**Figure 6.** **RNAi inhibition of both pch-2 in sir-2.1 over-expressing worms, and sir-2.1 in pch-2 over-expressing worms, shortens lifespan.** (**A**) Purple curves show lifespans of *sir-2.1* over-expressing worms, while red curves show lifespans of *pch-2* over-expressing worms. In *sir-2* over-expressing worms, *pch-2* RNAi significantly decreased lifespan (56% and 75% decrease in median and maximum lifespan, respectively). In *pch-2* over-expressing worms, *sir-2.1* RNAi induced a 57% and 70% decrease in median and maximum lifespans (*p* <0.0001 for both effects). (**B**) qRT-PCR validated the RNAi effect, indicating a significant reduction (~90%) of *pch-2* transcipts in *sir-2* over-expressing worms that were treated with *pch-2* RNAi. (**C**) qRT-PCR validating a significant reduction (~70%) of *sir-2* transcripts in *pch-2* over-expressing worms that were treated with *sir-2* RNAi. **p* <0.001.