Figure 1. SIRT1 expression is regulated post-transcriptionally in adult mouse tissues and during mESC differentiation.. (A-B) Protein and RNA were extracted from mESC and tissues from ~6-week-old mice. (A) Western blot analysis with antibodies against SIRT1 (Frye antiserum top blot; Upstate antiserum lower blot), HDAC1, HDAC2, and tubulin. (B) qRT-PCR analysis of SIRT1, HDAC1, and HDAC2 normalized to GAPDH levels. Data are mean ± s.d. for four samples. (C-D) Protein and RNA were isolated from mESCs differentiated in vitro for up to 20 days (EBs d2-20). (C) Western blots analysis of expression of SIRT1, various HDACs, markers of pluripotent embryonic stem cells, and markers of differentiation. Data are representative of four experiments. (D) qRT-PCR analysis of SIRT1, HDAC2, markers of pluripotent embryonic stem cells, and markers of differentiation. Data were normalized to GAPDH and plotted as expression relative to the mean of four mESC samples. Data are mean ± s.d. for four samples.