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Torres-Dowdall J, Karagic N, Prabhukumar F, Meyer A. Differential Regulation of Opsin Gene Expression in Response to Internal and External Stimuli. Genome Biol Evol 2024; 16:evae125. [PMID: 38860496 DOI: 10.1093/gbe/evae125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 05/24/2024] [Accepted: 06/01/2024] [Indexed: 06/12/2024] Open
Abstract
Determining how internal and external stimuli interact to determine developmental trajectories of traits is a challenge that requires the integration of different subfields of biology. Internal stimuli, such as hormones, control developmental patterns of phenotypic changes, which might be modified by external environmental cues (e.g. plasticity). Thyroid hormone (TH) modulates the timing of opsin gene expression in developing Midas cichlid fish (Amphilophus citrinellus). Moreover, fish reared in red light accelerate this developmental timing compared to fish reared in white light. Hence, we hypothesized that plasticity caused by variation in light conditions has coopted the TH signaling pathway to induce changes in opsin gene expression. We treated Midas cichlids with TH and crossed this treatment with two light conditions, white and red. We observed that not only opsin expression responded similarly to TH and red light but also that, at high TH levels, there is limited capacity for light-induced plasticity. Transcriptomic analysis of the eye showed that genes in the TH pathway were affected by TH, but not by light treatments. Coexpression network analyses further suggested that response to light was independent of the response to TH manipulations. Taken together, our results suggest independent mechanisms mediating development and plasticity during development of opsin gene expression, and that responses to environmental stimuli may vary depending on internal stimuli. This conditional developmental response to external factors depending on internal ones (e.g. hormones) might play a fundamental role in the patterns of phenotypic divergence observed in Midas cichlids and potentially other organisms.
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Affiliation(s)
- Julián Torres-Dowdall
- Zoology and Evolutionary Biology, Department of Biology, University of Konstanz, Konstanz, Germany
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Nidal Karagic
- Zoology and Evolutionary Biology, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Femina Prabhukumar
- Zoology and Evolutionary Biology, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Axel Meyer
- Zoology and Evolutionary Biology, Department of Biology, University of Konstanz, Konstanz, Germany
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2
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Pan H, Qin Y, Zhu J, Wang W, Liu Z, Huang X, Lam SM, Shui G, Wang Y, Jiang Y, Huang X. Centrins control chicken cone cell lipid droplet dynamics through lipid-droplet-localized SPDL1. Dev Cell 2023; 58:2528-2544.e8. [PMID: 37699389 DOI: 10.1016/j.devcel.2023.08.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 05/10/2023] [Accepted: 08/08/2023] [Indexed: 09/14/2023]
Abstract
As evolutionarily conserved organelles, lipid droplets (LDs) carry out numerous functions and have various subcellular localizations in different cell types and species. In avian cone cells, there is a single apically localized LD. We demonstrated that CIDEA (cell death inducing DFFA like effector a) and microtubules promote the formation of the single LD in chicken cone cells. Centrins, which are well-known centriole proteins, target to the cone cell LD via their C-terminal calcium-binding domains. Centrins localize on cone cell LDs with the help of SPDL1-L (spindle apparatus coiled-coil protein 1-L), a previously uncharacterized isoform of the kinetochore-associated dynein adaptor SPDL1. The loss of CETN3 or overexpression of a truncated CETN1 abrogates the apical localization of the cone cell LD. Simulation analysis showed that multiple LDs or a single mispositioned LD reduces the light sensitivity. Collectively, our findings identify a role of centrins in the regulation of cone cell LD localization, which is important for the light sensitivity of cone cells.
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Affiliation(s)
- Huimin Pan
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yaqiang Qin
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinglin Zhu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhonghua Liu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiahe Huang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Sin Man Lam
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guanghou Shui
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yingchun Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuqiang Jiang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xun Huang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China; Tianjian Laboratory of Advanced Biomedical Sciences, Zhengzhou 450001, China.
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3
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Gesemann M, Neuhauss SCF. Evolution of visual guanylyl cyclases and their activating proteins with respect to clade and species-specific visual system adaptation. Front Mol Neurosci 2023; 16:1131093. [PMID: 37008786 PMCID: PMC10061024 DOI: 10.3389/fnmol.2023.1131093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Accepted: 02/27/2023] [Indexed: 03/18/2023] Open
Abstract
Membrane guanylyl cyclase receptors are important regulators of local cGMP production, critically influencing cell growth and differentiation as well as ion transport, blood pressure and calcium feedback of vertebrate phototransduction. Currently, seven different subtypes of membrane guanylyl cyclase receptors have been characterized. These receptors have tissue specific expression and are activated either by small extracellular ligands, changing CO2 concentrations or, in the case of visual guanylyl cyclases, intracellularly interacting Ca2+-dependent activating proteins. In this report, we focus on the visual guanylyl cyclase receptors (GCs) GC-E (gucy2d/e) and GC-F (gucy2f) and their activating proteins (GCAP1/2/3; guca1a/b/c). While gucy2d/e has been detected in all analyzed vertebrates, GC-F receptors are missing in several clades (reptiles, birds, and marsupials) and/or individual species. Interestingly, the absence of GC-F in highly visual sauropsida species with up to 4 different cone-opsins is compensated by an increased number of guanylyl cyclase activating proteins, whereas in nocturnal or visually impaired species with reduced spectral sensitivity it is consolidated by the parallel inactivation of these activators. In mammals, the presence of GC-E and GC-F is accompanied by the expression of one to three GCAPs, whereas in lizards and birds, up to five different GCAPs are regulating the activity of the single GC-E visual membrane receptor. In several nearly blind species, a single GC-E enzyme is often accompanied by a single variant of GCAP, suggesting that one cyclase and one activating protein are both sufficient and required for conferring the basic detection of light.
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4
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Angueyra JM, Kunze VP, Patak LK, Kim H, Kindt K, Li W. Transcription factors underlying photoreceptor diversity. eLife 2023; 12:e81579. [PMID: 36745553 PMCID: PMC9901936 DOI: 10.7554/elife.81579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 01/22/2023] [Indexed: 02/07/2023] Open
Abstract
During development, retinal progenitors navigate a complex landscape of fate decisions to generate the major cell classes necessary for proper vision. Transcriptional regulation is critical to generate diversity within these major cell classes. Here, we aim to provide the resources and techniques required to identify transcription factors necessary to generate and maintain diversity in photoreceptor subtypes, which are critical for vision. First, we generate a key resource: a high-quality and deep transcriptomic profile of each photoreceptor subtype in adult zebrafish. We make this resource openly accessible, easy to explore, and have integrated it with other currently available photoreceptor transcriptomic datasets. Second, using our transcriptomic profiles, we derive an in-depth map of expression of transcription factors in photoreceptors. Third, we use efficient CRISPR-Cas9 based mutagenesis to screen for null phenotypes in F0 larvae (F0 screening) as a fast, efficient, and versatile technique to assess the involvement of candidate transcription factors in the generation of photoreceptor subtypes. We first show that known phenotypes can be easily replicated using this method: loss of S cones in foxq2 mutants and loss of rods in nr2e3 mutants. We then identify novel functions for the transcription factor Tbx2, demonstrating that it plays distinct roles in controlling the generation of all photoreceptor subtypes within the retina. Our study provides a roadmap to discover additional factors involved in this process. Additionally, we explore four transcription factors of unknown function (Skor1a, Sall1a, Lrrfip1a, and Xbp1), and find no evidence for their involvement in the generation of photoreceptor subtypes. This dataset and screening method will be a valuable way to explore the genes involved in many other essential aspects of photoreceptor biology.
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Affiliation(s)
- Juan M Angueyra
- Unit of Retinal Neurophysiology, National Eye Institute, National Institutes of HealthBethesdaUnited States
| | - Vincent P Kunze
- Unit of Retinal Neurophysiology, National Eye Institute, National Institutes of HealthBethesdaUnited States
| | - Laura K Patak
- Unit of Retinal Neurophysiology, National Eye Institute, National Institutes of HealthBethesdaUnited States
| | - Hailey Kim
- Unit of Retinal Neurophysiology, National Eye Institute, National Institutes of HealthBethesdaUnited States
| | - Katie Kindt
- Section on Sensory Cell Development and Function, National Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaUnited States
| | - Wei Li
- Unit of Retinal Neurophysiology, National Eye Institute, National Institutes of HealthBethesdaUnited States
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5
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Toomey MB, Marques CI, Araújo PM, Huang D, Zhong S, Liu Y, Schreiner GD, Myers CA, Pereira P, Afonso S, Andrade P, Gazda MA, Lopes RJ, Viegas I, Koch RE, Haynes ME, Smith DJ, Ogawa Y, Murphy D, Kopec RE, Parichy DM, Carneiro M, Corbo JC. A mechanism for red coloration in vertebrates. Curr Biol 2022; 32:4201-4214.e12. [PMID: 36049480 PMCID: PMC9588406 DOI: 10.1016/j.cub.2022.08.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 06/19/2022] [Accepted: 08/08/2022] [Indexed: 12/14/2022]
Abstract
Red coloration is a salient feature of the natural world. Many vertebrates produce red color by converting dietary yellow carotenoids into red ketocarotenoids via an unknown mechanism. Here, we show that two enzymes, cytochrome P450 2J19 (CYP2J19) and 3-hydroxybutyrate dehydrogenase 1-like (BDH1L), are sufficient to catalyze this conversion. In birds, both enzymes are expressed at the sites of ketocarotenoid biosynthesis (feather follicles and red cone photoreceptors), and genetic evidence implicates these enzymes in yellow/red color variation in feathers. In fish, the homologs of CYP2J19 and BDH1L are required for ketocarotenoid production, and we show that these enzymes are sufficient to produce ketocarotenoids in cell culture and when ectopically expressed in fish skin. Finally, we demonstrate that the red-cone-enriched tetratricopeptide repeat protein 39B (TTC39B) enhances ketocarotenoid production when co-expressed with CYP2J19 and BDH1L. The discovery of this mechanism of ketocarotenoid biosynthesis has major implications for understanding the evolution of color diversity in vertebrates.
