A stop-EGFP transgenic mouse to detect clonal cell lineages generated by mutation

Area of Science:

• Developmental Biology
• Stem Cell Biology
• Genetics

Background:

• Investigating cell lineages and tissue organization is crucial for understanding development and disease.
• Existing lineage tracing methods have limitations in scope and application.
• Novel tools are needed to study stem cell behavior in vivo.

Purpose of the Study:

• To develop and validate a novel transgenic mouse system for clonal cell lineage tracing.
• To apply this system for studying stem cell fate mapping and tissue regeneration.
• To investigate epidermal cell migration and the structure of epidermal proliferative units (EPUs).

Main Methods:

• Generation of a transgenic mouse with a fluorescent protein gene featuring a premature stop codon, enabling clonal labeling via random mutation.
• Application of the system for live imaging in epidermis and post-mortem analysis in kidney and liver.
• Analysis of cell lineage contribution from single epidermal stem cells.

Main Results:

• The system successfully generated a green fluorescent cell lineage, ensuring clonality.
• Efficient detection of mutations and stem cell fate mapping was achieved in epidermis, kidney, and liver.
• Single epidermal stem cells were shown to generate adjacent corneocytes, suggesting horizontal cell migration between EPUs, challenging the classical EPU model.

Conclusions:

• The developed transgenic mouse system is a versatile tool for clonal cell lineage tracing across multiple tissues.
• This system provides novel insights into stem cell dynamics and tissue organization, particularly in the epidermis.
• The findings challenge existing models of epidermal organization and highlight horizontal cell migration.