Fig. 2. Pygo is required for Wg signaling in various embryonic developmental processes. Wild-type (wt) and pygo mutant embryos are shown for expression of En (A,B), Wg (C,D), Labial (E,F) and Eve (G-J). All the pygo mutant embryos were derived from homozygous pygo^F107 mutant germline clones and paternally mutant for pygo^F66. En is normally expressed in stripes in the ectoderm of the thorax and abdomen during stage 10 (A). Wg is also expressed in stripes in the ectoderm of the thorax and abdomen (C) during stage 10. Both Wg and En stripes are strikingly reduced in pygo mutant embryos at stage 10 (B,D). The endoderm is normally subdivided into discrete domains by constrictions imposed by the visceral mesoderm and Labial is expressed in one of these domains (E). Labial expression is diminished in a pygo mutant embryo (F). Eve is normally expressed in specific subsets of cells derived from the somatic mesoderm that will form the heart (G) and also expressed in specific neurons in the central nervous system (CNS), including the RP2 neurons (arrow) (I). (H,J) In pygo mutant embryos, the expression of Eve-positive cells is absent in the somatic mesoderm cells (H) and in the RP2 neurons (J), respectively.