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Affiliation(s)
- Matthew B Toomey
- Department of Biological Science, University of Tulsa, Tulsa, OK, USA.
| | - Cristiana I Marques
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Universidade do Porto, Vairão, Portugal; BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, Portugal; Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - Pedro M Araújo
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Universidade do Porto, Vairão, Portugal; BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, Portugal; University of Coimbra, MARE - Marine and Environmental Sciences Centre, Department of Life Sciences, Coimbra, Portugal
| | - Delai Huang
- Department of Biology and Department of Cell Biology, University of Virginia, Charlottesville, VA, USA
| | - Siqiong Zhong
- Program in Human Nutrition, Department of Human Sciences, Ohio State University, Columbus, OH, USA
| | - Yu Liu
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, USA
| | - Gretchen D Schreiner
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, USA
| | - Connie A Myers
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, USA
| | - Paulo Pereira
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Universidade do Porto, Vairão, Portugal; BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, Portugal; Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - Sandra Afonso
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Universidade do Porto, Vairão, Portugal; BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, Portugal
| | - Pedro Andrade
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Universidade do Porto, Vairão, Portugal; BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, Portugal
| | - Małgorzata A Gazda
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Universidade do Porto, Vairão, Portugal
| | - Ricardo J Lopes
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Universidade do Porto, Vairão, Portugal; BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, Portugal; MHNC-UP, Natural History and Science Museum of the University of Porto, Porto, Portugal
| | - Ivan Viegas
- University of Coimbra, Centre for Functional Ecology, Department of Life Sciences, Coimbra, Portugal
| | - Rebecca E Koch
- Department of Biological Science, University of Tulsa, Tulsa, OK, USA
| | - Maureen E Haynes
- Department of Biological Science, University of Tulsa, Tulsa, OK, USA
| | - Dustin J Smith
- Department of Biological Science, University of Tulsa, Tulsa, OK, USA
| | - Yohey Ogawa
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, USA
| | - Daniel Murphy
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, USA
| | - Rachel E Kopec
- Program in Human Nutrition, Department of Human Sciences, Ohio State University, Columbus, OH, USA
| | - David M Parichy
- Department of Biology and Department of Cell Biology, University of Virginia, Charlottesville, VA, USA
| | - Miguel Carneiro
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Universidade do Porto, Vairão, Portugal; BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, Portugal.
| | - Joseph C Corbo
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, USA.
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6
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Liu F, Qin Y, Huang Y, Gao P, Li J, Yu S, Jia D, Chen X, Lv Y, Tu J, Sun K, Han Y, Reilly J, Shu X, Lu Q, Tang Z, Xu C, Luo D, Liu M. Rod genesis driven by mafba in an nrl knockout zebrafish model with altered photoreceptor composition and progressive retinal degeneration. PLoS Genet 2022; 18:e1009841. [PMID: 35245286 PMCID: PMC8926279 DOI: 10.1371/journal.pgen.1009841] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 03/16/2022] [Accepted: 02/17/2022] [Indexed: 12/25/2022] Open
Abstract
Neural retina leucine zipper (NRL) is an essential gene for the fate determination and differentiation of the precursor cells into rod photoreceptors in mammals. Mutations in NRL are associated with the autosomal recessive enhanced S-cone syndrome and autosomal dominant retinitis pigmentosa. However, the exact role of Nrl in regulating the development and maintenance of photoreceptors in the zebrafish (Danio rerio), a popular animal model used for retinal degeneration and regeneration studies, has not been fully determined. In this study, we generated an nrl knockout zebrafish model via the CRISPR-Cas9 technology and observed a surprising phenotype characterized by a reduced number, but not the total loss, of rods and over-growth of green cones. We discovered two waves of rod genesis, nrl-dependent and -independent at the embryonic and post-embryonic stages, respectively, in zebrafish by monitoring the rod development. Through bulk and single-cell RNA sequencing, we characterized the gene expression profiles of the whole retina and each retinal cell type from the wild type and nrl knockout zebrafish. The over-growth of green cones and mis-expression of green-cone-specific genes in rods in nrl mutants suggested that there are rod/green-cone bipotent precursors, whose fate choice between rod versus green-cone is controlled by nrl. Besides, we identified the mafba gene as a novel regulator of the nrl-independent rod development, based on the cell-type-specific expression patterns and the retinal phenotype of nrl/mafba double-knockout zebrafish. Gene collinearity analysis revealed the evolutionary origin of mafba and suggested that the function of mafba in rod development is specific to modern fishes. Furthermore, the altered photoreceptor composition and abnormal gene expression in nrl mutants caused progressive retinal degeneration and subsequent regeneration. Accordingly, this study revealed a novel function of the mafba gene in rod development and established a working model for the developmental and regulatory mechanisms regarding the rod and green-cone photoreceptors in zebrafish. Vision is mediated by two types of light-sensing cells named rod and cone photoreceptors in animal eyes. Abnormal generation, dysfunction or death of photoreceptor cells all cause irreversible vision problems. NRL is an essential gene for the generation and function of rod cells in mice and humans. Surprisingly, we found that in the zebrafish, a popular animal model for human diseases and therapeutic testing, there are two types of rod cells, and eliminating the function of nrl gene affects the rod cell formation at the embryonic stage but not at the juvenile and adult stages. The rod cell formation at the post-embryonic is driven by the mafba gene, which has not been reported to play a role in rod cells. In addition to the reduced number of rod cells, deletion of nrl also results in the emergence of rod/green-cone hybrid cells and an increased number of green cones. The ensuing cellular and molecular alterations collectively lead to retinal degeneration. These findings expand our understanding of photoreceptor development and maintenance and highlight the underlying conserved and species-specific regulatory mechanisms.
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Affiliation(s)
- Fei Liu
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P.R. China
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, The Innovative Academy of Seed Design, Hubei Hongshan Laboratory, Chinese Academy of Sciences, Wuhan, P.R. China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yayun Qin
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P.R. China
- Maternal and Child Health Hospital of Hubei Province, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Yuwen Huang
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Pan Gao
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Jingzhen Li
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Shanshan Yu
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Danna Jia
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Xiang Chen
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Yuexia Lv
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Jiayi Tu
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Kui Sun
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Yunqiao Han
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - James Reilly
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, Glasgow, United Kingdom
| | - Xinhua Shu
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, Glasgow, United Kingdom
| | - Qunwei Lu
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Zhaohui Tang
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P.R. China
| | - Chengqi Xu
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P.R. China
- * E-mail: (CX); (DL); (ML)
| | - Daji Luo
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, The Innovative Academy of Seed Design, Hubei Hongshan Laboratory, Chinese Academy of Sciences, Wuhan, P.R. China
- University of Chinese Academy of Sciences, Beijing, China
- * E-mail: (CX); (DL); (ML)
| | - Mugen Liu
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, P.R. China
- * E-mail: (CX); (DL); (ML)
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7
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Bery A, Bagchi U, Bergen AA, Felder-Schmittbuhl MP. Circadian clocks, retinogenesis and ocular health in vertebrates: new molecular insights. Dev Biol 2022; 484:40-56. [DOI: 10.1016/j.ydbio.2022.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 01/21/2022] [Accepted: 02/01/2022] [Indexed: 12/22/2022]
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8
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Gage E, Agarwal D, Chenault C, Washington-Brown K, Szvetecz S, Jahan N, Wang Z, Jones MK, Zack DJ, Enke RA, Wahlin KJ. Temporal and Isoform-Specific Expression of CTBP2 Is Evolutionarily Conserved Between the Developing Chick and Human Retina. Front Mol Neurosci 2022; 14:773356. [PMID: 35095414 PMCID: PMC8793361 DOI: 10.3389/fnmol.2021.773356] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 11/08/2021] [Indexed: 11/13/2022] Open
Abstract
Complex transcriptional gene regulation allows for multifaceted isoform production during retinogenesis, and novel isoforms transcribed from a single locus can have unlimited potential to code for diverse proteins with different functions. In this study, we explored the CTBP2/RIBEYE gene locus and its unique repertoire of transcripts that are conserved among vertebrates. We studied the transcriptional coregulator (CTBP2) and ribbon synapse-specific structural protein (RIBEYE) in the chicken retina by performing comprehensive histochemical and sequencing analyses to pinpoint cell and developmental stage-specific expression of CTBP2/RIBEYE in the developing chicken retina. We demonstrated that CTBP2 is widely expressed in retinal progenitors beginning in early retinogenesis but becomes limited to GABAergic amacrine cells in the mature retina. Inversely, RIBEYE is initially epigenetically silenced in progenitors and later expressed in photoreceptor and bipolar cells where they localize to ribbon synapses. Finally, we compared CTBP2/RIBEYE regulation in the developing human retina using a pluripotent stem cell derived retinal organoid culture system. These analyses demonstrate that similar regulation of the CTBP2/RIBEYE locus during chick and human retinal development is regulated by different members of the K50 homeodomain transcription factor family.
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Affiliation(s)
- Elizabeth Gage
- Department of Biology, James Madison University, Harrisonburg, VA, United States
| | - Devansh Agarwal
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, United States
- Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California, San Diego, La Jolla, CA, United States
| | - Calvin Chenault
- Department of Biology, James Madison University, Harrisonburg, VA, United States
| | | | - Sarah Szvetecz
- Department of Mathematics & Statistics, James Madison University, Harrisonburg, VA, United States
| | - Nusrat Jahan
- Department of Mathematics & Statistics, James Madison University, Harrisonburg, VA, United States
- The Center for Genome & Metagenome Studies, James Madison University, Harrisonburg, VA, United States
| | - Zixiao Wang
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Melissa K. Jones
- Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California, San Diego, La Jolla, CA, United States
| | - Donald J. Zack
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Ray A. Enke
- Department of Biology, James Madison University, Harrisonburg, VA, United States
- The Center for Genome & Metagenome Studies, James Madison University, Harrisonburg, VA, United States
| | - Karl J. Wahlin
- Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California, San Diego, La Jolla, CA, United States
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9
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Lonfat N, Wang S, Lee C, Garcia M, Choi J, Park PJ, Cepko C. Cis-regulatory dissection of cone development reveals a broad role for Otx2 and Oc transcription factors. Development 2021; 148:261747. [PMID: 33929509 DOI: 10.1242/dev.198549] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 03/31/2021] [Indexed: 11/20/2022]
Abstract
The vertebrate retina is generated by retinal progenitor cells (RPCs), which produce >100 cell types. Although some RPCs produce many cell types, other RPCs produce restricted types of daughter cells, such as a cone photoreceptor and a horizontal cell (HC). We used genome-wide assays of chromatin structure to compare the profiles of a restricted cone/HC RPC and those of other RPCs in chicks. These data nominated regions of regulatory activity, which were tested in tissue, leading to the identification of many cis-regulatory modules (CRMs) active in cone/HC RPCs and developing cones. Two transcription factors, Otx2 and Oc1, were found to bind to many of these CRMs, including those near genes important for cone development and function, and their binding sites were required for activity. We also found that Otx2 has a predicted autoregulatory CRM. These results suggest that Otx2, Oc1 and possibly other Onecut proteins have a broad role in coordinating cone development and function. The many newly discovered CRMs for cones are potentially useful reagents for gene therapy of cone diseases.
