These studies also generated a novel 681 bp GFAP promoter, gfaABC(1)D, that has essentially the same expression pattern as the 2210 bp gfa2 promoter, and about twofold greater activity, recommending it for gene targeting applications in which size matters. In addition, a 681 bp gfaABC(1)(mC(1.1))D variant was generated that could limit expression of transgenes to astrocytes in the dorsal and caudal cortex, hippocampus and caudal vermis of the cerebellum