Fig. 1.

HNF4A physically interacts with the core clock complex and transsuppresses the transcriptional activity of CLOCK:BMAL1. (A) Coimmunoprecipitation of transiently expressed core clock proteins and HNF4A from HEK 293T extract. (B and C) Coimmunoprecipitation of endogenous BMAL1 (B) or CRY1 (C), and HNF4A from HepG2 extract. (D–F) HNF4A inhibits CLOCK:BMAL1 activity in luminescent reporter assays. HEK 293T cells were cotransfected with reporter gene E-box-dLuc (D), Per2-dLuc (E), or Per1-Luc (F), CLOCK:BMAL1, and increasing amounts of EGFP, CRY1, or HNF4A plasmid (n = 3 for each condition, mean ± SD).