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Karaica D, Mihaljević I, Vujica L, Bošnjak A, Dragojević J, Otten C, Babić N, Lončar J, Smital T. Stage-dependent localization of F-actin and Na + /K + -ATPase in zebrafish embryos detected using optimized cryosectioning immunostaining protocol. Microsc Res Tech 2023; 86:294-310. [PMID: 36453864 DOI: 10.1002/jemt.24270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 11/10/2022] [Accepted: 11/23/2022] [Indexed: 12/04/2022]
Abstract
The increasing use of the zebrafish model in biomedical and (eco)toxicological studies aimed at understanding the function of various proteins highlight the importance of optimizing existing methods to study gene and protein expression and localization in this model. In this context, zebrafish cryosections are still underutilized compared with whole-mount preparations. In this study, we used zebrafish embryos (24-120 hpf) to determine key factors for the preparation of high-quality zebrafish cryosections and to determine the optimal protocol for (immuno)fluorescence analyses of Na+ /K+ -ATPase and F-actin, across developmental stages from 1 to 5 dpf. The results showed that the highest quality zebrafish cryosections were obtained after the samples were fixed in 4% paraformaldehyde (PFA) for 1 h, incubated in 2.5% bovine gelatin/25% sucrose mixture, embedded in OCT, and then sectioned to 8 μm thickness at -20°C. Fluorescence microscopy analysis of phalloidin-labeled zebrafish skeletal muscle revealed that 1-h-4% PFA-fixed samples allowed optimal binding of phalloidin to F-actin. Further immunofluorescence analyses revealed detailed localization of F-actin and Na+ /K+ -ATPase in various tissues of the zebrafish and a stage-dependent increase in their respective expression in the somitic muscles and pronephros. Finally, staining of zebrafish cryosections and whole-mount samples revealed organ-specific and zone-dependent localizations of the Na+ /K+ -ATPase α1-subunit. RESEARCH HIGHLIGHTS: This study brings optimization of existing protocols for preparation and use of zebrafish embryos cryosections in (immuno)histological analyses. It reveals stage-dependent localization/expression of F-actin and Na+ /K+ -ATPase in zebrafish embryos.
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Affiliation(s)
- Dean Karaica
- Molecular Toxicology Unit, Institute for Medical Research and Occupational Health, Zagreb, Croatia
| | - Ivan Mihaljević
- Laboratory for Molecular Ecotoxicology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Lana Vujica
- Laboratory for Molecular Ecotoxicology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Arvena Bošnjak
- Department of Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Jelena Dragojević
- Laboratory for Molecular Ecotoxicology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Cecile Otten
- Laboratory for Molecular Ecotoxicology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Nency Babić
- Department of Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Jovica Lončar
- Laboratory for Molecular Ecotoxicology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Tvrtko Smital
- Laboratory for Molecular Ecotoxicology, Ruđer Bošković Institute, Zagreb, Croatia
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2
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Chen C, Ni X, Yin X, Chen H, Zhou Y, Sun H, Qi C, Bu N, Wang S, Yu J, Yang J, Ao W, Zhao B, Dong W. Developmental disorders caused by cefixime in the otic vesicles of zebrafish embryos or larvae. Comp Biochem Physiol C Toxicol Pharmacol 2022; 255:109295. [PMID: 35134541 DOI: 10.1016/j.cbpc.2022.109295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/30/2022] [Accepted: 02/02/2022] [Indexed: 02/06/2023]
Abstract
To explore the developmental toxicity of cefixime (CE) in the developmental disorder and toxicity mechanism of CE on otic vesicles, zebrafish embryos were used as an animal model. The results showed that CE increased mortality in a dose-dependent manner and decreased the hatching rate of zebrafish larva at 96 hpf. Interestingly, CE significantly reduced the area of the saccule and utricle, as well as the area of otic vesicles in zebrafish larvae (p < 0.001). Fibroblast growth factor 8a (Fgf8a) inhibitors and bone morphogenetic protein (BMP) inhibitors caused similar morphological changes. CE decreased the lateral hair cells of zebrafish larvae in a dose-dependent manner. Furthermore, CE caused the downregulation of cartilage and bone-related genes and Na+/K+-ATPase-related genes of zebrafish larvae at 72 hpf and 120 hpf according to RT-qPCR. A comparison with the control group revealed that 100 μg/mL CE also caused a decrease in Na+/K+-ATPase activity (p < 0.01). In addition, antibody staining verified that CE inhibited the expression of Na+/K+-ATPase in the otic vesicles and the nephridium of zebrafish larvae. The data obtained in this study suggested that CE has significant ototoxicity during embryonic development of zebrafish, which is closely related to Na+/K+-ATPase and the regulation of the Fgf8a/BMP signaling pathways. The effects and toxicity of CE on ear development in other animal models need to be further explored.
