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Young RM, Hawkins TA, Cavodeassi F, Stickney HL, Schwarz Q, Lawrence LM, Wierzbicki C, Cheng BY, Luo J, Ambrosio EM, Klosner A, Sealy IM, Rowell J, Trivedi CA, Bianco IH, Allende ML, Busch-Nentwich EM, Gestri G, Wilson SW. Compensatory growth renders Tcf7l1a dispensable for eye formation despite its requirement in eye field specification. eLife 2019; 8:40093. [PMID: 30777146 PMCID: PMC6380838 DOI: 10.7554/elife.40093] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 01/26/2019] [Indexed: 12/18/2022] Open
Abstract
The vertebrate eye originates from the eye field, a domain of cells specified by a small number of transcription factors. In this study, we show that Tcf7l1a is one such transcription factor that acts cell-autonomously to specify the eye field in zebrafish. Despite the much-reduced eye field in tcf7l1a mutants, these fish develop normal eyes revealing a striking ability of the eye to recover from a severe early phenotype. This robustness is not mediated through genetic compensation at neural plate stage; instead, the smaller optic vesicle of tcf7l1a mutants shows delayed neurogenesis and continues to grow until it achieves approximately normal size. Although the developing eye is robust to the lack of Tcf7l1a function, it is sensitised to the effects of additional mutations. In support of this, a forward genetic screen identified mutations in hesx1, cct5 and gdf6a, which give synthetically enhanced eye specification or growth phenotypes when in combination with the tcf7l1a mutation. Left and right eyes develop independently, yet they consistently grow to roughly the same size in humans and other creatures. How they do this remains a mystery, though scientists have learned that both eyes originate from a single group of cells in the developing nervous system called the eye field. As development progresses, the eye field splits in two, and buds into the two separate compartments from which each eye forms. As the eyes grow, the cells in each compartment specialize, or ‘differentiate’, to make working left and right eyes. Scientists often study eye development in zebrafish embryos because it is easy to see each step in the process. Now, Young at al. show that zebrafish with a mutation that causes the eye field to be half its normal size go on to form normal-sized eyes. Somehow these developing embryos overcome this deleterious mutation. It turns out that the eyes of zebrafish with this mutation grow for a longer period of time than typical zebrafish eyes. This change allows the mutant fish’s eyes to catch up and reach normal size. When Young et al. removed some cells from one of the forming eyes of normal zebrafish embryos they found that same thing happened. The smaller eye developed for a longer time and delayed its differentiation until both eyes were the same size. Conversely, when eyes developed from a larger than normal eye field, growth stopped prematurely and differentiation began early preventing the eyes from ending up oversized. Though the fish were able to overcome the effects of one mutation to develop normal-sized eyes, adding a second mutation that affected eye development led to unusual sized eyes or absence of eyes. Together the experiments identify genes and mechanisms essential for the formation and size of the eyes. Given that the processes underlying eye formation are very similar in many animals, this new information should help scientists to better understand eye abnormalities in humans.
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Affiliation(s)
- Rodrigo M Young
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Thomas A Hawkins
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Florencia Cavodeassi
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Heather L Stickney
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Quenten Schwarz
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Lisa M Lawrence
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Claudia Wierzbicki
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Bowie Yl Cheng
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Jingyuan Luo
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | | | - Allison Klosner
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Ian M Sealy
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom.,Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Jasmine Rowell
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Chintan A Trivedi
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Isaac H Bianco
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Miguel L Allende
- Center for Genome Regulation, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Elisabeth M Busch-Nentwich
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom.,Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Gaia Gestri
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Stephen W Wilson
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
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Minegishi Y, Sheng X, Yoshitake K, Sergeev Y, Iejima D, Shibagaki Y, Monma N, Ikeo K, Furuno M, Zhuang W, Liu Y, Rong W, Hattori S, Iwata T. CCT2 Mutations Evoke Leber Congenital Amaurosis due to Chaperone Complex Instability. Sci Rep 2016; 6:33742. [PMID: 27645772 PMCID: PMC5028737 DOI: 10.1038/srep33742] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 09/02/2016] [Indexed: 12/22/2022] Open
Abstract
Leber congenital amaurosis (LCA) is a hereditary early-onset retinal dystrophy that is accompanied by severe macular degeneration. In this study, novel compound heterozygous mutations were identified as LCA-causative in chaperonin-containing TCP-1, subunit 2 (CCT2), a gene that encodes the molecular chaperone protein, CCTβ. The zebrafish mutants of CCTβ are known to exhibit the eye phenotype while its mutation and association with human disease have been unknown. The CCT proteins (CCT α-θ) forms ring complex for its chaperon function. The LCA mutants of CCTβ, T400P and R516H, are biochemically instable and the affinity for the adjacent subunit, CCTγ, was affected distinctly in both mutants. The patient-derived induced pluripotent stem cells (iPSCs), carrying these CCTβ mutants, were less proliferative than the control iPSCs. Decreased proliferation under Cct2 knockdown in 661W cells was significantly rescued by wild-type CCTβ expression. However, the expression of T400P and R516H didn’t exhibit the significant effect. In mouse retina, both CCTβ and CCTγ are expressed in the retinal ganglion cells and connecting cilium of photoreceptor cells. The Cct2 knockdown decreased its major client protein, transducing β1 (Gβ1). Here we report the novel LCA mutations in CCTβ and the impact of chaperon disability by these mutations in cellular biology.
