DNA polymerases η and κ levels are regulated by the proteasome degradation pathway.

(A) Immunoblot analyses of polymerase levels at indicated days after transduction and selection with control or Ras^G12V vectors. h-TERT BJ5a cells were either treated with DMSO or MG132 (10μM) for 4 hours prior to harvesting. Immunoblot analysis represent one of three biological replicates (see S1 Fig for additional replicates). (B) Relative polymerase levels in BJ5a cells. Adjusted relative intensity values were calculated using ImageJ; data are from three biological replicates. (C) Side-by-side comparison of primary fibroblast IMR90 and BJ5a cells infected with control or Ras^G12V at day 8. Cells were treated with DMSO or MG132 (10 μM) for 4 hours prior to harvest. The BJ5a results shown here are an independent biological replicate of Fig 3A. *Asterisk indicates a non-specific band.