REQUIREMENT OF A SMALL CYTOPLASMIC RNA FOR THE ESTABLISHMENT OF THERMOTOLERANCE

Thermotolerance is an inducible state that endows cells with an enhanc ed resistance to thermal killing. Heat shock proteins are believed, an d in a few instances have been shown, to be the agents conferring this resistance. The role of a small cytoplasmic RNA (G8 RNA) in developin g thermotolerance in Tetrahymena thermophila was investigated by creat ing a strain devoid of all functional G8 genes. These G8 null cells mo unted an apparently normal heat shock response, but they were unable t o establish thermotolerance.