The transgene consists of the human GFAP promoter fused to an Hras1 cDNA, an IRES-lacZ cassette, and a floxed PGK-neo cassette. The human GFAP promoter directs transgene expression in the astrocytes. The Hras1 sequence contains an HA tag at the amino terminus. Western blot analysis of astrocytes from transgenic animals confirmed cell-specific expression of the transgene. Northern blot analysis of brain RNA also confirmed transgene expression.