Figure 3.

Myeloid-specific transcriptional activation by mMZF-2. (A) Schematic drawing of the reporter and effector plasmids. The reporter plasmid (4xF113B) carries a tetramer of the MZF binding site (F113B) upstream of the TATA box of the murine G-CSF and luciferase genes. The reporter gene (TATA) without MZF-binding site was also used as a control. The effector plasmid harbors the coding sequence for the epitope-tagged mMZF-2 or its derivative under the human elongation factor (EF)-1α promoter. (B) Transcriptional activation by mMZF-2 and its derivatives. Mouse LG, LGM-1, LyD9, WR19L, NIH 3T3 and L929 cells were transfected with the indicated effector plasmids together with the reporter plasmids of either pBPA-4xF113B-Luc (4xF113B) or pBPA-TATALuc (TATA). As a control for transfection efficiency, a β-galactosidase plasmid (pSV-β-gal) was also included. The cells were harvested after 24 (LGM-1, LG, LyD9, WR19L) or 48 h (NIH 3T3, L929) for the luciferase assay. The luciferase activity of each sample was normalized to the β-galactosidase activity. Each bar represents the average of at least three independent transfection experiments. Luciferase activities detected in the presence of mMZF-2 or its derivatives are shown as values relative to the activity observed with the empty vector (pEF-BOS-EX, indicated as BOS). The absolute luciferase activity obtained with the reporter plasmid and the empty vector was low in any cell lines we have used.