High Notch1 and Notch2 expression in cultured HRS and ALCL cells.

(A) Upper panel: Western blot analysis of cell lysate proteins from Hodgkin (lanes 1-5) cell lines, non-Hodgkin (lanes 6-10) cell lines, mature CD2⁺ T cells (lane 11), and mature CD19⁺B cells (lane 12) showing bands of full-length Notch1 (300 kd) and 110-kd major cleavage product (N^TM). Lower panel: Notch2 protein expression in cell lines indicated. (left margin) Size markers in kilodalton. (B) Cocultivation of HtTA-jag10 cells expressing the Notch1 ligand, Jagged1, under tetracycline control and lymphoma cells expressing various amounts of endogenous Notch1 receptors. Jagged1 expression in HtTA-jag10 cells was either uninduced (+tet) or induced (−tet). Northern blot analysis showing increased levels of endogenous Hes-1 transcripts in HRS (lanes 1-6) and ALCL cells (lanes 7-10) after activation by Jagged1. The myeloma cell line U266 served as a negative control (lanes 11, 12).