PMCC PMCC

Search tips
Search criteria

Advanced
Results 1-16 (16)
 

Clipboard (0)
None

Select a Filter Below

Journals
more »
Year of Publication
Document Types
1.  Overlapping Expression Patterns and Redundant Roles for AP-2 Transcription Factors in the Developing Mammalian Retina 
Background
We have previously shown that the transcription factor AP-2α (Tcfap2a) is expressed in postmitotic developing amacrine cells in the mouse retina. Although retina-specific deletion of Tcfap2a did not affect retinogenesis, two other family members, AP-2β and AP-2γ, showed expression patterns similar to AP-2α.
Results
Here we show that, in addition to their highly overlapping expression patterns in amacrine cells, AP-2α and AP-2β are also co-expressed in developing horizontal cells. AP-2γ expression is restricted to amacrine cells, in a subset that is partially distinct from the AP-2α/β-immunopositive population. To address possible redundant roles for AP-2α and AP-2β during retinogenesis, Tcfap2a/b-deficient retinas were examined. These double mutants showed a striking loss of horizontal cells and an altered staining pattern in amacrine cells that were not detected upon deletion of either family member alone.
Conclusions
These studies have uncovered critical roles for AP-2 activity in retinogenesis, delineating the overlapping expression patterns of Tcfap2a, Tcfap2b, and Tcfap2c in the neural retina, and revealing a redundant requirement for Tcfap2a and Tcfap2b in horizontal and amacrine cell development.
doi:10.1002/dvdy.23762
PMCID: PMC3700368  PMID: 22411557
AP-2 transcription factors; retinal development; horizontal cell; amacrine cell; Tcfap2a/b double mutant; redundant roles
2.  Activation of the Hedgehog Signaling Pathway in the Developing Lens Stimulates Ectopic FoxE3 Expression and Disruption in Fiber Cell Differentiation 
Purpose.
The signaling pathways and transcriptional effectors responsible for directing mammalian lens development provide key regulatory molecules that can inform our understanding of human eye defects. The hedgehog genes encode extracellular signaling proteins responsible for patterning and tissue formation during embryogenesis. Signal transduction of this pathway is mediated through activation of the transmembrane proteins smoothened and patched, stimulating downstream signaling resulting in the activation or repression of hedgehog target genes. Hedgehog signaling is implicated in eye development, and defects in hedgehog signaling components have been shown to result in defects of the retina, iris, and lens.
Methods.
We assessed the consequences of constitutive hedgehog signaling in the developing mouse lens using Cre-LoxP technology to express the conditional M2 smoothened allele in the embryonic head and lens ectoderm.
Results.
Although initial lens development appeared normal, morphological defects were apparent by E12.5 and became more significant at later stages of embryogenesis. Altered lens morphology correlated with ectopic expression of FoxE3, which encodes a critical gene required for human and mouse lens development. Later, inappropriate expression of the epithelial marker Pax6, and as well as fiber cell markers c-maf and Prox1 also occurred, indicating a failure of appropriate lens fiber cell differentiation accompanied by altered lens cell proliferation and cell death.
Conclusions.
Our findings demonstrate that the ectopic activation of downstream effectors of the hedgehog signaling pathway in the mouse lens disrupts normal fiber cell differentiation by a mechanism consistent with a sustained epithelial cellular developmental program driven by FoxE3.
This study shows the ability of the lens to respond to altered Smoothened activity. Constitutive activation of Smoothened in the surface ectoderm and derivatives, including the lens results in altered expression of lens markers and abnormal lens differentiation and morphology.
doi:10.1167/iovs.12-9595
PMCID: PMC3385968  PMID: 22491411
3.  Temporal Changes in MMP mRNA Expression in the Lens Epithelium during Anterior Subcapsular Cataract Formation 
Experimental eye research  2008;88(2):323-330.
