Identification of transcription factor in the promoter region of rat regucalcin gene: binding of nuclear factor I-A1 to TTGGC motif.

Hepatic nuclear protein has been reported to bind specifically to the TTGGC sequence of the rat regucalcin gene promoter region in stimulating the promoter activity (Misawa and Yamaguchi [2000] Biochem. Biophys. Res. Commun. 279: 275-281). The present study was undertaken to identify transcription factor, which binds to TTGGC motif in the rat regucalcin gene promoter, using the yeast one-hybrid system. The sequence between -525 and -504, which has been defined as a functional promoter element II-b, was used as bait to screen a rat liver cDNA library. Two cDNA clones were identified as a nuclear factor I-A1 (NF1-A1). The results of gel mobility shift assay and mutation analysis using recombinant NF1-A1 protein showed that this protein could specifically bind to TTGGC motif of the II-b oligonucleotide in promoter region. The expression of NF1-A1 mRNA was found in the liver, kidney, heart, spleen, and brain of rats. This study demonstrates that NF1-A1 is a transcription factor in stimulating the rat regucalcin gene promoter activity. Copyright 2002 Wiley‐Liss, Inc.