Figure 7. Nord is a dosage-dependent modulator of the Bone Morphogenetic Protein (BMP) signaling.

(A) Upper row: schematic diagram of temporal UAS-Nord expression in the posterior compartment of wing discs using the temperature-sensitive Gal80 (Gal80^ts) system. At the permissive temperature (18°C), Gal4 activity is blocked by Gal80^ts. At the restrictive temperature (29°C), Gal80^ts is unable to repress Gal4, which then induces expression of the UAS-transgenes. Middle and lower rows: timing of temperature shift. Embryos and larvae are grown at 18°C, and prepupae are transferred to 29°C at the indicated time points before eclosion (middle row) or before dissection (lower row). (B) Representative adult wings from flies that carry the indicated transgenes under the control of tub-Gal80^ts together with hh-Gal4 or en-Gal4. The animals were grown at 18°C till prepupa stage, and then transferred to 29°C at 78 hr before eclosion. Yellow arrowhead indicates ectopic posterior crossvein (PCV); yellow arrow indicates reduced PCV; blue arrowhead indicates ectopic anterior crossvein (ACV); blue arrow indicates reduced ACV. Scale bar, 500 μm. (C) Quantification of PCV phenotypes in adult wings of female and male flies with indicated genotypes. The animals were grown at 18°C till prepupa stage, and then transferred to 29°C around 78, 72, or 66 (±1) hr before eclosion. n > 30 wings for each genotype at a given temperature shift time point. (D) Representative pupal wing from larvae that carry the indicated transgenes under the control of tub-Gal80^ts together with en-Gal4. The animals were grown at 18°C till prepupa stage, and then transferred to 29°C at 12 hr before dissection. The collected pupal wings were immunostained for anti-pMad (red), anti-Ptc (blue), and anti-GFP (Nord-GFP, green). Yellow arrowhead indicates ectopic pMad around the primordial PCV; yellow arrow indicates reduced pMad signal around the primordial PCV. Scale bar, 100 μm.

Figure 7—figure supplement 1. Spaciotemporal expression of exogenous Nord in the pupal wing leads to abnormal posterior crossvein (PCV) patterning.

Quantification of PCV phenotypes in adult wings from female and male flies carrying tub-Gal80^ts together with hh-Gal4-driven UAS-GFP or UAS-Nord. The animals were grown at 18°C till prepupa stage, and then transferred to 29°C around 78, 72, or 66 (±1) hr before eclosion. n > 30 wings for each genotype at a given temperature shift time point. Representative adult wings are shown in Figure 8D.

Figure 7—figure supplement 2. Ectopic Nord secreted from the posterior compartment induces ectopic crossvein growth in the anterior compartment.

Adult wings from flies that carry 2XUAS-Nord under the control of tub-Gal80^ts together with hh-Gal4. The animals were grown at 18°C till prepupa stage, and then transferred to 29°C at 78 hr before eclosion. Yellow arrowhead indicates ectopic posterior crossvein (PCV); yellow arrow indicates reduced PCV; blue arrowhead indicates ectopic crossvein in the anterior compartment. Scale bar, 500 μm.