Transforming growth factor beta (TGFβ) has been known to play a role in anterior subcapsular cataract (ASC) formation and posterior capsule opacification (PCO), both of which are fibrotic pathologies of the lens. Several models have been utilized to study ASC formation, including the TGFβ1 transgenic mouse model and the ex-vivo rat lens model. A distinct characteristic of ASC development within these models includes the formation of isolated fibrotic plaques or opacities which form beneath the lens capsule. A hallmark feature of ASC formation is the epithelial to mesenchymal transition (EMT) of lens epithelial cells (LECs) into myofibroblasts. Recently, the matrix metalloproteinases (MMPs) have been implicated in the formation of these cataracts through their involvement in EMT. In the present study, we sought to further investigate the role of MMPs in subcapsular cataract formation in a time course manner, through the examination of gene expression and morphological changes which occur during this process. RT-QPCR and immunohistochemical analysis was carried out on lenses treated with TGFβ for a period of 2, 4 and 6 days. Laser capture microdissection (LCM) was utilized to specifically isolate cells within the plaque region and cells from the adjacent epithelium in lenses treated for a 6 day period. Multilayering of LECs was observed as early as day 2, which preceded the presence of alpha smooth muscle actin (α-SMA) immunoreactivity that was evident following 4 days of treatment with TGFβ. A slight reduction in E-cadherin mRNA was detected at day 2, although this was not significant until the day 4 time point. Importantly, our results also indicate an early induction of MMP-9 mRNA following 2 days of TGFβ treatment, whereas MMP-2 was found to be upregulated at the later 4 day time point. Further experiments using FHL 124 cells show an induction in MMP-2 protein levels following treatment with recombinant MMP-9. Together these findings suggest an upstream role for MMP-9 in ASC formation.
doi:10.1016/j.exer.2008.08.014
PMCID: PMC3408229  PMID: 18809398
4.  Co-operative roles for E-cadherin and N-cadherin during lens vesicle separation and lens epithelial cell survival 
Developmental biology  2008;326(2):403-417.
The classical cadherins are known to have both adhesive and signaling functions. It has also been proposed that localized regulation of cadherin activity may be important in cell assortment during development. In the context of eye development, it has been suggested that cadherins are important for separation of the invaginated lens vesicle from the surface ectoderm. To test this hypothesis, we conditionally deleted N-cadherin or E-cadherin from the presumptive lens ectoderm of the mouse. Conditional deletion of either cadherin alone did not produce a lens vesicle separation defect. However, these conditional mutants did exhibit common structural deficits, including microphthalmia, severe iris hyperplasia, persistent vacuolization within the fibre cell region, and eventual lens epithelial cell deterioration. To assess the co-operative roles of E-cadherin and N-cadherin within the developing lens, double conditional knockout embryos were generated. These mice displayed distinct defects in lens vesicle separation and persistent expression of another classical cadherin, P-cadherin, within the cells of the persistent lens stalk. Double mutant lenses also exhibited severe defects in lens epithelial cell adhesion and survival. Finally, the severity of the lens phenotype was shown to be sensitive to the number of wild-type E- and N-cadherin alleles. These data suggest that the co-operative expression of both E- and N-cadherin during lens development is essential for normal cell sorting and subsequent lens vesicle separation.
doi:10.1016/j.ydbio.2008.10.011
PMCID: PMC3408230  PMID: 18996109
5.  AP-2α knockout mice exhibit optic cup patterning defects and failure of optic stalk morphogenesis 
Human Molecular Genetics  2010;19(9):1791-1804.
Appropriate development of the retina and optic nerve requires that the forebrain-derived optic neuroepithelium undergoes a precisely coordinated sequence of patterning and morphogenetic events, processes which are highly influenced by signals from adjacent tissues. Our previous work has suggested that transcription factor activating protein-2 alpha (AP-2α; Tcfap2a) has a non-cell autonomous role in optic cup (OC) development; however, it remained unclear how OC abnormalities in AP-2α knockout (KO) mice arise at the morphological and molecular level. In this study, we show that patterning and morphogenetic defects in the AP-2α KO optic neuroepithelium begin at the optic vesicle stage. During subsequent OC formation, ectopic neural retina and optic stalk-like tissue replaced regions of retinal pigment epithelium. AP-2α KO eyes also displayed coloboma in the ventral retina, and a rare phenotype in which the optic stalk completely failed to extend, causing the OCs to be drawn inward to the midline. We detected evidence of increased sonic hedgehog signaling in the AP-2α KO forebrain neuroepithelium, which likely contributed to multiple aspects of the ocular phenotype, including expansion of PAX2-positive optic stalk-like tissue into the OC. Our data suggest that loss of AP-2α in multiple tissues in the craniofacial region leads to severe OC and optic stalk abnormalities by disturbing the tissue–tissue interactions required for ocular development. In view of recent data showing that mutations in human TFAP2A result in similar eye defects, the current findings demonstrate that AP-2α KO mice provide a valuable model for human ocular disease.
