Skeletal defects in Osterix-Cre transgenic mice.

Cre/loxP recombination is a powerful strategy widely used for in vivo conditional gene targeting. This technique has made possible many important discoveries of gene function in normal and disease biology. However, due to the transgenic nature of most Cre mouse strains undesired phenotypes occasionally occur in Cre mice. Here we report skeletal defects in Osterix-Cre (Osx-Cre) transgenic mice including delayed calvarial ossification and fracture calluses at multiple skeletal sites. These data suggest that Osx-Cre containing controls should be used for both in vivo and in vitro skeletal analyses of conditional knockout mice generated with this Osx-Cre mouse strain.