Figure 2.

Transient expression of Tax induces Bim protein degradation in CTLL-2 cells. (A) CTLL-2 cells were infected with lentivirus expressing Tax or control EGFP. Total cell lysates were prepared from the infected cells cultured in the absence of IL-2 for 18 h, and the levels of Bim, p-Erk, Tax, and α-tubulin were analyzed by western blotting using the corresponding antibodies. (B) CTLL-2 cells infected with Tax- or EGFP-expressing lentiviruses were cultured without IL-2 for 18 h. The amount of Bim transcript in these cells was measured by real-time PCR analysis and normalized to the amount of GAPDH RNA. (C) CTLL-2 cells were infected with the lentivirus coexpressing Tax and blasticidin-S-deaminase, selected with blasticidin for 7 days, and cultured without IL-2 for 18 h in the absence (DMSO) or presence of 10 μmol/L U0126. Total cell lysates were prepared and the expression of Bim, p-Erk, Tax, and α-tubulin proteins was determined by western blot analysis. (D) CTLL-2 cells were infected as in (C) and cultured without IL-2 for 18 h in the absence or presence of 1, 3, and 10 μmol/L U0126. Total cell lysates were prepared and the expression of Bim, p-Erk, Tax, and α-tubulin proteins was determined by western blot analysis. (E) CTLL-2 cells were infected with the indicated lentiviruses, selected with blasticidin for 7 days and cultured without IL-2 for 18 h. Total cell lysates were prepared and the expression of Bim, p-Erk, Tax, and α-tubulin proteins was determined by western blot analysis. Band intensities of Bim and p-Erk were quantified and normalized to α-tubulin and Erk, respectively.