doi:10.1093/hmg/ddq060
PMCID: PMC2850623  PMID: 20150232
6.  Development and Use of the Lens Epithelial Explant System to Study Lens Differentiation and Cataractogenesis 
Over the last two decades much progress has been made in identifying and characterizing many of the molecules involved in understanding normal lens biology and its pathology. Much of this has been made possible through the establishment and use of the lens epithelial explant system. This simplistic tissue culture model, comprised of a sheet of lens epithelium on its native substratum, has been used effectively to study many cellular processes, including lens epithelial cell proliferation, fiber cell differentiation, cell apoptosis as well as epithelial to mesenchymal transformation of cells. In doing so, a number of key growth factors and cytokines, including members of the FGF, Wnt and TGFβ family have been shown to play essential roles in many of these cellular events. This has led to further studies exploring the signaling pathways downstream of these molecules in the lens, paving the way for the development of a number of in situ models (primarily transgenic mouse lines) to further explore in more detail the nature of these molecular and cellular interactions. To reciprocate, the lens epithelial explant system is increasingly being used to further characterize the nature of many complex phenotypes and pathologies observed in these in situ models, allowing us to selectively isolate and examine the direct impact of an individual molecule on a specific cellular response in lens cells. There is no question that the lens epithelial explant system has served as a powerful tool to further our understanding of lens biology and pathology, and there is no doubt that it will continue to serve in such a capacity, as new developments are realized and putative treatments for aberrant lens cell behaviour are to be trialed.
doi:10.1016/j.preteyeres.2009.12.001
PMCID: PMC2964862  PMID: 20006728
7.  Lens-Specific Expression of TGF-β Induces Anterior Subcapsular Cataract Formation in the Absence of Smad3 
Purpose
Smad3, a mediator of TGF-β signaling has been shown to be involved in the epithelial-to-mesenchymal transformation (EMT) of lens epithelial cells in a lens injury model. In this study, the role of Smad3 in anterior subcapsular cataract (ASC) formation was investigated in a transgenic TGF-β/Smad3 knockout mouse model.
Methods
TGF-β1 transgenic mice (containing a human TGF-β1 cDNA construct expressed under the αA-crystallin promoter) were bred with mice on a Smad3-null background to generate mice with the following genotypes: TGF-β1/Smad3-/- (null), TGF-β1/Smad3+/-, TGF-β1/Smad3+/+, and nontransgenic/Smad3+/+. Lenses from mice of each genotype were dissected and prepared for histologic or optical analyses.
Results
All transgenic TGF-β1 lenses demonstrated subcapsular plaque formation and EMT as indicated by the expression of α-smooth muscle actin. However, the sizes of the plaques were reduced in the TGF-β1/Smad3-/- lenses, as was the level of type IV collagen deposition when compared with TGF-β1/Smad3+/- and TGF-β1/Smad3+/+ lenses. An increased number of apoptotic figures was also observed in the plaques of the TGF-β1/Smad3-/- lenses compared with TGF-β1/Smad3+/+ littermates.
Conclusions
Lens-specific expression of TGF-β1 induced ASC formation in the absence of the Smad3 signaling mediator, suggests that alternative TGF-β-signaling pathways participate in this ocular fibrotic model.
doi:10.1167/iovs.05-1208
PMCID: PMC2811063  PMID: 16877415
8.  Matrix Metalloproteinases as Mediators of Primary and Secondary Cataracts 
Expert review of ophthalmology  2007;2(6):931-938.
The matrix metalloproteinases (MMPs) are a family of endopeptidases involved in numerous remodeling and fibrotic disorders. Although MMPs have been shown to play important roles in regenerative and disease processes in many parts of the eye, including the cornea, retina and trabecular meshwork, the role of MMPs in the normal and cataractous lens has only recently been studied. These investigations have shown that multiple MMPs are expressed in the lens and their expression is altered in a number of cataract phenotypes. However, anterior subcapsular cataract and posterior capsular opacification, cataracts of a fibrotic nature, show a particular involvement of MMPs. This review will highlight recent findings that suggest a causative role for MMPs in these fibrotic cataract phenotypes.
doi:10.1586/17469899.2.6.931
PMCID: PMC2583795  PMID: 19018298
cataract; EMT; fibrosis; lens; MMPIs; matrix metalloproteinase
9.  Targeted Deletion of AP-2α Leads to Disruption in Corneal Epithelial Cell Integrity and Defects in the Corneal Stroma 
Purpose
The present study was undertaken to create a conditional knockout of AP-2α in the corneal epithelium.
