Talk:Vision - Retina Development: Difference between revisions
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This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial Share Alike License, which permits unrestricted non-commercial use, distribution and reproduction in any medium provided that the original work is properly cited and all further distributions of the work or adaptation are subject to the same Creative Commons License terms. | This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial Share Alike License, which permits unrestricted non-commercial use, distribution and reproduction in any medium provided that the original work is properly cited and all further distributions of the work or adaptation are subject to the same Creative Commons License terms. | ||
==2011== | |||
===The cell adhesion-associated protein Git2 regulates morphogenetic movements during zebrafish embryonic development=== | |||
Dev Biol. 2011 Jan 15;349(2):225-37. Epub 2010 Oct 26. | |||
Yu JA, Foley FC, Amack JD, Turner CE. | |||
Source | |||
Department of Cell and Developmental Biology, State University of New York, Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210, USA. | |||
Abstract | |||
Signaling through cell adhesion complexes plays a critical role in coordinating cytoskeletal remodeling necessary for efficient cell migration. During embryonic development, normal morphogenesis depends on a series of concerted cell movements; but the roles of cell adhesion signaling during these movements are poorly understood. The transparent zebrafish embryo provides an excellent system to study cell migration during development. Here, we have identified zebrafish git2a and git2b, two new members of the GIT family of genes that encode ArfGAP proteins associated with cell adhesions. Loss-of-function studies revealed an essential role for Git2a in zebrafish cell movements during gastrulation. Time-lapse microscopy analysis demonstrated that antisense depletion of Git2a greatly reduced or arrested cell migration towards the vegetal pole of the embryo. These defects were rescued by expression of chicken GIT2, indicating a specific and conserved role for Git2 in controlling embryonic cell movements. Git2a knockdown embryos showed defects in cell morphology that were associated with reduced cell contractility. We show that Git2a is required for phosphorylation of myosin light chain (MLC), which regulates myosin II-mediated cell contractility. Consistent with this, embryos treated with Blebbistatin-a small molecule inhibitor for myosin II activity-exhibited cell movement defects similar to git2a knockdown embryos. These observations provide in vivo evidence of a physiologic role for Git2a in regulating cell morphogenesis and directed cell migration via myosin II activation during zebrafish embryonic development. | |||
Copyright © 2010 Elsevier Inc. All rights reserved. | |||
PMID 21034731 | |||
==2010== | ==2010== | ||
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PMID 20130177 | PMID 20130177 | ||
==2009== | ==2009== | ||
Revision as of 21:16, 15 April 2012
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Cite this page: Hill, M.A. (2024, May 2) Embryology Vision - Retina Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Vision_-_Retina_Development |
2012
A complex choreography of cell movements shapes the vertebrate eye
Development. 2012 Jan;139(2):359-72.
Kwan KM, Otsuna H, Kidokoro H, Carney KR, Saijoh Y, Chien CB.
Source Department of Neurobiology and Anatomy, Salt Lake City, UT 84132, USA. kristen.kwan@neuro.utah.edu
Abstract
Optic cup morphogenesis (OCM) generates the basic structure of the vertebrate eye. Although it is commonly depicted as a series of epithelial sheet folding events, this does not represent an empirically supported model. Here, we combine four-dimensional imaging with custom cell tracking software and photoactivatable fluorophore labeling to determine the cellular dynamics underlying OCM in zebrafish. Although cell division contributes to growth, we find it dispensable for eye formation. OCM depends instead on a complex set of cell movements coordinated between the prospective neural retina, retinal pigmented epithelium (RPE) and lens. Optic vesicle evagination persists for longer than expected; cells move in a pinwheel pattern during optic vesicle elongation and retinal precursors involute around the rim of the invaginating optic cup. We identify unanticipated movements, particularly of central and peripheral retina, RPE and lens. From cell tracking data, we generate retina, RPE and lens subdomain fate maps, which reveal novel adjacencies that might determine corresponding developmental signaling events. Finally, we find that similar movements also occur during chick eye morphogenesis, suggesting that the underlying choreography is conserved among vertebrates.
PMID 22186726
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3243097
http://dev.biologists.org/content/suppl/2011/12/16/139.2.359.DC1
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial Share Alike License, which permits unrestricted non-commercial use, distribution and reproduction in any medium provided that the original work is properly cited and all further distributions of the work or adaptation are subject to the same Creative Commons License terms.
2011
The cell adhesion-associated protein Git2 regulates morphogenetic movements during zebrafish embryonic development
Dev Biol. 2011 Jan 15;349(2):225-37. Epub 2010 Oct 26.
Yu JA, Foley FC, Amack JD, Turner CE. Source Department of Cell and Developmental Biology, State University of New York, Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210, USA.
Abstract
Signaling through cell adhesion complexes plays a critical role in coordinating cytoskeletal remodeling necessary for efficient cell migration. During embryonic development, normal morphogenesis depends on a series of concerted cell movements; but the roles of cell adhesion signaling during these movements are poorly understood. The transparent zebrafish embryo provides an excellent system to study cell migration during development. Here, we have identified zebrafish git2a and git2b, two new members of the GIT family of genes that encode ArfGAP proteins associated with cell adhesions. Loss-of-function studies revealed an essential role for Git2a in zebrafish cell movements during gastrulation. Time-lapse microscopy analysis demonstrated that antisense depletion of Git2a greatly reduced or arrested cell migration towards the vegetal pole of the embryo. These defects were rescued by expression of chicken GIT2, indicating a specific and conserved role for Git2 in controlling embryonic cell movements. Git2a knockdown embryos showed defects in cell morphology that were associated with reduced cell contractility. We show that Git2a is required for phosphorylation of myosin light chain (MLC), which regulates myosin II-mediated cell contractility. Consistent with this, embryos treated with Blebbistatin-a small molecule inhibitor for myosin II activity-exhibited cell movement defects similar to git2a knockdown embryos. These observations provide in vivo evidence of a physiologic role for Git2a in regulating cell morphogenesis and directed cell migration via myosin II activation during zebrafish embryonic development. Copyright © 2010 Elsevier Inc. All rights reserved.
