Retroviral or lentiviral constructs were transfected into HEK293T cells with their packaging vectors indicated below using FuGENE6 reagent (Promega). pMX-puro-STAT5A* (kindly provided by Toshio Kitamura, University of Tokyo): pCMV-Gag-Pol and pCMV-VSV-G; Plenti-EF-FH-TAZ-S89A: psPAX2 and pVSV-G; PLKO-NS and shTAZ lentiviral construct (kindly provided by Corinne Linardic, Duke University): pCMV-Rev, pCVM-VSVG; pMDL. Retroviral or lentiviral supernatants were collected and filtered 24 h and 48 h post-transfection. 1833 cells were incubated 48 h with retroviruses or lentiviruses medium in the presence of 8μg/mL Polybrene. Cells were cultured at least 3 days in 3μg/mL Puromycin or 5μg/mL Blasticidin for selection. Lentiviral shRNA-mediated knockdown of ABL1/ABL2 and expression of mouse Abl1/Abl2 were conducted as described previously (20 , 21 (link), 59 (link)). Lentiviral shRNA-mediated knockdown of STAT5A and STAT5B was conducted per manufacturer’s instruction (Dharmacon RHS4531-EG6776, EG6777).