Mutation of the TATA box alters the CDX1 transactivation of the Glc6Pase promoter. (A) Mutations (M1 and M2) introduced in the TATAAAA region of the Glc6Pase promoter. Wild type (WT) TATA-box site is underlined. Mutated bases are in lowercase and bold. (B and C) HepG2 cells were transiently transfected with the –80/+60B and –55/+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. (B) Basal transcription activity of the wild type and mutated forms of the –80/+60B constructs. The transcriptional activity of each construct is expressed relative to the LUC activity of pGL2‘basic’ and is the mean ± S.E.M. of at least three independent experiments performed in duplicate. **, significantly different from pGL2basic activity, P < 0.01. (C) Transactivation level by CDX1, expressed as fold of induction over the basal condition (without CDX1). Results are the mean ± S.E.M. of at least three independent experiments performed in duplicate. **, significantly different from without pCDX1-S, P < 0.01.