S were conducted in compliance with the recommendations of the Association for Research in Vision and Ophthalmology (ARVO). The protocol was approved by the Committee on the SPDB custom synthesis Ethics of Animal Experiments of the University of Illinois at Chicago (Protocol Number: 11-183). All surgeries were performed under general anesthesia, and all efforts were made to minimize suffering. We developed mice with conditional deletion of Notch1 in the surface epithelium similar to that ML240 described earlier by another group [14,15]. We used Notch1 flox/flox mice (B6.129X1Notch1tm2Rko/GridJ, The Jackson Laboratory, Bar Harbor, Maine, USA) in which loxP sites flank exon 1 of the Notch1 gene [27]. To conditionally delete Notch1, we used K14-CreERT mice expressing Cre-ERT under the keratin14 (K14) promoter (KRT14-Cre/ERT) 20Efu/J, The Jackson Laboratory) as previously described [28]. Cre-ERT is a Cre-recombinase that has been fused with an estrogen receptor which upon binding of tamoxifen, is translocated into the nucleus. In these mice, the expression of Cre-ERT is targeted to epithelial tissues that express K14, a marker of basal (undifferentiated) epithelial cells. On the ocular surface, K14 is expressed in the basal layer of the corneal and conjunctival epithelium as well as the epithelial linings of both lacrimal and meibomian glands. We first mated Notch1flox/flox with K14-Cre-ERT+/+ mice to obtain the double heterozygote Notch1 Notch1flox/+, K14-CreERT+/- mice. These mice were then back-crossed with Notch1 Notch1flox/flox mice which, as expected by Mendelian ratio, resulted in ?having a genotype of Notch1flox/flox, K14-Cre-ERT +/. Notch1 was conditionally deleted in 2-4 month old Notch1flox/ flox , K14-Cre-ERT+/- mice with 3-5 consecutive days of either intraperitoneal injection (1 mg/20 g body weight) or topical (0.1 mg/ml dissolved in mineral oil) application of 4hydroxytamoxifen (4-OHT).ImmunostainingImmunostaining of mouse eye cryo-sections or cultured mouse corneal epithelial cells were performed according to our previously published protocol [29] using the following antibodies: polyclonal rabbit anti-K10 (Covance, Princeton, NJ, dilution 1:500), rat anti-zonula occludens (ZO)-1 (R-26-4C, Dep. of Anatomy and cell biology, Harvard Medical School, Boston, MA ?obtained through Developmental Studies Hybridoma Bank, University of Iowa ?dilution 1:10), FITC conjugated anti-rabbit and anti-rat IgG (dilution 1:250; both from Jackson Immunoresearch, West Grove, PA). The sections were examined using a spinning disc confocal microscope (Z1, Carl Zeiss, Thornwood, NY), and photographed with an AxioCam (Carl Zeiss) camera.Western BlotsWestern blots were performed as previously described [22]. The following antibodies were used: rabbit anti-cleaved-Notch1 Val1744 (Cell Signaling, Danvers, MA, dilution1:500), monoclonal rabbit anti-GAPDH (Cell Signaling1:5000) and monoclonal rabbit anti-Notch1 (D1E11) xp (Cell Signaling,Notch1 and Corneal Epithelial Barrierdilution 1:500). Detection was performed by ImageQuant LAS 1040 detection system and quantified using ImageQuant software (both from GE Healthcare, Piscataway, NJ).coated tissue culture plates or chamber slides. Cells were treated with 1 4-OHT, diluted in D-KSFM for 48 h to induce Notch1 deletion.HistologyHematoxylin and eosin (H E) staining was performed according to previously published methods [30]. Oil Red O staining was used to visualize the lipids (in the meibomian glands). This was done using cryo-sections.S were conducted in compliance with the recommendations of the Association for Research in Vision and Ophthalmology (ARVO). The protocol was approved by the Committee on the Ethics of Animal Experiments of the University of Illinois at Chicago (Protocol Number: 11-183). All surgeries were performed under general anesthesia, and all efforts were made to minimize suffering. We developed mice with conditional deletion of Notch1 in the surface epithelium similar to that described earlier by another group [14,15]. We used Notch1 flox/flox mice (B6.129X1Notch1tm2Rko/GridJ, The Jackson Laboratory, Bar Harbor, Maine, USA) in which loxP sites flank exon 1 of the Notch1 gene [27]. To conditionally delete Notch1, we used K14-CreERT mice expressing Cre-ERT under the keratin14 (K14) promoter (KRT14-Cre/ERT) 20Efu/J, The Jackson Laboratory) as previously described [28]. Cre-ERT is a Cre-recombinase that has been fused with an estrogen receptor which upon binding of tamoxifen, is translocated into the nucleus. In these mice, the expression of Cre-ERT is targeted to epithelial tissues that express K14, a marker of basal (undifferentiated) epithelial cells. On the ocular surface, K14 is expressed in the basal layer of the corneal and conjunctival epithelium as well as the epithelial linings of both lacrimal and meibomian glands. We first mated Notch1flox/flox with K14-Cre-ERT+/+ mice to obtain the double heterozygote Notch1 Notch1flox/+, K14-CreERT+/- mice. These mice were then back-crossed with Notch1 Notch1flox/flox mice which, as expected by Mendelian ratio, resulted in ?having a genotype of Notch1flox/flox, K14-Cre-ERT +/. Notch1 was conditionally deleted in 2-4 month old Notch1flox/ flox , K14-Cre-ERT+/- mice with 3-5 consecutive days of either intraperitoneal injection (1 mg/20 g body weight) or topical (0.1 mg/ml dissolved in mineral oil) application of 4hydroxytamoxifen (4-OHT).ImmunostainingImmunostaining of mouse eye cryo-sections or cultured mouse corneal epithelial cells were performed according to our previously published protocol [29] using the following antibodies: polyclonal rabbit anti-K10 (Covance, Princeton, NJ, dilution 1:500), rat anti-zonula occludens (ZO)-1 (R-26-4C, Dep. of Anatomy and cell biology, Harvard Medical School, Boston, MA ?obtained through Developmental Studies Hybridoma Bank, University of Iowa ?dilution 1:10), FITC conjugated anti-rabbit and anti-rat IgG (dilution 1:250; both from Jackson Immunoresearch, West Grove, PA). The sections were examined using a spinning disc confocal microscope (Z1, Carl Zeiss, Thornwood, NY), and photographed with an AxioCam (Carl Zeiss) camera.Western BlotsWestern blots were performed as previously described [22]. The following antibodies were used: rabbit anti-cleaved-Notch1 Val1744 (Cell Signaling, Danvers, MA, dilution1:500), monoclonal rabbit anti-GAPDH (Cell Signaling1:5000) and monoclonal rabbit anti-Notch1 (D1E11) xp (Cell Signaling,Notch1 and Corneal Epithelial Barrierdilution 1:500). Detection was performed by ImageQuant LAS 1040 detection system and quantified using ImageQuant software (both from GE Healthcare, Piscataway, NJ).coated tissue culture plates or chamber slides. Cells were treated with 1 4-OHT, diluted in D-KSFM for 48 h to induce Notch1 deletion.HistologyHematoxylin and eosin (H E) staining was performed according to previously published methods [30]. Oil Red O staining was used to visualize the lipids (in the meibomian glands). This was done using cryo-sections.
