The antiproliferative effect of PU.1 is down-regulated by AML1-ETO in mouse bone marrow cells.

(A) AML1-ETO causes proliferation in mouse bone marrow cells. Live transduced mouse bone marrow cells with PU.1, AML1-ETO, or PU.1 and AML1-ETO were counted on days 3, 6, and 12 after trypan blue staining. Because both the empty vectors gave the same cell count, only one vector (PINCO) has been represented as mock. (B) Expression of PU.1 in mouse bone marrow cells. The cells of the transduction described in the legend to Panel A were lysed and immunoblot assays were performed for PU.1 and β-tubulin. NGFR (N; lysate of empty vector of PU.1), N-PU.1 (NGFR-PU.1–transduced cells), PINCO (P; lysate of empty vector of AML1-ETO–transduced cells), P-AML1-ETO (lysate of PINCO-AML1-ETO–transduced cells), and P-AML1-ETO+N-PU.1 (lysate of PINCO-AML1-ETO– and NGFR-PU.1–transduced cells) were analyzed. The ratio of PU.1/β-tubulin was calculated after densitometric quantification of the bands.