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Affiliation(s)
- Nicolas Lonfat
- Department of Genetics, Blavatnik Institute; Harvard Medical School, Boston, MA 02115, USA.,Department of Ophthalmology, Blavatnik Institute; Harvard Medical School, Boston, MA 02115, USA
| | - Su Wang
- Department of Biomedical Informatics, Blavatnik Institute; Harvard Medical School, Boston, MA 02115, USA
| | - ChangHee Lee
- Department of Genetics, Blavatnik Institute; Harvard Medical School, Boston, MA 02115, USA
| | - Mauricio Garcia
- Department of Genetics, Blavatnik Institute; Harvard Medical School, Boston, MA 02115, USA.,Department of Ophthalmology, Blavatnik Institute; Harvard Medical School, Boston, MA 02115, USA
| | - Jiho Choi
- Department of Genetics, Blavatnik Institute; Harvard Medical School, Boston, MA 02115, USA.,Department of Ophthalmology, Blavatnik Institute; Harvard Medical School, Boston, MA 02115, USA
| | - Peter J Park
- Department of Biomedical Informatics, Blavatnik Institute; Harvard Medical School, Boston, MA 02115, USA
| | - Connie Cepko
- Department of Genetics, Blavatnik Institute; Harvard Medical School, Boston, MA 02115, USA.,Department of Ophthalmology, Blavatnik Institute; Harvard Medical School, Boston, MA 02115, USA.,Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
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10
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Yamagata M, Yan W, Sanes JR. A cell atlas of the chick retina based on single-cell transcriptomics. eLife 2021; 10:e63907. [PMID: 33393903 PMCID: PMC7837701 DOI: 10.7554/elife.63907] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 01/01/2021] [Indexed: 12/14/2022] Open
Abstract
Retinal structure and function have been studied in many vertebrate orders, but molecular characterization has been largely confined to mammals. We used single-cell RNA sequencing (scRNA-seq) to generate a cell atlas of the chick retina. We identified 136 cell types plus 14 positional or developmental intermediates distributed among the six classes conserved across vertebrates - photoreceptor, horizontal, bipolar, amacrine, retinal ganglion, and glial cells. To assess morphology of molecularly defined types, we adapted a method for CRISPR-based integration of reporters into selectively expressed genes. For Müller glia, we found that transcriptionally distinct cells were regionally localized along the anterior-posterior, dorsal-ventral, and central-peripheral retinal axes. We also identified immature photoreceptor, horizontal cell, and oligodendrocyte types that persist into late embryonic stages. Finally, we analyzed relationships among chick, mouse, and primate retinal cell classes and types. Our results provide a foundation for anatomical, physiological, evolutionary, and developmental studies of the avian visual system.
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Affiliation(s)
- Masahito Yamagata
- Center for Brain Science and Department of Molecular and Cellular Biology, Harvard UniversityCambridgeUnited States
| | - Wenjun Yan
- Center for Brain Science and Department of Molecular and Cellular Biology, Harvard UniversityCambridgeUnited States
| | - Joshua R Sanes
- Center for Brain Science and Department of Molecular and Cellular Biology, Harvard UniversityCambridgeUnited States
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11
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Enright JM, Zhang S, Thebeau C, Siebert E, Jin A, Gadiraju V, Zhang X, Chen S, Semenkovich CF, Rajagopal R. Fenofibrate Reduces the Severity of Neuroretinopathy in a Type 2 Model of Diabetes without Inducing Peroxisome Proliferator-Activated Receptor Alpha-Dependent Retinal Gene Expression. J Clin Med 2020; 10:jcm10010126. [PMID: 33396512 PMCID: PMC7794763 DOI: 10.3390/jcm10010126] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/27/2020] [Accepted: 12/09/2020] [Indexed: 12/11/2022] Open
Abstract
Fenofibrate slows the progression of clinical diabetic retinopathy (DR), but its mechanism of action in the retina remains unclear. Fenofibrate is a known agonist of peroxisome proliferator-activated receptor alpha (PPARα), a transcription factor critical for regulating metabolism, inflammation and oxidative stress. Using a DR mouse model, db/db, we tested the hypothesis that fenofibrate slows early DR progression by activating PPARα in the retina. Relative to healthy littermates, six-month-old db/db mice exhibited elevated serum triglycerides and cholesterol, retinal gliosis, and electroretinography (ERG) changes including reduced b-wave amplitudes and delayed oscillatory potentials. These pathologic changes in the retina were improved by oral fenofibrate. However, fenofibrate did not induce PPARα target gene expression in whole retina or isolated Müller glia. The capacity of the retina to respond to PPARα was further tested by delivering the PPARα agonist GW590735 to the intraperitoneal or intravitreous space in mice carrying the peroxisome proliferator response element (PPRE)-luciferase reporter. We observed strong induction of the reporter in the liver, but no induction in the retina. In summary, fenofibrate treatment of db/db mice prevents the development of early DR but is not associated with induction of PPARα in the retina.
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Affiliation(s)
- Jennifer M. Enright
- John F. Hardesty Department of Ophthalmology, Washington University in St. Louis, St. Louis, MO 63110, USA; (J.M.E.); (S.Z.); (C.T.); (X.Z.); (S.C.)
| | - Sheng Zhang
- John F. Hardesty Department of Ophthalmology, Washington University in St. Louis, St. Louis, MO 63110, USA; (J.M.E.); (S.Z.); (C.T.); (X.Z.); (S.C.)
| | - Christina Thebeau
- John F. Hardesty Department of Ophthalmology, Washington University in St. Louis, St. Louis, MO 63110, USA; (J.M.E.); (S.Z.); (C.T.); (X.Z.); (S.C.)
| | - Emily Siebert
- Department of Pediatrics, UT Southwestern Medical Center, Dallas, TX 75390, USA;
| | - Alexander Jin
- St. Louis University School of Medicine, St. Louis, MO 63104, USA;
| | - Veda Gadiraju
- University of Washington Medical School, Seattle, WA 98195, USA;
| | - Xiaodong Zhang
- John F. Hardesty Department of Ophthalmology, Washington University in St. Louis, St. Louis, MO 63110, USA; (J.M.E.); (S.Z.); (C.T.); (X.Z.); (S.C.)
| | - Shiming Chen
- John F. Hardesty Department of Ophthalmology, Washington University in St. Louis, St. Louis, MO 63110, USA; (J.M.E.); (S.Z.); (C.T.); (X.Z.); (S.C.)
| | - Clay F. Semenkovich
- Division of Endocrinology, Metabolism and Lipid Research, Washington University in St. Louis, St. Louis, MO 63110, USA;
| | - Rithwick Rajagopal
- John F. Hardesty Department of Ophthalmology, Washington University in St. Louis, St. Louis, MO 63110, USA; (J.M.E.); (S.Z.); (C.T.); (X.Z.); (S.C.)
- Correspondence:
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12
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Oel AP, Neil GJ, Dong EM, Balay SD, Collett K, Allison WT. Nrl Is Dispensable for Specification of Rod Photoreceptors in Adult Zebrafish Despite Its Deeply Conserved Requirement Earlier in Ontogeny. iScience 2020; 23:101805. [PMID: 33299975 PMCID: PMC7702016 DOI: 10.1016/j.isci.2020.101805] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 10/06/2020] [Accepted: 11/10/2020] [Indexed: 12/11/2022] Open
Abstract
The transcription factor NRL (neural retina leucine zipper) has been canonized as the master regulator of photoreceptor cell fate in the retina. NRL is necessary and sufficient to specify rod cell fate and to preclude cone cell fate in mice. By engineering zebrafish, we tested if NRL function has conserved roles beyond mammals or beyond nocturnal species, i.e., in a vertebrate possessing a greater and more typical diversity of cone sub-types. Transgenic expression of Nrl from zebrafish or mouse was sufficient to induce rod photoreceptor cells. Zebrafish nrl−/− mutants lacked rods (and had excess UV-sensitive cones) as young larvae; thus, the conservation of Nrl function between mice and zebrafish appears sound. Strikingly, however, rods were abundant in adult nrl−/− null mutant zebrafish. Rods developed in adults despite Nrl protein being undetectable. Therefore, a yet-to-be-revealed non-canonical pathway independent of Nrl is able to specify the fate of some rod photoreceptors. Nrl is conserved and sufficient to specify rod photoreceptors in the zebrafish retina Nrl is necessary for rod photoreceptors in early ontogeny of zebrafish larvae Zebrafish Nrl is functionally conserved with mouse and human NRL Remarkably, Nrl is dispensable for rod specification in adult zebrafish
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Affiliation(s)
- A Phillip Oel
- Department of Biological Sciences, University of Alberta, Edmonton AB, T7Y 1C4, Canada
| | - Gavin J Neil
- Department of Biological Sciences, University of Alberta, Edmonton AB, T7Y 1C4, Canada
| | - Emily M Dong
- Department of Biological Sciences, University of Alberta, Edmonton AB, T7Y 1C4, Canada
| | - Spencer D Balay
- Department of Biological Sciences, University of Alberta, Edmonton AB, T7Y 1C4, Canada
| | - Keon Collett
- Department of Biological Sciences, University of Alberta, Edmonton AB, T7Y 1C4, Canada
| | - W Ted Allison
- Department of Biological Sciences, University of Alberta, Edmonton AB, T7Y 1C4, Canada.,Department of Medical Genetics, University of Alberta, Edmonton AB, T6G 2R3, Canada
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13
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Schumacker ST, Coppage KR, Enke RA. RNA sequencing analysis of the human retina and associated ocular tissues. Sci Data 2020; 7:199. [PMID: 32581312 PMCID: PMC7314755 DOI: 10.1038/s41597-020-0541-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 06/02/2020] [Indexed: 11/08/2022] Open
Abstract
The retina is a stratified layer of sensory neurons lining the posterior portion of the eye. In humans, fine detail and color vision are enabled by the macula, a central region of the retina dense in cone photoreceptors (PRs). Achromatic low light and peripheral vision are facilitated by rod PRs found with increasing density outside the macula in the peripheral retina. The outer retina is nourished by choroidal blood flow regulated by a single layer of intervening retinal pigment epithelial (RPE) cells. Existing human retinal transcriptome projects have been critical for studying aspects of retinal development and disease however, there are currently no publicly available data sets accurately describing the aging human central retina, peripheral retina, and supporting RPE/choroid. Here we used Illumina RNA sequencing (RNA-seq) analysis to characterize the mRNA transcriptome of rod and cone PR-enriched human retina as well as supporting macular RPE/choroid tissue. These data will be valuable to the vision research community for characterizing global changes in gene expression in clinically relevant ocular tissues.
