[Characterization and expression of the insulin receptor gene and its promoter]

Insulin initiates diverse biological effects by binding to the insulin receptor. The insulin receptor gene is located on the short arm of chromosome 19 and is more than 130 kb in length and contains 22 exons. Two species of mRNAs encoding insulin receptors that differ 12 amino acids in length exist by alternative splicing of the exon 11. The promoter region of the human insulin receptor gene is extremely GC rich and lacks typical TATA and CAAT boxes but contains multiple potential binding sites of Sp1, which are the characteristics of a "housekeeping" gene. Possible regulation of the expression of the insulin receptor gene by hormones such as insulin and dexamethasone and some transcription factors including Sp1 and C/EBP have been shown at the mRNA and transcription levels.