Crystallins during Xenopus laevis free lens formation

1988 ◽  
Vol 197 (3) ◽  
pp. 190-192 ◽  
Author(s):  
Samir Brahma ◽  
Horst Grunz
Keyword(s):  
Xenopus Laevis ◽  
Lens Formation

scholarly journals Role of the hypoxia response pathway in lens formation during embryonic development of Xenopus laevis

FEBS Open Bio ◽  
2013 ◽  
Vol 3 (1) ◽  
pp. 490-495 ◽  
Author(s):  
Kazunobu Baba ◽  
Taichi Muraguchi ◽  
Susumu Imaoka
Keyword(s):  
Embryonic Development ◽  
Xenopus Laevis ◽  
Hypoxia Response ◽  
Lens Formation

Reinvestigation of the role of the optic vesicle in embryonic lens induction

Development ◽  
1988 ◽  
Vol 102 (3) ◽  
pp. 517-526 ◽  
Author(s):  
R.M. Grainger ◽  
J.J. Herry ◽  
R.A. Henderson
Keyword(s):  
Xenopus Laevis ◽  
Optic Vesicle ◽  
Multistep Process ◽  
Optic Vesicles ◽  
Original Report ◽  
Lens Formation ◽  
Embryonic Ectoderm ◽  
Transplantation Experiments ◽  
Xenopus Laevis Embryos

The induction of the lens by the optic vesicle in amphibians is often cited as support for the view that a single inductive event can lead to determination in a multipotent tissue. This conclusion is based on transplantation experiments whose results indicate that many regions of embryonic ectoderm which would normally form epidermis can form a lens if brought into contact with the optic vesicle. Although additional evidence argues that during normal development other tissues, acting before the optic vesicle, also contribute to lens induction, it is still widely held, on the basis of these transplantation experiments, that the optic vesicle alone can elicit lens formation in ectoderm. While testing this conclusion by transplanting optic vesicles beneath ventral ectoderm in Xenopus laevis embryos, it became apparent that contamination of optic vesicles by presumptive lens ectoderm cells can generate lenses in these experiments, illustrating the need for adequate host and donor marking procedures. Since previous studies rarely used host and donor marking, it was not clear whether they actually demonstrated that the optic vesicle can induce lenses. Using careful host and donor marking procedures with horseradish peroxidase as a lineage tracer, we show that the optic vesicle cannot stimulate lens formation in neurula- or gastrula-stage ectoderm of Xenopus laevis. Since the general conclusion that the optic vesicle is sufficient for lens induction rests on studies in many organisms, we felt it was important to begin to test this conclusion in other amphibians as well. Similar experiments were therefore performed with Rana Palustris embryos, since it was in this organism that optic vesicle transplant studies had originally argued that this tissue alone can cause lens induction. Under conditions similar to those used in the original report, but with careful controls to assess the origin of lenses in transplants, we found that the optic vesicle alone cannot elicit lens formation. Our data lead us to propose that the optic vesicle in amphibians is not generally sufficient for lens induction. Instead, we argue that lens induction occurs by a multistep process in which an essential phase in lens determination occurs as a result of inductive interactions preceding contact of ectoderm with the optic vesicle.

scholarly journals FGF1 Promotes Xenopus laevis Lens Regeneration

2018 ◽  
Author(s):  
Lisa Moore ◽  
Kimberly J. Perry ◽  
Cindy Sun ◽  
Jonathan J. Henry
Keyword(s):  
Xenopus Laevis ◽  
Culture Method ◽  
Dominant Negative ◽  
Dependent Manner ◽  
Regeneration Rate ◽  
Culture Techniques ◽  
Lens Regeneration ◽  
Fgfr Signaling ◽  
Lens Formation

AbstractBackgroundThe frog Xenopus laevis has notable regenerative capabilities, including that of the lens. The neural retina provides the factors that trigger lens regeneration from the cornea, but the identity of these factors is largely unknown. In contrast to the cornea, fibroblast growth factors FGF1, 8, and 9 are highly expressed within the retina, and are potential candidates for those factors. The purpose of this study is to determine whether specific FGF proteins can induce lens formation, and if perturbation of FGFR signaling inhibits lens regeneration.MethodsA novel cornea epithelial culture method was developed to investigate the sufficiency of FGFs in lens regeneration. Additionally, transgenic larvae expressing dominant negative FGFR1 were used to investigate the necessity of FGFR signaling in lens regeneration.ResultsTreatment of cultured corneas with FGF1 induced lens regeneration in a dose-dependent manner, whereas treatment with FGF2, FGF8, or FGF9 did not result in significant lens regeneration. Inhibition of FGFR signaling decreased the lens regeneration rate for in vitro eye cultures.ConclusionThe culture techniques developed here, and elsewhere, have provided reliable methods for examining the necessity of various factors that may be involved in lens regeneration. Based on the results demonstrated in this study, we found that FGF1 signaling and FGFR activation are key factors for lens regeneration in Xenopus.

scholarly journals Xpitx3 : a member of the Rieg/Pitx gene family expressed during pituitary and lens formation in Xenopus laevis

2001 ◽  
Vol 102 (1-2) ◽  
pp. 255-257 ◽  
Author(s):  
Dagmar Pommereit ◽  
Tomas Pieler ◽  
Thomas Hollemann
Keyword(s):  
Xenopus Laevis ◽  
Gene Family ◽  
Lens Formation

