A diet with a high carbohydrate/fat ratio enhances jejunal SI gene expression. Using ChIP assay, we revealed that the acetylation of historic H3 on transcriptional region and H4 on promoter region, respectively, of mouse SI gene are high. The acetylation of historic H3 and H4 as well as binding of HNF-1 and Cdx-2 on SI gene, was enhanced by increase in carbohydrate/fat ratio in the diet. These suggest that induction of SI gene by the diet rich in carbohydrate is associated with acetylation of histone H3 and H4 as well as binding of HNF-1 and Cdx-2 on SI gene. (c) 2007 Elsevier Inc. All rights reserved.