Fig. 3.

Promoter-specific recruitment of CRP2, SWI/SNF complexes, and chromatin modifiers in transgenic cardiomyocytes. ChIP analyses of transcriptional activators (CRP2 and SRF; lanes 1 and 2), SWI/SNF remodeling complexes (Brg1, Brm, and core subunit Ini1; lanes 3–5), chromatin coactivators/corepressors (HDAC1 and p300; lanes 6 and 7), and histone modifications (Ac-H3 and AcH4; lanes 8 and 9) were performed by using a variety of promoters (schematic on the left), which are either exogenously up-regulated (SM-MHC, calponin, and SM γ-actin), constitutively activated (Ca α-actin, and Ca α MHC), or permanently inactivated (β-globin) in the heart cells. Briefly, cardiomyocytes from α MHC-CRP2 transgenic (Tg) or nontransgenic (NTg) littermate mice were harvested and treated with formaldehyde to cross-link DNA. DNA recovered from immunoprecipitated samples by using specific antibodies (lanes 1–9) or no-antibody negative control (10) was subjected to PCR amplification, employing primers directed against various promoters. Amplification products contain the regulatory sequence elements (CArG boxes, filled ovals or GATA-binding sites) were shown schematically in the top box. Genomic DNA input (10%, lane 11, open oval) was included as a positive control.