Figure 4.

Steady-state luciferase mRNA levels correlate with luciferase protein levels in 293-ebf2 semi-stable cell lines. The steady-state levels of mRNA containing either the (A) 5′- or (B) 3′-TSSs of the predicted luciferase constructs correlated with levels of luciferase secreted by the semi-stable 293-ebf2 cell lines. Those cells carrying mutations of the proximal olf-1 site (D1 and M1) showed higher copy numbers of luciferase-coding mRNA, compared with cells carrying the WT, D2 and M2 constructs. (C) Ratios of the levels of luciferase mRNA containing different TSSs showed a shift in the starting position of this gene product, which was induced by the deletion of the distal olf-1 site. *P<0.01 (analysis of variance and Holm-Sidak post-hoc test) vs. all other groups. **P<0.01 vs. WT, D2 and M2 293-ebf2 cells; ^†P<0.01 vs. D2/293-ebf2 cells. n=9 experiments per group. WT, wild-type; D, deletion; M, mutation; ebf2, early B-cell factor 2; TSS, transcription start site.