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Affiliation(s)
- Scott T Schumacker
- Department of Biology, James Madison University, Harrisonburg, VA, 22807, USA
| | - Krista R Coppage
- Department of Biology, James Madison University, Harrisonburg, VA, 22807, USA
| | - Ray A Enke
- Department of Biology, James Madison University, Harrisonburg, VA, 22807, USA.
- Center for Genome & Metagenome Studies, James Madison University, Harrisonburg, VA, 22807, USA.
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14
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Thyroid hormone receptors mediate two distinct mechanisms of long-wavelength vision. Proc Natl Acad Sci U S A 2020; 117:15262-15269. [PMID: 32541022 DOI: 10.1073/pnas.1920086117] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Thyroid hormone (TH) signaling plays an important role in the regulation of long-wavelength vision in vertebrates. In the retina, thyroid hormone receptor β (thrb) is required for expression of long-wavelength-sensitive opsin (lws) in red cone photoreceptors, while in retinal pigment epithelium (RPE), TH regulates expression of a cytochrome P450 enzyme, cyp27c1, that converts vitamin A1 into vitamin A2 to produce a red-shifted chromophore. To better understand how TH controls these processes, we analyzed the phenotype of zebrafish with mutations in the three known TH nuclear receptor transcription factors (thraa, thrab, and thrb). We found that no single TH nuclear receptor is required for TH-mediated induction of cyp27c1 but that deletion of all three (thraa -/- ;thrab -/- ;thrb -/- ) completely abrogates its induction and the resulting conversion of A1- to A2-based retinoids. In the retina, loss of thrb resulted in an absence of red cones at both larval and adult stages without disruption of the underlying cone mosaic. RNA-sequencing analysis revealed significant down-regulation of only five genes in adult thrb -/- retina, of which three (lws1, lws2, and miR-726) occur in a single syntenic cluster. In the thrb -/- retina, retinal progenitors destined to become red cones were transfated into ultraviolet (UV) cones and horizontal cells. Taken together, our findings demonstrate cooperative regulation of cyp27c1 by TH receptors and a requirement for thrb in red cone fate determination. Thus, TH signaling coordinately regulates both spectral sensitivity and sensory plasticity.
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15
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Gazda MA, Araújo PM, Lopes RJ, Toomey MB, Andrade P, Afonso S, Marques C, Nunes L, Pereira P, Trigo S, Hill GE, Corbo JC, Carneiro M. A genetic mechanism for sexual dichromatism in birds. Science 2020; 368:1270-1274. [DOI: 10.1126/science.aba0803] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Accepted: 04/10/2020] [Indexed: 12/13/2022]
Abstract
Sexual dichromatism, a difference in coloration between males and females, may be due to sexual selection for ornamentation and mate choice. Here, we show that carotenoid-based dichromatism in mosaic canaries, a hybrid phenotype that arises in offspring of the sexually dichromatic red siskin and monochromatic canaries, is controlled by the gene that encodes the carotenoid-cleaving enzyme β-carotene oxygenase 2 (BCO2). Dichromatism in mosaic canaries is explained by differential carotenoid degradation in the integument, rather than sex-specific variation in physiological functions such as pigment uptake or transport. Transcriptome analyses suggest that carotenoid degradation in the integument might be a common mechanism contributing to sexual dichromatism across finches. These results suggest that differences in ornamental coloration between sexes can evolve through simple molecular mechanisms controlled by genes of major effect.
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Affiliation(s)
- Małgorzata A. Gazda
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Universidade do Porto, 4485-661 Vairão, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - Pedro M. Araújo
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Universidade do Porto, 4485-661 Vairão, Portugal
- MARE – Marine and Environmental Sciences Centre, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Ricardo J. Lopes
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Universidade do Porto, 4485-661 Vairão, Portugal
| | - Matthew B. Toomey
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Biological Science, University of Tulsa, Tulsa, OK 74104, USA
| | - Pedro Andrade
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Universidade do Porto, 4485-661 Vairão, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - Sandra Afonso
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Universidade do Porto, 4485-661 Vairão, Portugal
| | - Cristiana Marques
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Universidade do Porto, 4485-661 Vairão, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - Luís Nunes
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - Paulo Pereira
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Universidade do Porto, 4485-661 Vairão, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - Sandra Trigo
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Universidade do Porto, 4485-661 Vairão, Portugal
| | - Geoffrey E. Hill
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Joseph C. Corbo
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Miguel Carneiro
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Universidade do Porto, 4485-661 Vairão, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
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16
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Buenaventura DF, Corseri A, Emerson MM. Identification of Genes With Enriched Expression in Early Developing Mouse Cone Photoreceptors. Invest Ophthalmol Vis Sci 2019; 60:2787-2799. [PMID: 31260032 PMCID: PMC6607928 DOI: 10.1167/iovs.19-26951] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Purpose The early transcriptional events that occur in newly generated cone photoreceptors are not well described. Knowledge of these events is critical to provide benchmarks for in vitro-derived cone photoreceptors and to understand the process of cone and rod photoreceptor diversification. We sought to identify genes with differential gene expression in embryonic mouse cone photoreceptors. Methods The specificity of expression of the LHX4 transcription factor in developing cone photoreceptors was examined using immunofluorescence visualization in both mouse and chicken retinas. A LHX4 transgenic reporter line with high specificity for developing mouse cone photoreceptors was identified and used to purify early-stage cone photoreceptors for profiling by single-cell RNA sequencing. Comparisons were made to previous datasets targeting photoreceptors. Results The LHX4 transcription factor and a transgenic reporter were determined to be highly specific to early developing cone photoreceptors in the mouse. Single-cell transcriptional profiling identified new genes with enriched expression in cone photoreceptors relative to concurrent cell populations. Comparison to previous profiling datasets allowed for further characterization of these genes across developmental time, species, photoreceptor type, and gene regulatory network. Conclusions The LHX4 gene is highly enriched in developing cone photoreceptors as are several new genes identified through transcriptional profiling, some of which are expressed in subclusters of cones. Many of these cone-enriched genes do not show obvious de-repression in profiling of retinas mutant for the rod-specific transcription factor NRL, highlighting differences between endogenous cones and those induced in NRL mutants.
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Affiliation(s)
- Diego F Buenaventura
- Department of Biology, The City College of New York, City University of New York, New York, New York, United States.,Biology PhD Program, Graduate Center, City University of New York, New York, New York, United States
| | - Adrianne Corseri
- Department of Biology, The City College of New York, City University of New York, New York, New York, United States
| | - Mark M Emerson
- Department of Biology, The City College of New York, City University of New York, New York, New York, United States.,Biology PhD Program, Graduate Center, City University of New York, New York, New York, United States.,Biochemistry PhD Program, Graduate Center, City University of New York, New York, New York, United States
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17
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Blond F, Léveillard T. Functional Genomics of the Retina to Elucidate its Construction and Deconstruction. Int J Mol Sci 2019; 20:E4922. [PMID: 31590277 PMCID: PMC6801968 DOI: 10.3390/ijms20194922] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 10/01/2019] [Indexed: 12/20/2022] Open
Abstract
The retina is the light sensitive part of the eye and nervous tissue that have been used extensively to characterize the function of the central nervous system. The retina has a central position both in fundamental biology and in the physiopathology of neurodegenerative diseases. We address the contribution of functional genomics to the understanding of retinal biology by reviewing key events in their historical perspective as an introduction to major findings that were obtained through the study of the retina using genomics, transcriptomics and proteomics. We illustrate our purpose by showing that most of the genes of interest for retinal development and those involved in inherited retinal degenerations have a restricted expression to the retina and most particularly to photoreceptors cells. We show that the exponential growth of data generated by functional genomics is a future challenge not only in terms of storage but also in terms of accessibility to the scientific community of retinal biologists in the future. Finally, we emphasize on novel perspectives that emerge from the development of redox-proteomics, the new frontier in retinal biology.
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Affiliation(s)
- Frédéric Blond
- Department of Genetics, Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, F-75012 Paris, France.
| | - Thierry Léveillard
- Department of Genetics, Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, F-75012 Paris, France.
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18
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Lukowski SW, Lo CY, Sharov AA, Nguyen Q, Fang L, Hung SS, Zhu L, Zhang T, Grünert U, Nguyen T, Senabouth A, Jabbari JS, Welby E, Sowden JC, Waugh HS, Mackey A, Pollock G, Lamb TD, Wang PY, Hewitt AW, Gillies MC, Powell JE, Wong RC. A single-cell transcriptome atlas of the adult human retina. EMBO J 2019; 38:e100811. [PMID: 31436334 DOI: 10.15252/embj.2018100811] [Citation(s) in RCA: 153] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 07/29/2019] [Accepted: 07/31/2019] [Indexed: 01/12/2023] Open
Abstract
The retina is a specialized neural tissue that senses light and initiates image processing. Although the functional organization of specific retina cells has been well studied, the molecular profile of many cell types remains unclear in humans. To comprehensively profile the human retina, we performed single-cell RNA sequencing on 20,009 cells from three donors and compiled a reference transcriptome atlas. Using unsupervised clustering analysis, we identified 18 transcriptionally distinct cell populations representing all known neural retinal cells: rod photoreceptors, cone photoreceptors, Müller glia, bipolar cells, amacrine cells, retinal ganglion cells, horizontal cells, astrocytes, and microglia. Our data captured molecular profiles for healthy and putative early degenerating rod photoreceptors, and revealed the loss of MALAT1 expression with longer post-mortem time, which potentially suggested a novel role of MALAT1 in rod photoreceptor degeneration. We have demonstrated the use of this retina transcriptome atlas to benchmark pluripotent stem cell-derived cone photoreceptors and an adult Müller glia cell line. This work provides an important reference with unprecedented insights into the transcriptional landscape of human retinal cells, which is fundamental to understanding retinal biology and disease.
