LIVE ASTROCYTES VISUALIZED BY GREEN FLUORESCENT PROTEIN IN TRANSGENICMICE

Green fluorescent protein (hGFP-S65T) was expressed in transgenic mice under the control of the astrocyte-specific glial fibrillary acidic p rotein (GFAP) promoter. Tissues from two independent transgenic Lines were characterized by Northern blot analysis and by confocal microscop y. The expression pattern in these two lines was identical in all tiss ues examined, and similar to that found previously with a lacZ transge ne driven by the same promoter. Bright fluorescence was observed in th e cell bodies and processes of unfixed or fixed astrocytes, using both whole mount and brain slice preparations, from multiple areas of the central nervous system. However, in contrast to GFAP-lacZ transgenics, retinal Muller cells expressed the GFP transgene in response to degen eration of neighboring photoreceptors. These data indicate that the 2. 2-kb hGFAP promoter contains sufficient regulatory elements to direct expression in Muller cells, and that GFP is a suitable reporter gene f or use in living preparations of the mammalian nervous system. Such mi ce should prove useful for studies of dynamic changes in astrocyte mor phology during development, and in response to physiological and patho logical conditions. (C) 1997 Academic Press.