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The COP9 signalosome converts temporal hormone signaling to spatial restriction on neural competence.

Huang YC, Lu YN, Wu JT, Chien CT, Pi H - PLoS Genet. (2014)

Bottom Line: We found that the COP9 signalosome (CSN) suppresses the neural competence of non-innervated bristles at the PWM.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.

View Article: PubMed Central - PubMed

Affiliation: 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.

ABSTRACT
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.

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The CSN suppresses BR-Z1 expression after prepupa-to-pupa transition.(A–F′) BR-Z1 (red) expression in CSN4 clones in wing discs from late third-instar larval to pupal stages 24–28 h APF. (A–C′) BR-Z1 expression was not affected in CSN4 clones at late third larval instar (A, A′) and prepupal stages (B–C′). (D–F′) BR-Z1 levels in CSN4 clones were upregulated at pupal stages. (G) Diagram showing the mean anti-BR-Z1 immunofluorescent intensity from 0 to 34 h APF. The dashed line represents the mean relative intensities of anti-BR-Z1/anti-H3 in wild-type w1118 discs. The solid line represents the relative mean intensity of anti-BR-Z1 in CSN4 cells/neighboring CSN4/+ cells. The arrow marks the starting point when the BR-Z1 expression was significantly upregulated in CSN4 clones. Error bars represent the standard deviation (SD). Five w1118 wing discs were scored (N = 5) for each time point, and at least three CSN4 wing discs were scored (N≥3) for each time point, except for 12–14 h APF (N = 2).
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pgen-1004760-g004: The CSN suppresses BR-Z1 expression after prepupa-to-pupa transition.(A–F′) BR-Z1 (red) expression in CSN4 clones in wing discs from late third-instar larval to pupal stages 24–28 h APF. (A–C′) BR-Z1 expression was not affected in CSN4 clones at late third larval instar (A, A′) and prepupal stages (B–C′). (D–F′) BR-Z1 levels in CSN4 clones were upregulated at pupal stages. (G) Diagram showing the mean anti-BR-Z1 immunofluorescent intensity from 0 to 34 h APF. The dashed line represents the mean relative intensities of anti-BR-Z1/anti-H3 in wild-type w1118 discs. The solid line represents the relative mean intensity of anti-BR-Z1 in CSN4 cells/neighboring CSN4/+ cells. The arrow marks the starting point when the BR-Z1 expression was significantly upregulated in CSN4 clones. Error bars represent the standard deviation (SD). Five w1118 wing discs were scored (N = 5) for each time point, and at least three CSN4 wing discs were scored (N≥3) for each time point, except for 12–14 h APF (N = 2).

Mentions: In response to ecdysone pulses, BR-Z1 expression is upregulated in wing-disc cells at late third-instar larval stages and peaked at the prepupal stage of 2–6 h APF (GFP-positive cells in Figure 4A–B′) [48]. BR-Z1 expression declined starting around 6–8 h APF and continued declining to almost undetectable level 24–28 h APF (GFP-positive cells in Figure 4C–F′). Quantification of immunofluorescent intensity following co-staining revealed that the BR-Z1 intensity was 1.6-fold of H3 intensity 2–6 h APF, but dramatically dropped to 0.07-fold of H3 24–28 h APF (dashed line in Figure 4G, and Figure S4A–B″), with the strongest reduction occurring between 12–14 h to 16–18 h APF.


The COP9 signalosome converts temporal hormone signaling to spatial restriction on neural competence.

Huang YC, Lu YN, Wu JT, Chien CT, Pi H - PLoS Genet. (2014)

The CSN suppresses BR-Z1 expression after prepupa-to-pupa transition.(A–F′) BR-Z1 (red) expression in CSN4 clones in wing discs from late third-instar larval to pupal stages 24–28 h APF. (A–C′) BR-Z1 expression was not affected in CSN4 clones at late third larval instar (A, A′) and prepupal stages (B–C′). (D–F′) BR-Z1 levels in CSN4 clones were upregulated at pupal stages. (G) Diagram showing the mean anti-BR-Z1 immunofluorescent intensity from 0 to 34 h APF. The dashed line represents the mean relative intensities of anti-BR-Z1/anti-H3 in wild-type w1118 discs. The solid line represents the relative mean intensity of anti-BR-Z1 in CSN4 cells/neighboring CSN4/+ cells. The arrow marks the starting point when the BR-Z1 expression was significantly upregulated in CSN4 clones. Error bars represent the standard deviation (SD). Five w1118 wing discs were scored (N = 5) for each time point, and at least three CSN4 wing discs were scored (N≥3) for each time point, except for 12–14 h APF (N = 2).
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4230841&req=5

pgen-1004760-g004: The CSN suppresses BR-Z1 expression after prepupa-to-pupa transition.(A–F′) BR-Z1 (red) expression in CSN4 clones in wing discs from late third-instar larval to pupal stages 24–28 h APF. (A–C′) BR-Z1 expression was not affected in CSN4 clones at late third larval instar (A, A′) and prepupal stages (B–C′). (D–F′) BR-Z1 levels in CSN4 clones were upregulated at pupal stages. (G) Diagram showing the mean anti-BR-Z1 immunofluorescent intensity from 0 to 34 h APF. The dashed line represents the mean relative intensities of anti-BR-Z1/anti-H3 in wild-type w1118 discs. The solid line represents the relative mean intensity of anti-BR-Z1 in CSN4 cells/neighboring CSN4/+ cells. The arrow marks the starting point when the BR-Z1 expression was significantly upregulated in CSN4 clones. Error bars represent the standard deviation (SD). Five w1118 wing discs were scored (N = 5) for each time point, and at least three CSN4 wing discs were scored (N≥3) for each time point, except for 12–14 h APF (N = 2).
Mentions: In response to ecdysone pulses, BR-Z1 expression is upregulated in wing-disc cells at late third-instar larval stages and peaked at the prepupal stage of 2–6 h APF (GFP-positive cells in Figure 4A–B′) [48]. BR-Z1 expression declined starting around 6–8 h APF and continued declining to almost undetectable level 24–28 h APF (GFP-positive cells in Figure 4C–F′). Quantification of immunofluorescent intensity following co-staining revealed that the BR-Z1 intensity was 1.6-fold of H3 intensity 2–6 h APF, but dramatically dropped to 0.07-fold of H3 24–28 h APF (dashed line in Figure 4G, and Figure S4A–B″), with the strongest reduction occurring between 12–14 h to 16–18 h APF.

Bottom Line: We found that the COP9 signalosome (CSN) suppresses the neural competence of non-innervated bristles at the PWM.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.

View Article: PubMed Central - PubMed

Affiliation: 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.

ABSTRACT
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.

Show MeSH
Related in: MedlinePlus