Methods
A line of mice expressing Cre-recombinase specifically in the early lens placode was crossed with mice in which the AP-2α allele is flanked by two loxP sites. The resultant Le-AP-2α mutants exhibited a targeted deletion of AP-2α in lens placode derivatives, including the differentiating corneal epithelium.
Results
The Le-AP-2α mutant mice were viable and had a normal lifespan. The adult corneal epithelium exhibited a variation in the number of stratified epithelial layers, ranging from 2 to 10 cell layers. A substantial decrease in expression of the cell–cell adhesion molecule, E-cadherin, was observed in all layers of the Le-AP-2α mutant corneal epithelium. The basement membrane, or Bowman's layer, was thinner in the mutant cornea and in many regions was discontinuous. These defects corresponded with altered distribution of laminin and entactin, and to a lesser degree, type IV collagen. The Le-AP-2α mutant cornea also exhibited stromal defects, including disrupted organization of the collagen lamellae and accumulation of fibroblasts beneath the epithelium that showed increased immunoreactivity for proliferating cell nuclear antigen (PCNA), α-smooth muscle actin (α-SMA), p-Smad2, and TGF-β2.
Conclusions
In the absence of AP-2α, the corneal epithelium exhibits altered cell adhesion and integrity and defects in its underlying basement membrane. These defects likely caused the alterations in the corneal stroma.
doi:10.1167/iovs.05-0028
PMCID: PMC2517422  PMID: 16186342
10.  Cell Autonomous Roles for AP-2α in Lens Vesicle Separation and Maintenance of the Lens Epithelial Cell Phenotype 
In this study, we have created a conditional deletion of AP-2α in the developing mouse lens (Le-AP-2α mutants) to determine the cell-autonomous requirement(s) for AP-2α in lens development. Embryonic and adult Le-AP-2α mutants exhibited defects confined to lens placode derivatives, including a persistent adhesion of the lens to the overlying corneal epithelium (or lens stalk). Expression of known regulators of lens vesicle separation, including Pax6, Pitx3, and Foxe3 was observed in the Le-AP-2α mutant lens demonstrating that these genes do not lie directly downstream of AP-2α. Unlike germ-line mutants, Le-AP-2α mutants did not exhibit defects in the optic cup, further defining the tissue specific role(s) for AP-2α in eye development. Finally, comparative microarray analysis of lenses from the Le-AP-2α mutants vs. wild-type littermates revealed differential expression of 415 mRNAs, including reduced expression of genes important for maintaining the lens epithelial cell phenotype, such as E-cadherin.
doi:10.1002/dvdy.21445
PMCID: PMC2517426  PMID: 18224708
activating protein-2alpha; lens development; E-cadherin; epidermal growth factor receptor
11.  Positive influence of AP-2α transcription factor on cadherin gene expression and differentiation of the ocular surface 
The family of transcription factors Activating protein-2 (AP-2) are known to play important roles in numerous developmental events, including those associated with differentiation of stratified epithelia. However, to date, the influence of the AP-2 genes on endogenous gene expression in the stratified epithelia and how this affects differentiation has not been well defined. The following study examines the detailed expression of the AP-2α and AP-2β proteins in the stratified epithelia of the ocular surface, including that in the cornea and developing eyelids. The effect of altered levels of the AP-2α gene on ocular surface differentiation was also examined using a corneal epithelial cell line and AP-2α chimeric mice. Immunolocalization studies revealed that, while AP-2β was broadly expressed throughout all cell layers of the stratified corneal epithelium, AP-2α expression was confined to cell compartments more basally located. AP-2α was also highly expressed in the less differentiated cell layers of the eyelid epidermis. Overexpression of the AP-2α gene in the corneal cell line, SIRC, resulted in a dramatic change in cell phenotype including a clumping growth behavior that was distinct from the smooth monolayer of the parent cell line. Accompanying this change was an up-regulation in levels of the cell adhesion molecule, N-cadherin. Examination of the ocular surface of AP-2α chimeric mice, derived from a mixed population of AP-2α−/− and AP-2α+/+, revealed that a down-regulation in E-cadherin expression is correlated with location of the AP-2α−/− null cells. Together, these findings demonstrate that AP-2α participates in regulating differentiation of the ocular surface through induction in cadherin expression.