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Affiliation(s)
- Chaobao Chen
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, Collage of Animal Science and Technology, Inner Mongolia Minzu University, Tongliao 028000, China
| | - Xuan Ni
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, Collage of Animal Science and Technology, Inner Mongolia Minzu University, Tongliao 028000, China
| | - Xiaoyu Yin
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, Collage of Animal Science and Technology, Inner Mongolia Minzu University, Tongliao 028000, China
| | - Hao Chen
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, Collage of Animal Science and Technology, Inner Mongolia Minzu University, Tongliao 028000, China
| | - Yini Zhou
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, Collage of Animal Science and Technology, Inner Mongolia Minzu University, Tongliao 028000, China
| | - Huiying Sun
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, Collage of Animal Science and Technology, Inner Mongolia Minzu University, Tongliao 028000, China
| | - Chelimuge Qi
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, Collage of Animal Science and Technology, Inner Mongolia Minzu University, Tongliao 028000, China
| | - Nini Bu
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, Collage of Animal Science and Technology, Inner Mongolia Minzu University, Tongliao 028000, China
| | - Shuaiyu Wang
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, Collage of Animal Science and Technology, Inner Mongolia Minzu University, Tongliao 028000, China
| | - Jianhua Yu
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, Collage of Animal Science and Technology, Inner Mongolia Minzu University, Tongliao 028000, China
| | - Jingfeng Yang
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, Collage of Animal Science and Technology, Inner Mongolia Minzu University, Tongliao 028000, China
| | - Wuliji Ao
- Inner Mongolia Research Institute of Traditional Mongolian Medicine Engineering Technology/College of Mongolian Medicine and Pharmacy, Inner Mongolia Minzu University, Tongliao 028000, China
| | - Baoquan Zhao
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing 100850, China
| | - Wu Dong
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, Collage of Animal Science and Technology, Inner Mongolia Minzu University, Tongliao 028000, China.
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3
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Mosaliganti KR, Swinburne IA, Chan CU, Obholzer ND, Green AA, Tanksale S, Mahadevan L, Megason SG. Size control of the inner ear via hydraulic feedback. eLife 2019; 8:39596. [PMID: 31571582 PMCID: PMC6773445 DOI: 10.7554/elife.39596] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 08/26/2019] [Indexed: 01/05/2023] Open
Abstract
Animals make organs of precise size, shape, and symmetry but how developing embryos do this is largely unknown. Here, we combine quantitative imaging, physical theory, and physiological measurement of hydrostatic pressure and fluid transport in zebrafish to study size control of the developing inner ear. We find that fluid accumulation creates hydrostatic pressure in the lumen leading to stress in the epithelium and expansion of the otic vesicle. Pressure, in turn, inhibits fluid transport into the lumen. This negative feedback loop between pressure and transport allows the otic vesicle to change growth rate to control natural or experimentally-induced size variation. Spatiotemporal patterning of contractility modulates pressure-driven strain for regional tissue thinning. Our work connects molecular-driven mechanisms, such as osmotic pressure driven strain and actomyosin tension, to the regulation of tissue morphogenesis via hydraulic feedback to ensure robust control of organ size. Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).
