Figure 1.

Ras up-regulates RbAp46 expression in various human cancer cell lines and in mouse fibroblast 7–4 cells. (A) MCF-7-ras human breast carcinoma cells containing an inducible Ha-ras^val12 oncogene were treated with IPTG for 48 hr to induce Ras expression. Cells were harvested and the RNA was isolated for real-time RT-PCR analysis of RbAP46. Peptidylprolyl isomerase A (PPIA) was used for normalization of RbAp46 mRNA levels (upper panel). Ras expression induced by IPTG was confirmed by Western blotting using anti-Ras antibody (lower panel). β-actin was used as the internal control. (B) MCF-7-ras cells were treated with IPTG to induce Ras expression for various durations. Cell lysates were harvested and the expression levels of Ras and RbAp46 protein were evaluated by Western blotting using anti-Ras and anti-RbAp46 antibodies. The band intensity was quantified by a densitometer. (C) The 7–4 cells were treated with IPTG and transfected with different dosages of ras siRNA for 48 hr. The protein expression levels of Ras and RbAp46 were determined using the specific antibodies by Western blotting. c-Met siRNA was used as the negative control. (D) T24 cells were transfected with ras-specific siRNA at different dosages. After 48 hr, the protein expression levels of Ras and RbAp46 were determined.