Figure 1. TTR-RBP expression in WI-38 human diploid fibroblasts (HDFs). WI-38 HDFs were cultured for extended population doublings (pdls), until they reached senescence at ~pdl 52. The abundance of TTR-RBPs HuR, AUF1 (all four isoforms indicated), TIA-1, and TTP was assessed by Western blot analysis. GAPDH signals were included as a loading control.