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Affiliation(s)
| | - Ian A Swinburne
- Department of Systems Biology, Harvard Medical School, Boston, United States
| | - Chon U Chan
- School of Engineering and Applied Sciences, Harvard University, Cambridge, United States
| | - Nikolaus D Obholzer
- Department of Systems Biology, Harvard Medical School, Boston, United States
| | - Amelia A Green
- Department of Systems Biology, Harvard Medical School, Boston, United States
| | - Shreyas Tanksale
- Department of Systems Biology, Harvard Medical School, Boston, United States
| | - L Mahadevan
- School of Engineering and Applied Sciences, Harvard University, Cambridge, United States.,Department of Organismal and Evolutionary Biology, Harvard University, Cambridge, United States.,Department of Physics, Harvard University, Cambridge, United States.,Kavli Institute for NanoBio Science and Technology, Harvard University, Cambridge, United States
| | - Sean G Megason
- Department of Systems Biology, Harvard Medical School, Boston, United States
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4
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Jia Y, Liu X. Expression of Na +/K +-ATPase Was Affected by Salinity Change in Pacific abalone Haliotis discus hannai. Front Physiol 2018; 9:1244. [PMID: 30245637 PMCID: PMC6137147 DOI: 10.3389/fphys.2018.01244] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 08/17/2018] [Indexed: 11/30/2022] Open
Abstract
Na+/K+-ATPase (NKA) belongs to the P-type ATPase family, whose members are located in the cell membrane and are distributed in diverse tissues and cells. The main function of the NKA is to regulate osmotic pressure. To better understand the role of NKA in osmoregulation, we first cloned and characterized the full-length cDNAs of NKA α subunit and β subunit from Pacific abalone Haliotis discus hannai in the current study. The predicted protein sequence of the NKA α subunit, as the catalytic subunit, was well conserved. In contrast, the protein sequence of the β subunit had low similarity with those of other species. Phylogenetic analysis revealed that both the α and β subunits of the NKA protein of Pacific abalone were clustered with those of the Gastropoda. Then, the relationship between salinity changes and the NKA was investigated. Sudden salinity changes (with low-salinity seawater (LSW) or high-salinity seawater (HSW)) led to clear changes in ion concentration (Na+ and K+) in hemolymph; however, the relative stability of ion concentrations in tissue revealed that Pacific abalone has a strong osmotic pressure regulation ability when faced with these salinity changes. Meanwhile, the expression and activity of the NKA was significantly decreased (in LSW group) or increased (in HSW group) during the ion concentration re-establishing stages, which was consistent with the coordinated regulation of ion concentration in hemolymph. Moreover, a positive correlation between cyclic adenosine monophosphate (cAMP) concentrations and NKA mRNA expression (NKA activity) was observed in mantle and gill. Therefore, the sudden salinity changes may affect NKA transcription activation, translation and enzyme activity via a cAMP-mediated pathway.
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Affiliation(s)
- Yanglei Jia
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology and Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Xiao Liu
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology and Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
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5
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Gibert Y, Sassi-Messai S, Fini JB, Bernard L, Zalko D, Cravedi JP, Balaguer P, Andersson-Lendahl M, Demeneix B, Laudet V. Bisphenol A induces otolith malformations during vertebrate embryogenesis. BMC DEVELOPMENTAL BIOLOGY 2011; 11:4. [PMID: 21269433 PMCID: PMC3040707 DOI: 10.1186/1471-213x-11-4] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Accepted: 01/26/2011] [Indexed: 01/09/2023]
Abstract
Background The plastic monomer and plasticizer bisphenol A (BPA), used for manufacturing polycarbonate plastic and epoxy resins, is produced at over 2.5 million metric tons per year. Concerns have been raised that BPA acts as an endocrine disruptor on both developmental and reproductive processes and a large body of evidence suggests that BPA interferes with estrogen and thyroid hormone signaling. Here, we investigated BPA effects during embryonic development using the zebrafish and Xenopus models. Results We report that BPA exposure leads to severe malformations of the otic vesicle. In zebrafish and in Xenopus embryos, exposure to BPA during the first developmental day resulted in dose-dependent defects in otolith formation. Defects included aggregation, multiplication and occasionally failure to form otoliths. As no effects on otolith development were seen with exposure to micromolar concentrations of thyroid hormone, 17-ß-estradiol or of the estrogen receptor antagonist ICI 182,780 we conclude that the effects of BPA are independent of estrogen receptors or thyroid-hormone receptors. Na+/K+ ATPases are crucial for otolith formation in zebrafish. Pharmacological inhibition of the major Na+/K+ ATPase with ouabain can rescue the BPA-induced otolith phenotype. Conclusions The data suggest that the spectrum of BPA action is wider than previously expected and argue for a systematic survey of the developmental effects of this endocrine disruptor.
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Affiliation(s)
- Yann Gibert
- Institut de Génomique Fonctionnelle de Lyon; Université de Lyon; Université Lyon 1; CNRS; INRA; Ecole Normale Supérieure de Lyon; 46 allée d'Italie, 69364 Lyon Cedex 07, France.
