A novel immediate early response gene, IEX-1, is induced by ultraviolet radiation in human keratinocytes

Rajiv Kumar, Teruaki Kobayashi, Gina M. Warner, Yanhong Wu, Jeffrey L. Salisbury, Wilma Lingle, Mark R. Pittelkow

Research output: Contribution to journalArticlepeer-review

41 Scopus citations


Skin cancer is the most common human malignancy and is strongly associated with exposure to ultraviolet radiation (UVR). Several mechanisms including an increase in immediate early gene activation have been postulated to be involved in UVR-mediated carcinogenesis. We show that in a dose-dependent manner, UVR induces the expression of messenger RNA of a novel immediate early response gene, IEX-1, in human keratinocytes. Human keratinocytes and mouse fibroblasts transfected with an expression plasmid for IEX-1 grow at a faster rate than keratinocytes transfected with a similar plasmid that does not contain the IEX-1 sequence. IEX-1 protein is localized predominantly in the nucleus of keratinocytes by fluorescent antibody methods and by examination of the location of a green fluorescence IEX-1 fusion protein. Epidermal growth factor (EGF), a major mitogen of keratinocytes, and a tumor-promoting phorbol ester increase IEX-1 mRNA expression. IEX-1 may play a role in keratinocyte proliferation especially following UVR.

Original languageEnglish (US)
Pages (from-to)336-341
Number of pages6
JournalBiochemical and Biophysical Research Communications
Issue number2
StatePublished - Dec 18 1998

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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