ind, dichaete, and vnd regulate ac minigene expression. Endogenous ac expression (A, C, E, and G) or ac expression as driven by pG4 or pG7 (B, D, F, and H) in wild-type (A and B), ind (C and D), Dichaete (E and F), and vnd (G and H) embryos. Embryos in B, D, F, and H are also homo- or hemizygous for In (1)y3PLsc8R. (A) ac is normally expressed in the medial and lateral columns of rows 3 and 7. (B) The pG4 minigenes only drive ac expression in row 3. (C and D) Loss of ind function causes derepression of endogenous ac and ac-pG4 as well as ac-pG7 (data not shown) expression in the intermediate column (arrows); loss of Dichaete causes modest derepression of endogenous ac and ac-pG4 expression in this domain (E and F). (G and H) In vnd embryos, endogenous ac expression and ac-pG7 expression is lost from the medial column. Anterior, left; line, ventral midline. m, i, and l indicate positions of medial, intermediate, and lateral columns, respectively.