Transcriptional derepression of the Saccharomyces cerevisiae HSP26 gene during heat shock.

Abstract

hsp26, the small heat shock protein of Saccharomyces cerevisiae, accumulates in response to heat and other types of stress. It also accumulates during the normal course of development, as cells enter stationary phase growth or begin to sporulate (S. Kurtz, J. Rossi, L. Petko, and S. Lindquist, Science 231:1154-1157, 1986). Analysis of deletion and insertion mutations demonstrated that transcriptional control plays a critical role in regulating HSP26 expression. The HSP26 promoter was found to be complex and appears to contain repressing elements as well as activating elements. Several upstream deletion mutations resulted in strong constitutive expression of HSP26. Furthermore, upstream sequences from the HSP26 gene repressed the constitutive expression of a heterologous heat shock gene. We propose that basal repression and heat-induced depression of transcription play major roles in regulating the expression of HSP26. None of the recombinant constructs that we analyzed separated cis-regulatory sequences responsible for heat shock regulation from those responsible for developmental regulation of HSP26. Depression of HSP26 transcription may be the general mechanism of HSP26 induction in yeast cells. This regulatory scheme is very different from that described for the regulation of most other heat shock genes.

A heat shock gene from Saccharomyces cerevisiae encoding a secretory glycoprotein.

“…2). The flanking region downstream of HSP150 contains two putative yeast mRNA 3' end-forming signals, TATATA (21) and T-ll--lTT-TTATA (22) three or more contiguous repeats of the element NGAAN in alternating orientations (23,24). Northern analysis of total RNA revealed a constitutively expressed HSP150 transcript of -1.6 kb that which showed a substantial increase in steady-state level after heat shock (Fig.…”

Transcriptomic and Proteomic Approach for Understanding the Molecular Basis of Adaptation of Saccharomyces cerevisiae to Wine Fermentation

“…Hsp26p is a molecular chaperone (23) induced under many sets of stress conditions (7,14,22,34,37,46). In our experiments, two protein species of Hsp26p with different isoelectric points appear differentially expressed and each is more abundant in a different strain.…”

Changes in disulfide bond content of proteins in a yeast strain lacking major sources of NADPH

“…Alternatively, these proteins could represent some of the most abundant modified proteins in both screens. However, among carbonylated proteins that did not contain disulfide bonds were heat shock protein Hsp26p, a very abundant protein in stressed yeast cells [48], and Cpr1p, a member of the cyclophilin A family that exhibits peptidyl-prolyl-isomerase activity and is involved as a chaperone in protein localization [49,50]. These proteins, along with glyceraldehyde-3-dehydrogenase isozyme 2 (Tdh2p), mitochondrial alcohol dehydrogenase (Adh3p), and mitochondrial NADH cytochrome b5 reductase (Mcr1p), were not detectably carbonylated in the mutant strain shifted to oleate medium in the presence of external reductants (Table 3).…”