Abstract
Scid cells are sensitive to heat treatment. We analyzed the DNA double-strand breaks induced by heat treatment in scid cells using rH2AX foci formation. Scid cells and Hybrid cells were ideal system to study the DNA double-strand breaks repair mechanisms, because their genetic backgrounds were identical except DNA-PK activity. To clarify the relationship between thermotolerance and heat-induced DSB, scid cells and hybrid cells were conditioned by preheating at 44C and then incubated at 37C for various intervals. Scid cells were heated at 44C for different periods. In the present study, we found that a preheat treatment led to heat-induced thermotoleranace. It was confirmed that the number of rH2AX foci was reduced in preheated cells later treated with a challenge heat. From these results, it is suggested that thermotolerance is related with heat-induced DSB. We considered that the main effect of DNA double-strand break repair of scid cells deduced to the lack of DNA-PK activity.
