Accumulation of tumor suppressor p53 in rat muscle after a space flight.

Tumor suppressor p53 functions as a cell cycle checkpoint under stressful conditions. Early studies have shown that genotoxic stress activates p53 pathway. Recently, many kinds of non-genotoxic stress such as heat shock, cold shock, and low pH also have been found to activate p53 pathway. The effects on living organism remains to be explored. Here, we show that an 18-day space flight induced a 3.6 fold accumulation of p53 in rat skeletal muscle. This results suggests that the p53 pathway plays a role in safeguarding genomic stability against the stressful space environments and supports our previous observation of p53 accumulation in rat skin after a space flight.