FIG. 11.

Loss of GATA-4 following doxorubicin exposure is not mediated by depletion of p300 protein. Primary neonatal rat cardiomyocytes were isolated and maintained in normal medium in medium supplemented with 1 μM doxorubicin (Dox), or in medium containing doxorubicin and MG-132. After 48 h, nuclear proteins were extracted and p300, GATA-4, and p53 protein levels were measured by Western blot analysis using specific antibodies. The residual proteins in the gel that did not transfer were stained with Coomassie brilliant blue, which showed that similar amounts of nuclear proteins were analyzed. This experiment was repeated three times with three independent preparations of cardiomyocytes.