This transgene comprises a 1.8 kb 5' fragment of the human glial fibrillary acidic protein (GFAP) gene driving expression of the E. coli beta-galactosidase (lacZ) coding sequence. X-gal staining of brain sections of developing mouse embryos showed expression to be limited to the central nervous system (CNS), including the eye, and to vertebral chondrocytes forming around the notochord at embryonic day (E) 14.5. Expression occurs in different CNS regions at specific times during development, reflecting the expression pattern of endongenous mouse Gfap mRNA detected by reverse transcription-polymerase chain reaction (RT-PCR) anaylsis and RNA in-situ hybridization. (J:71425)