Developmentally Regulated Expression of KLF6 in the Mouse Cornea and Lens

Purpose: To examine the expression of transcription factor Kruppel-like factor-6 (KLF6) in the cornea and lens of mouse eyes throughout developmental stages.

Methods: C57BL/6 mice were set up for timed mating. Embryos on embryonic day (E)10.5, E12.5, E15.5, and E18.5 and eyes from mice on postnatal day (P)0, P7, P11, P15, P30, and P60 were collected for immunofluorescence staining. Transcript of KLF6 was detected by in situ hybridization with digoxigenin-labeled RNA probes. Relative quantitative reverse transcription (RT)-PCR was performed to measure the KLF6 transcript level in eyes enucleated at embryonic stages, and the corneas and lenses isolated at postnatal stages.

Results: Staining for the KLF6 protein was observed at E10.5 in the lens pit and at E12.5 in the ectoderm, the mesenchyme, and the lens epithelium. Nuclear staining for KLF6 protein was evident at E15.5 in the corneal epithelium and the stroma. The staining was abundant between E18.5 and P60. In the lens epithelium, nuclear staining was detected at P0, P7, and P11. The staining intensity declined subsequently. The KLF6 transcript was found in the lens pit at E10.5 and in the ectoderm and mesenchyme at E12.5. The KLF6 mRNA level in corneal layers remained relatively constant until P60. In the lens epithelium, it was high during embryonic stages but decreased with development.

Conclusions: KLF6 is expressed in both the cornea and the lens in mouse eyes. Its expression in the lens is temporally regulated, suggesting that it has a central role in lens development.