Research Techniques Made Simple Lineage Tracing Mediated by

Research Techniques Made Simple: Lineage Tracing Mediated by Cre-Recombinase Activity Susanne Vorhagen, Joanna Jackow, Simona Georgina Mohor; Giel Tanghe; Luna Tanrikulu, Claudia Skazik-Vogt; Frederik Tellkamp

Lineage Tracing… … allows us to follow cell fate decisions of stem/ progenitor cell populations and their descendants within a living organism. … is based on the visualization of the cell lineage via a time and spatially controlled reporter gene expression in stem/progenitor cells that is passed onto their cell progeny. … enables us to study the dynamic of proliferation, differentiation, and migration of these cells in an in vivo context during development, homeostasis, and disease.

Cre-Recombinase-Mediated Reporter Gene Expression • A cell population specific promoter can be used to control Cre-recombinase expression in the cell population of interest • Upon Cre-recombinase expression, the stop codon is excised and leads to reporter gene expression • Reporter genes: • fluorescent proteins or lac. Z tracing of the cell progeny

Example: Tracing of the hair follicle stem cell progeny Interfollicular epidermis Hair follicle stem cells Hair follicle Cre-mediated induction of reporter-gene expression in hair follicle stem cells

Example: Tracing of the hair follicle stem cell progeny Interfollicular epidermis Hair follicle stem cells Hair follicle Tracing of hair follicle stem cell progeny – independently of Cre-expression