly, MCCs could not be isolated from corneas of adult animals. We conclude that MCCs are stem cell-like cells of an early postnatal period of murine eye growth, probably involved in the early development of the postnatal cornea.
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Affiliation(s)
- Caroline Brandl
- Department of Operative Dentistry and Periodontology, Institute of Human Genetics, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany
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