FIG. 11.

The activity of PNR-binding factor(s) is upregulated in the hypertrophied heart. An acute pressure overload (PO) was induced by aortic coarctation as described in Materials and Methods, and nuclear extracts obtained from the sham-operated (Sham) and hypertrophied (PO) hearts were used for the EMSAs. (A) Measurement of left ventricular weight (LV) and body weight (BW) of rats subjected to sham operation and aortic coarctation. (B) EMSA was performed with PNR oligonucleotide as a labeled probe and cardiac nuclear extracts from the same rats as in panel A. (C) A probe corresponding to the α-MHC BF-2 site (Fig. 2B) was used as a negative control in the EMSA. (D) Specific DNA-protein complexes obtained from the EMSA in panel B were cut out from the gel, counted for radioactivity, and plotted as a function of the total protein used in the EMSA binding reaction. (E) Primary cultures of cardiac myocytes were transfected with pMP1.0CAT or pMP0.67CAT and treated with 4 μl of NE to induce hypertrophy. After 72 h of NE treatment, the cells were harvested and the CAT activity was measured. Bars represent the mean values of five separate experiments.