Msn2p, a zinc finger DNA-binding protein, is the transcriptional activator of the multistress response in Saccharomyces cerevisiae.

TLDR

The STRE element drives increased transcription of stress‑responsive genes in *Saccharomyces cerevisiae*. A lambda gt11 library screen identified MSN2, a zinc‑finger transcriptional activator that binds STRE. Msn2p is required for STRE‑dependent transcription and heat‑shock induction; its loss abolishes binding and gene activation, overexpression enhances these responses, MSN4 can partially compensate, and additional factors also contribute to the multistress response.

Abstract

The stress response promoter element (STRE) confers increased transcription to a set of genes following environmental or metabolic stress in Saccharomyces cerevisiae. A lambda gt11 library was screened to isolate clones encoding STRE-binding proteins, and one such gene was identified as MSN2, which encoded a zinc-finger transcriptional activator. Disruption of the MSN2 gene abolished an STRE-binding activity in crude extracts as judged by both gel mobility-shift and Southwestern blot experiments, and overexpression of MSN2 intensified this binding activity. Northern blot analysis demonstrated that for the known or suspected STRE-regulated genes DDR2, CTT1, HSP12, and TPS2, transcript induction was impaired following heat shock or DNA damage treatment in the msn2-disrupted strain and was constitutively activated in a strain overexpressing MSN2. Furthermore, heat shock induction of a STRE-driven reporter gene was reduced more than 6-fold in the msn2 strain relative to wild-type cells. Taken together, these data indicate that Msn2p is the transcription factor that activates STRE-regulated genes in response to stress. Whereas nearly 85% of STRE-mediated heat shock induction was MSN2 dependent, there was significant MSN2-independent expression. We present evidence that the MSN2 homolog, MSN4, can partially replace MSN2 for transcriptional activation following stress. Moreover, our data provides evidence for the involvement of additional transcription factors in the yeast multistress response.