GFAP promoter directs astrocyte-specific expression in transgenic mice.
We are studying transcriptional regulation of the GFAP gene to gain insight into astrocyte function and also to develop an astrocyte-specific expression system for manipulating brain physiology. In addition, the upregulation of GFAP gene activity that follows injury to the brain was mimicked by the transgene. One of the transgenes was found to be X-linked and appeared to undergo the usual random inactivation that achieves gene dosage compensation in females. The brains of hemizygous females stained uniformly rather than displaying mosaic patches, indicating that astrocytes intermingle following their formation. The specific expression of the GFAP-lacZ transgene means that it is now possible to target expression of other heterologous genes to astrocytes in vivo, and to study the mechanisms for reactive gliosis at the DNA level.