Differential expression of keratin genes during mouse development.

Area of Science:

• Developmental Biology
• Molecular Biology
• Cell Biology

Background:

• The epidermis utilizes specific keratins for structural integrity.
• Understanding keratin gene expression during development is crucial for epidermal differentiation.

Purpose of the Study:

• To investigate the temporal and spatial expression patterns of keratin mRNAs during mouse embryonic development.
• To explore the relationship between early keratin-related gene expression and later epidermal keratinization.

Main Methods:

• Cloning and characterization of cDNA sequences for epidermal keratin mRNAs.
• Hybridization selection assays to identify homologous RNAs in embryonic samples.
• In situ hybridization to determine the cellular localization of keratin mRNA.

Main Results:

• Two novel embryonic RNAs (2.8 and 1.8 kb) with homology to epidermal keratins were identified at Day 11 of gestation.
• These early RNAs were not detected in later embryonic stages.
• Epidermal keratin RNAs (2.0 and 2.4 kb) were first detected between Day 13 and 15, with 59-kDa keratin mRNA localized to spinous and granular layers.

Conclusions:

• Keratin expression is sequential during epidermal differentiation.
• Proteins related to specific keratinizing cell keratins are expressed earlier in embryonic development.