scholarly journals AP-2αTranscription Factor Is Required for Early Morphogenesis of the Lens Vesicle

1999 ◽  
Vol 206 (1) ◽  
pp. 46-62 ◽  
Author(s):  
Judith A. West-Mays ◽  
Jian Zhang ◽  
Timothy Nottoli ◽  
Stephanie Hagopian-Donaldson ◽  
Derek Libby ◽  
...  
Keyword(s):  
Lens Vesicle

A STUDY OF THE INHIBITORY EFFECTS OF CHICK WHOLE EYE EXTRACT ON THE DEVELOPMENT OF THE LENS OF THE CHICK EMBRYO IN VITRO

1966 ◽  
Vol 44 (4) ◽  
pp. 661-676 ◽  
Author(s):  
Robert P. Thompson
Keyword(s):  
Chick Embryo ◽  
Nutrient Medium ◽  
Inhibitory Effect ◽  
Reactive System ◽  
Vesicle Formation ◽  
Inhibitory Effects ◽  
Muscle Extract ◽  
Lens Vesicle ◽  
And Control

To demonstrate the phenomenon of homologous inhibition by clearly interpretable results in a readily reactive system, experiments were carried out to study the effect of chick whole eye extract on the development of the vesicular lens of the chick embryo in vitro. The heads of embryos of 11 through 13 somites were explanted onto nutrient medium diluted with varying amounts of the extract, and cultured for 30 hours. A total of 35 embryos exposed to concentrations of 1:1, 1:2, and 1:4 (extract to medium) showed complete inhibition of lens vesicle formation. Of a total of 53 embryos on concentrations of 1:8, 1:16, 1:32, and 1:64, more than 50% showed inhibition of vesicle formation. The inhibitory effect disappeared at a concentration of 1:128. Control material exposed to some equivalent concentrations of nutrient medium – saline mixtures showed inhibition of vesicle formation in only 15% of 33 embryos. Of a total of 27 control embryos exposed to ventricular muscle extract, approximately one-third showed inhibition of vesicle formation at concentrations of 1:8 and 1:16, with the inhibitory effect disappearing at 1:32. The implications of this result are discussed. Other factors and control experiments are described and their value is assessed.

The upstream ectoderm enhancer in Pax6 has an important role in lens induction

Development ◽  
2001 ◽  
Vol 128 (22) ◽  
pp. 4415-4424 ◽  
Author(s):  
Patricia V. Dimanlig ◽  
Sonya C. Faber ◽  
Woytek Auerbach ◽  
Helen P. Makarenkova ◽  
Richard A. Lang
Keyword(s):  
Transcriptional Control ◽  
Control Element ◽  
Pax6 Gene ◽  
Pax6 Expression ◽  
Surface Ectoderm ◽  
Targeted Deletion ◽  
Lens Vesicle ◽  
Normal Lens ◽  
Lens Formation ◽  
Lens Placode

The Pax6 gene has a central role in development of the eye. We show, through targeted deletion in the mouse, that an ectoderm enhancer in the Pax6 gene is required for normal lens formation. Ectoderm enhancer-deficient embryos exhibit distinctive defects at every stage of lens development. These include a thinner lens placode, reduced placodal cell proliferation, and a small lens pit and lens vesicle. In addition, the lens vesicle fails to separate from the surface ectoderm and the maturing lens is smaller and shows a delay in fiber cell differentiation. Interestingly, deletion of the ectoderm enhancer does not eliminate Pax6 production in the lens placode but results in a diminished level that, in central sections, is apparent primarily on the nasal side. This argues that Pax6 expression in the lens placode is controlled by the ectoderm enhancer and at least one other transcriptional control element. It also suggests that Pax6 enhancers active in the lens placode drive expression in distinct subdomains, an assertion that is supported by the expression pattern of a lacZ reporter transgene driven by the ectoderm enhancer. Interestingly, deletion of the ectoderm enhancer causes loss of expression of Foxe3, a transcription factor gene mutated in the dysgenetic lens mouse. When combined, these data and previously published work allow us to assemble a more complete genetic pathway describing lens induction. This pathway features (1) a pre-placodal phase of Pax6 expression that is required for the activity of multiple, downstream Pax6 enhancers; (2) a later, placodal phase of Pax6 expression regulated by multiple enhancers; and (3) the Foxe3 gene in a downstream position. This pathway forms a basis for future analysis of lens induction mechanism.