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Affiliation(s)
- Samuel W Lukowski
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Qld, Australia
| | - Camden Y Lo
- Monash University, Melbourne, Vic., Australia
| | - Alexei A Sharov
- National Institute for Aging, National Institutes of Health, Baltimore, MD, USA
| | - Quan Nguyen
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Qld, Australia
| | - Lyujie Fang
- Centre for Eye Research Australia, Melbourne, Vic., Australia.,Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Vic., Australia.,Jinan University, Guangzhou, China
| | - Sandy Sc Hung
- Centre for Eye Research Australia, Melbourne, Vic., Australia.,Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Vic., Australia
| | - Ling Zhu
- The University of Sydney, Faculty of Medicine, Save Sight Institute, Sydney, NSW, Australia
| | - Ting Zhang
- The University of Sydney, Faculty of Medicine, Save Sight Institute, Sydney, NSW, Australia
| | - Ulrike Grünert
- The University of Sydney, Faculty of Medicine, Save Sight Institute, Sydney, NSW, Australia
| | - Tu Nguyen
- Centre for Eye Research Australia, Melbourne, Vic., Australia.,Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Vic., Australia
| | - Anne Senabouth
- Garvan-Weizmann Centre for Cellular Genomics, Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Jafar S Jabbari
- Australian Genome Research Facility, Melbourne, Vic., Australia
| | - Emily Welby
- Stem Cells and Regenerative Medicine Section, NIHR Great Ormond Street Hospital Biomedical Research Centre, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Jane C Sowden
- Stem Cells and Regenerative Medicine Section, NIHR Great Ormond Street Hospital Biomedical Research Centre, UCL Great Ormond Street Institute of Child Health, London, UK
| | | | | | | | - Trevor D Lamb
- John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - Peng-Yuan Wang
- Department of Chemistry and Biotechnology, Swinburne University of Technology, Melbourne, Vic., Australia.,Center for Human Tissues and Organs Degeneration, Institute of Biomedicine and Biotechnology, Shenzhen Institute of Advanced Technology, Chinese Academy of Science, Shenzhen, China
| | - Alex W Hewitt
- Centre for Eye Research Australia, Melbourne, Vic., Australia.,Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Vic., Australia.,Menzies Institute for Medical Research, University of Tasmania, Hobart, Tas., Australia
| | - Mark C Gillies
- The University of Sydney, Faculty of Medicine, Save Sight Institute, Sydney, NSW, Australia
| | - Joseph E Powell
- Garvan-Weizmann Centre for Cellular Genomics, Garvan Institute of Medical Research, Sydney, NSW, Australia.,UNSW Cellular Genomics Futures Institute, University of New South Wales, Sydney, NSW, Australia
| | - Raymond Cb Wong
- Centre for Eye Research Australia, Melbourne, Vic., Australia.,Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Vic., Australia.,Shenzhen Eye Hospital, Shenzhen University School of Medicine, Shenzhen, China
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19
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Lineage tracing analysis of cone photoreceptor associated cis-regulatory elements in the developing chicken retina. Sci Rep 2019; 9:9358. [PMID: 31249345 PMCID: PMC6597718 DOI: 10.1038/s41598-019-45750-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 06/14/2019] [Indexed: 02/02/2023] Open
Abstract
During vertebrate retinal development, transient populations of retinal progenitor cells with restricted cell fate choices are formed. One of these progenitor populations expresses the Thrb gene and can be identified by activity of the ThrbCRM1 cis-regulatory element. Short-term assays have concluded that these cells preferentially generate cone photoreceptors and horizontal cells, however developmental timing has precluded an extensive cell type characterization of their progeny. Here we describe the development and validation of a recombinase-based lineage tracing system for the chicken embryo to further characterize the lineage of these cells. The ThrbCRM1 element was found to preferentially form photoreceptors and horizontal cells, as well as a small number of retinal ganglion cells. The photoreceptor cell progeny are exclusively cone photoreceptors and not rod photoreceptors, confirming that ThrbCRM1 progenitor cells are restricted from the rod fate. In addition, specific subtypes of horizontal cells and retinal ganglion cells were overrepresented, suggesting that ThrbCRM1 progenitor cells are not only restricted for cell type, but for cell subtype as well.
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DuVal MG, Allison WT. Photoreceptor Progenitors Depend Upon Coordination of gdf6a, thrβ, and tbx2b to Generate Precise Populations of Cone Photoreceptor Subtypes. Invest Ophthalmol Vis Sci 2019; 59:6089-6101. [PMID: 30592497 DOI: 10.1167/iovs.18-24461] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Replacing cone photoreceptors, the units of the retina necessary for daytime vision, depends upon the successful production of a full variety of new cones from, for example, stem cells. Using genetic experiments in a model organism with high cone diversity, zebrafish, we map the intersecting effects of cone development factors gdf6a, tbx2b, and thrβ. Methods We investigated these genes of interest by using genetic combinations of mutants, gene knockdown, and dominant negative gene expression, and then quantified cone subtype outcomes (which normally develop in tightly regulated ratios). Results Gdf6a mutants have reduced blue cones and, discovered here, reduced red cones. In combined gdf6a/tbx2b disruption, the loss of gdf6a in heterozygous tbx2b mutants reduced UV cones. Intriguingly, when we disrupted thrβ in gdf6a mutants by using a thrβ morpholino, their combined early disruption revealed a lamination phenotype. Disrupting thrβ activity via expression of a dominant negative thrβ (dnthrβ) at either early or late retinal development had differential outcomes on red cones (reduced abundance), versus UV and blue cones (increased abundance). By using dnthrβ in gdf6a mutants, we revealed that disrupting thrβ activity did not change gdf6a mutant cone phenotypes. Conclusions Gdf6a loss directly affects blue and red cones and indirectly affects UV cones by increasing sensitivity to additional disruption, such as reduced tbx2b, resulting in fewer UV cones. The effects of thrβ change through photoreceptor development, first promoting red cones and restricting UV cones, and later restricting UV and blue cones. The effects of gdf6a on UV, blue, and red cone development overlap with, but likely supersede, those of thrβ.
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Affiliation(s)
- Michèle G DuVal
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - W Ted Allison
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.,Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada.,Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
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Six6 and Six7 coordinately regulate expression of middle-wavelength opsins in zebrafish. Proc Natl Acad Sci U S A 2019; 116:4651-4660. [PMID: 30765521 PMCID: PMC6410792 DOI: 10.1073/pnas.1812884116] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Color discrimination in the vertebrate retina is mediated by a combination of cone cell types expressing UV (SWS1), blue (SWS2), green (RH2), and red (LWS) opsins. Although the tetrachromatic cone system is retained in most nonmammalian vertebrate lineages, the transcriptional mechanism underlying gene expression of cone opsins remains elusive. Here, we found that the retinal transcription factors, sine oculis homeobox 6 (Six6b) and Six7, synergistically and positively regulate gene expression of zebrafish SWS2 and RH2 opsins. Larvae deficient for both of these transcription factors showed heavily impaired visually driven foraging behavior and were unable to compete for food when reared in a group with normal siblings. The results suggest that six6b and six7 play a pivotal role in blue- and green-light sensitivity and daylight vision. Color discrimination in the vertebrate retina is mediated by a combination of spectrally distinct cone photoreceptors, each expressing one of multiple cone opsins. The opsin genes diverged early in vertebrate evolution into four classes maximally sensitive to varying wavelengths of light: UV (SWS1), blue (SWS2), green (RH2), and red (LWS) opsins. Although the tetrachromatic cone system is retained in most nonmammalian vertebrate lineages, the transcriptional mechanism underlying gene expression of the cone opsins remains elusive, particularly for SWS2 and RH2 opsins, both of which have been lost in the mammalian lineage. In zebrafish, which have all four cone subtypes, rh2 opsin gene expression depends on a homeobox transcription factor, sine oculis homeobox 7 (Six7). However, the six7 gene is found only in the ray-finned fish lineage, suggesting the existence of another evolutionarily conserved transcriptional factor(s) controlling rh2 opsin expression in vertebrates. Here, we found that the reduced rh2 expression caused by six7 deficiency was rescued by forced expression of six6b, which is a six7-related transcription factor conserved widely among vertebrates. The compensatory role of six6b was reinforced by ChIP-sequencing analysis, which revealed a similar pattern of Six6b- and Six7-binding sites within and near the cone opsin genes. TAL effector nuclease-induced genetic ablation of six6b and six7 revealed that they coordinately regulate SWS2 opsin gene expression. Mutant larvae deficient for these transcription factors showed severely impaired visually driven foraging behavior. These results demonstrate that in zebrafish, six6b and six7 govern expression of the SWS2 and RH2 opsins responsible for middle-wavelength sensitivity, which would be physiologically important for daylight vision.
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Jean-Charles N, Buenaventura DF, Emerson MM. Identification and characterization of early photoreceptor cis-regulatory elements and their relation to Onecut1. Neural Dev 2018; 13:26. [PMID: 30466480 PMCID: PMC6251108 DOI: 10.1186/s13064-018-0121-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 10/31/2018] [Indexed: 12/19/2022] Open
Abstract
Background Cone and rod photoreceptors are two of the primary cell types affected in human retinal disease. Potential strategies to combat these diseases are the use of gene therapy to rescue compromised photoreceptors or to generate new functional photoreceptors to replace those lost in the diseased retina. Cis-regulatory elements specific to cones, rods, or both types of photoreceptors are critical components of successful implementation of these two strategies. The purpose of this study was to identify and characterize the cell type specificity and activity of cis-regulatory elements active in developing photoreceptors. Methods Cis-regulatory elements were introduced into the developing chicken and mouse retina by electroporation. Characterization of reporter activity in relation with cell type markers was determined using confocal microscopy. In addition, two high-throughput flow cytometry assay were developed to assess whether these elements were downstream of Onecut1 in the photoreceptor specification network. Results The majority of cis-regulatory elements were active in both cone and rod photoreceptors and were largely uninfluenced by a Onecut1 dominant-negative construct. Elements associated with the Thrb, Nr2e3, and Rhodopsin genes showed highly enriched activity in cones or rods, and were affected by interference in Onecut1 signaling. Rhodopsin promoter activity was the most highly influenced by Onecut1 activity and its induction could be modulated by the Maf family transcription factor L-Maf. Nr2e3 elements were observed to have activity in cone photoreceptors and Nr2e3 protein was expressed in developing cone photoreceptors, suggesting a role for this predominant rod gene in cone photoreceptor development. Conclusions The analysis presented here provides an experimental framework to determine the specificity and strength of photoreceptor elements within specific genetic networks during development. The Onecut1 transcription factor is one such factor that influences the gene regulatory networks specific to cones and rods, but not those that are common to both. Electronic supplementary material The online version of this article (10.1186/s13064-018-0121-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Nathalie Jean-Charles
- Department of Biology, The City College of New York, City University of New York, New York, NY, 10031, USA.,Current Address: The Public Health Laboratory, NYC Department of Health and Mental Hygeine, New York, NY, 10016, USA
| | - Diego F Buenaventura
- Department of Biology, The City College of New York, City University of New York, New York, NY, 10031, USA.,Biology Ph.D. Program, Graduate Center, City University of New York, New York, NY, 10031, USA
| | - Mark M Emerson
- Department of Biology, The City College of New York, City University of New York, New York, NY, 10031, USA. .,Biology Ph.D. Program, Graduate Center, City University of New York, New York, NY, 10031, USA.
