Irradiation of mammalian cells with ultraviolet light (200-400 nm) res
ults in the activation of a number of genes, the so-called ''UV respon
se'' (Herrlich et al., Rev. Physiol. Biochem. Pharmacol., 119:187-223,
1992). Many of the UV responsive genes are also transcriptionally act
ivated by growth factors and mitogens. Two transcription factors have
been demonstrated to acutely respond to these stimuli, namely AP-1 and
NF-kappa B. Whereas NF-kappa B proteins are primarily controlled via
proteolysis of regulatory domains which prevent nuclear translocation,
the AP-1 proteins are regulated at several levels including transcrip
tion and posttranslational modification. Here, we discuss progress in
the identification of the components of pathways acutely regulating th
ese transcription factors.