Fig 2.

Senescence in HuR-depleted MEFs is dependent on the ARF-p53 pathway. (A) MEFs prepared from ARF- or p53-null animals were infected with control or sh-HuR retroviruses. Infected cells were stained for SA-β-Gal. Bars, 25 μm. (B) Control or sh-HuR MEFs with the indicated genotypes were analyzed for their growth rates. Error bars represent means ± SE of results from triplicate wells. (C) Cell lysates were prepared from wild-type MEFs infected with control or sh-HuR retroviruses. The expression of the indicated proteins was analyzed by immunoblotting. γ-Tubulin was used as a loading control. (D) Wild-type MEFs were infected with two independent sh-HuR retroviruses that target different regions of HuR mRNA. Cell lysates were prepared at 4, 8, and 12 days postinfection and analyzed for the expression of the indicated proteins by immunoblotting.