Lung Cell-Specific Cre Deleter Mouse Strains: Going Back to Move Forward

The lung is highly complex, composed of multiple cell types. As such, the molecular dissection of pulmonary biology has been significantly supported by in vivo models. Genetic manipulations leading to transgenic overexpression or knockdown of specific genes in mammalian models, particularly mice, are commonplace in respiratory research. Although it is often informative to conduct genetic manipulations without consideration for tissue or cell type, such as in the generation of germline knockouts of genes to evaluate gene function, use of cell type--specific transgenic strains is often the only feasible approach to study lung-specific effects. Using this useful paradigm, they quantified the extent of cell-specific deletion after dox exposure at two developmental stages. As expected, minimal deletion occurred in mesenchymal or hematopoietic cells. However, in no case was the deletion complete in the cells of interest, and in no case was it specific to only one cell type. The authors also found significant leakiness, especially in untreated CCSP-tTg mice.