Figure 2. Growth of tumors with conditionally active Pax5.

(A) Reconstitution of Myc5-M5 cells with Pax5ER. Immunoblotting on transduced cell lysates was performed using an anti-Pax5 antibody. (B) Enhanced nuclear localization of Pax5ER following treatment with 4OHT. Right panels show immunocytochemical staining with an anti-Pax5 antibody. Left panels show counterstaining of nuclei with DAPI. (C) Kinetics of tumor growth by Pax5ER and control (GFP only) cells in animals treated with 4OHT or vehicle only. (D) Kinetics of tumor growth by short-term Myc5 cultures expressing either Pax5 or its dominant-negative mutant (Pax5DN) lacking the activation domain. The small increase in tumor size conferred by Pax5 expression was not statistically significant; the decrease in tumor sizes conferred by overexpression of the dominant-negative Pax5 mutant was significant.