The cTnI GATA elements do not bind GATA-2, -3 and -4 protein in muscle cell nuclear extracts. The 32P-labeled cTnI GATA probe was incubated with C2C12 nuclear extracts, Jurkat or cardiomyocyte nuclear extracts were used as controls. For supershift experiments, nuclear extracts were preincubated with anti-GATA-2, -3 or -4 antibody. In the presence of the anti-GATA-2 antibody, the major complex observed in the binding reaction of cTnI GATA probe with Jurkat nuclear extracts (arrow) is partially inhibited (compare lanes 1 and 2), while no inhibition is observed with the nuclear extract of C2C12 muscle cells (compare lanes 4 and 5). In the presence of the anti-GATA-3 antibody, a supershift is observed with Jurkat nuclear extract (compare lanes 1 and 3), but no supershift is seen with C2C12 nuclear extract (compare lanes 4 and 6). A supershift is also observed with cardiomyocyte nuclear extract in the presence of the anti-GATA-4 antibody (compare lanes 7 and 8), but no supershift is seen with C2C12 nuclear extracts (compare lanes 9 and 10).