Figure 6

Dominant inhibitory effect of Δex2/3p73 on transcription but not mitochondrial apoptosis. (A) Western immunoblot on 30 μg of total protein extract from HCT116 cells expressing vector-only or Δex2/3p73, documenting the expression of Δex2/3p73. p73 was detected with monoclonal antibody cocktail p73Ab-4 (1:200). (B) RT-PCR on total RNA prepared from the indicated cell lines at 24 h after mock-treatment or treatment with 375 μM 5FU. The primers were specific for the p53-regulated p21 transcript and for the gapdh transcript as a control. (C) Percentage of apoptosis in the indicated cell lines and at 48 h after mock-treatment or exposure to α-amanitin (10 μM; A), 5FU (375 μM; F), or both combined (FA). Apoptosis was measured by determining the numbers of cells with a sub-2n DNA content after PI staining, as described in Materials and methods.