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. Author manuscript; available in PMC: 2009 Jul 14.
Published in final edited form as: Neuron. 2007 Dec 20;56(6):1090–1102. doi: 10.1016/j.neuron.2007.10.036

Figure 5. Impaired olfactory learning with over-expression of Rdl in adult MBs.

Figure 5

(A) Flies over-expressing RDL in the MBs during adulthood were impaired for olfactory learning performance. The experimental flies carried the c772-Gal4 driver, the UAS-Rdl-G transgene, and a temperature sensitive Gal80 (Gal80ts) transgene in which Gal80ts was driven by the ubiquitously expressed tubulin promoter. All the flies were raised at 18 °C to inhibit Gal4 activity with the active form of the Gal80ts repressor. No impairment was observed when the flies were raised to adulthood and trained and tested at 18 °C (left). When the flies were shifted to 32 °C for two days after eclosion to de-repress Gal4 and allow for over-expression of Rdl, this adulthood over-expression produced a learning defect when compared with the two control groups of flies carrying only the c772-Gal4 driver or the UAS-Rdl-G transgene alone (right).

(B) The impairment of learning produced by Rdl over-expression was reversible. The same three groups of flies as in (A) were raised at 18 °C and maintained at 18 °C for three days after eclosion. They were then shifted to 32°C for one day prior to training. The over-expression group showed decreased performance after one-day of over-expression of Rdl in adulthood. A separate group of c772-Gal4, Gal80ts; UAS-Rdl-G flies were raised at 18°C and shifted to 32°C for one day after eclosion to de-repress Gal4 activity. Then they were shifted back to 18°C for three more days to re-repress Gal4 activity. This recovery treatment restored learning performance to a level indistinguishable from the control groups. n = 6 for each group. *: P<0.05; **: P<0.01.

(C) Time course of the effect of Rdl over-expression on learning. Flies carrying the c772-Gal4 driver, the UAS-Rdl-G transgene and Gal80ts were raised at 18 °C and shifted to 32 °C for 0, 3, 6, 16 and 48 hours after eclosion to induce the over-expression of Rdl. The performance index at 3 min after training is shown for each group. For all panels, n = 6 for each group. Means ± SEM are shown. **: P<0.01, compared with 0 h.