Cornea-specific expression of K12 keratin during mouse development

Area of Science:

• Molecular Biology
• Developmental Biology
• Ophthalmology

Background:

• Keratins are intermediate filament proteins crucial for epithelial cell structure and function.
• K12 keratin is a specific type of keratin found in the cornea, but its precise expression patterns and regulation are not fully understood.

Purpose of the Study:

• To characterize the full-length cDNA of mouse K12 keratin.
• To investigate the tissue specificity, developmental regulation, and differentiation-dependent expression of K12 keratin.
• To examine the effect of epidermal growth factor (EGF) on K12 keratin expression during corneal development.

Main Methods:

• Sequencing of overlapping cDNA clones from a mouse cornea cDNA library.
• Northern blot hybridization to detect K12 mRNA in various tissues and developmental stages.
• In situ hybridization using a radio-labeled cDNA probe.
• Immunohistochemical studies using antibodies against K12 keratin.
• Administration of EGF to neonatal mice to study its effects on corneal development and K12 expression.

Main Results:

• Mouse K12 keratin mRNA is specifically expressed in the adult cornea, not in other tested tissues.
• K12 keratin expression begins at 4 days postnatal in mouse corneas, coinciding with epithelial stratification.
• K12 keratin is present in all cell layers of the adult corneal epithelium and suprabasal layers of the limbal epithelium, but not the basal layer.
• EGF promotes corneal epithelial stratification but delays K12 keratin expression in neonatal mice.

Conclusions:

• K12 keratin expression is cornea-specific, differentiation-dependent, and developmentally regulated.
• EGF's role in corneal development is complex, promoting stratification while potentially inhibiting K12 keratin expression.
• These findings contribute to understanding the molecular mechanisms underlying corneal development and differentiation.