Expression of a truncated FGF receptor results in defective lens development in transgenic mice

Members of the fibroblast growth factor (FGF) family are thought to initiate biological responses through the activation of cell surface receptors which must dimerize to transmit an intracellular signal. Mammalian lens epithelial cells respond to exogenous extracellular FGF, either in tissue culture or in transgenic mice, by initiating fiber cell differentiation. The role of FGF signalling in normal lens development was evaluated by lens-specific synthesis of a kinase-deficient FGF receptor type I (FGFR1) in transgenic mice. This truncated FGF receptor is thought to act as a dominant negative protein by heterodimerization with endogenous FGF receptors. The presence of transgenic mRNA in the lens was confirmed by in situ hybridization and by polymerase chain reaction amplification of reverse transcribed lens RNA (RT-PCR). The presence of transgenic protein was determined by Western blotting with antibodies to an extracellular domain of FGFR1. Three of four transgenic families expressing the truncated FGF receptor exhibited lens defects ranging from cataracts to severe microphthalmia. While the microphthalmic lenses displayed a normal pattern of differentiation-specific crystallin expression, the lens epithelial cells were reduced in number and the lens fiber cells displayed characteristics consistent with the induction of apoptosis. Our results support the view that FGF receptor signalling plays an essential role in normal lens biology.

Download Full-text

Type I Collagen Accelerates the Spreading of Lens Epithelial Cells through the Expression and Activation of Matrix Metalloproteinases

Current Eye Research ◽

10.3109/02713683.2013.853194 ◽

2014 ◽

Vol 39 (5) ◽

pp. 460-471 ◽

Cited By ~ 7

Author(s):

Arata Shimada ◽

Yoshiki Miyata ◽

Hiroshi Kosano

Keyword(s):

Epithelial Cells ◽

Matrix Metalloproteinases ◽

Type I Collagen ◽

Lens Epithelial Cells ◽

Type I

Download Full-text

FGF suppresses apoptosis and induces differentiation of fibre cells in the mouse lens

Development ◽

10.1242/dev.121.12.4383 ◽

1995 ◽

Vol 121 (12) ◽

pp. 4383-4393 ◽

Cited By ~ 4

Author(s):

R.L. Chow ◽

G.D. Roux ◽

M. Roghani ◽

M.A. Palmer ◽

D.B. Rifkin ◽

...

Keyword(s):

Growth Factor ◽

Transgenic Mice ◽

Dominant Negative ◽

Fgf Receptor ◽

Fibre Cell ◽

Dominant Negative Form ◽

Lens Fibre ◽

Mouse Lens ◽

Negative Form

To determine whether fibroblast growth factor (FGF) has a role in lens development, we have generated transgenic mice expressing a dominant-negative form of the murine FGF receptor-1 (FGFRDN) in the lens. Using the fibre cell-specific alpha A-crystallin promoter to express the FGFRDN, we have asked whether FGF is required for fibre cell differentiation. The transgenic mice display diminished differentiation of fibre cells as indicated by their reduced elongation. In addition, transgenic lenses have an unusual refractile anomaly that morphological and biochemical data show results from the apoptosis of fibre cells in the central region of the lens. These results show that lens fibre cells are dependent on FGF for their survival and differentiation, and demonstrate that growth factor deprivation in vivo can lead to apoptosis.

Download Full-text

Fgf receptor signaling plays a role in lens induction

Development ◽

10.1242/dev.128.22.4425 ◽

2001 ◽

Vol 128 (22) ◽

pp. 4425-4438 ◽

Cited By ~ 3

Author(s):

Sonya C. Faber ◽

Patricia Dimanlig ◽

Helen P. Makarenkova ◽

Sanjay Shirke ◽

Kyung Ko ◽

...

