Identification of cis-regulatory elements and trans-acting proteins of the rat carbohydrate response element binding protein gene.
Carbohydrate response element binding protein (ChREBP) is a transcription factor that activates liver glycolytic and lipogenetic enzyme genes in response to high carbohydrate diet. Here we report the transcriptional regulatory mechanisms for the rat ChREBP gene. Firstly, we determined the transcription initiation site and the nucleotide sequences of the rat ChREBP promoter region encompassing approximately 900bp from the ATG initiation codon. Reporter gene assays demonstrated that the major positive regulatory region exists in the nucleotide sequence between -163 and -32 of the ChREBP gene. This region contains a cluster of putative transcription factor binding elements that consist of two specificity protein 1 (Sp1) binding sites (-66 to -50 and -93 to -78), a sterol regulatory element (-101 to -110), and two nuclear factor-Y (NF-Y) binding sites (-23 to -19 and -131 to -127). Mutations introduced into these sites caused marked reduction of ChREBP promoter activities. Functional synergisms were observed between Sp1/NF-Y and Sp1/sterol regulatory element-binding protein. Additionally, electrophoretic mobility shift assays and chromatin immunoprecipitation assays demonstrated that these factors bound to these elements. Thus, we conclude that functional synergisms between these transcription factors are critical for ChREBP gene transcription.
Satoh
Shin-Ichi
S
Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa-ku, Nagoya 464-8601, Japan.
Masatoshi
Sakie
S
Shou
Zhangfei
Z
Yamamoto
Taichi
T
Ishigure
Tatsuya
T
Semii
Atsushi
A
Yamada
Kazuya
K
Noguchi
Tamio
T
D000818:Animals; D001483:Base Sequence; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / Q000096:biosynthesis / Q000235:genetics*; D023081:CCAAT-Binding Factor / Q000235:genetics; D019556:COS Cells; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D006367:HeLa Cells; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D005810:Multigene Family; D011401:Promoter Regions, Genetic; D011485:Protein Binding / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D050436:Regulatory Elements, Transcriptional / Q000235:genetics*; D016329:Sp1 Transcription Factor / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics / Q000502:physiology*; D024363:Transcription Initiation Site / Q000502:physiology
D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D023081:CCAAT-Binding Factor; C442825:Mlxipl protein, rat; D016329:Sp1 Transcription Factor; D015534:Trans-Activators