(A) Schematic structure of wild-type PU.1 and two kinds of deletion mutants, PU.1-Δ E and PU.1-Δ A. The Ets domain and glutamine-rich domain are indicated by the hatched box. (B) Northern blot analysis of induction of expression of the mutant PU.1/Spi-1 genes, PU.1-Δ E and PU.1-Δ A, in the transfectants. Total RNA was extracted from PU.1-Δ E-sense clone 1 cells and PU.1-Δ A-sense clone 1 cells cultured for 6 hours with or without 100 μmol/L ZnCl₂ and was hybridized with ³²P-labeled probes. (C) Western blot analysis of induction of expression of the mutant PU.1 proteins in the transfectants. Total protein was extracted from PU.1-Δ E-sense clone 1 cells and PU.1-Δ A-sense clone 1 cells cultured for 8 hours with or without 100 μmol/L ZnCl₂ and was probed with antimouse PU.1 antibody.