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6
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Feng Y, Xu Q. Pivotal role of hmx2 and hmx3 in zebrafish inner ear and lateral line development. Dev Biol 2010; 339:507-18. [DOI: 10.1016/j.ydbio.2009.12.028] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Revised: 12/17/2009] [Accepted: 12/18/2009] [Indexed: 10/20/2022]
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7
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Abbas L, Whitfield TT. The zebrafish inner ear. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/s1546-5098(10)02904-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
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8
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Abbas L, Whitfield TT. Nkcc1 (Slc12a2) is required for the regulation of endolymph volume in the otic vesicle and swim bladder volume in the zebrafish larva. Development 2009; 136:2837-48. [PMID: 19633174 DOI: 10.1242/dev.034215] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Endolymph is the specialised extracellular fluid present inside the inner ear. In mammals, disruptions to endolymph homeostasis can result in either collapse or distension of the endolymphatic compartment in the cochlea, with concomitant hearing loss. The zebrafish little ears (lte) mutant shows a collapse of the otic vesicle in the larva, apparently owing to a loss of endolymphatic fluid in the ear, together with an over-inflation of the swim bladder. Mutant larvae display signs of abnormal vestibular function by circling and swimming upside down. The two available alleles of lte are homozygous lethal: mutant larvae fail to thrive beyond 6 days post-fertilisation. Patterning of the otic vesicle is apparently normal. However, the expression of several genes thought to play a role in endolymph production is downregulated, including the sodium-potassium-chloride cotransporter gene nkcc1 (slc12a2) and several Na(+)/K(+)-ATPase channel subunit genes. We show here that lte mutations correspond to lesions in nkcc1. Each allele has a point mutation that disrupts splicing, leading to frame shifts in the coding region that predict the generation of truncated products. Endolymph collapse in the lte/nkcc1 mutant shows distinct parallels to that seen in mouse Nkcc1 mutants, validating zebrafish as a model for the study of endolymph disorders. The collapse in ear volume can be ameliorated in the to27d allele of lte by injection of a morpholino that blocks splicing at an ectopic site introduced by the mutation. This exemplifies the use of morpholinos as potential therapeutic agents for genetic disease.
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Affiliation(s)
- Leila Abbas
- MRC Centre for Developmental and Biomedical Genetics and Department of Biomedical Science, University of Sheffield, Sheffield, UK
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9
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Wang L, Sewell WF, Kim SD, Shin JT, MacRae CA, Zon LI, Seidman JG, Seidman CE. Eya4 regulation of Na+/K+-ATPase is required for sensory system development in zebrafish. Development 2008; 135:3425-34. [PMID: 18799547 DOI: 10.1242/dev.012237] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To investigate the mechanisms by which mutations in the human transcriptional co-activator EYA4 gene cause sensorineural hearing loss that can occur in association with dilated cardiomyopathy, we studied eya4 expression during zebrafish development and characterized eya4 deficiency. eya4 morphant fish embryos had reduced numbers of hair cells in the otic vesicle and lateral line neuromasts with impaired sensory responses. Analyses of candidate genes that are known to be expressed in a temporal and spatial pattern comparable to eya4 focused our analyses on atp1b2b, which encodes the beta2b subunit of the zebrafish Na+/K+-ATPase. We demonstrate atp1b2b levels are reduced in eya4 morphant fish and that morpholino oligonucleotides targeting the atp1b2b gene recapitulated the eya4 deficiency phenotypes, including heart failure, decreased sensory hair cell numbers in the otic vesicle and neuromasts, and abnormal sensory responses. Furthermore, atp1b2b overexpression rescued these phenotypes in eya4 morphant fish. We conclude that eya4 regulation of Na+/K+-ATPase is crucial for the development of mechanosensory cells and the maintenance of cardiac function in zebrafish.
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Affiliation(s)
- Libin Wang
- Harvard Medical School, Department of Genetics, and Howard Hughes Medical Institute, Division of Hematology/Oncology, Children's Hospital Boston, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
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10
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Shen YC, Jeyabalan AK, Wu KL, Hunker KL, Kohrman DC, Thompson DL, Liu D, Barald KF. The transmembrane inner ear (tmie) gene contributes to vestibular and lateral line development and function in the zebrafish (Danio rerio). Dev Dyn 2008; 237:941-52. [PMID: 18330929 DOI: 10.1002/dvdy.21486] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The inner ear is a complex organ containing sensory tissue, including hair cells, the development of which is not well understood. Our long-term goal is to discover genes critical for the correct formation and function of the inner ear and its sensory tissue. A novel gene, transmembrane inner ear (Tmie), was found to cause hearing-related disorders when defective in mice and humans. A homologous tmie gene in zebrafish was cloned and its expression characterized between 24 and 51 hours post-fertilization. Embryos injected with morpholinos (MO) directed against tmie exhibited circling swimming behavior (approximately 37%), phenocopying mice with Tmie mutations; semicircular canal formation was disrupted, hair cell numbers were reduced, and maturation of electrically active lateral line neuromasts was delayed. As in the mouse, tmie appears to be required for inner ear development and function in the zebrafish and for hair cell maturation in the vestibular and lateral line systems as well.
