Figure 2
Lack of Ate1 increases the light sensitivity of ON bipolar cells. (A–D) Representative electroretinograph (ERG) responses (B-wave, 22.5 Hz low-pass filtered) of an Ate1 conditional knockout (KO, red) and a wild type (WT, blue) littermate after a prolonged dark adaptation (see "Methods"). Light flashes were delivered to the dark-adapted retina at time zero. The rod ON-bipolar sensitivity was probed with a scotopic dim flash (A) and a scotopic saturating flash (B), a 0.00022 and 0.011 \(cd{\cdot }s/m^2\) green light, respectively. The cone ON-bipolar sensitivity was probed with a photopic dim flash (C) and a photopic saturating flash (D), a 1.0 \(cd{\cdot }s/m^2\) green light and a 1000 \(cd{\cdot }s/m^2\) Xenon light, respectively. See Fig. S2 for the representative and averaged responses to the full ranges of flashes. To probe cone ON-bipolar responses, rod ON-bipolar responses were suppressed by a constant background of 30 \(cd/m^2\) green light during photopic flashes. (E) Quantification of the sensitivity of ERG response. The KO had significantly higher sensitivity than WT (\(p=0.03\) and \(p=0.01\) for rod ON-bipolar (scotopic) and cone ON-bipolar (photopic) B-wave, respectively). (F) Quantification of the maximum amplitude of the ERG response. The maximum amplitude did not change significantly between KO and WT. In (E) and (F), error bars represent the SEM, the p-values are from paired Student’s t-test for 7 pairs of littermates, and the data points from each pair are plotted with a unique symbol in E and F. The differences between KO and WT were also evaluated with a non-parametric statistical hypothesis test (Fig. S3), which confirmed the conclusions in (E) and (F). The B-wave sensitivity and the maximum amplitude were calculated from Eq. (1).
