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 conta ining GFP gene linked to rat stress-inducible hsp70.1 gene promoter. Transf ected cells show in vitro variable basal levels of fluorescence depending o n stress response induced at physiological temperature by growth conditions . Lack of manipulations except medium change resulted in reduction of cellu lar fluorescence. GFP expression in experimental murine tumors dropped to l evels undetectable at physiological temperature. Heat shock induced signifi cant fluorescence of tumor cells both in vitro and in vivo. GFP protein cou ld be a useful marker for studies of mammalian hsp70i gene promoters.