UVB irradiation-induced activator protein-1 activation correlates with increased c-fos gene expression in a human keratinocyte cell line

Weixing Chen, Alexander H. Borcherst, Zigang Dong, Marianne B. Powell, G. Tim Bowden

Research output: Contribution to journalArticlepeer-review

84 Scopus citations

Abstract

The effects of UVB irradiation on transcription factor activator protein-1 (AP-1) DNA binding and AP-1 transactivation were studied in a human keratinocyte cell line, HaCaT. UVB-induced AP-1 binding to a consensus AP-1 binding site was observed by gel shift assays with maximum stimulation at 12 h after UVB irradiation. A promoter region of the human collagenase-1 gene containing the same AP-1 binding sequence linked to a luciferase reporter gene was stably transfected into HaCaT cells. UVB irradiation significantly increased luciferase activity in these stably transfected cells, with maximum activity observed at 24 h after UVB irradiation. c-Fos and Jun D were identified by antibody clearing assays as the main components of the bound AP-1 complexes. Inhibition of transcription with actinomycin D and inhibition of protein synthesis with cycloheximide significantly abrogated the effect of UVB on AP-1 DNA binding, indicating that transcription and translation were required for AP-1 activation. Northern and Western analyses revealed a correlation between increased AP-1 activity and accumulation of c-fos mRNA and c-Fos protein after UVB irradiation. UVB irradiation increased c-fos transcription in HaCaT cells stably transfected with a plasmid containing the human c-fos promoter driving a luciferase reporter gene. These results suggest that increased c-fos expression may play an important role in UVB- induced AP-1 activation in HaCaT cells.

Original languageEnglish (US)
Pages (from-to)32176-32181
Number of pages6
JournalJournal of Biological Chemistry
Volume273
Issue number48
DOIs
StatePublished - Nov 27 1999

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