A. NIH 3T3 fibroblasts were transfected with a mixture of siRNAs directed against MTA-1, 2, and 3. Twenty-four hours post transfection, total cell lysates were prepared and western analysis was performed using an antibody to MTA-1 (top panel) or MTA-2 (bottom panel). B. NIH 3T3 fibroblasts were transfected with siRNAs directed against MTA-1, 2, and 3. Twenty-four hours later, cells were transfected with a reporter plasmid containing 638 bp of the ANF promoter driving human growth hormone (hGH) and expression plasmids for murine GATA4 and FOG-2 or Hey2. Forty-eight hours later, the media was assayed for hGH and normalized for transfection efficiency. Fold repression is calculated as the ratio of the GATA-mediated transactivation of the ANF promoter in the absence vs. presence of FOG-2 or Hey2. Results represent the mean ± S.E.M. (n=6).