Jejunal induction of SI and SGLT1 genes in rats by high-starch/low-fat diet is associated with histone acetylation and binding of GCN5 on the genes.

The intestinal expression of genes involved in carbohydrate digestion and absorption, such as sucrase-isomaltase (SI) and sodium-dependent glucose cotransporter (SGLT1), is higher in rodents fed a high-starch/low-fat (HS) diet than in those fed a low-starch/high-fat (LS) diet. In the present study, we investigated whether the HS diet-induced induction of SI and SGLT1 in the rat jejunum is coordinately regulated by nuclear transcription factors, histone acetylation, or histone acetyltransferases. HS diet intake induced jejunal expression of a histone acetyltransferase, general control of amino acid synthesis (GCN5), concurrently with the SI and SGLT1 genes; however, gene expression of nuclear transcription factors such as hepatocyte nuclear factor-1, caudal type homeobox-2, and GATA-binding protein-4 was unaffected by the HS diet. Acetylation of histones H3/H4 and binding of acetyltransferase GCN5 on the promoter/enhancer and transcribed regions of SI and SGLT1 genes were significantly higher in HS diet-fed rats than in LS diet-fed rats, but transcription factor binding was not affected by the HS diet. Our results suggest that the concomitant induction of SI and SGLT1 genes in the jejunum by the HS diet is closely associated with the binding of GCN5 and acetylation of histones H3/H4 on these genes.