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23
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Hughes AEO, Myers CA, Corbo JC. A massively parallel reporter assay reveals context-dependent activity of homeodomain binding sites in vivo. Genome Res 2018; 28:1520-1531. [PMID: 30158147 PMCID: PMC6169884 DOI: 10.1101/gr.231886.117] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 08/27/2018] [Indexed: 12/20/2022]
Abstract
Cone-rod homeobox (CRX) is a paired-like homeodomain transcription factor (TF) and a master regulator of photoreceptor development in vertebrates. The in vitro DNA binding preferences of CRX have been described in detail, but the degree to which in vitro binding affinity is correlated with in vivo enhancer activity is not known. In addition, paired-class homeodomain TFs can bind DNA cooperatively as both homodimers and heterodimers at inverted TAAT half-sites separated by 2 or 3 nucleotides. This dimeric configuration is thought to mediate target specificity, but whether monomeric and dimeric sites encode distinct levels of activity is not known. Here, we used a massively parallel reporter assay to determine how local sequence context shapes the regulatory activity of CRX binding sites in mouse photoreceptors. We assayed inactivating mutations in more than 1700 TF binding sites and found that dimeric CRX binding sites act as stronger enhancers than monomeric CRX binding sites. Furthermore, the activity of dimeric half-sites is cooperative, dependent on a strict 3-bp spacing, and tuned by the identity of the spacer nucleotides. Saturating single-nucleotide mutagenesis of 195 CRX binding sites showed that, on average, changes in TF binding site affinity are correlated with changes in regulatory activity, but this relationship is obscured when considering mutations across multiple cis-regulatory elements (CREs). Taken together, these results demonstrate that the activity of CRX binding sites is highly dependent on sequence context, providing insight into photoreceptor gene regulation and illustrating functional principles of homeodomain binding sites that may be conserved in other cell types.
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Affiliation(s)
- Andrew E O Hughes
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | - Connie A Myers
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | - Joseph C Corbo
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Buenaventura DF, Ghinia-Tegla MG, Emerson MM. Fate-restricted retinal progenitor cells adopt a molecular profile and spatial position distinct from multipotent progenitor cells. Dev Biol 2018; 443:35-49. [PMID: 30145104 DOI: 10.1016/j.ydbio.2018.06.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 06/14/2018] [Accepted: 06/23/2018] [Indexed: 12/22/2022]
Abstract
During development, multipotent retinal progenitor cells generate a large number of unique cell types. Recent evidence suggests that there are fate-restricted progenitor cell states in addition to multipotent ones. Here we report a transcriptomic analysis of fate- restricted progenitor cells biased to produce cone photoreceptors and horizontal cells, marked by the THRB cis-regulatory element ThrbCRM1. Comparison to a control population enriched in multipotent progenitor cells identified several genes considered to be pan-progenitor, such as VSX2, LHX2, and PAX6, as downregulated in these fate- restricted retinal progenitor cells. This differential regulation occurs in chick and in a different restricted progenitor population in mouse suggesting that this is a conserved feature of progenitor dynamics during retinal development. S-phase labeling also revealed that nuclear positions of restricted progenitor populations occupy distinct spatial niches within the developing chick retina. Using a conserved regulatory element proximal to the VSX2 gene, a potential negative feedback mechanism from specific transcription factors enriched in cone/horizontal cell progenitor cells was identified. This study identifies conserved molecular and cellular changes that occur during the generation of fate restricted retinal progenitor cells from multipotent retinal progenitor cells.
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Affiliation(s)
- Diego F Buenaventura
- Department of Biology, The City College of New York, City University of New York, New York, NY 10031, United States; Biology Ph.D. Program, Graduate Center, City University of New York, New York, NY 10031, United States
| | - Miruna G Ghinia-Tegla
- Department of Biology, The City College of New York, City University of New York, New York, NY 10031, United States
| | - Mark M Emerson
- Department of Biology, The City College of New York, City University of New York, New York, NY 10031, United States; Biology Ph.D. Program, Graduate Center, City University of New York, New York, NY 10031, United States.
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25
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Moroz LL. NeuroSystematics and Periodic System of Neurons: Model vs Reference Species at Single-Cell Resolution. ACS Chem Neurosci 2018; 9:1884-1903. [PMID: 29989789 DOI: 10.1021/acschemneuro.8b00100] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
There is more than one way to develop neuronal complexity, and animals frequently use different molecular toolkits to achieve similar functional outcomes (=convergent evolution). Neurons are different not only because they have different functions, but also because neurons and circuits have different genealogies, and perhaps independent origins at the broadest scale from ctenophores and cnidarians to cephalopods and primates. By combining modern phylogenomics, single-neuron sequencing (scRNA-seq), machine learning, single-cell proteomics, and metabolomic across Metazoa, it is possible to reconstruct the evolutionary histories of neurons tracing them to ancestral secretory cells. Comparative data suggest that neurons, and perhaps synapses, evolved at least 2-3 times (in ctenophore, cnidarian and bilateral lineages) during ∼600 million years of animal evolution. There were also several independent events of the nervous system centralization either from a common bilateral/cnidarian ancestor without the bona fide neurons or from the urbilaterian with diffuse, nerve-net type nervous system. From the evolutionary standpoint, (i) a neuron should be viewed as a functional rather than a genetic character, and (ii) any given neural system might be chimeric and composed of different cell lineages with distinct origins and evolutionary histories. The identification of distant neural homologies or examples of convergent evolution among 34 phyla will not only allow the reconstruction of neural systems' evolution but together with single-cell "omic" approaches the proposed synthesis would lead to the "Periodic System of Neurons" with predictive power for neuronal phenotypes and plasticity. Such a phylogenetic classification framework of Neuronal Systematics (NeuroSystematics) might be a conceptual analog of the Periodic System of Chemical Elements. scRNA-seq profiling of all neurons in an entire brain or Brain-seq is now fully achievable in many nontraditional reference species across the entire animal kingdom. Arguably, marine animals are the most suitable for the proposed tasks because the world oceans represent the greatest taxonomic and body-plan diversity.
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Affiliation(s)
- Leonid L. Moroz
- Department of Neuroscience and McKnight Brain Institute, University of Florida, 1149 Newell Drive, Gainesville, Florida 32611, United States
- Whitney Laboratory for Marine Bioscience, University of Florida, 9505 Ocean Shore Blvd., St. Augustine, Florida 32080, United States
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26
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Sun C, Mitchell DM, Stenkamp DL. Isolation of photoreceptors from mature, developing, and regenerated zebrafish retinas, and of microglia/macrophages from regenerating zebrafish retinas. Exp Eye Res 2018; 177:130-144. [PMID: 30096325 DOI: 10.1016/j.exer.2018.08.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 07/30/2018] [Accepted: 08/06/2018] [Indexed: 12/16/2022]
Abstract
This paper describes experimental procedures for the dissociation of retinal cells of the zebrafish (Danio rerio) for subsequent fluorescence-activated cell sorting (FACS) and gene expression studies. Methods for dissociation of zebrafish retinas followed by FACS and RNA isolation were optimized. This methodology was applied to isolate pure sorted samples of rods, long wavelength-sensitive (LWS) cones, medium wavelength-sensitive (MWS; RH2-2) cones, short wavelength-sensitive (SWS2) cones, and UV-sensitive (SWS1) cones from retinas obtained at selective life-history stages of the zebrafish, and for some of these photoreceptors, following retinal regeneration. We also successfully separated lws1-expressing and lws2-expressing LWS cones from fish of a transgenic line in which lws1 is reported with green fluorescence protein (GFP) and lws2 is reported with red fluorescence protein (RFP). Microglia/macrophages were successfully sorted from regenerating retinas (7 days after a cytotoxic lesion) of a transgenic line in which these immune cells express GFP. Electropherograms verified downstream isolation of high-quality RNA from sorted samples. Examples of post-sorting analysis, as well as results of qRT-PCR studies, validated the purity of sorted populations. For example, qRT-PCR samples derived from isolated Rh2-2 cones contained detectable rh2-2 (opn1mw2) opsin transcripts, but lws opsin transcripts (lws1/opn1lw1, lws2/opn1lw2) were not detected, suggesting that the procedure likely separated double cone pairs. Through this method, pure, sorted cell samples can provide RNA that is reliable for downstream gene expression analyses, such as qRT-PCR and RNA-seq, which may reveal molecular signatures of photoreceptors and microglia for comparative transcriptomics studies.
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Affiliation(s)
- Chi Sun
- Department of Biological Sciences, University of Idaho, Moscow, ID, 83844, USA
| | - Diana M Mitchell
- Department of Biological Sciences, University of Idaho, Moscow, ID, 83844, USA
| | - Deborah L Stenkamp
- Department of Biological Sciences, University of Idaho, Moscow, ID, 83844, USA.
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Sandkam B, Dalton B, Breden F, Carleton K. Reviewing guppy color vision: integrating the molecular and physiological variation in visual tuning of a classic system for sensory drive. Curr Zool 2018; 64:535-545. [PMID: 30108634 PMCID: PMC6084590 DOI: 10.1093/cz/zoy047] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 06/02/2018] [Indexed: 12/11/2022] Open
Abstract
Sensory drive predicts coevolution of mate choice signals with the sensory systems detecting those signals. Guppies are a classic model for sensory drive as mate preferences based on coloration differ across individuals and populations. A large body of work has identified variation in color vision, yet we lack a direct tie between how such variation in color vision influences variation in color preference. Here we bring together studies that have investigated guppy vision over the past 40 years to: (1) highlight our current understanding of where variation occurs in the guppy color vision pathway and (2) suggest future avenues of research into sources of visual system variation that could influence guppy color preference. This will allow researchers to design careful studies that couple measures of color preference with measures of visual system variation from the same individual or population. Such studies will finally provide important answers as to what sets the direction and speed of mate preference evolution via sensory drive.