PMID 21034731
2010
Role of afferents in the differentiation of bipolar cells in the mouse retina
J Neurosci. 2010 Feb 3;30(5):1677-85.
Keeley PW, Reese BE. Department of Molecular, Cellular, and Developmental Biology, and Neuroscience Research Institute, University of California at Santa Barbara, Santa Barbara, California 93106, USA.
Abstract To establish dendritic arbors that integrate properly into a neural circuit, neurons must rely on cues from the local environment. The neurons presynaptic to these arbors, the afferents, are one potential source of these cues, but the particular dendritic features they regulate remain unclear. Retinal bipolar cells can be classified by the type of photoreceptor, cone or rod, forming synaptic contacts with their dendrites, suggesting a potential role of these afferents in shaping the bipolar cell dendritic arbor. In the present investigation, the role of photoreceptors in directing the differentiation of bipolar cells has been studied using two genetically modified "coneless" and "conefull" mice. Single cone (Type 7/CB4a) and rod bipolar cells were labeled with DiI to reveal the entire dendritic arbor and subsequently analyzed for several morphological features. For both cone and rod bipolar cells, the dendritic field area, number of dendritic terminals, and stratification of terminals in the outer plexiform layer were comparable among coneless, conefull, and wild-type retinas, and the overall morphological appearance of each type of cell was essentially conserved, indicating an independence from afferent specification. The presence of normal afferents was, however, found to be critical for the proper spatial distribution of dendritic terminals, exhibiting a clustered distribution for the cone bipolar cells and a dispersed distribution for the rod bipolar cells. These results demonstrate a selectivity in the afferent dependency of bipolar cell differentiation, their basic morphogenetic plan commanded cell intrinsically, and their fine terminal connectivity directed by the afferents themselves.
PMID 20130177
2009
Dynamic coupling of pattern formation and morphogenesis in the developing vertebrate retina
PLoS Biol. 2009 Oct;7(10):e1000214. Epub 2009 Oct 13.
Picker A, Cavodeassi F, Machate A, Bernauer S, Hans S, Abe G, Kawakami K, Wilson SW, Brand M. Center of Regenerative Therapies Dresden, Biotechnology Center, Dresden University of Technology, Dresden, Germany. alexander.picker@biotec.tu-dresden.de
Abstract During embryonic development, pattern formation must be tightly synchronized with tissue morphogenesis to coordinate the establishment of the spatial identities of cells with their movements. In the vertebrate retina, patterning along the dorsal-ventral and nasal-temporal (anterior-posterior) axes is required for correct spatial representation in the retinotectal map. However, it is unknown how specification of axial cell positions in the retina occurs during the complex process of early eye morphogenesis. Studying zebrafish embryos, we show that morphogenetic tissue rearrangements during eye evagination result in progenitor cells in the nasal half of the retina primordium being brought into proximity to the sources of three fibroblast growth factors, Fgf8/3/24, outside the eye. Triple-mutant analysis shows that this combined Fgf signal fully controls nasal retina identity by regulating the nasal transcription factor Foxg1. Surprisingly, nasal-temporal axis specification occurs very early along the dorsal-ventral axis of the evaginating eye. By in vivo imaging GFP-tagged retinal progenitor cells, we find that subsequent eye morphogenesis requires gradual tissue compaction in the nasal half and directed cell movements into the temporal half of the retina. Balancing these processes drives the progressive alignment of the nasal-temporal retina axis with the anterior-posterior body axis and is controlled by a feed-forward effect of Fgf signaling on Foxg1-mediated cell cohesion. Thus, the mechanistic coupling and dynamic synchronization of tissue patterning with morphogenetic cell behavior through Fgf signaling leads to the graded allocation of cell positional identity in the eye, underlying retinotectal map formation.
PMID 19823566
2008
Iris development in vertebrates; genetic and molecular considerations
Brain Res. 2008 Feb 4;1192:17-28. Epub 2007 Mar 20.
Davis-Silberman N, Ashery-Padan R. Sackler Faculty of Medicine, Department of Human Molecular Genetics and Biochemistry, Tel Aviv University, Ramat Aviv 69978, Tel Aviv, Israel.
Abstract The iris plays a key role in visual function. It regulates the amount of light entering the eye and falling on the retina and also operates in focal adjustment of closer objects. The iris is involved in circulation of the aqueous humor and hence functions in regulation of intraocular pressure. Intriguingly, iris pigmented cells possess the ability to transdifferentiate into different ocular cell types of retinal pigmented epithelium, photoreceptors and lens cells. Thus, the iris is considered a potential source for cell-replacement therapies. During embryogenesis, the iris arises from both the optic cup and the periocular mesenchyme. Its interesting mode of development includes specification of the peripheral optic cup to a non-neuronal fate, migration of cells from the surrounding periocular mesenchyme and an atypical formation of smooth muscles from the neuroectoderm. This manner of development raises some interesting general topics concerning the early patterning of the neuroectoderm, the specification and differentiation of diverse cell types and the interactions between intrinsic and extrinsic factors in the process of organogenesis. In this review, we discuss iris anatomy and development, describe major pathologies of the iris and their molecular etiology and finally summarize the recent findings on genes and signaling pathways that are involved in iris development.
PMID 17466284
