Fig. 4. TPO-inducible GPIX-reporter activity is also dependent on an intact inverted Ets motif at -45. UT-7 EPO/Mpl cells were transfected with GPIX-reporter constructs as described in "Materials and Methods." A, UT-7 EPO/Mpl cells were transfected with nested 5'-deletions of the GPIX promoter. B, UT-7 EPO/Mpl cells were transfected with the GPIX-reporter constructs bearing mutations of either the GATA or the Ets motifs. {square}, culture in basal culture medium; {blacksquare}, culture in the presence of 20 ng/ml TPO. Results represent normalized mean ± SD and are representative of at least three independent experiments performed in duplicate.