The two proteins were identified on N-terminal amino acid sequence analysis as calreticulin and mitochondrial matrix protein P1, which are known as heat shock proteins, respectively. This suggests that Bm induces the transcriptional activation of stress-heat shock genes. We constructed an expression vector for mammalian cells, which is controlled by the calreticulin promoter. Since Bm effectively inhibits the growth of malignant cells, it is frequently used to treat human malignancies.
Cells respond to injury by synthesizing a family of heat shock proteins.
The heat shock response comprises rapid but transient reprogramming of cellular activities to ensure survival during the stress period, to protect essential cell components against heat damage and to allow the resumption of normal cellular activities during the recovery period. The values are presented as the means for three independent experiments. Calreticulin is a heat shock protein. Therefore a reporter gene, that is under the control of the calreticulin promoter, must be inducibly expressed on heat shock treatment. Therefore, the decrease in luciferase activity in our experiment could have been a response to the heat challenge.