FIG. 1.

Stat5a and Stat5b DNA binding in mammary cells (EMSA). (A) A 6-μg amount of HC11 nuclear protein extract prepared from cell cultures treated for the indicated times with lactogenic hormones (lanes 2 to 7) or noninduced cells (lane 1) was incubated with radiolabeled oligonucleotide containing the Stat5 binding site. Complexes were electrophoresed in a 4% polyacrylamide native gel. (B and C) EMSA performed in the presence of the indicated antisera by using 6 μg of nuclear protein extracts from HC11 cells treated with lactogenic hormones for 7 min or 1 μg of nuclear protein extracts from lactating mammary gland, respectively. Prolactin, insulin, and dexamethasone were at concentrations of 5 μg/ml, 5 μg/ml, and 1 μM, respectively.