DNA Damage Signaling and p53-dependent Senescence after Prolonged -Interferon Stimulation

Supplemental Material

This article contains the following supporting material:

• Figure 1 - Additional markers of senescence in cells treated with β-interferon.
  A) Phospho-ERK1/2 immunofluorescence and quantitation of the percent of cells with poor nuclear staining of phospho-ERK1/2. B) Immunoblot for phospho-STAT1 (pSTAT1), phospho-p38 MAP kinase (pp38) and the ERK1/2 nuclear export factor PEA-15. C) RT-PCR to measure expression of total PML and PML-IV. D) Immunofluorescence for methyl-K9-histone 3.

• Figure 2 - Senescence in cells treated with α- or β-interferon
  A) SA-β-Gal staining of cells treated with α- or β-interferon. B) Immunoblot for phospho-STAT1 in cells as before.

• Figure 3 - β-interferon signals to p53 via pCAF.
  A) β-Interferon induces pCAF at the protein level. B) β-Interferon induces pCAF at the mRNA level. C) Immunoblot showing that E7 blocks p53 acetylation at K320 in response to β-interferon. E7 mutants (kindly provided by Dr D. Galloway) known for being defective in binding pCAF can not inhibit p53 acetylation in response to β-interferon.

• Figure 4 - Representative fields of IMR90 cells expressing E6 or a control vector and treated with β-interferon or vehicle. Cells were stained for SA-β-Gal. Quantitation of this data is presented in figure 4C.

• Methods