CLOCK and BMAL1 up-regulate the expression of C/ebpα promoter.
(A) Comparison of mouse rat and human C/ebpα E-boxes. C/ebpα promoter contains two putative E-boxes within 1.4 kb region upstream of transcription start site. Consensus E-box sequences are shown in bold type. Positions from transcription start sites are shown in parentheses. This figure is based on information derived from the Mammalian Promoter/Enhancer Database (http://promoter.cdb.riken.jp/). (B) Schematic representation of reporter gene and constructs of C/ebpαpromoter region. Plasmid pGL3-1400 contains 1.4 kb upstream region of the C/ebpα transcription start site. Plasmid pGL3-BASIC does not contain C/ebpα promoter region. (C) Reporter gene assay for C/ebpα promoter. CLOCK, BMAL1 and CRY1 are overexpressed with the reporter constructs in NIH 3T3. pGL3-1400 reporter was up-regulated by CLOCK and BMAL1 then CRY1 supressed the expression. Each column comes from triplicate experiments. Data are presented as mean ± SEM (n = 3, *: p<0.01).