Fig. 4. upd has only minimal effect on hindgut patterning. Spatially localized patterns of gene expression in distinct domains of the stage 14 hindgut and posterior midgut are summarized in A; points of renal tubule attachment are indicated by `V'. Gene expression patterns in A are shown in wholemounts of wild-type (wt), upd loss-of-function (upd^os1A) and upd gain-of-function (byn-GAL4; UAS-upd) embryos (B). In the absence of upd activity (upd^os1A), expression of Wg at the most anterior of the small intestine is reduced (white arrowhead), while expression patterns of hh and Ser in small intestine, En in large intestine, dri in boundary cells and hh, Ser and Wg in rectum are not affected. When upd is expressed uniformly throughout the hindgut (byn-GAL4; UAS-upd), expression of Wg in the anterior small intestine is slightly upregulated (black arrowhead), while all other spatially localized gene expression patterns examined appear normal. Expression of hh, Ser and dri was detected by in situ hybridization, that of Wg and En by antibody staining.