Construction Of A Single Cell Labeling System Mediated By Cre And Flp

Cell labeling and tracing provides a promising approach for studying cell biology and developmental biology. A creative, effective and convenient cell tracing technology is likely to bring about a profound influence to related research areas. Unfortunately, single cell labeling, in contrast to the well-established group marking system, which has the potential to follow the developmental fate(s) of an individual progenitor, has not been reported. Toward this end, we designed an individual cell labeling technique mediated by both Cre-loxP and Flp-Frt site specific recombination systems. The major theme of this technique comprised two parts: a genomic tag containing four Frt sites which was separated by stuffer sequences of different length; and a transiently expressing dual recombinase system (Cre/Flp) which could carry out a random recombination between Frt sites and thus generated eight permutations. In this study, we have successfully inserted one copy of the Frt tag into the genome of 293FT cells, and also verified the transient expression characteristic of the dual recombinase system. By using this technique, we would be able to generate eight 293FT clones carrying distinct Frt tags permanently from the original 293FT clone. Theoretically, by increasing the number of Frt sites, this technique should be able to label individual tissue stem cells and trace their offspring, so that direct verification of the multipotency of a single tissue stem cell could be possible. Therefore, this novel single cell labeling technique could be invaluable to studies in cell biology and developmental biology.