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Affiliation(s)
- Yu-Chi Shen
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan 48109-2200, USA
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11
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Rotllant J, Liu D, Yan YL, Postlethwait JH, Westerfield M, Du SJ. Sparc (Osteonectin) functions in morphogenesis of the pharyngeal skeleton and inner ear. Matrix Biol 2008; 27:561-72. [PMID: 18430553 DOI: 10.1016/j.matbio.2008.03.001] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Revised: 03/03/2008] [Accepted: 03/03/2008] [Indexed: 12/21/2022]
Abstract
Sparc (Osteonectin), a matricellular glycoprotein expressed by many differentiated cells, is a major non-collagenous constituent of vertebrate bones. Recent studies indicate that Sparc expression appears early in development, although its function and regulation during embryogenesis are largely unknown. We cloned zebrafish sparc and investigated its role during development, using a mo rpholino antisense oligonucleotide-based knockdown approach. Consistent with its strong expression in the otic vesicle and developing pharyngeal cartilages, knockdown of Sparc function resulted in specific inner ear and cartilage defects that are highlighted by changes in gene expression, morphology and behavior. We rescued the knockdown phenotypes by co-injecting sparc mRNA, providing evidence that the knockdown phenotype is due specifically to impairment of Sparc function. A comparison of the phenotypes of Sparc knockdown and known zebrafish mutants with similar defects places Sparc downstream of sox9 in the genetic network that regulates development of the pharyngeal skeleton and inner ear of vertebrates.
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Affiliation(s)
- Josep Rotllant
- Center of Marine Biotechnology, University of Maryland Biotechnology Institute, Baltimore, MD 21202, USA.
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12
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Blasiole B, Canfield VA, Vollrath MA, Huss D, Mohideen MAPK, Dickman JD, Cheng KC, Fekete DM, Levenson R. Separate Na,K-ATPase genes are required for otolith formation and semicircular canal development in zebrafish. Dev Biol 2006; 294:148-60. [PMID: 16566913 DOI: 10.1016/j.ydbio.2006.02.034] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2005] [Revised: 02/17/2006] [Accepted: 02/21/2006] [Indexed: 11/21/2022]
Abstract
We have investigated the role of Na,K-ATPase genes in zebrafish ear development. Six Na,K-ATPase genes are differentially expressed in the developing zebrafish inner ear. Antisense morpholino knockdown of Na,K-ATPase alpha1a.1 expression blocked formation of otoliths. This effect was phenocopied by treatment of embryos with ouabain, an inhibitor of Na,K-ATPase activity. The otolith defect produced by morpholinos was rescued by microinjection of zebrafish alpha1a.1 or rat alpha1 mRNA, while the ouabain-induced defect was rescued by expression of ouabain-resistant zebrafish alpha1a.1 or rat alpha1 mRNA. Knockdown of a second zebrafish alpha subunit, alpha1a.2, disrupted development of the semicircular canals. Knockdown of Na,K-ATPase beta2b expression also caused an otolith defect, suggesting that the beta2b subunit partners with the alpha1a.1 subunit to form a Na,K-ATPase required for otolith formation. These results reveal novel roles for Na,K-ATPase genes in vestibular system development and indicate that different isoforms play distinct functional roles in formation of inner ear structures. Our results highlight zebrafish gene knockdown-mRNA rescue as an approach that can be used to dissect the functional properties of zebrafish and mammalian Na,K-ATPase genes.
