This transgene contains the coding sequence for Cre recombinase, followed by a polyadenylation signal to terminate the fusion transcript immediately after the recombinase gene, inserted into the mouse genomic bacterial artificial chromosome (BAC) RP24-186D18 at the ATG transcription initiation codon of the Purkinje cell protein 2 (L7) gene so that expression of the recombinase is driven by the regulatory sequences of the mouse gene.