Investigation of Genes That May Be Required for the Predictive Ability of the Phsp-16.2::GFP Reporter

In Caenorhabditis elegans expression of the fluorescent reporter (Phsp16.2::GFP) is driven by transcription of a stress-responsive promoter sequence and has been shown to predict subsequent stress resistance (thermotolerance) and lifespan of individual animals within an isogenic population (Rea et al., 2005). The mechanism behind the predictive nature of this reporter is poorly understood. To better understand how this reporter works, stress-responsive genes were examined to determine if they were required for the ability of the reporter to predict thermotolerance or lifespan. Animals that had low or high expression of the Phsp-16.2::GFP reporter and contained loss-of-function mutations in select stress-responsive genes were tested to determine whether the animals with higher expression of the reporter still had improved thermotolerance or lifespan. The results revealed that none of the tested stressresponsive genes were necessary for the predictive power of the reporter. In some mutants, the reporter maintained its predictive ability even though the overall thermotolerance was greatly reduced. This implies that the predictive ability of the reporter is not linked to the stress resistance (thermotolerance) of the animal, as originally expected.