Figure 1.
Hairy and Emc expression in the eye disc.
(A) Wild type eye disc labeled for Hairy protein (red), Emc (Green) and Senseless (blue). Arrowhead indicates the downregulation of Hairy just ahead of the morphogenetic furrow. Emc is downregulated almost simultaneously; Sens reports the first steps of differentiation soon afterwards. (B) Clones of cells homozygous for the null allele h22 lack almost all Hairy antigen. Eye differentiation, as recorded by the pan-neuronal marker Elav (blue), is hardly affected.
Figure 2.
Da, Emc and Hairy expression are independent of hairy.
Clones of homozygous mutant cells are labeled by the lack of GFP expression (green). (A) In h22 mutant clones, Da expression (magenta) both inside and outside of the furrow remained unaffected. (B) In h22 mutant clones, Emc expression (magenta) both inside and outside of the furrow remained unaffected. (C) In h22 mutant clones, Ato expression (magenta) was unaffected. (D) Cell-autonomous high Da expression (magenta) in emcAP6 h22 double mutant cells. Note the very similar levels of Da in emcAP6 h22 double mutant cells and emcAP6 mutant cells (compare panel E). (E) Cell-autonomous high Da expression (magenta) in emcAP6 mutant cells. Note the very similar levels of Da in emcAP6 mutant cells and emcAP6 h22 double mutant cells (compare panel D). Genotype: (A–C) ywhsF; h22 FRT80/[Ubi-GFP] M(3)67C FRT80; (D) ywhsF; emcAP6 h22 FRT80/[Ubi-GFP] M(3)67C FRT80; (E) ywhsF; emcAP6 FRT80/[Ubi-GFP] M(3)67C FRT80.
Figure 3.
Morphogenetic furrow progression is regulated by emc not by hairy.
Clones of homozygous mutant cells are labeled by the lack of GFP or LacZ expression (green). Sens labeling in magenta. (A) In h22 mutant clones, differentiation remained unaffected. (B) In emcAP6 mutant clones, differentiation was significantly advanced compared to neighboring tissue, more so in clones extending further in the anterior-posterior axis like the one nearer the top of the disc. (C) In emcAP6 h22 double mutant clones, morphogenetic furrow progression was significantly advanced compared to neighboring tissue, more so in clones extending further in the anterior-posterior axis like the one nearer the top of the disc. Genotype: (A) ywhsF; h22 FRT80/[Ubi-GFP] M(3)67C FRT80; (B) ywhsF; emcAP6 FRT80/[Ubi-GFP] M(3)67C FRT80; (C) ywhsF; emcAP6 h22 FRT80/[Ubi-GFP] M(3)67C FRT80.
Figure 4.
Hairy expression is independent of Emc and Da.
Clones of homozygous mutant cells are labeled by the lack of GFP expression (green). (A) Hairy expression (magenta) continues longer in the center of da clones, indicating a requirement for da in non-autonomous signals that regulate Hairy, not any direct cell-autonomous effect. There may also sometimes be a non-autonomous delay in the start of Hairy expression. (B) Hairy expression (magenta) is lost slightly earlier as furrow progression occurs more rapidly in emc clones. Mutant genotypes: (A) ywhsF; da10 FRT40/[UbiGFP] FRT40; (B) ywhsF; emcAP6 FRT80/[Ubi-GFP] M(3)67C FRT80.