Constitutive oligomerization of the WT and Δ319 G-CSFR forms in vivo. CHO cells transiently transfected with the WT, Δ319, or both G-CSFR forms (WT/Δ319) were lysed, immunoprecipitated with the indicated antibodies (anti-Myc or anti-V5), and then immunoblotted with anti–G-CSFR antibody (sc9173). Unt indicates untransfected cells as a negative control; Mix, prior to immunoprecipitation WT lysates were mixed 1:1 with Δ319 lysates; WCL, protein extract from WT cells (50μg), as a positive control.