Early tissue interactions leading to embryonic lens formation in Xenopus laevis

1990 ◽  
Vol 141 (1) ◽  
pp. 149-163 ◽  
Author(s):  
Jonathan J. Henry ◽  
Robert M. Grainger
Keyword(s):  
Xenopus Laevis ◽  
Tissue Interactions ◽  
Lens Formation

scholarly journals Growth and Cellular Proliferation in the Early Rudiments of the Eye and the Lens

1952 ◽  
Vol s3-93 (23) ◽  
pp. 357-368
Author(s):  
B. I. BALINSKY
Keyword(s):  
Xenopus Laevis ◽  
Mitotic Index ◽  
Cellular Proliferation ◽  
Lens Development ◽  
Morphogenetic Movements ◽  
Duration Of Mitosis ◽  
Morphogenetic Movement ◽  
The Future ◽  
Lens Formation ◽  
Lens Material

1. The relation between growth, cellular proliferation, and morphogenetic movements was investigated in the case of lens formation in Elephantulus myurus jamesoni and Xenopus laevis. 2. For this purpose the volume of the eye cup and lens rudiments was estimated, counts of cells were made, and at the same time counts of cells in mitosis. The mitotic index was calculated, and the material wherever possible was treated statistically. 3. The lens rudiment grows at a greater rate than the eye cup rudiment during the stages in which the lens is being formed. The rate of cellular proliferation in the lens rudiment is also higher than in the eye cup rudiment. The size of the lens cells remains constant whilst the size of the eye cup cells diminishes during the period investigated (at least in Xenopus). 4. The mitotic index in the lens material is lower than in the eye cup material. This indicates that the duration of mitosis in relation to the interkinetic period is, in the eye cup rudiment, greater than in the lens rudiment. 5. The mitotic index in the lens material does not increase or decrease significantly during any stage of the lens development, nor were there found any other indications of an increased or decreased growth or proliferation of the lens material. It is therefore concluded that the formation of a visible lens rudiment is due to morphogenetic movement--contraction of a sheet of cells towards the centre of the future eye cup.

Secondary lens formation from the cornea following implantation of larval tissues between the inner and outer corneas of Xenopus laevis tadpoles

Development ◽  
1981 ◽  
Vol 64 (1) ◽  
pp. 121-132
Author(s):  
Julie G. Reeve ◽  
Arthur E. Wild
Keyword(s):  
Experimental Design ◽  
Xenopus Laevis ◽  
Basal Layer ◽  
Limb Bud ◽  
Lens Regeneration ◽  
Body Tissues ◽  
Single Lens ◽  
Brain Implants ◽  
Lens Formation ◽  
Stimulatory Factor

Secondary lens formation from the cornea of larval Xenopus laevis has been used as a measure of the lens-inducing capacities of various larval Xenopus tissues. The experimental design employed involved implantation of selected body tissues between the inner and outer corneas of stage-5O tadpole eyes, in such a way that the integrity of the inner cornea and eye cup was not disrupted. Implantation of retina, pituitary, limb blastema or limb bud resulted in secondary lens formation from the outer cornea. Such lenses were similar in appearance to stage-5 lens regenerates described by Freeman (1963). No secondary lenses were observed in eyes receiving either heart or hind brain implants or in eyes which underwent corneal separation but which received no implant. It is concluded that the retina is the natural source of a stimulatory factor which initiates and maintains corneal transformation to lens during lens regeneration following lensectomy. Influences emanating from pituitary, limb blastema and limb bud, but apparently not from heart or hind brain, are able to act on cornea in a way similar to the retinal factor. Furthermore, our findings support the contention that in the normal eye, the inner cornea is a barrier to the passage of retinal factor and so maintains the single lens structure of the eye. When this barrier is by-passed by lens-inducing tissue, as in the present experimental design, lens formation from the cornea is able to take place. Electronmicroscopical studies have shown that the inner cornea, in the stage-50 tadpole eye, consists of a dense meshwork of collagen fibrils and a basal layer of cohesive elongated mesenchymal cells well suited for this barrier function.

Androgen-induced plasticity at a “vocal” neuromuscular synapse

1994 ◽  
Vol 52 ◽  
pp. 32-33
Author(s):  
Darcy B. Kelley ◽  
Martha L. Tobias ◽  
Mark Ellisman
Keyword(s):  
Xenopus Laevis ◽  
Motor Neurons ◽  
Sexual Differentiation ◽  
Molecular Basis ◽  
Neuromuscular Synapse ◽  
Sexually Dimorphic ◽  
Intracellular Protein ◽  
Developmental Program ◽  
Androgen Action ◽  
Clawed Frog

Brain and muscle are sexually differentiated tissues in which masculinization is controlled by the secretion of androgens from the testes. Sensitivity to androgen is conferred by the expression of an intracellular protein, the androgen receptor. A central problem of sexual differentiation is thus to understand the cellular and molecular basis of androgen action. We do not understand how hormone occupancy of a receptor translates into an alteration in the developmental program of the target cell. Our studies on sexual differentiation of brain and muscle in Xenopus laevis are designed to explore the molecular basis of androgen induced sexual differentiation by examining how this hormone controls the masculinization of brain and muscle targets.Our approach to this problem has focused on a highly androgen sensitive, sexually dimorphic neuromuscular system: laryngeal muscles and motor neurons of the clawed frog, Xenopus laevis. We have been studying sex differences at a synapse, the laryngeal neuromuscular junction, which mediates sexually dimorphic vocal behavior in Xenopus laevis frogs.

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