Ecdysone signaling regulates specification of neurons with a male-specific neurite in Drosophila

摘要

Some mAL neurons in the male brain form the ipsilateral neurite (ILN[+]) in a manner dependent on FruBM, a male-specific transcription factor. FruBM repressesrobo1transcription, allowing the ILN to form. We found that the proportion of ILN[+]-mALs in all observed single cell clones dropped from ～90% to ～30% by changing the heat-shock timing for clone induction from 4-5?days after egg laying (AEL) to 6-7?days AEL, suggesting that the ILN[+]-mALs are produced predominantly by young neuroblasts. Upon EcR-A knockdown, ILN[+]-mALs were produced at a high rate (～60%), even when heat shocked at 6-7?days AEL, yet EcR-B1 knockdown reduced the proportion of ILN[+]-mALs to ～30%. Immunoprecipitation assays in S2 cells demonstrated that EcR-A and EcR-B1 form a complex with FruBM.robo1reporter transcription was repressed by FruBM and ecdysone counteracted FruBM. We suggest that ecdysone signaling modulates the FruBM action to produce an appropriate number of male-type neurons.