Insertion of CDX-BS to overcome the lack of functional TATA box. (A) The mutations introduced to replace the TATA box of the Glc6Pase promoter in the –80/+60B TATAM2 construct. Wild-type (WT) TATA box site is in bold uppercase. Mutated bases are in lowercase and bold. The mutants contain one CDX-BS (T-CBS-S, T-CBS-AS) or two CDX-BS (T-CBS-AS+S and T-CBS-AS+AS) instead of the TATA-box. Arrows indicate the CDX-BS in sense and antisense orientation. Sense orientation corresponds to the CDX-BS formed by the TATA-box. (B) Relative transactivation level by CDX1 of the mutants compared to the wild type construct. HepG2 cells were transiently transfected with the –80/+60B wild type (WT) or mutated constructs (1 µg) together with pCMV-RL (2 ng, used as internal control), without or with 100 ng of pCDX1-S. LUC activities were determined 48 h after transfection and were normalized with regards to the level of RL activities. Transactivation level by CDX1 was expressed as fold of induction over the basal condition (without CDX1) and compared with that obtained with the WT construct (100%). Results are the mean ± S.E.M. of at least three independent experiments performed in duplicate. **, significantly different from WT construct transactivation, P < 0.01.