FIG 8.

Translational regulation of cell cycle regulators by OLA1. (A) Polysome profiling of Ola1^+/+ and Ola1^−/− MEFs under baseline and overnight serum starvation conditions. For each profile, 7 fractions of gradient samples were collected. Free ribosomal subunits (40S and 60S), monosomes (80S), and polysomes are indicated. (B) Percentage distributions of individual mRNAs in the polysome profiles. Total RNAs were isolated from each fraction, and the levels of p53, p21, ccnd1, and β-actin mRNAs were measured using qRT-PCR. (C) Prevention of p21 protein accumulation by the eIF2-selective inhibitor salubrinal. Ola1^+/+ and Ola1^−/− MEFs were serum deprived overnight and subsequently treated or not with salubrinal (Sal) for 6 h. Immunoblotting was used to evaluate the levels of p21 and ATF4, with GAPDH used as the loading control.