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The torso response element binds GAGA and NTF-1/Elf-1, and regulates tailless by relief of repression.

Genes & development · 1995 · Unclear · Insufficient evidence

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The tor response element (tor-RE) in the tll promoter was mapped to an 11-bp sequence that binds the proteins GAGA and NTF-1/Elf-1. NTF-1 can be phosphorylated by MAPK, and tll expression is expanded in embryos lacking maternal NTF-1 activity, supporting a mo…

Study snapshot

PublicationGenes & development · 1995
Study typeother
Reported directionUnclear
Evidence ratingInsufficient

Abstract

Modulation of transcription factor activity leading to changes in cell behavior (e.g., differentiation versus proliferation) is one of the critical outcomes of receptor tyrosine kinase (RTK) stimulation. In the early Drosophila embryo, activation of the torso (tor) RTK at the poles of the embryo activates a phosphorylation cascade that leads to the spatially specific transcription of the tailless (tll) gene. Our analysis of the tor response element (tor-RE) in the tll promoter indicates that the key activity modulated by the tor RTK pathway is a repressor present throughout the embryo. We have mapped the tor-RE to an 11-bp sequence; using this sequence as the basis for protein purification, we have determined that the proteins GAGA and NTF-1 (also known as Elf-1, product of the grainyhead gene) bind to the tor-RE. We demonstrate that NTF-1 can be phosphorylated by MAPK (mitogen-activated protein kinase), and that tll expression is expanded in embryos lacking maternal NTF-1 activity; these results make NTF-1 a likely target for modulation by the tor RTK pathway in vivo. The data presented here support a model in which activation of the tor RTK at the poles of the embryos leads to inactivation of the repressor and therefore, to transcriptional activation (by activators present throughout the embryo) of the tll gene at the poles of the embryo.

Machine Enhanced Logic

AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeother
Effect directionunclear
PopulationEarly Drosophila embryo
Sample sizeNot supplied
ExposureNot supplied
Evidence strengthInsufficientConfidence: 90% · Peer reviewed: yes

Main findings

The tor response element (tor-RE) in the tll promoter was mapped to an 11-bp sequence that binds the proteins GAGA and NTF-1/Elf-1. NTF-1 can be phosphorylated by MAPK, and tll expression is expanded in embryos lacking maternal NTF-1 activity, supporting a model where torso RTK activation relieves repression to allow tll transcription at embryo poles.

Outcomes measured

  • Binding of transcription factors (GAGA, NTF-1/Elf-1) to the torso response element (tor-RE) in the tailless (tll) promoter
  • Phosphorylation of NTF-1 by MAPK
  • Spatial expression pattern/expansion of tailless (tll) in embryos lacking maternal NTF-1 activity
  • Model of transcriptional regulation via relief of repression downstream of torso RTK signaling

Limitations

  • No EMF exposure or electromagnetic field measurements described in the provided abstract/metadata
  • Sample size and quantitative effect estimates are not reported in the provided abstract
View raw extracted JSON
{
  "study_type": "other",
  "exposure": {
    "band": null,
    "source": null,
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": "Early Drosophila embryo",
  "sample_size": null,
  "outcomes": [
    "Binding of transcription factors (GAGA, NTF-1/Elf-1) to the torso response element (tor-RE) in the tailless (tll) promoter",
    "Phosphorylation of NTF-1 by MAPK",
    "Spatial expression pattern/expansion of tailless (tll) in embryos lacking maternal NTF-1 activity",
    "Model of transcriptional regulation via relief of repression downstream of torso RTK signaling"
  ],
  "main_findings": "The tor response element (tor-RE) in the tll promoter was mapped to an 11-bp sequence that binds the proteins GAGA and NTF-1/Elf-1. NTF-1 can be phosphorylated by MAPK, and tll expression is expanded in embryos lacking maternal NTF-1 activity, supporting a model where torso RTK activation relieves repression to allow tll transcription at embryo poles.",
  "effect_direction": "unclear",
  "limitations": [
    "No EMF exposure or electromagnetic field measurements described in the provided abstract/metadata",
    "Sample size and quantitative effect estimates are not reported in the provided abstract"
  ],
  "evidence_strength": "insufficient",
  "confidence": 0.9,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "Drosophila",
    "torso receptor tyrosine kinase",
    "tailless",
    "promoter",
    "tor response element",
    "GAGA",
    "NTF-1",
    "Elf-1",
    "grainyhead",
    "MAPK",
    "phosphorylation",
    "transcriptional repression"
  ],
  "suggested_hubs": []
}
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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1101/gad.9.24.3163
PubMed: 8543159

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