Modulation of Fos and Jun in Response to Adverse Environmental Agents
This chapter describes the knowledge of stress-induced posttranslational activation of activator protein (AP-1). It discusses the processes involved in enhanced Fos and Jun synthesis. The chapter also describes the signal chain leading from the primary interaction of the noxious agent with the cell to the activation of AP-1. It discusses the possible consequences of enhanced AP-1 activity for the fate of the cell. Modulation of c-fos gene expression has also been seen after irradiation of whole animals with long-wavelength ultraviolet (UV), gamma-rays, or neutrons. UV-induced DNA damage, or a consequence of it, is recognized by recA protein, whose activation initiates the SOS response. Environmental noxes, such as carcinogens, activate AP-1 by inducing the posttranslational modification of the constituent proteins Fos and Jun and by inducing their synthesis. As a consequence, the transcription of many genes may be activated and other genes may be repressed.