Figure 4

Akt1 is the major kinase of HIRA in myoblasts. (a) Knock-down of each Akt isoform using specific siRNAs. C2C12 cells were treated with control siRNA or siRNAs specifically targeting Akt1 or Akt2 for 72 h. Total RNA was isolated to determine the steady-state level of each Akt by qRT-PCR. The PCR values were normalized to β-actin and presented as values relative to the control, which was set as 1. (b, c) C2C12 cells were treated with control siRNA or siRNAs for Akt1 or Akt2 for 72 h. Whole-cell extracts were then subjected to western blotting using the indicated antibodies (b) or subjected to IP using an anti-p-HIRA antibody (c), as described in Figure 3. siRNA, small interfering RNA; qRT-PCR, quantitative reverse transcription PCR.