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A transcriptional inhibitor induced in human melanoma cells upon ultraviolet irradiation

Y M Yang1, S E Rutberg, F C Luo

  • 1Molecular Carcinogenesis Program, American Health Foundation, Valhalla, New York 10595.

Cell Growth & Differentiation : the Molecular Biology Journal of the American Association for Cancer Research
|July 1, 1993
PubMed

Insights

UV irradiation induces a novel inhibitor in melanoma cells that blocks DNA binding and transcription. This tissue-specific protein may regulate cellular responses to UV damage in both normal and malignant melanocytes.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Biochemistry

Background:

  • Nuclear proteins in human melanoma cells bind strongly to UV response elements.
  • UV-C irradiation inhibits this binding in melanoma cells.
  • Conversely, UV irradiation enhances binding in rodent fibroblasts and human keratinocytes.

Purpose of the Study:

  • To investigate the molecular mechanisms underlying differential UV response element binding in various cell types.
  • To identify and characterize the factor responsible for altered binding activity post-UV irradiation in melanoma cells.

Main Methods:

  • UV-C irradiation of human melanoma cells, rodent fibroblasts, and human keratinocytes.
  • Nuclear protein extraction and analysis.
  • Electrophoretic mobility shift assays (EMSAs).
  • Fast protein liquid chromatography (FPLC) for protein purification.
  • In vitro transcription assays.

Main Results:

  • UV-C irradiation of melanoma cells induced an inhibitor of UV response element binding.
  • This inhibitor consists of 12 and 14 kilodalton proteins.
  • The inhibitor also blocked binding to AP1, CREB, and PEBP2 sequences and inhibited in vitro transcription.
  • The inhibitor was found in UV-irradiated melanocytes, indicating tissue specificity.

Conclusions:

  • UV irradiation induces a tissue-specific transcriptional inhibitor in melanoma cells.
  • This inhibitor plays a role in regulating the transcriptional response to UV irradiation.
  • Understanding this mechanism is crucial for both normal and malignant melanocyte responses to UV damage.

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