Analysis of Heat-Shock Transcription Factor and Element-Binding Activity

Abstract

Stress response is nearly universal. Living organisms respond to the changes in their chemical, physical, and biological environments by synthesizing a group of proteins called stress or heat-shock proteins (1). The preferential synthesis of these proteins appears to be involved in induced transient thermal resistance (2). It is well known that transcription of heat-shock genes is regulated by heat-shock transcription factors (HSFs), which bind to heat-shock elements (HSEs) located in the promoter region of genes encoding heat-shock proteins (3). Heat-shock protein gene promoter contains three heat-shock elements (HSE, 5′-GAAnnTTCnnGAA-3′) (4). The HSE is known as a conserved motif present in the promoters of many heat-inducible heat-shock protein genes. Many studies have demonstrated that stress-induced denatured, unfolded, or malfolded proteins trigger the activation of heat shock transcription factors (HSFs) (5–7). In mammalian cells, the activated HSF binds to the HSE and then stimulates transcription.