The 189 kb C57BL/6J mouse bacterial artificial chromosome (BAC) RP23-257E12, containing the entire Ctgf locus (and other genes), was modified by targeting a Cre recombinase coding sequence (the CreERT2 sequence modified back to encode the normal Cre recombinase gene), SV40 polyA signal, and frt-flanked neomycin cassette to the ATG start site of the Ctgf locus. The targeted BAC sequences were further modified using FLP recombination to remove the selection cassette and linearized to remove its original vector backbone. Cre expression is directed to cortex and hippocampus by the Ctgf promoter/enhancer regions within the BAC transgene.