PMCID: PMC2517417  PMID: 12694203
ocular surface; cell adhesion; transcription factors; AP-2; cornea; eyelids; differentiation
12.  The keratocyte: Corneal stromal cell with variable repair phenotypes 
Keratocytes, also known as fibroblasts, are mesencyhmal-derived cells of the corneal stroma. These cells are normally quiescent, but they can readily respond and transition into repair phenotypes following injury. Cytokines and other growth factors that provide autocrine signals for stimulating wound responses in resident cells are typically presented by platelets at the site of an injury. However, due to the avascular nature of the cornea many of the environmental cues are derived from the overlying epithelium. Corneal epithelial-keratocyte cell interactions have thus been extensively studied in numerous in vivo corneal wound healing settings, as well as in in vitro culture models. Exposure to the different epithelial-derived factors, as well as the integrity of the epithelial substratum, are factors known to impact the keratocyte response and determine whether corneal repair will be regenerative or fibrotic in nature. Finally, the recent identification of bone-marrow derived stem cells in the corneal stroma suggests a further complexity in the regulation of the keratocyte phenotype following injury.
doi:10.1016/j.biocel.2006.03.010
PMCID: PMC2505273  PMID: 16675284
Keratocyte; Cornea; Injury; Apoptosis; Myofibroblasts; Transparency; Plasticity
13.  Conditional Deletion of Activating Protein 2α (AP-2α) in the Developing Retina Demonstrates Non-Cell-Autonomous Roles for AP-2α in Optic Cup Development▿  
Molecular and Cellular Biology  2007;27(21):7497-7510.
Activating protein 2α (AP-2α) is known to be expressed in the retina, and AP-2α-null mice exhibit defects in the developing optic cup, including patterning of the neural retina (NR) and a replacement of the dorsal retinal pigmented epithelium (RPE) with NR. In this study, we analyzed the temporal and spatial retinal expression patterns of AP-2α and created a conditional deletion of AP-2α in the developing retina. AP-2α exhibited a distinct expression pattern in the developing inner nuclear layer of the retina, and colocalization studies indicated that AP-2α was exclusively expressed in postmitotic amacrine cell populations. Targeted deletion of AP-2α in the developing retina did not result in observable retinal defects. Further examination of AP-2α-null mutants revealed that the severity of the RPE defect was variable and, although defects in retinal lamination occur at later embryonic stages, earlier stages showed normal lamination and expression of markers for amacrine and ganglion cells. Together, these data demonstrate that, whereas AP-2α alone does not play an intrinsic role in retinogenesis, it has non-cell-autonomous effects on optic cup development. Additional expression analyses showed that multiple AP-2 proteins are present in the developing retina, which will be important to future studies.
doi:10.1128/MCB.00687-07
PMCID: PMC2169054  PMID: 17724084
14.  Differential Regulation of Components of the Ubiquitin-Proteasome Pathway during Lens Cell Differentiation 
Purpose
To investigate the role for the ubiquitin-proteasome pathway in controlling lens cell proliferation and differentiation and the regulation of the ubiquitin conjugation machinery during the differentiation process.
Methods
bFGF-induced lens cell proliferation and differentiation was monitored in rat lens epithelial explants by bromodeoxyuridine (BrdU) incorporation and expression of crystallins and other differentiation markers. Levels of typical substrates for the ubiquitin-proteasome pathway, p21WAF and p27Kip, were monitored during the differentiation process, as were levels and activities of the enzymes involved in ubiquitin conjugation.
Results
Explants treated with bFGF initially underwent enhanced proliferation as indicated by BrdU incorporation. Then they withdrew from the cell cycle as indicated by diminished BrdU incorporation and accumulation of p21WAF and p27Kip. bFGF-induced cell proliferation was prohibited or delayed by proteasome inhibitors. Lens epithelial explants treated with bFGF for 7 days displayed characteristics of lens fibers, including expression of large quantities of crystallins. Whereas levels of E1 remained constant during the differentiation process, the levels of ubiquitin-conjugating enzyme (Ubc)-1 increased approximately twofold, and the thiol ester form of Ubc1 increased approximately threefold on 7 days of bFGF treatment. Levels of Ubc2 increased moderately on bFGF treatment, and most of the Ubc2 was found in the thiol ester form. Although levels of total Ubc3 and -7 remained unchanged, the proportions of Ubc3 and -7 in the thiol ester form were significantly higher in the bFGF-treated explants. Levels of Ubc4/5 and -9 also increased significantly on treatment with bFGF, and more than 90% of Ubc9 was found in the thiol ester form in the bFGF-treated explants. In contrast, levels of Cul1, the backbone of the SCF type of E3s, decreased 50% to 70% in bFGF-treated explants.
