Expression of ▵STAT5 and p210Bcr/Abl in Ba/F3-p210 cells.

Ba/F3 cells transfected with p210Bcr/Abl and either the empty pTRE plasmid (Ba/F3p210Ctrl) or pTRE ΔSTAT5 (Ba/F3p210ΔSTAT5) were maintained in either the presence or absence of doxycycline (1 μg/mL) for 18 hours and then subjected to Western blot analysis. Although all cell lines were found to express both forms of STAT5 (STAT5A and STAT5B), incubation with doxycycline induced the truncated form of STAT5 (estimated molecular weight, 78 kd) in 3 clones of Ba/F3p210ΔSTAT5 (lower panel). No induction of ΔSTAT5 protein was found in Ba/F3p210Ctrl cells. Probing with an Abl antibody revealed expression of c-abl (145 kd) and of p210Bcr/Abl (210 kd) (upper panel).