Temperature regulation of heat-labile enterotoxin (LT) synthesis in Escherichia coli is mediated by an interaction of H-NS protein with the LT A-subunit DNA

Experiments were performed to investigate the mechanism behind the temperature-regulation of heat-labile enterotoxin (LT) synthesis in Escherichia coli. DNA manipulation and analysis of Ent plasmids, transmissible plasmids that encode LT and heat-stable enterotoxin, showed that protein and messengerRNA levels of LT were highest at 37 degrees centigrade and established a direct relationship between protein levels and temperature. The involvement of downstream regulatory element in the temperature regulation of LT synthesis was ruled out.