1. The growth inhibitory factor (GIF) is a 68-amino acid protein which is capable of inhibiting the growth of neuronal cells in vitro. 2. We have cloned and sequenced the 5'-flanking region of the mouse GIF gene, which spans from the transcriptional initiation site to the -1854 nucleotide. 3. This region contains sequences homologous to hgcs, SPE, and the JCV silencer domain that functions in a glial cell specific manner. This region also contains two metal responding elements and putative binding sites for AP-1, AP-2, Sp-1, SP-2, NF-1, and CREB. 4. An analysis of the reporter plasmids containing the various regions of the 5'-flanking sequence revealed that the region indeed functioned in a tissue-specific manner in glial cells and that the region between -328 and 175 is responsible for suppression, while the region between -175 and -49 is involved in the activation of gene expression.