Keyword(s):

Kinase Activity ◽

Fibroblast Growth Factor Receptor ◽

Genetic Interaction ◽

Growth Factor Receptor ◽

Dominant Negative ◽

Lens Development ◽

Fgf Receptor ◽

Fgfr Signaling ◽

Lens Placode ◽

Experimental Strategies

We describe experiments showing that fibroblast growth factor receptor (Fgfr) signaling plays a role in lens induction. Three distinct experimental strategies were used: (1) using small-molecule inhibitors of Fgfr kinase activity, we showed that both the transcription level and protein expression of Pax6, a transcription factor critical for lens development, was diminished in the presumptive lens ectoderm; (2) transgenic mice (designated Tfr7) that expressed a dominant-negative Fgf receptor exclusively in the presumptive lens ectoderm showed defects in formation of the lens placode at E9.5 but in addition, showed reduced levels of expression for Pax6, Sox2 and Foxe3, all markers of lens induction; (3) by performing crosses between Tfr7 transgenic and Bmp7-null mice, we showed that there is a genetic interaction between Fgfr and Bmp7 signaling at the induction phases of lens development. This manifested as exacerbated lens development defects and lower levels of Pax6 and Foxe3 expression in Tfr7/Tfr7, Bmp7+/– mice when compared with Tfr7/Tfr7 mice alone. As Bmp7 is an established lens induction signal, this provides further evidence that Fgfr activity is important for lens induction. This analysis establishes a role for Fgfr signaling in lens induction and defines a genetic pathway in which Fgfr and Bmp7 signaling converge on Pax6 expression in the lens placode with the Foxe3 and Sox2 genes lying downstream.

Download Full-text

Quercetin Attenuates UV- and H2O2-induced Decrease of Collagen Type I in Cultured Human Lens Epithelial Cells

Journal of Ocular Pharmacology and Therapeutics ◽

10.1089/jop.2007.0073 ◽

2008 ◽

Vol 24 (2) ◽

pp. 164-174 ◽

Cited By ~ 10

Author(s):

Qin Jiang ◽

Cong Cao ◽

Changlin Zhou ◽

Xiuzu Song ◽

Sarah Healey ◽

...

Keyword(s):

Epithelial Cells ◽

Collagen Type ◽

Collagen Type I ◽

Human Lens ◽

Lens Epithelial Cells ◽

Type I ◽

Human Lens Epithelial Cells

Download Full-text

Overlapping effects of different members of the FGF family on lens fiber differentiation in transgenic mice

Development ◽

10.1242/dev.125.17.3365 ◽

1998 ◽

Vol 125 (17) ◽

pp. 3365-3377 ◽

Cited By ~ 14

Author(s):

F.J. Lovicu ◽

P.A. Overbeek

Keyword(s):

Epithelial Cells ◽

Transgenic Mice ◽

Expression Patterns ◽

Lens Epithelial Cells ◽

Developmental Study ◽

Ocular Development ◽

Spatial Regulation ◽

Temporal And Spatial ◽

Induced Changes ◽

Downstream Signalling Pathway

Fibroblast growth factors (FGFs), such as FGF-1, have been shown to induce differentiation of lens epithelial cells both in tissue culture and in transgenic mice. In the present study, using the alpha A-crystallin promoter, we generated transgenic mice that express different FGFs (FGF-4, FGF-7, FGF-8, FGF-9) specifically in the lens. All four FGFs induced changes in ocular development. Microphthalmic eyes were evident in transgenic mice expressing FGF-8, FGF-9 and some lines expressing FGF-4. A developmental study of the microphthalmic eyes revealed that, by embryonic day 15, expression of these FGFs induced lens epithelial cells to undergo premature fiber differentiation. In less severely affected lines expressing FGF-4 or FGF-7, the lens epithelial cells exhibited a premature exit from the cell cycle and underwent a fiber differentiation response later in development, leading to cataract formation. The responsiveness of lens cells to different FGFs indicates that these proteins stimulate the same or overlapping downstream signalling pathway(s). These overlapping effects of different FGFs on a common cell type indicate that the normal developmental roles for these genes are determined by the temporal and spatial regulation of their expression patterns. The fact that any of these FGFs can induce ocular defects and loss of lens transparency implies that it is essential for the normal eye to maintain very specific spatial control over FGF expression in order to prevent cataract induction.