Closure of Lens Vesicle

1989 ◽  
pp. 73-77 ◽  
Author(s):  
Karl Theiler
Keyword(s):  
Lens Vesicle

scholarly journals Mutation in the mouse histone gene Hist2h3c1 leads to degeneration of the lens vesicle and severe microphthalmia

2019 ◽  
Vol 188 ◽  
pp. 107632 ◽  
Author(s):  
Sharmilee Vetrivel ◽  
Natascia Tiso ◽  
Andrea Kügler ◽  
Martin Irmler ◽  
Marion Horsch ◽  
...  
Keyword(s):  
Histone Gene ◽  
Lens Vesicle

scholarly journals Cell autonomous roles for AP-2α in lens vesicle separation and maintenance of the lens epithelial cell phenotype

2008 ◽  
Vol 237 (3) ◽  
pp. 602-617 ◽  
Author(s):  
Giuseppe F. Pontoriero ◽  
Paula Deschamps ◽  
Ruth Ashery-Padan ◽  
Ryan Wong ◽  
Ying Yang ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Lens Epithelial Cell ◽  
Cell Phenotype ◽  
Lens Vesicle

scholarly journals Rubella cataract in vitro: Sensitive period of the developing human lens.

1975 ◽  
Vol 141 (6) ◽  
pp. 1238-1248 ◽  
Author(s):  
M Karkinen-Jääskeläinen ◽  
L Saxén ◽  
A Vaheri ◽  
P Leinikki
Keyword(s):  
Clinical Findings ◽  
Lens Capsule ◽  
Human Lens ◽  
Sensitive Period ◽  
Fiber Damage ◽  
Viral Antigens ◽  
Lens Vesicle ◽  
Lens Placode ◽  
Made In

The clinically known sensitive period of rubella cataract was studied in vitro by infecting 79 human eye rudiments from embryos aged 4-10 wk with rubella virus. The course of the infection was followed by histological and indirect immunofluorescence methods. Of the rudiments, 12 pairs were in the lens placode or open-lens-vesicle stage, 40 already had closed lens vesicles and in another 27 closed-stage pairs an incision was made in the lens capsule before infection to allow the virus to enter the lens. Uninfected controls differentiated well in vitro for 4-6 wk. The eye rudiments infected in the open-lens-vesicle stage showed lens fiber destruction and viral antigens within the lens. No damage or viral antigens were detected in rudiments infected in the closed stage unless the lens capsule was incisedmwhen this was done, however, fiber damage ensued and viral antigens appeared. The lens capsule was concluded to form a protective barrier around the sensirive fibers at the time of closure of the lens vesicle, confirming the earlier hypothesis and clinical findings.

scholarly journals CHANGES IN CELL FINE STRUCTURE DURING LENS REGENERATION IN XENOPUS LAEVIS

1965 ◽  
Vol 24 (2) ◽  
pp. 211-222 ◽  
Author(s):  
Jane Overton
Keyword(s):  
Fine Structure ◽  
Xenopus Laevis ◽  
Normal Development ◽  
Low Density ◽  
Morphological Complexity ◽  
Lens Fibers ◽  
Lens Regeneration ◽  
Lens Vesicle ◽  
Rough Er ◽  
Two Phases

Changes at the level of cell fine structure have been studied during lens regeneration in the toad, Xenopus laevis, where cornea gives rise to the new lens. The transformation of these cells may be divided into three phases. (1) In the cornea, flattened cells become cuboidal and rough endoplasmic reticulum increases in amount. (2) In the new lens vesicle, cisternae of the rough ER break down into vesicles, smooth-walled vesicles and free ribosomes increase in number, and mitochondria can become enlarged and irregular, then centrally attenuated. Rudimentary cilia form. (3) As new lens fibers form, ribosomes become very numerous and low density fibrous elements and dense clumps appear in the cytoplasm. These phases are accompanied by marked nucleolar changes. The changes during the 3rd phase are similar to changes in the lens during normal development. The first two phases show an unexpected morphological complexity.

The Behaviour of Basophil Cytoplasmic Substances during Neural Induction in the Chick

Development ◽  
1957 ◽  
Vol 5 (2) ◽  
pp. 111-121
Author(s):  
J. O. Lavarack
Keyword(s):  
Nucleic Acid ◽  
Nucleic Acids ◽  
Neural Induction ◽  
Cell Group ◽  
Chemical Mechanisms ◽  
Cytoplasmic Material ◽  
Large Particles ◽  
Lens Vesicle ◽  
Organizer Activity

On the possible role of nucleic acids in organizer activity Brachet's (1940) histochemical researches show that a basophil cytoplasmic material, which he identifies with ribose nucleic acid, is present generally in regions of active differentiation and that it accumulates at interfaces between inductors and the cells responsive to them. These conclusions are supported by Gallera & Oprecht (1948). Further, it is known that much of the ribose nucleic acid of cytoplasm is bound to the submicroscopic particulates and certain observations suggest that neural induction (Holtfreter, 1933; Brachet, 1950) and induction of the lens vesicle (McKeehan, 1951) depend at some stage on contact or the transfer of relatively large particles from one cell group to another. It may well be that any chemical mechanisms concerned are complex and include chains of reactions involving a number of substances. Among possible participants nucleic acids are of particular interest because of their metabolic relationships with proteins.

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