Patterns of epithelial expression of Fos protein suggest important role in the transition from viable to cornified cell during keratinization

The study used an antibody against c-fos to identify Fos protein distribution in epithelial tissues, finding that Fos protein was present in the nuclei of epithelial cells during late differentiation stages, just before cornification. This pattern was observed in various keratinized tissues, including the epidermis and hair follicle cells, indicating a surge in Fos expression before cell death and cornification. Non-keratinized tissues showed little Fos labelling. The study also noted that the Erf Er mutant epidermis, which cannot keratinize, overexpressed Fos across all cell layers. The findings suggested that Fos expression was closely linked to epithelial cell differentiation, particularly in the transition to cornification and cell death.