Difference between revisions of "Talk:Sensory - Vision Development"

From Embryology
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===Embryology of the eye and its adnexae===
Dev Ophthalmol. 1992;24:1-142.
Barishak YR.
Sackler School of Medicine, University of Tel Aviv, Ramat Gan, Israel.
The embryonal and fetal development of the human eye includes a series of sequential events starting with the fertilization of the ovum and culminating in the birth of a normal baby. Three main periods can be distinguished in the prenatal development of the eye. The first period called embryogenesis is characterized by the establishment of the primary organ rudiments and ends at the end of the 3rd week with the appearance of the optic sulci on both sides of the midline at the expanded cranial end of the still open neural folds. The second period called organogenesis includes the development of the primary organ rudiments and extends till the end of the 8th week. The third period involves the differentiation of each of the primitive organs into a fully or partially active organ and is called differentiation. The period of embryogenesis is characterized by the appearance and migration of the neural crest cells and by the formation of the primary brain vesicles. The period of organogenesis extends from the 4th week till the end of the 8th week. The 4th week shows the closure of the neural canal anteriorly with the subsequent evagination of its lateral wall into optic vesicles, the invagination of the lower nasal wall of the optic vesicle causing the formation of the optic cup, and the development of the lens plate, retinal disk and embryonic fissure. The embryonic fissure extends into the optic stalk which connects the cavity of the optic vesicle with the cavity of the neural canal; the hyaloid artery penetrates into the optic cup through the embryonic fissure. During the 5th week, the optic cup is concluded, and the cells of its external layer acquire pigmentation as a result of contact with developing capillaries in the periocular mesenchyme; these capillaries anastomose with each other and form anteriorly the annular vessel. The lens plate develops into a lens pit and later into a lens vesicle which separates soon thereafter from the surface ectoderm. Inside the optic cup, the hyaloid vessels form the capillaries of the posterior tunica vasculosa lentis and through the capillaries of the lateral tunica vasculosa lentis anastomose with the annular vessel. The primary vitreous forms and the surface ectoderm overlying the lens vesicle differentiates into a primitive corneal epithelium. The facial and orbital structures also develop at this stage. The 6th week shows the incipient differentiation of the inner layer of the optic cup into a sensory retina, the formation of the secondary vitreous, the transformation of the posterior cells of the lens vesicle into primary lens fibers, the development of the periocular vasculature and the appearance of the first eyelid folds and of the anlage of the nasolacrimal duct. However, the dominating factor is the closure of the embryonic fissure.(ABSTRACT TRUNCATED AT 400 WORDS)
PMID: 1628748

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Cite this page: Hill, M.A. (2021, October 23) Embryology Sensory - Vision Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Sensory_-_Vision_Development


Progenitor cells of the rod-free area centralis originate in the anterior dorsal optic vesicle

Shin SK, O'Brien KM. BMC Dev Biol. 2009 Nov 25;9:57. PMID: 19939282


Rearrangement of retinogeniculate projection patterns after eye-specific segregation in mice

Hayakawa I, Kawasaki H. PLoS One. 2010 Jun 8;5(6):e11001. PMID: 20544023


Generation of functional eyes from pluripotent cells

PLoS Biol. 2009 Aug;7(8):e1000174. Epub 2009 Aug 18.

Viczian AS, Solessio EC, Lyou Y, Zuber ME.

Department of Ophthalmology, State University of New York (SUNY) Upstate Medical University, Syracuse, New York, United States of America. Comment in:

PLoS Biol. 2009;7(8):e1000175. Abstract Pluripotent cells such as embryonic stem (ES) and induced pluripotent stem (iPS) cells are the starting point from which to generate organ specific cell types. For example, converting pluripotent cells to retinal cells could provide an opportunity to treat retinal injuries and degenerations. In this study, we used an in vivo strategy to determine if functional retinas could be generated from a defined population of pluripotent Xenopus laevis cells. Animal pole cells isolated from blastula stage embryos are pluripotent. Untreated, these cells formed only epidermis, when transplanted to either the flank or eye field. In contrast, misexpression of seven transcription factors induced the formation of retinal cell types. Induced retinal cells were committed to a retinal lineage as they formed eyes when transplanted to the flanks of developing embryos. When the endogenous eye field was replaced with induced retinal cells, they formed eyes that were molecularly, anatomically, and electrophysiologically similar to normal eyes. Importantly, induced eyes could guide a vision-based behavior. These results suggest the fate of pluripotent cells may be purposely altered to generate multipotent retinal progenitor cells, which differentiate into functional retinal cell classes and form a neural circuitry sufficient for vision.

PMID: 19688031


Shaping the vertebrate eye

Martinez-Morales JR, Wittbrodt J. Curr Opin Genet Dev. 2009 Oct;19(5):511-7. Epub 2009 Oct 8. Review. For over a century, the vertebrate eye has served as a paradigm for organogenesis. It forms through a complex sequence of morphogenetic events, involving the lateral evagination of the optic vesicles and their subsequent folding into the optic cups. Through intensive studies by experimental embryologists, anatomical descriptions of the process were available since many decades. Recent genetic and molecular work has illuminated essential features of the stereotyped cellular behaviour driving eye morphogenesis. The first pieces of the molecular machinery operating in each individual progenitor cell have been identified. These studies now set the groundwork for a system-wide approach towards understanding the cellular and molecular mechanisms involved in shaping the vertebrate eye.

