Cloning of the rat insulin-like growth factor binding protein-1 gene and analysis of its 5′ promoter region

To understand specific mechanisms involved in the regulation of insulin-like growth factor binding protein-1 (IGFBP-1), an important modulator of IGF bioactivity, we cloned the rat IGFBP-1 gene and sequenced a 1.5 kb Sph1-Sph1 fragment containing 1110 bases upstream from the translation start site. computer analysis reveals the presence of ATA, CACCC, and CCAAT elements, and putative homeodomain, AP-1, insulin and glucocorticoid response elements in the 5′ promoter. Primer extension and ribonuclease protection studies reveal a single cap site in RNA from rat hepatoma cells and both control and diabetic rat liver.