In Atm-/- astrocytes, ERK1/2 is constitutively
activated and CDK inhibitors are up-regulated. A and B,
for Atm+/+ and Atm-/- astrocytes,
levels of phospho-ERK1/2, ERK1/2, and Bmi-1 (A) and levels of p53,
p21cip1, and p16Ink4a (B)
were assessed by direct Western blotting analysis. C, levels of
Bmi-1, p53, p21cip1, p16Ink4a, and
phospho-Rb were compared for Atm+/+ and
Atm-/- cerebella tissues by direct Western blotting
analysis. The means ± S.D. of three different mice tissues are shown.
*, p < 0.05; **, p < 0.01 when
Atm-/- tissues was compared with
Atm+/+ tissues. D, Atm+/+ and
Atm-/- astrocytes were treated with 100 μm
H2O2. The cells were then harvested to access levels of
Bmi-1 and p16Ink4a at the indicated times after
H2O2 treatment. E, Atm+/+
and Atm-/- astrocytes were either left untreated or
treated with 100 μm H2O2. Levels of
phospho-ERK1/2, ERK1/2, p16Ink4a, and phospho-Rb were
determined by direct Western blotting analysis.