PMID: 19819125 http://www.ncbi.nlm.nih.gov/pubmed/19819125


The other pigment cell: specification and development of the pigmented epithelium of the vertebrate eye

Bharti K, Nguyen MT, Skuntz S, Bertuzzi S, Arnheiter H. Pigment Cell Res. 2006 Oct;19(5):380-94. Review.

Vertebrate retinal pigment epithelium (RPE) cells are derived from the multipotent optic neuroepithelium, develop in close proximity to the retina, and are indispensible for eye organogenesis and vision. Recent advances in our understanding of RPE development provide evidence for how critical signaling factors operating in dorso-ventral and distal-proximal gradients interact with key transcription factors to specify three distinct domains in the budding optic neuroepithelium: the distal future retina, the proximal future optic stalk/optic nerve, and the dorsal future RPE. Concomitantly with domain specification, the eye primordium progresses from a vesicle to a cup, RPE pigmentation extends towards the ventral side, and the future ciliary body and iris form from the margin zone between RPE and retina. While much has been learned about the molecular networks controlling RPE cell specification, key questions concerning the cell proliferative parameters in RPE and the subsequent morphogenetic events still need to be addressed in greater detail.

PMID: 16965267 http://www.ncbi.nlm.nih.gov/pubmed/16965267

Genetic aspects of embryonic eye development in vertebrates

Graw J. Dev Genet. 1996;18(3):181-97. Review.

The vertebrate eye comprises tissues from different embryonic origins, e.g., iris and ciliary body are derived from the wall of the diencephalon via optic vesicle and optic cup. Lens and cornea, on the other hand, come from the overlying surface ectoderm. The timely action of transcription factors and inductive signals ensure the correct development of the different eye components. Establishing the genetic basis of eye defects has been an important tool for the detailed analysis of this complex process. One of the main control genes for eye development was discovered by the analysis of the allelic series of the Small eye mouse mutants and characterized as Pax6. It is involved in the interaction between the optic cup and the overlaying ectoderm. The central role for Pax6 in eye development is conserved throughout the animal kingdom as the murine Pax6 gene induces ectopic eyes in transgenic Drosophila despite the obvious diverse organization of the eye in the fruit fly compared to vertebrates. In human, mutations in the PAX6 gene are responsible for aniridia and Peter's anomaly. In addition to Pax6, other mutations affecting the interaction of the optic cup and the lens placode have been documented in the mouse. For the differentiation of the retina from the optic cup several genes are responsible: Mi leads to microphthalmia, if mutated, and encodes for a transcription factor, which is expressed in the melanocytes of the pigmented layer of the retina. In addition, further genes are implicated in the correct development of the retina, e.g., Chx10, Dlx1, GH6, Msx1 and -2, Otx1 and -2, or Wnt7b. Mutations within the retinoblastoma gene (RB1) are responsible for retinal tumors. Knock-out mutants of RB1 exhibit a block of lens differentiation prior to the retinal defect. Besides the influence of Rb1, the lens differentiates under the influence of growth factors (e.g., FGF, IGF, PDGF, TGF), and specific genes become activated encoding cytoskeletal proteins (e.g., filensin, phakinin, vimentin), structural proteins (e.g., crystallins) or membrane proteins (e.g., Mip). The optic nerve originates from the neural retina; ganglion cells grow to the optic stalk, forming the optic nerve. Its retrograde walk to the brain through the rudiment of the optic stalk depends on the correct Pax2 expression.

PMID: 8631154 http://www.ncbi.nlm.nih.gov/pubmed/8631154


Non-vascular smooth muscle cells in the human choroid: distribution, development and further characterization

J Anat. 2005 Oct;207(4):381-90.

May CA.

Department of Anatomy, Medical Faculty Carl Gustav Carus, TU Dresden, Dresden, Germany. Albrecht.May@mailbox.tu-dresden.de Abstract To characterize further non-vascular smooth muscle cells (NVSMC) in the choroid of the human eye, extensive morphological studies were performed including a three-dimensional distribution of NVSMC in the adult human eye and their appearance during development. Whole mounts and sections through the choroid and sclera of eyes of 42 human donors (between the 13th week of gestation and 89 years of age) were stained with antibodies against smooth muscle actin and other markers for smooth muscle cells. On the basis of their morphological localization, three groups of NVSMC could be distinguished in the adult eyes: (a) a semicircular arrangement of NVSMC in the suprachoroid and inner sclera, around the entry of posterior ciliary arteries and nerves; (b) NVSMC parallel to the vessels in the posterior eye segment between the point of entry of the posterior ciliary arteries and the point of exit of the vortex veins; and (c) a dense plaque-like arrangement of NVSMC in the suprachoroid, overlying the foveal region. The last of these groups showed most pronounced interindividual differences. During development, the first NVSMC to be observed at the 20th week of gestation belonged to group b. A complete NVSMC network was first observed in a 6-year-old donor eye. All three groups stained positive for smoothelin, caldesmon and calponin in all localizations. The NVSMC show a distinct distribution that might reflect different aspects of their function in the choroid and suprachoroid. All cells could be histochemically characterized as truly contractile.

PMID: 16191166