This transgene consists of a 835 bp fragment of the purkinje cell protein 2 5' regulatory region, 1.3 kb of Cre recombinase, and 240 bp of simian virus 40 polyA signal. This transgene expresses cre specifically in Purkinje cells. A transgenic line Tg(Pcp2-cre)1Mdk was also produced but was less effective.