In Vivo Search for Butyrate Responsive Sequences Using Transgenic Mice Carrying Gene Promoter Mutants

We describe an in vivo approach, in transgenic mice, aimed to identify promotar elements responsible for the induction of y globin expression by butyrate. Transgenic lines carrying human ‘ y gene promoter truncations at position -141, -201, -382, and -730 ‘y were treated with a amino butyric acid (aABA), and effects on y globin expression were analved at the m-nger RNA level. No induction of y gene expression was observed in animals carrying promoters truncated at positions -141, -201, or -382 ’y, suggesting either that butyrate response elements (BREI are not located in the proximal y gene promoter or, if they were, they require the cooperation of upstream sequences for y gene induction. Two animals from one line carrying the -730 *y truncation