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Affiliation(s)
- Benjamin Sandkam
- Department of Biology, University of Maryland, College Park, College Park, MD, USA
| | - Brian Dalton
- Department of Biology, University of Maryland, College Park, College Park, MD, USA
| | - Felix Breden
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada
| | - Karen Carleton
- Department of Biology, University of Maryland, College Park, College Park, MD, USA
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Galicia CA, Sukeena JM, Stenkamp DL, Fuerst PG. Expression patterns of dscam and sdk gene paralogs in developing zebrafish retina. Mol Vis 2018; 24:443-458. [PMID: 30078982 PMCID: PMC6054835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 07/17/2018] [Indexed: 11/21/2022] Open
Abstract
Purpose The differential adhesion hypothesis states that a cell adhesion code provides cues that direct the specificity of nervous system development. The Down syndrome cell adhesion molecule (DSCAM) and sidekick (SDK) proteins belong to the immunoglobulin superfamily of cell adhesion molecules (CAMs) and provide both attractive and repulsive cues that help to organize the nervous system during development, according to the differential adhesion hypothesis. The zebrafish genome is enriched in dscam and sdk genes, making the zebrafish an excellent model system to further test this hypothesis. The goal of this study is to describe the phylogenetic relationships of the paralogous CAM genes and their spatial expression and co-expression patterns in the embryonic zebrafish retina. Methods Exon-intron structures, karyotypic locations, genomic context, and amino acid sequences of the zebrafish CAM genes (dscama, dscamb, dscaml1, sdk1a, sdk1b, sdk2a, and sdk2b) were obtained from the Ensembl genome database. The Prosite and SMART programs were used to determine the number and identity of protein domains for each CAM gene. The randomized axelerated maximum likelihood (RaxML) program was used to perform a phylogenetic analysis of the zebrafish CAM genes and orthologs in other vertebrates. A synteny analysis of regions surrounding zebrafish CAM paralogs was performed. Digoxigenin (dig)-labeled cRNA probes for each CAM gene were generated to perform in situ hybridization of retinal cryosections from zebrafish embryos and larvae. Dual in situ hybridization of retinal cryosections from zebrafish larvae was performed with dig- and fluorescein-labeled cRNA probes. Results We found the studied zebrafish CAM genes encode similar protein domain structures as their corresponding orthologs in mammals and possess similar intron-exon organizations. CAM paralogs were located on different chromosomes. Phylogenetic and synteny analyses provided support for zebrafish dscam and sdk2 paralogs having originated during the teleost genome duplication. We found that dscama and dscamb are co-expressed in the ganglion cell layer (GCL) and the basal portion of the inner nuclear layer (INL), with weak expression in the photoreceptor-containing outer nuclear layer (ONL). Of the dscam genes, only dscamb was strongly expressed in ONL. Sdk1a and sdk1b were co-expressed in the GCL and the basal portion of the INL. Sdk2a and sdk2b also showed co-expression in the GCL and basal portion of the INL. All Sdk genes were expressed in the ciliary marginal zone (CMZ). Dual in situ hybridizations revealed alternating patterns of co-expression and exclusive expression for the dscam and sdk1 paralogs in cells of the GCL and the INL. The same alternating pattern was observed between dscam and sdk2 paralogs and between sdk1 and sdk2 paralogs. The expression of dscaml1 was observed in the INL and the GCL, with some cells in the basal portion of the INL showing co-expression of dscaml1 and dscama. Conclusions These findings suggest that zebrafish dscam and sdk2 paralogs were likely the result of the teleost whole genome duplication and that all CAM duplicates show some differential expression patterns. We also demonstrate that the comparative expression patterns of CAM genes in the zebrafish are distinct from the exclusive expression patterns observed in chick retina, in which retinal ganglion cells express one of the four chick Dscam or Sdk genes only. The patterns in zebrafish are more similar to those of mice, in which co-expression of Dscam and Sdk genes is observed. These findings provide the groundwork for future functional analysis of the roles of the CAM paralogs in zebrafish.
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Affiliation(s)
| | | | | | - Peter G. Fuerst
- University of Idaho, Department of Biological Sciences, Moscow, ID,University of Washington School of Medicine, WWAMI Medical Education Program, Moscow, ID
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Toomey MB, Corbo JC. Evolution, Development and Function of Vertebrate Cone Oil Droplets. Front Neural Circuits 2017; 11:97. [PMID: 29276475 PMCID: PMC5727011 DOI: 10.3389/fncir.2017.00097] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 11/20/2017] [Indexed: 11/24/2022] Open
Abstract
To distinguish colors, the nervous system must compare the activity of distinct subtypes of photoreceptors that are maximally sensitive to different portions of the light spectrum. In vertebrates, a variety of adaptations have arisen to refine the spectral sensitivity of cone photoreceptors and improve color vision. In this review article, we focus on one such adaptation, the oil droplet, a unique optical organelle found within the inner segment of cone photoreceptors of a diverse array of vertebrate species, from fish to mammals. These droplets, which consist of neutral lipids and carotenoid pigments, are interposed in the path of light through the photoreceptor and modify the intensity and spectrum of light reaching the photosensitive outer segment. In the course of evolution, the optical function of oil droplets has been fine-tuned through changes in carotenoid content. Species active in dim light reduce or eliminate carotenoids to enhance sensitivity, whereas species active in bright light precisely modulate carotenoid double bond conjugation and concentration among cone subtypes to optimize color discrimination and color constancy. Cone oil droplets have sparked the curiosity of vision scientists for more than a century. Accordingly, we begin by briefly reviewing the history of research on oil droplets. We then discuss what is known about the developmental origins of oil droplets. Next, we describe recent advances in understanding the function of oil droplets based on biochemical and optical analyses. Finally, we survey the occurrence and properties of oil droplets across the diversity of vertebrate species and discuss what these patterns indicate about the evolutionary history and function of this intriguing organelle.
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Affiliation(s)
- Matthew B Toomey
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, United States
| | - Joseph C Corbo
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, United States
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Musser JM, Arendt D. Loss and gain of cone types in vertebrate ciliary photoreceptor evolution. Dev Biol 2017; 431:26-35. [DOI: 10.1016/j.ydbio.2017.08.038] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Revised: 08/28/2017] [Accepted: 08/30/2017] [Indexed: 01/09/2023]
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Whole genome DNA methylation sequencing of the chicken retina, cornea and brain. Sci Data 2017; 4:170148. [PMID: 28994822 PMCID: PMC5634322 DOI: 10.1038/sdata.2017.148] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 08/22/2017] [Indexed: 01/23/2023] Open
Abstract
Whole genome bisulfite sequencing (WGBS) analysis of DNA methylation uses massively parallel next generation sequencing technology to characterize global epigenetic patterns and fluctuations throughout a range of tissue samples. Development of the vertebrate retina is thought to involve extensive epigenetic reprogramming during embryogenesis. The chicken embryo (Gallus gallus) is a classic model system for studying developmental biology and retinogenesis, however, there are currently no publicly available data sets describing the developing chicken retinal methylome. Here we used Illumina WGBS analysis to characterize genome-wide patterns of DNA methylation in the developing chicken retina as well as cornea and brain in an effort to further our understanding of retina-specific epigenetic regulation. These data will be valuable to the vision research community for correlating global changes in DNA methylation to differential gene expression between ocular and neural tissues during critical developmental time points of retinogenesis in the chicken retina.
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Morshedian A, Toomey MB, Pollock GE, Frederiksen R, Enright JM, McCormick SD, Cornwall MC, Fain GL, Corbo JC. Cambrian origin of the CYP27C1-mediated vitamin A 1-to-A 2 switch, a key mechanism of vertebrate sensory plasticity. ROYAL SOCIETY OPEN SCIENCE 2017; 4:170362. [PMID: 28791166 PMCID: PMC5541561 DOI: 10.1098/rsos.170362] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 06/07/2017] [Indexed: 05/16/2023]
Abstract
The spectral composition of ambient light varies across both space and time. Many species of jawed vertebrates adapt to this variation by tuning the sensitivity of their photoreceptors via the expression of CYP27C1, an enzyme that converts vitamin A1 into vitamin A2, thereby shifting the ratio of vitamin A1-based rhodopsin to red-shifted vitamin A2-based porphyropsin in the eye. Here, we show that the sea lamprey (Petromyzon marinus), a jawless vertebrate that diverged from jawed vertebrates during the Cambrian period (approx. 500 Ma), dynamically shifts its photoreceptor spectral sensitivity via vitamin A1-to-A2 chromophore exchange as it transitions between photically divergent aquatic habitats. We further show that this shift correlates with high-level expression of the lamprey orthologue of CYP27C1, specifically in the retinal pigment epithelium as in jawed vertebrates. Our results suggest that the CYP27C1-mediated vitamin A1-to-A2 switch is an evolutionarily ancient mechanism of sensory plasticity that appeared not long after the origin of vertebrates.