Download Full-text

Neural and Angiogenic Defects in Eyes of Transgenic Mice Expressing a Dominant-Negative FGF Receptor in the Pigmented Cells

Experimental Eye Research ◽

10.1006/exer.2000.0892 ◽

2000 ◽

Vol 71 (4) ◽

pp. 395-404 ◽

Cited By ~ 34

Author(s):

Benoı̂t Rousseau ◽

David Dubayle ◽

Florian Sennlaub ◽

Jean-Claude Jeanny ◽

Pierre Costet ◽

...

Keyword(s):

Transgenic Mice ◽

Dominant Negative ◽

Fgf Receptor

Download Full-text

Bone morphogenetic protein receptor signaling is necessary for normal murine postnatal bone formation

The Journal of Cell Biology ◽

10.1083/jcb.200109012 ◽

2002 ◽

Vol 157 (6) ◽

pp. 1049-1060 ◽

Cited By ~ 127

Author(s):

Ming Zhao ◽

Stephen E. Harris ◽

Diane Horn ◽

Zhaopo Geng ◽

Riko Nishimura ◽

...

Keyword(s):

Bone Formation ◽

Transgenic Mice ◽

Bone Matrix ◽

Dominant Negative ◽

Type I ◽

Receptor Signaling ◽

Mineral Density ◽

Bmp Receptor

Functions of bone morphogenetic proteins (BMPs) are initiated by signaling through specific type I and type II serine/threonine kinase receptors. In previous studies, we have demonstrated that the type IB BMP receptor (BMPR-IB) plays an essential and specific role in osteoblast commitment and differentiation. To determine the role of BMP receptor signaling in bone formation in vivo, we generated transgenic mice, which express a truncated dominant-negative BMPR-IB targeted to osteoblasts using the type I collagen promoter. The mice are viable and fertile. Tissue-specific expression of the truncated BMPR-IB was demonstrated. Characterization of the phenotype of these transgenic mice showed impairment of postnatal bone formation in 1-mo-old homozygous transgenic mice. Bone mineral density, bone volume, and bone formation rates were severely reduced, but osteoblast and osteoclast numbers were not significantly changed in the transgenic mice. To determine whether osteoblast differentiation is impaired, we used primary osteoblasts isolated from the transgenic mice and showed that BMP signaling is blocked and BMP2-induced mineralized bone matrix formation was inhibited. These studies show the effects of alterations in BMP receptor function targeted to the osteoblast lineage and demonstrate a necessary role of BMP receptor signaling in postnatal bone growth and bone formation in vivo.

Download Full-text

Etv transcription factors functionally diverge from their upstream FGF signaling in lens development

eLife ◽

10.7554/elife.51915 ◽

2020 ◽

Vol 9 ◽

Cited By ~ 3

Author(s):

Ankur Garg ◽

Abdul Hannan ◽

Qian Wang ◽

Neoklis Makrides ◽

Jian Zhong ◽

...

Keyword(s):

Transcription Factors ◽

Functional Divergence ◽

Transitional Zone ◽

Lens Development ◽

Fgf Receptor ◽

Erk Phosphorylation ◽

Normal Lens ◽

Transcriptional Output ◽

Fiber Gene ◽

Mtor Activity

The signal regulated transcription factors (SRTFs) control the ultimate transcriptional output of signaling pathways. Here, we examined a family of FGF-induced SRTFs – Etv1, Etv 4, and Etv 5 – in murine lens development. Contrary to FGF receptor mutants that displayed loss of ERK signaling and defective cell differentiation, Etv deficiency augmented ERK phosphorylation without disrupting the normal lens fiber gene expression. Instead, the transitional zone for lens differentiation was shifted anteriorly as a result of reduced Jag1-Notch signaling. We also showed that Etv proteins suppresses mTOR activity by promoting Tsc2 expression, which is necessary for the nuclei clearance in mature lens. These results revealed the functional divergence between Etv and FGF in lens development, demonstrating that these SRTFs can operate outside the confine of their upstream signaling.

Download Full-text