Fig. 5.

Disrupted expression of Ube3a produces the inability to forget. (A) Immediate memory scores for learning ability show normal learning in the Ube3a^EP3214 mutant. (B) Immediate memory scores for reversal-learning show a profound defect in the Ube3a^EP3214 mutant. (C) Immediate memory scores obtained through the third-odor test after reversal-learning training. The new memory was normal in the Ube3a^EP3214 mutant, whereas the old memory was significantly enhanced in mutant flies. (D) Normal learning ability in transgenic flies with acute down-regulation of Ube3a by the elav-GS system. (E) Reduced reversal-learning in transgenic flies with down-regulation of Ube3a by the elav-GS system. (F) Enhanced old memory in transgenic flies subjected to reversal-learning training. Acute down-regulation of Ube3a expression led to enhanced old memory in the third-odor test after reversal-learning training. n = 6–8 for all behavioral data. (G) The inability to activate Rac1 in the Ube3a^EP3214 mutant. Rac-GTP was significantly activated in WT flies, whereas there was little activation in the Ube3a^EP3214 mutant (n = 3).