Fig. 5.

Hsf1 depletion downregulates SIRT1 and HuR. (A) Retroviral control or Hsf1 shRNA were expressed in early passage TIG-1 fibroblasts. Puromycin selected cells were treated with nutlin-3 for 5 days to induce senescence. Levels of SIRT1 and HuR were measured by immunoblotting. (B) Levels of SIRT1 and HuR mRNA were measured in cells described in (A). (C and D) Brain and soleus muscles were harvested from 12 months old Hsf1 null (−/−) mice (n = 2) and age-matched control mice (n = 3) and preserved in RNA stable buffer. RNA from whole brain and soleus muscle were isolated, and qRT-PCR was performed with mouse HuR-, SIRT1-, and GAPDH-specific primers. (E) SIRT1 and HuR protein levels were measured by immunoblotting in samples used in C and D.