The heat shock transcription factors (Hsfs) are members of a key transcription factor gene family that responds to heat stress and plays an important role in heat resistance. Previous reports have shown that Hsf family genes contain several conserved domains. At the N terminus is a DNA-binding domain (DBD) that can recognize promoter elements of heat-responsive genes. An adjacent oligomerization domain (OD or HR-A/B) is found in all Hsf family genes and comprises mainly hydrophobic heptad repeats. HSFs are sequence-specific DNA binding proteins that bind specifically to heat-shock elements (HSEs) with high affinity.