Vision - Lens Development: Difference between revisions
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* '''Review - The cellular and molecular mechanisms of vertebrate lens development'''<ref name=PMID25406393><pubmed>25406393</pubmed></ref>| [http://dev.biologists.org/content/141/23/4432.full?sid=9c0c0b67-790f-42a6-8551-73876896a0d6 Development] "The ocular lens is a model system for understanding important aspects of embryonic development, such as cell specification and the spatiotemporally controlled formation of a three-dimensional structure. The lens, which is characterized by transparency, refraction and elasticity, is composed of a bulk mass of fiber cells attached to a sheet of lens epithelium. Although lens induction has been studied for over 100 years, recent findings have revealed a myriad of extracellular signaling pathways and gene regulatory networks, integrated and executed by the transcription factor Pax6, that are required for lens formation in vertebrates." | |||
* '''Pax6-dependent, but β-catenin-independent, function of Bcl9 proteins in mouse lens development'''<ref><pubmed>25184676</pubmed></ref> "While lens development is critically dependent on the presence of the HD1 domain, it is not affected by the lack of the HD2 domain, indicating that Bcl9/9l act in this context in a β-catenin-independent manner. Furthermore, we uncover a new regulatory circuit in which Pax6, the master regulator of eye development, directly activates Bcl9/9l transcription." | * '''Pax6-dependent, but β-catenin-independent, function of Bcl9 proteins in mouse lens development'''<ref><pubmed>25184676</pubmed></ref> "While lens development is critically dependent on the presence of the HD1 domain, it is not affected by the lack of the HD2 domain, indicating that Bcl9/9l act in this context in a β-catenin-independent manner. Furthermore, we uncover a new regulatory circuit in which Pax6, the master regulator of eye development, directly activates Bcl9/9l transcription." | ||
* '''On the growth and internal structure of the human lens'''<ref><pubmed>20171212</pubmed></ref> "Growth of the human lens and the development of its internal features are examined using in vivo and in vitro observations on dimensions, weights, cell sizes, protein gradients and other properties. In vitro studies have shown that human lens growth is biphasic, asymptotic until just after birth and linear for most of postnatal life." | * '''On the growth and internal structure of the human lens'''<ref><pubmed>20171212</pubmed></ref> "Growth of the human lens and the development of its internal features are examined using in vivo and in vitro observations on dimensions, weights, cell sizes, protein gradients and other properties. In vitro studies have shown that human lens growth is biphasic, asymptotic until just after birth and linear for most of postnatal life." |
Revision as of 21:30, 3 March 2015
Embryology - 16 May 2024 Expand to Translate |
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Introduction
The lens or crystalline lens or aquula (Latin, aquula = a little stream) has a key role in focussing light (with the cornea) upon the neural retina. The lens embryonic origin is from surface ectoderm of the sensory placodes that form in the head region (More? Placodes).
The lens focusses by refracting light as it passes through the biconvex lens, which can be altered in shape (accommodation) by surrounding ciliary muscles. These ciliary muscles are activated (contracted) by parasympathetic innervation from the ciliary ganglion itself innervated by the oculomotor nerve (Cranial Nerve III).
The lens has recently been shown in the chicken model to not be required for specification of the iris and ciliary body.[1]
Some Recent Findings
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More recent papers |
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This table allows an automated computer search of the external PubMed database using the listed "Search term" text link.
More? References | Discussion Page | Journal Searches | 2019 References | 2020 References Search term: Lens Embryology <pubmed limit=5>Lens Embryology</pubmed> |
Development Overview
surface ectoderm -> lens placode -> lens pit -> lens vesicle -> lens fibres -> lens capsule and embryonic/fetal nucleus.
Week 4
Human Embryo Carnegie stage 11 optic pit
Week 5
Week 8
The images below link to virtual slides of the human developing eye at Carnegie stage 22. Click on the image to open or select specific regions from the regions of interest links.
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Virtual Slide - Regions of Interest |
Links: Carnegie stage 22 | Embryo Virtual Slides
Molecular Signaling
Wnt mediates lens repression by neural crest cells and Transforming growth factor-β[6] (open image for full description)
- Links: Lens Development | Neural Crest Development | Wnt | Lens repression by neural crest cells | Proposed model how NCCs organize the eye | molecular model to explain TGF-β- and Wnt-mediated lens restriction
References
- ↑ <pubmed>17275804</pubmed>
- ↑ <pubmed>25406393</pubmed>
- ↑ <pubmed>25184676</pubmed>
- ↑ <pubmed>20171212</pubmed>
- ↑ <pubmed>20105280</pubmed>
- ↑ Grocott T, Johnson S, Bailey AP, Streit A. Neural crest cells organize the eye via TGF-β and canonical Wnt signalling. Nat Commun. 2011 Apr;2:265. PMID21468017 | Nat Commun.
Glossary Links
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Cite this page: Hill, M.A. (2024, May 16) Embryology Vision - Lens Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Vision_-_Lens_Development
- © Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G