Figure 3.

Changes in localization of βIII tubulin, GAP43, and L1CAM take place over time. (A) The expression of βIII tubulin in ICBNs is maximal 90 minutes before the time when lights are turned on at ZT 22.5; thereafter, βIII tubulin expression remains the same in the ICBNs. GAP43 expression in the ICBNs does not change significantly over time. The ratio of GAP43/βIII tubulin is lowest at ZT 22.5 and higher at all other time points indicating that axons are actively growing while the lights are on and continue to grow for 90 minutes after the lights are turned off at ZT 13.5. (B) ICNTs in the middle layers of the corneal epithelium appear as puncta. Significant differences are seen between ZT 22.5 and ZT 1.5 and between ZT 1.5 and ZT 13.5 for βIII tubulin. No significant differences are seen in GAP43; the ratio of GAP43/βIII tubulin in the ICNTs is highest at ZT 1.5. (C) In the apical aspect of the cornea where the ICNTs turn and assume a parallel orientation, there is a significant drop in the lengths of the pICNTs between ZT 22.5 and ZT 1.5 that is observed when the lengths of the pICNTs are quantified using βIII tubulin and GAP43; this is not observed when the lengths of the pICNTs are assessed using L1CAM.