Constitutively active STAT5 induces chromatin remodeling and β-casein expression in the absence of laminin-111 signals. (A–C) Introducing constitutively activated STAT5A/B (STAT5A/B 1*6) is sufficient to induce chromatin remodeling and β-casein transcription in the absence of lrECM on polyHEMA. EpH4 cells infected with retrovirus (vector control) or expressing STAT5A/B 1*6 were treated with Prl and 2% lrECM on polyHEMA for 24 h. (A) Phosphorylation of STAT5 was detected by Western blot assays. (B) ChIP analysis of levels of acetylated histone H4 at β-casein promoter. (C) The mRNA levels of β-casein were measured by real-time RT-PCR.