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Affiliation(s)
- Yuriko Minegishi
- Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - XunLun Sheng
- Ningxia Eye Hospital, Ningxia People's Hospital, Ningxia, China
| | - Kazutoshi Yoshitake
- Laboratory of DNA Data Analysis, National Institute of Genetics, Shizuoka, Japan
| | - Yuri Sergeev
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Daisuke Iejima
- Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - Yoshio Shibagaki
- Division of Biochemistry, School of Pharmaceutical Science, Kitasato University, Tokyo, Japan
| | - Norikazu Monma
- Laboratory of DNA Data Analysis, National Institute of Genetics, Shizuoka, Japan
| | - Kazuho Ikeo
- Laboratory of DNA Data Analysis, National Institute of Genetics, Shizuoka, Japan
| | - Masaaki Furuno
- RIKEN Center for Life Science Technologies, Division of Genomic Technologies, Life Science Accelerator Technology Group, Transcriptome Technology Team, Yokohama, Japan
| | - Wenjun Zhuang
- Ningxia Eye Hospital, Ningxia People's Hospital, Ningxia, China
| | - Yani Liu
- Ningxia Eye Hospital, Ningxia People's Hospital, Ningxia, China
| | - Weining Rong
- Ningxia Eye Hospital, Ningxia People's Hospital, Ningxia, China
| | - Seisuke Hattori
- Division of Biochemistry, School of Pharmaceutical Science, Kitasato University, Tokyo, Japan
| | - Takeshi Iwata
- Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
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Tseng TJ, Chen CC, Hsieh YL, Hsieh ST. Influences of surgical decompression on the dorsal horn after chronic constriction injury: changes in peptidergic and delta-opioid receptor (+) nerve terminals. Neuroscience 2008; 156:758-68. [PMID: 18773941 DOI: 10.1016/j.neuroscience.2008.08.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2008] [Revised: 08/06/2008] [Accepted: 08/07/2008] [Indexed: 12/30/2022]
Abstract
To understand plastic changes in the dorsal horn related to neuropathic pain, we developed a model of decompression in rats with chronic constriction injury (CCI) and investigated corresponding changes in the dorsal horn. At postoperative week 4 (POW 4) of CCI, rats were divided into a decompression group, in which ligatures were removed, and a CCI group, in which ligatures remained. Spinal cords were immunostained for substance P (SP), the delta-opioid receptor (DOR), and calcitonin gene-related peptide (CGRP). Areas of immunoreactive nerve terminals in the dorsal horn were quantified and expressed as the dorsal horn index (immunoreactive areas of the operated side compared with those of the contralateral side). At POW 4, dorsal horn indexes of all of these molecules were significantly reduced in both groups to similar degrees (0.36-0.43). At POW 8, neuropathic pain behaviors had completely disappeared in the decompression group with significant reversal of the dorsal horn indexes compared with the CCI group (0.81+/-0.02 vs. 0.58+/-0.09, P < 0.001 for SP and 0.75+/-0.04 vs. 0.55+/-0.03, P < 0.001 for DOR). In the CCI group, neuropathic pain behaviors became normalized at POW 12 with corresponding changes in dorsal horn indexes for both SP and DOR similar to those of the decompression group. In contrast, changes in the dorsal horn indexes of CGRP were similar in both the CCI and decompression groups throughout the experimental period. These findings suggest that CCI and decompression cause different patterns in peptidergic and DOR (+) nerve terminals in the dorsal horn.
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Affiliation(s)
- T-J Tseng
- Department of Anatomy and Cell Biology, National Taiwan University College of Medicine, Taipei, Taiwan
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