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Affiliation(s)
- Ala Morshedian
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Matthew B. Toomey
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Gabriel E. Pollock
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Rikard Frederiksen
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118, USA
| | - Jennifer M. Enright
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Stephen D. McCormick
- Conte Anadromous Fish Research Laboratory, US Geological Survey, Leetown Science Center, Turners Falls, MA 01370, USA
| | - M. Carter Cornwall
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118, USA
| | - Gordon L. Fain
- Department of Ophthalmology and Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
- Authors for correspondence: Gordon L. Fain e-mail:
| | - Joseph C. Corbo
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110, USA
- Authors for correspondence: Joseph C. Corbo e-mail:
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Sætre GP, Cuevas A, Hermansen JS, Elgvin TO, Fernández LP, Sæther SA, Cascio Sætre CL, Eroukhmanoff F. Rapid polygenic response to secondary contact in a hybrid species. Proc Biol Sci 2017; 284:20170365. [PMID: 28446700 PMCID: PMC5413929 DOI: 10.1098/rspb.2017.0365] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 03/22/2017] [Indexed: 12/26/2022] Open
Abstract
Secondary contact between closely related species can have genetic consequences. Competition for essential resources may lead to divergence in heritable traits that reduces interspecific competition leading to increased rate of genetic divergence. Conversely, hybridization and backcrossing can lead to genetic convergence. Here, we study a population of a hybrid species, the Italian sparrow (Passer italiae), before and after it came into secondary contact with one of its parent species, the Spanish sparrow (P. hispaniolensis), in 2013. We demonstrate strong consequences of interspecific competition: Italian sparrows were kept away from a popular feeding site by its parent species, resulting in poorer body condition and a significant drop in population size. Although no significant morphological change could be detected, after only 3 years of sympatry, the Italian sparrows had diverged significantly from the Spanish sparrows across a set of 81 protein-coding genes. These temporal genetic changes are mirrored by genetic divergence observed in older sympatric Italian sparrow populations within the same area of contact. Compared with microallopatric birds, sympatric ones are genetically more diverged from Spanish sparrows. Six significant outlier genes in the temporal and spatial comparison (i.e. showing the greatest displacement) have all been found to be associated with learning and neural development in other bird species.
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Affiliation(s)
- Glenn-Peter Sætre
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, PO Box 1066, Blindern, 0316 Oslo, Norway
| | - Angélica Cuevas
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, PO Box 1066, Blindern, 0316 Oslo, Norway
| | - Jo S Hermansen
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, PO Box 1066, Blindern, 0316 Oslo, Norway
| | - Tore O Elgvin
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, PO Box 1066, Blindern, 0316 Oslo, Norway
| | - Laura Piñeiro Fernández
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, PO Box 1066, Blindern, 0316 Oslo, Norway
| | - Stein A Sæther
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, PO Box 1066, Blindern, 0316 Oslo, Norway
- Norwegian Institute for Nature Research (NINA), PO Box 5685, Sluppen, 7485 Trondheim, Norway
| | - Camilla Lo Cascio Sætre
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, PO Box 1066, Blindern, 0316 Oslo, Norway
| | - Fabrice Eroukhmanoff
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, PO Box 1066, Blindern, 0316 Oslo, Norway
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Cell Type-Specific Epigenomic Analysis Reveals a Uniquely Closed Chromatin Architecture in Mouse Rod Photoreceptors. Sci Rep 2017; 7:43184. [PMID: 28256534 PMCID: PMC5335693 DOI: 10.1038/srep43184] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 01/19/2017] [Indexed: 12/24/2022] Open
Abstract
Rod photoreceptors are specialized neurons that mediate vision in dim light and are the predominant photoreceptor type in nocturnal mammals. The rods of nocturnal mammals are unique among vertebrate cell types in having an ‘inverted’ nuclear architecture, with a dense mass of heterochromatin in the center of the nucleus rather than dispersed clumps at the periphery. To test if this unique nuclear architecture is correlated with a unique epigenomic landscape, we performed ATAC-seq on mouse rods and their most closely related cell type, cone photoreceptors. We find that thousands of loci are selectively closed in rods relative to cones as well as >60 additional cell types. Furthermore, we find that the open chromatin profile of photoreceptors lacking the rod master regulator Nrl is nearly indistinguishable from that of native cones, indicating that Nrl is required for selective chromatin closure in rods. Finally, we identified distinct enrichments of transcription factor binding sites in rods and cones, revealing key differences in the cis-regulatory grammar of these cell types. Taken together, these data provide insight into the development and maintenance of photoreceptor identity, and highlight rods as an attractive system for studying the relationship between nuclear organization and local changes in gene regulation.
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35
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RNA sequencing analysis of the developing chicken retina. Sci Data 2016; 3:160117. [PMID: 27996968 PMCID: PMC5170595 DOI: 10.1038/sdata.2016.117] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 11/08/2016] [Indexed: 12/17/2022] Open
Abstract
RNA sequencing transcriptome analysis using massively parallel next generation sequencing technology provides the capability to understand global changes in gene expression throughout a range of tissue samples. Development of the vertebrate retina requires complex temporal orchestration of transcriptional activation and repression. The chicken embryo (Gallus gallus) is a classic model system for studying developmental biology and retinogenesis. Existing retinal transcriptome projects have been critical to the vision research community for studying aspects of murine and human retinogenesis, however, there are currently no publicly available data sets describing the developing chicken retinal transcriptome. Here we used Illumina RNA sequencing (RNA-seq) analysis to characterize the mRNA transcriptome of the developing chicken retina in an effort to identify genes critical for retinal development in this important model organism. These data will be valuable to the vision research community for characterizing global changes in gene expression between ocular tissues and critical developmental time points during retinogenesis in the chicken retina.
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Toomey MB, Lind O, Frederiksen R, Curley RW, Riedl KM, Wilby D, Schwartz SJ, Witt CC, Harrison EH, Roberts NW, Vorobyev M, McGraw KJ, Cornwall MC, Kelber A, Corbo JC. Complementary shifts in photoreceptor spectral tuning unlock the full adaptive potential of ultraviolet vision in birds. eLife 2016; 5:e15675. [PMID: 27402384 PMCID: PMC4947394 DOI: 10.7554/elife.15675] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 06/13/2016] [Indexed: 01/01/2023] Open
Abstract
Color vision in birds is mediated by four types of cone photoreceptors whose maximal sensitivities (λmax) are evenly spaced across the light spectrum. In the course of avian evolution, the λmax of the most shortwave-sensitive cone, SWS1, has switched between violet (λmax > 400 nm) and ultraviolet (λmax < 380 nm) multiple times. This shift of the SWS1 opsin is accompanied by a corresponding short-wavelength shift in the spectrally adjacent SWS2 cone. Here, we show that SWS2 cone spectral tuning is mediated by modulating the ratio of two apocarotenoids, galloxanthin and 11’,12’-dihydrogalloxanthin, which act as intracellular spectral filters in this cell type. We propose an enzymatic pathway that mediates the differential production of these apocarotenoids in the avian retina, and we use color vision modeling to demonstrate how correlated evolution of spectral tuning is necessary to achieve even sampling of the light spectrum and thereby maintain near-optimal color discrimination.
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Affiliation(s)
- Matthew B Toomey
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, United States
| | - Olle Lind
- Department of Philosophy, Lund University, Lund, Sweden
| | - Rikard Frederiksen
- Department of Physiology and Biophysics, Boston University, Boston, United States
| | - Robert W Curley
- College of Pharmacy, The Ohio State University, Columbus, United States
| | - Ken M Riedl
- Department of Food Science and Technology, The Ohio State University, Columbus, United States
- Nutrient and Phytochemical Shared Resource of the OSU-Comprehensive Cancer Center, Columbus, United States
| | - David Wilby
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | - Steven J Schwartz
- Department of Food Science and Technology, The Ohio State University, Columbus, United States
| | - Christopher C Witt
- Department of Biology, University of New Mexico, Albuquerque, United States
- Museum of Southwestern Biology, University of New Mexico, Albuquerque, United States
| | - Earl H Harrison
- Department of Human Nutrition, The Ohio State University, Columbus, United States
| | - Nicholas W Roberts
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | - Misha Vorobyev
- Department of Optometry and Vision Science, University of Auckland, Auckland, New Zealand
| | - Kevin J McGraw
- School of Life Sciences, Arizona State University, Tempe, United States
| | - M Carter Cornwall
- Department of Physiology and Biophysics, Boston University, Boston, United States
| | - Almut Kelber
- Department of Biology, Lund University, Lund, Sweden
| | - Joseph C Corbo
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, United States
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Sotolongo-Lopez M, Alvarez-Delfin K, Saade CJ, Vera DL, Fadool JM. Genetic Dissection of Dual Roles for the Transcription Factor six7 in Photoreceptor Development and Patterning in Zebrafish. PLoS Genet 2016; 12:e1005968. [PMID: 27058886 PMCID: PMC4825938 DOI: 10.1371/journal.pgen.1005968] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 03/09/2016] [Indexed: 11/30/2022] Open
Abstract
The visual system of a particular species is highly adapted to convey detailed ecological and behavioral information essential for survival. The consequences of structural mutations of opsins upon spectral sensitivity and environmental adaptation have been studied in great detail, but lacking is knowledge of the potential influence of alterations in gene regulatory networks upon the diversity of cone subtypes and the variation in the ratio of rods and cones observed in numerous diurnal and nocturnal species. Exploiting photoreceptor patterning in cone-dominated zebrafish, we uncovered two independent mechanisms by which the sine oculis homeobox homolog 7 (six7) regulates photoreceptor development. In a genetic screen, we isolated the lots-of-rods-junior (ljrp23ahub) mutation that resulted in an increased number and uniform distribution of rods in otherwise normal appearing larvae. Sequence analysis, genome editing using TALENs and knockdown strategies confirm ljrp23ahub as a hypomorphic allele of six7, a teleost orthologue of six3, with known roles in forebrain patterning and expression of opsins. Based on the lack of predicted protein-coding changes and a deletion of a conserved element upstream of the transcription start site, a cis-regulatory mutation is proposed as the basis of the reduced expression of six7 in ljrp23ahub. Comparison of the phenotypes of the hypomorphic and knock-out alleles provides evidence of two independent roles in photoreceptor development. EdU and PH3 labeling show that the increase in rod number is associated with extended mitosis of photoreceptor progenitors, and TUNEL suggests that the lack of green-sensitive cones is the result of cell death of the cone precursor. These data add six7 to the small but growing list of essential genes for specification and patterning of photoreceptors in non-mammalian vertebrates, and highlight alterations in transcriptional regulation as a potential source of photoreceptor variation across species.
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Affiliation(s)
- Mailin Sotolongo-Lopez
- Department of Biological Science, The Florida State University, Tallahassee, Florida, United States of America
| | - Karen Alvarez-Delfin
- Department of Biological Science, The Florida State University, Tallahassee, Florida, United States of America
| | - Carole J. Saade
- Department of Biological Science, The Florida State University, Tallahassee, Florida, United States of America
- Program in Neuroscience, The Florida State University, Tallahassee, Florida, United States of America
| | - Daniel L. Vera
- Center for Genomics and Personalized Medicine, The Florida State University, Tallahassee, Florida, United States of America
| | - James M. Fadool
- Department of Biological Science, The Florida State University, Tallahassee, Florida, United States of America
- Program in Neuroscience, The Florida State University, Tallahassee, Florida, United States of America
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