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Affiliation(s)
- Brian Blasiole
- Department of Pharmacology, Penn State University College of Medicine, H078, Hershey, PA 17033, USA
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13
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Shiao JC, Lin LY, Horng JL, Hwang PP, Kaneko T. How can teleostean inner ear hair cells maintain the proper association with the accreting otolith? J Comp Neurol 2005; 488:331-41. [PMID: 15952167 DOI: 10.1002/cne.20578] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The perception of equilibrium and sound in fish depends on the deflection of hair bundles of hair cell by the otolith. However, the accreting nature of teleostean otoliths poses a problem for maintenance of proper contact between the hair bundle and the otolith surface. Immunocytochemical staining localizes abundant proton-secreting H(+)-ATPase in the apical membrane of the hair cells. The H(+)-ATPase-mediated proton secretion into the endolymph causes an approximately 0.4-unit pH decrease, which was quantified by an H(+)-selective microelectrode. Thus, the hair cells maintain the proper distance from the otolith by neutralizing the alkaline endolymph to retard CaCO(3) deposition on the otolith opposite the sensory macula. Carbonic anhydrase, which hydrolyses CO(2) and produces HCO(3) (-) and H(+), was also localized in the hair cells. Ionocytes showed prominent immunostaining of carbonic anhydrase and Na(+)-K(+)-ATPase, indicating its role in transepithelial transport of HCO(3) (-) across the membranous labyrinth into the endolymph. Ionocytes form a ring closely surrounding the sensory macula. HCO(3) (-) secreted from the ionocytes may serve as a barrier to neutralize H(+) diffused from the sensory macula while keeping the endolymph alkaline outside the sensory macula. The ingenious arrangement of ionocytes and hair cells results in a unique sculptured groove, which is a common feature on the proximal surface of all teleostean otoliths.
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14
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Deane EE, Woo NYS. Cloning and characterization of sea bream Na+-K+-ATPase alpha and beta subunit genes: in vitro effects of hormones on transcriptional and translational expression. Biochem Biophys Res Commun 2005; 331:1229-38. [PMID: 15883007 DOI: 10.1016/j.bbrc.2005.04.038] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2005] [Indexed: 11/25/2022]
Abstract
The full length genes encoding the catalytic alpha and glycosylated beta subunits of the sodium pump (Na+-K+-ATPase) were cloned and characterized from silver sea bream gill. Using in vitro preparations of gill tissue it was found that growth hormone (10 and 100 ng/ml) caused an increase in subunit transcription, translation, and Na+-K+-ATPase enzyme activity. Similarly, insulin-like growth factor 1 (10 and 100 ng/ml) also caused an increase in Na+-K+-ATPase subunit amounts and enzyme activity. Cortisol (10 and 100 ng/ml) increased alpha subunit transcript and protein but did not modulate beta subunit expression or enzyme activity. Ovine prolactin did not cause any changes in Na+-K+-ATPase subunit transcription, translation or enzyme activity. This study is the first to describe how both Na+-K+-ATPase alpha and beta subunits are modulated at transcriptional and translational levels in fish osmoregulatory tissue upon exposure to hormones.
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Affiliation(s)
- Eddie E Deane
- Department of Biology, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
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15
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Lowery LA, Sive H. Initial formation of zebrafish brain ventricles occurs independently of circulation and requires the nagie oko and snakehead/atp1a1a.1 gene products. Development 2005; 132:2057-67. [PMID: 15788456 DOI: 10.1242/dev.01791] [Citation(s) in RCA: 162] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The mechanisms by which the vertebrate brain develops its characteristic three-dimensional structure are poorly understood. The brain ventricles are a highly conserved system of cavities that form very early during brain morphogenesis and that are required for normal brain function. We have initiated a study of zebrafish brain ventricle development and show here that the neural tube expands into primary forebrain, midbrain and hindbrain ventricles rapidly, over a 4-hour window during mid-somitogenesis. Circulation is not required for initial ventricle formation, only for later expansion. Cell division rates in the neural tube surrounding the ventricles are higher than between ventricles and, consistently, cell division is required for normal ventricle development. Two zebrafish mutants that do not develop brain ventricles are snakehead and nagie oko. We show that snakehead is allelic to small heart, which has a mutation in the Na+K+ ATPase gene atp1a1a.1. The snakehead neural tube undergoes normal ventricle morphogenesis; however, the ventricles do not inflate, probably owing to impaired ion transport. By contrast, mutants in nagie oko, which was previously shown to encode a MAGUK family protein, fail to undergo ventricle morphogenesis. This correlates with an abnormal brain neuroepithelium, with no clear midline and disrupted junctional protein expression. This study defines three steps that are required for brain ventricle development and that occur independently of circulation: (1) morphogenesis of the neural tube, requiring nok function; (2) lumen inflation requiring atp1a1a.1 function; and (3) localized cell proliferation. We suggest that mechanisms of brain ventricle development are conserved throughout the vertebrates.
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Affiliation(s)
- Laura Anne Lowery
- Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142, USA
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