The human growth hormone receptor gene - characterisation of the liver-specific promoter.

Several variants (V1-V8) have been described for the 5' untranslated region of human growth hormone receptor cDNA (Pekhletsky, R.I., Chernov B.K., Rubtsov, P.M., 1992. Variants of the 5'-untranslated sequence of human growth hormone receptor mRNA. Mol. Cell. Endocrinol. 90, 103-109). Transcription of one of these, variant V1, is under the control of a liver-specific promoter (Zou, L., Burmeister L.A., Sperling, M.A., 1997. Isolation of a liver-specific promoter for human growth hormone receptor gene. Endocrinology 138, 1771-1774). Further characterisation of this promoter shows that: (1) a cluster of exon 1 variants, which includes that coding for V1, is located about 13 kb upstream of the first coding exon; (2) the human V1 promoter (and not V7, as previously suggested) is homologous to liver-specific regulatory regions of rat and mouse GH receptor genes; (3) the transcription start site for V1 is 27 bp further upstream than previously reported; (4) a 158-bp sequence is sufficient for basal promoter activity, while larger constructs provide evidence for negative elements further upstream; and (5) nuclear proteins from HepG2 hepatoma cells protect regions of the V1 promoter from DNase digestion, revealing putative regulatory sites.