Likewise, BrmDN-overexpressing (n = 10; Torin 1 concentration Figure 4E) and brm MARCM (n = 6; data not shown) ddaF neurons survived, whereas the wild-type ddaF neurons underwent apoptosis by 18 hr APF (n = 15; Figure 4D). CBP RNAi partially inhibited ddaD/E dendrite pruning (n = 15; Figure 4C′) because

the knockdown of CBP using the Gal42-21 driver was less efficient (data not shown). RNAi knockdown of CBP using the Gal4109(2)80 driver completely blocked ddaF apoptosis (n = 13; Figure 4F). Thus, Brm and CBP, like EcR-B1 and Sox14, are involved in regulating ddaD/E dendrite pruning as well as ddaF apoptosis. We then assessed the effects of brm and CBP on axon pruning of MB γ neurons. In wild-type MB γ neurons, the medial and dorsal axon branches that formed Selleck FK228 during the larval stages (data not shown) were pruned by 24 hr APF (n = 11; Figure 4G). The axon branches of BrmDN-overexpressing MB γ neurons

persisted at 24 hr APF (100%, n = 18; Figure 4H). Overexpression of CBP-ΔQ exhibited severe axon pruning defects in MB γ neurons at 24 hr APF as well (78%, n = 18; Figure 4I). Taken together, Brm and CBP play critical roles in the remodeling of sensory neurons and MB γ neurons during early metamorphosis. Given the essential role of CBP as both a transcriptional coactivator and a HAT during gene activation, we next tested whether CBP acts at the top of the EcR-B1/Sox14/Mical cascade to facilitate EcR-B1 expression in response to ecdysone. Surprisingly, EcR-B1 expression does not require CBP function, because upregulation of EcR-B1 expression

could be observed at the WP stage in CBP RNAi ddaC neurons (n = 13; Figures 5D and 5G; wild-type ddaC neurons, n = 11; Figures 5A and 5G). In contrast, Sox14 was absent or strongly reduced in 89% of CBP RNAi ddaCs (n = 17; Figures 5E and 5H; wild-type ddaC neurons, n = 11; Figures 5B and 5H), suggesting that CBP, like Brm, activates sox14 expression at the WP stage. Accompanying Sox14 downregulation, Mical expression was significantly reduced in the majority of CBP RNAi ddaC neurons (87.5%, n = 8; Figures 5F and 5I), as compared to that in wild-type (n = 23; Figures 5C else and 5I). Sox14 overexpression fully restored Mical expression (n = 46; Figure 5J compared with Figure 5F) and rescued the pruning defects (n = 25; Figure 5K, compared with the MicalN-term overexpression control, Figure 5L) in CBP RNAi ddaCs, suggesting that CBP functions upstream of Sox14 to promote dendrite pruning and seems to not be required for the expression of Mical. Thus, CBP appears to play a specific role in regulating EcR-B1/Usp-induced Sox14 expression in the activation of the EcR-B1/Sox14/Mical pathway during ddaC dendrite pruning. The levels of Usp and Brm remained largely unchanged in CBP RNAi ddaC neurons (n = 16 and n = 11, respectively; Figures S4B and S4D).