Figure 5.

dPIS is required for phototransduction. A, The dPIS protein is not detected in 7-d-old dpis¹;P[hs–dpis] flies, which were heat shocked during development. The dpis¹;P[hs–dpis] flies underwent daily heat shock before eclosion, resulting in expression of dPIS–Myc. After eclosion, the flies were maintained in the dark at 25°C and were not exposed further to heat shock treatments. The extracts used for the Western blots were prepared from wild-type (wt) flies and dpis;P[hs–dpis] flies after the following times after eclosion: (1) 12 h (D₀), (2) 3 d (D₃), and (3) 7 d (D₇). The Western blot was probed with anti-dPIS antibodies and reprobed with anti-Rh1 antibodies. Molecular weight markers (kilodaltons) are indicated to the left. B–E, ERGs of wild-type as well as D₀, D₃, and D₇ dpis¹;P[hs–dpis] flies. The flies were dark adapted for 2 min and then exposed to three pulses of orange light (∼1800 lux): P1 (5 s), P2 (30 s), and P3 (5 s). The maintained component (mc) and on- and off-transients are indicated. F, Comparison of the P1 and P3 ERG amplitudes from B–E (n ≥7; error bars represent SDs). G–J, ERGs of wild-type as well as D₀, D₃, and D₇ dpis¹;P[hs–dpis] flies after 2 min exposure to orange light and a 3 s dark adaptation. K, Quantification of the ERG amplitudes. The flies were light adapted for 2 min (∼1800 lux) and then dark adapted for the times indicated. The amplitudes are indicated in millivolts ± SDs (n ≥8).