Conclusions
The data show that proteolysis through the ubiquitin-proteasome pathway is required for bFGF-induced lens cell proliferation and differentiation. Various components of the ubiquitin-proteasome pathway are differentially regulated during lens cell differentiation. The downregulation of Cul1 appears to contribute to the accumulation of p21WAF and p27Kip, which play an important role in establishing a differentiated phenotype.
doi:10.1167/iovs.03-0830
PMCID: PMC1446108  PMID: 15037588
15.  Adenoviral gene transfer of bioactive TGFβ1 to the rodent eye as a novel model for anterior subcapsular cataract 
Molecular Vision  2007;13:457-469.
Purpose
To produce a gene-transfer model of rodent anterior subcapsular cataracts (ASC) using a replication-deficient, adenoviral vector containing active TGFβ1. Establishment of this model will be important for further investigations of TGFβ-induced signaling cascades in ASC.
Methods
Adenovirus containing the transgene for active TGFβ1 (AdTGFβ1), β-galactosidase (AdLacZ), green fluorescent protein (AdGFP) or no transgene (AdDL) was injected into the anterior chamber of C57Bl/6, Smad3 WT and Smad3 KO mice. Four and 21 days after injection, animals were enucleated and eyes were processed and examined by routine histology. Immunolocalization of markers indicative of epithelial to mesenchymal transition (EMT), fibrosis, proliferation and apoptosis was also carried out.
Results
By day 4, treatment with AdLacZ demonstrated transgene expression in multiple structures of the anterior chamber including the lens epithelium. In contrast to AdDL, treatment with AdTGFβ1 produced αSMA-positive subcapsular plaques in all three groups of mice, which shared features reminiscent of human ASC. At day 21, plaques remained αSMA-positive and extensive extracellular matrix deposition was observed. The AdTGFβ1 model was further employed in Smad3 deficient mice and this resulted in the development of small ASC.
Conclusions
Gene transfer of active TGFβ1 using an adenoviral vector produced cataractous plaques four days postinjection, which were found to develop independent of functional Smad3.
PMCID: PMC2647562  PMID: 17417606
16.  Transcription Factors Pax6 and AP-2α Interact To Coordinate Corneal Epithelial Repair by Controlling Expression of Matrix Metalloproteinase Gelatinase B 
Molecular and Cellular Biology  2004;24(1):245-257.
Pax6 is a paired box containing transcription factor that resides at the top of a genetic hierarchy controlling eye development. It continues to be expressed in tissues of the adult eye, but its role in this capacity is unclear. Pax6 is present in the adult corneal epithelium, and we showed that the amount of Pax6 is increased at the migrating front as the epithelium resurfaces the cornea after injury (J. M. Sivak, R. Mohan, W. B. Rinehart, P. X. Xu, R. L. Maas, and M. E. Fini, Dev. Biol. 222:41-54, 2000). We also showed that Pax6 controls activity of the transcriptional promoter for the matrix metalloproteinase, gelatinase B (gelB; MMP-9) in cell culture transfection studies. gelB expression is turned on at the migrating epithelial front in the cornea, and it coordinates and effects aspects of epithelial regeneration (R. Mohan, S. K. Chintala, J. C. Jung, W. V. Villar, F. McCabe, L. A. Russo, Y. Lee, B. E. McCarthy, K. R. Wollenberg, J. V. Jester, M. Wang, H. G. Welgus, J. M. Shipley, R. M. Senior, and M. E. Fini, J. Biol. Chem. 277:2065-2072). We define here two positively acting Pax6 response elements in the gelB promoter. Pax6 binds directly to one of these sites through the paired DNA-binding domain. It binds the second site indirectly by interaction with AP-2α, a transcription factor that also exerts control over eye development. Pax6 control of gelB expression was examined in vivo by using a corneal reepithelialization model in mice heterozygous for a Pax6 paired-domain mutation (Sey+/−). A reduced Pax6 dosage in these mice resulted in a loss of gelB expression at the migrating epithelial front. This effect was correlated with an increase in inflammation and the rate of reepithelialization, a finding consistent with the phenotype of gelB knockout mice. Together, these data indicate that Pax6 controls activity of the gelB promoter through cooperative interactions with AP-2α and support an active role for Pax6 in maintenance and repair of the adult corneal epithelium.
doi:10.1128/MCB.24.1.245-257.2004
PMCID: PMC303332  PMID: 14673159

Results 1-16 (16)