Fig. 5. Effect of targeted TRX. (A) The pattern of expression of embryos carrying both BHL4 and hs-LexA-PC heat shocked at 2-3 hours is the same in a wild-type and in a homozygous trx background (trx). (B) BHL4G4 expression in early embryos (left) and after germ band retraction (right) with no induction of GAL-TRX (no hs). When GAL-TRX is induced at 2-3 hours, expression is enhanced only in regions where the gene was active (parasegments 6, 8, 10 and 12). In older embryos, after ectopic expression appears in the thorax, expression is stimulated everywhere. (C) The effect of GAL-TRX is transient and its induction at blastoderm does not stimulate expression in larvae (hs at 2-3 hours). A series of heat shocks 2 days before staining strongly enhances expression in leg discs (series hs). D) When both GAL-TRX and LexA-PC proteins are induced, LexA-PC recruits a repressive complex in the thorax (left), while GAL-TRX stimulates expression in the abdomen. Embryos heat shocked as in (B).