Figure 3.

Binding of Sp proteins and COUP-TF to the MCAD promoter unit NRRE-1/Site A is induced in response to pressure overload. (A) Representative EMSAs performed with site A and NRRE-1 probes with nuclear protein extract (CNE) prepared from RV of sham-operated control mice (C), RV subjected to PAB for 7 days (H), and normal fetal (E16.5) mouse heart (F). Specific complexes are denoted by roman numerals and nonspecific interactions by NS (as defined by competition studies with unlabeled DNA fragments). (B) Antibody supershift studies performed with NRRE-1 and site A probes and nuclear protein extracts prepared from the RV of the PAB mice. Antibodies (Ab) to COUP-TF (COUP), Sp1, and Sp3 were added to the samples in lanes 3, 6, 7, and 8. Preimmune serum (PI) was added to lanes 2 and 5 as a control. Supershifted immune complexes (IC) are denoted by brackets at right margins.