Mouse keratin 19: complete amino acid sequence and gene expression during development

Area of Science:

• Developmental biology
• Molecular biology
• Genomics

Background:

• Keratins are intermediate filament proteins crucial for epithelial cell structure and function.
• Keratin 19 (K19) is a type I keratin found in various epithelial tissues.
• Understanding K19's role in early development is essential for comprehending tissue formation.

Purpose of the Study:

• To determine the complete amino acid sequence of mouse keratin 19 (K19).
• To investigate the expression pattern of the K19 gene during mouse embryonic development.
• To analyze the genomic organization of the K19 gene in mice.

Main Methods:

• cDNA sequencing from embryonic libraries and genomic DNA amplification.
• RNase protection assays to examine gene expression during development.
• Southern blot analysis to assess gene copy number.

Main Results:

• The complete amino acid sequence of mouse K19 was elucidated, showing evolutionary conservation.
• K19 gene expression was detected in extra-embryonic tissues by day 8.5 and in the embryo proper by day 9.5.
• The K19 gene exists as a unique copy in the mouse genome, contrasting with the human genome containing pseudogenes.

Conclusions:

• Mouse K19 is synthesized early in embryonic development, similar to the K8-K18 pair.
• The unique genomic organization of K19 in mice may have implications for its regulation and function.
• K19 plays a role in early mouse embryogenesis and differentiation.