Green fluorescent protein as a marker for monitoring activity of stress-inducible hsp70 rat gene promoter

Murine melanoma cells B16(F10) were stably transfected with a plasmid containing GFP gene linked to rat stress-inducible hsp70.1 gene promoter. Transfected cells show in vitro variable basal levels of fluorescence depending on stress response induced at physiological temperature by growth conditions. Lack of manipulations except medium change resulted in reduction of cellular fluorescence. GFP expression in experimental murine tumors dropped to levels undetectable at physiological temperature. Heat shock induced significant fluorescence of tumor cells both in vitro and in vivo. GFP protein could be a useful marker for studies of mammalian hsp70i gene promoters.