A nested deletion approach to generate Cre deleter mice with progressive Hox profiles

In mice, the loxP/Cre recombinase-dependent system of recombination offers powerful possibilities for engineering genetic configurations of interest. This system can also be advantageously used for conditional mutagenesis in vivo, whenever such an approach is required due to deleterious effects of either one mutation, or a combination thereof. Here, we report on the production of an allelic series of insertions of a Hoxd11/Cre fusion transgene at different positions within the HoxD complex, in order to produce the CRE recombinase with a 'Hox profile' progressively more extended. We used the R26R (R26R) reporter mouse line to functionally assess the distribution and efficiency of the CRE enzyme and discuss the usefulness of these various lines as deleter strains.