The COP9 signalosome converts temporal hormone signaling to spatial restriction on neural competence.
During development, neural competence is conferred and maintained by integrating spatial and temporal regulations. The Drosophila sensory bristles that detect mechanical and chemical stimulations are arranged in stereotypical positions. The anterior wing margin (AWM) is arrayed with neuron-innervated sensory bristles, while posterior wing margin (PWM) bristles are non-innervated. We found that the COP9 signalosome (CSN) suppresses the neural competence of non-innervated bristles at the PWM. In CSN mutants, PWM bristles are transformed into neuron-innervated, which is attributed to sustained expression of the neural-determining factor Senseless (Sens). The CSN suppresses Sens through repression of the ecdysone signaling target gene broad (br) that encodes the BR-Z1 transcription factor to activate sens expression. Strikingly, CSN suppression of BR-Z1 is initiated at the prepupa-to-pupa transition, leading to Sens downregulation, and termination of the neural competence of PWM bristles. The role of ecdysone signaling to repress br after the prepupa-to-pupa transition is distinct from its conventional role in activation, and requires CSN deneddylating activity and multiple cullins, the major substrates of deneddylation. Several CSN subunits physically associate with ecdysone receptors to represses br at the transcriptional level. We propose a model in which nuclear hormone receptors cooperate with the deneddylation machinery to temporally shutdown downstream target gene expression, conferring a spatial restriction on neural competence at the PWM.
Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan; Department of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan; Insitute of Molecular Biology, Academia Sinica, Taipei, Taiwan.
Yi-Chun
YC
Huang
Department of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan.
Yu-Nung
YN
Lu
Institute of Molecular Biology, National Taiwan University, Taipei, Taiwan.
June-Tai
JT
Wu
Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan; Insitute of Molecular Biology, Academia Sinica, Taipei, Taiwan.
Cheng-Ting
CT
Chien
Department of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan.
Haiwei
H
Pi
D000818:Animals; D000075686:COP9 Signalosome Complex; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics / Q000254:growth & development; D004440:Ecdysone / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D046912:Multiprotein Complexes / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D009474:Neurons / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D010447:Peptide Hydrolases / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014921:Wings, Animal / Q000254:growth & development*
C102117:Br protein, Drosophila; D029721:Drosophila Proteins; D046912:Multiprotein Complexes; D009687:Nuclear Proteins; D014157:Transcription Factors; C413162:sens protein, Drosophila; D004440:Ecdysone; D010447:Peptide Hydrolases; D000075686:COP9 Signalosome Complex