![Fig. 5. Differential regulation of STAT5-induced genes,CIS and BclX, in Bcr/Abl transformed cells. / (A) Inhibition of CIS protein expression by ΔSTAT5 expression. Lysates from Ba/F3p210ΔSTAT5 cells (after treatment with or without doxycycline [1 μg/mL] for 24 hours) were incubated with a CIS antibody and protein G beads. Immunoprecipitates were then subjected to SDS-PAGE (9%). Probing with anti-CIS antibody revealed constitutive expression of CIS protein (37 kd) in Bcr/Abl-transformed cells, and expression of ΔSTAT5 inhibited CIS protein expression. Addition of doxycycline had no effect on CIS protein expression in Ba/F3p210Ctrl cells. A larger, presumably ubiquitinated form of CIS protein (∼ 45 kd) was also expressed in Ba/F3p210 cells. (B) Lack of effect on BclX protein expression of induction of ΔSTAT5. Lysates from Ba/F3 and Ba/F3p210 cells (maintained in the presence of WEHI-CM) were subjected to SDS-PAGE. Ba/F3p210 cells expressed more BclXLthan untransformed Ba/F3 cells (upper left-hand panel). Enhanced BclXL expression could be attributed directly to Bcr/Abl, since incubation with Bcr/Abl kinase inhibitor STI571 (1 μmol/L for 24 hours) reversed the enhanced BclXL expression in Ba/F3p210 cells. However, induction of ΔSTAT5 with doxycycline (1 μg/mL for 3 days) had no effect on BclXL expression in Ba/F3p210ΔSTAT5 cells (upper right-hand panel). Induction of ΔSTAT5 in Ba/F3p210ΔSTAT5 cells is shown as a control (lower panel).](https://ash.silverchair-cdn.com/ash/content_public/journal/blood/95/6/10.1182_blood.v95.6.2118/6/bloo00605005bw.jpeg?Expires=1722774631&Signature=h1GlgBx3Psj9d4akWfkz1cjoA0xNQjr9bXFYjgdYQGRnnczmrmaEFNusQqc74E5LU673nCF4TzD1yQ4Cc~acnqZWCxQZ78Lo2UyVPoYeJlFGkedyvFJj2DlUUBeNAv5Y0YlPey0cQU1E4b5SHhx1tvG95z4OsqNhYMUhFxM94tQMuuT1KebP2KsFNTeFP~cg3XYRqNIYrg4vHOeeXmrZoJvlnxc62c3SbnjEVpRNYmMb7zljMrTyuBaQXbulIM9Ekf0rXDId3UN9ddy1lSGhgcJiM8CqOl~cBPpou8h3FvnDlDUBI9K5nmmja5EIIWfkNxTjf88iFqhLUBLmwPDQxw__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
Differential regulation of STAT5-induced genes,CIS and BclX, in Bcr/Abl transformed cells.
(A) Inhibition of CIS protein expression by ΔSTAT5 expression. Lysates from Ba/F3p210ΔSTAT5 cells (after treatment with or without doxycycline [1 μg/mL] for 24 hours) were incubated with a CIS antibody and protein G beads. Immunoprecipitates were then subjected to SDS-PAGE (9%). Probing with anti-CIS antibody revealed constitutive expression of CIS protein (37 kd) in Bcr/Abl-transformed cells, and expression of ΔSTAT5 inhibited CIS protein expression. Addition of doxycycline had no effect on CIS protein expression in Ba/F3p210Ctrl cells. A larger, presumably ubiquitinated form of CIS protein (∼ 45 kd) was also expressed in Ba/F3p210 cells. (B) Lack of effect on BclX protein expression of induction of ΔSTAT5. Lysates from Ba/F3 and Ba/F3p210 cells (maintained in the presence of WEHI-CM) were subjected to SDS-PAGE. Ba/F3p210 cells expressed more BclXLthan untransformed Ba/F3 cells (upper left-hand panel). Enhanced BclXL expression could be attributed directly to Bcr/Abl, since incubation with Bcr/Abl kinase inhibitor STI571 (1 μmol/L for 24 hours) reversed the enhanced BclXL expression in Ba/F3p210 cells. However, induction of ΔSTAT5 with doxycycline (1 μg/mL for 3 days) had no effect on BclXL expression in Ba/F3p210ΔSTAT5 cells (upper right-hand panel). Induction of ΔSTAT5 in Ba/F3p210ΔSTAT5 cells is shown as a control (lower panel).
