The transcriptional activation region of Msn2p, in Saccharomyces cerevisiae, is regulated by stress but is insensitive to the cAMP signalling pathway

Msn2p is a transcription factor that mediates a transient cellular response to multiple stresses and to changes in the nutritional environment. It was previously shown that the C-terminal half of Msn2p contains the DNA binding domain, a nuclear localization signal and nuclear export determinants which are activated by stress. In this report, we demonstrate that the N-terminal half of Msn2p contains the transcriptional activation domain(s). In addition, we present evidence that this region of Msn2p is able to mediate both the activation of transcription and export of the protein from the nucleus in response to stress. Interestingly, while the stress response integrated by the components of the C-terminal half that are involved in nucleocytoplasmic localization is reversed by elevated levels of cAMP, the effects of stress on the transcriptional activation domain and the localization determinants present in the N-terminal half of Msn2p are insensitive to variations in the intracellular cAMP concentrations.