FIG. 8.

Functional inactivation of p53 in Bop1Δ-expressing cells does not affect rRNA processing block but decreases p21 induction. (A) Synthesis of 28S rRNA is impaired in Bop1Δ/6 cells expressing GSE56. rRNA processing was analyzed by [³H]uridine labeling as in Fig. 4; note the lack of 28S rRNA labeling and aberrant accumulation of the 36S precursor. (B) Expression of Bop1Δ was induced in puromycin-selected Bop1Δ/6 cell populations infected with pBabe-puro or pBabe-puro-GSE56. Cell lysates were prepared at different times after induction, normalized to protein content, and analyzed by immunoblotting with antibodies against p21.