CHARACTERIZATION OF THE 5'-FLANKING REGION OF THE HUMAN PREPROGALANINGENE

Expression of the human galanin gene was analysed using a 3.5-kb DNA f ragment comprising the 5'-flanking sequence of the gene, This sequence contains a TATA box (ATATATA) preceded by numerous potential binding sites for transcription factors such as SP1, AP2, and NF kappa B. Thre e half-palindromic estrogen response elements (EREs, GGTCA) are also f ound at positions -1,162, -361, and -122 bp relative to the transcript ion start site, To localize functionally important portions of the pro moter region, several shorter fragments of the galanin 5'-flanking reg ion were placed upstream from the chloramphenicol acetyltransferase (C AT) reporter gene, In transient transfection assays, all constructs de monstrated substantial transcriptional activity in both rat glioma/mou se neuroblastoma hybrid cells (NG108-15) and Chinese hamster ovary (CH O-K1) cells, Comparison of the basal expression levels of the differen t constructs suggests the presence of a negative modulator between pos itions -1,891 and -207. When cotransfected into NG108-15 cells with th e human estrogen receptor cDNA, estrogen did not induce transcription of the human galanin gene at physiological levels of estrogen receptor , although transcription was induced up to 30-fold in the presence of high levels of receptor.