Definition of a high affinity growth hormone DNA response element

Abstract

Rat liver contains a growth hormone inducible nuclear factor complex, GHINF, that binds to the growth hormone response element (GHRE) of the serine protease inhibitor (Spi) 2.1 gene. GHINF contains Stat5 and binds to paired γ-activated sites (GAS) within the GHRE, but poorly to either one alone. By analysis of the sequence of various GAS sites that bind the GHINF complex (based on the GHRE 3′ GAS motif), we demonstrate that a 13 nucleotide high affinity DNA recognition sequence (haGHRE) for GHINF complex binding is ANTTC C/ TN A/ GGAA A/ T A/ T. One copy of the haGHRE will replace the requirement for two GAS elements present in the wild type promoter in supporting a GH response in primary hepatocyte culture. Mutation of the native Spi 2.1 from a paired GAS site to a single haGHRE does not appreciably change its affinity for binding to the GHINF complex, nor does it alter its sensitivity to GH concentration.