Figure 2.

Inhibition of cyclin D1 translation by PERK. (A) After infection of NIH 3T3 cells with virus encoding PERK (lanes 5–8) or empty virus (lanes 1–4 and 9–12), cells were left untreated or were treated with 0.5 μg/ml tunicamycin for 5 h and were subsequently pulse labeled with ³⁵S-methionine for the indicated intervals. Cyclin D1 was immunoprecipitated from lysates, resolved on a denaturing gel, and visualized by autoradiography. (B) Total RNA was isolated from NIH 3T3 cells infected with PERK (lane 3), Ire1β (lane 4), empty virus (lane 1), or empty virus with tunicamycin treatment for 6 h and subjected to Northern blot analysis with probes specific for cyclin D1 and γ-actin.