An Emx1 positive PAC clone frome the RPCI-21 PAC mouse genomic library (PAC-Emx1#1) was modified by the insertion of an NLS-Cre-poly(A) cassette into the NotI site by homologous recombination in bacteria. Two independent recombination events were identified. This transgenic line was generated from the PAC-Cre-B fragment and has 7-9 copies of the transgene. (J:88421)