Fig. 3.

Klg is regulated by Notch and LTM-dependent increases in Klg require Notch activity. (A) Heat-shock (+hs, 37 °C for 30 min) induction of a dominant-negative N^Δcdc10rpts transgene significantly decreases Klg protein amounts in head extracts from hs-N^Δcdc10rpts (hs-N^Δcdc) flies. Conversely, Klg amounts are up-regulated by induction of a WT Notch transgene in hs-N⁺ flies. Flies were heat-shocked 5 h before fly head collection. The Klg/Tub ratio in nonheat-shocked WT flies was defined as 1.0. *P < 0.05. (B) Generation of the NICD upon LTM induction. The amounts of NICD in head extracts of naive flies (n) and flies harvested 3 and 6 h after massed (m) or spaced (s) training were measured. The amounts of NICD (120 kDa) and full length of Notch (N_FL, 350 kDa) were determined using an anti-NICD monoclonal antibody. NICD levels increased significantly in spaced-trained flies compared to naive and massed-trained flies. The NICD/Tub ratio in naive WT flies was defined as 1.0. *, P < 0.03 and **, P < 0.005. (C) Induction of the dominant negative N^Δcdc10rpts transgene in hs-N^Δcdc flies suppresses the LTM-dependent increase in Klg protein in fly heads. The N^Δcdc10rpts transgene was induced by heat-shocking flies for 30 min at 37 °C, 5 h before training (+hs). Heat-shocked naive flies were heat-shocked 5 h before head collection. Relative Klg amounts in naive flies and in spaced-trained flies at 0 and 24 h after training are indicated. *, P < 0.05.