Fig. 6. phyl expression is negatively regulated by N signaling. Whole-mount in situ hybridization of phyl mRNA in wing disks (A-D) and embryos (E-L). (A) phyl expression in wild-type wing disk. (B,C) Higher magnification of the phyl expression in SOP cells of wing margin (B) and macrochaetes (C). (D) phyl expression in N^ts mutant wing disk. (E-G) Late third instar larvae of N^ts were incubated at 30°C for 5 hours before dissecting. In the embryos, phyl mRNA is expressed in (E) neuroblasts at stage 9 (ventral view), (F) SOP cells at stage 11 (lateral view), and (G) a subset of PNS cells at stage 13 (lateral view). (H) phyl mRNA in PNS is no longer detected in the numb¹ mutant, and (I) is reduced in the sca-GAL4/+;UAS-N^ACT/+ embryo. (J) In wild-type embryos, phyl is expressed in approximately 20-30 SOP cells in each hemisegment at stage 11. (K,L) phyl is expressed in many more cells in the N^55e11 (K) and E(spl)^{b32.2 gro+} (L) mutant embryos at stage 11. (M,N) Confocal images of the embryonic abdominal hemisegments stained with anti-Elav antibody (red) and anti-prospero antibody (green). (M) sca-GAL4/+; UAS-N^ACT/+ embryo. (N) sca-GAL4/+; UAS-NACT UAS-phyl embryo.