Identification of a Novel Class of Target Genes and a Novel Type of Binding Sequence of Heat Shock Transcription Factor in Saccharomyces cerevisiae

Abstract

In response to hyperthermia, heat shock transcription factor (HSF) activates transcription of a set of genes encoding heat shock proteins (HSPs). The promoter regions of HSP genes contain the HSF binding sequence called the heat shock element (HSE), which consists of contiguous inverted repeats of the sequence 5-nGAAn-3 (where n is any nucleotide). We have constructed an hsf1 mutant of Saccharomyces cerevisiae and analyzed genome-wide changes in heat shock response in the mutant cells. The results have revealed that Hsf1 is necessary for heat-induced transcription of not only HSP but also genes encoding proteins involved in diverse cellular processes such as protein degradation, detoxification, energy generation, carbohydrate metabolism, and maintenance of cell wall integrity. Approximately half of the Hsf1-regulated genes lacked the typical HSE in their promoter regions. Instead, several of these genes have a novel Hsf1 binding sequence that contains three direct repeats of nTTCn (or nGAAn) interrupted by 5 bp. The number and spacing of the repeating units are critical determinants for heat-induced transcription as well as for recognition by Hsf1. In the yeast genome, the presence of the sequence is enriched in Hsf1-regulated genes, suggesting that it is generally used as an HSE in the Hsf1 regulon.

Deletion Analysis of the Catalase-Encoding Gene (catB) Promoter fromAspergillus oryzae

“…It has beeen reported that the HSE and its binding protein heat shock transcription factor are highly conserved from yeast to humans. [19][20][21] It is well known that heat shock and hydrogen peroxide induces catalase gene expression in Aspergilli 5,[22][23][24] and other species, [6][7][8]25) and that each catalase gene promoter has regulatory element for stress response. But the regulatory elements are different in species.…”

“…NS indicates nonspecific competitor. Either 10 pmol (lanes 3,6,9,12,15,20,23,26,29, and 32), 5 pmol (lanes 4, 7, 10, 13, 16, 21, 24, 27, and 30), or 1 pmol (lanes 5,8,11,14,17,22,25,28, and 31) of the competitors were added. SB and FP indicate the shifted band and the free probe, respectively.…”

A comprehensive functional portrait of two heat shock factor-type transcriptional regulators involved in Candida albicans morphogenesis and virulence

“…ScSFL1 encodes a negative regulator of pseudohyphal growth and invasion [31] and was isolated based on its ability to suppress flocculation defects in yeast [32]. ScSfl1p carries a putative heat shock factor (HSF)-type DNA binding domain and binds in vitro to a GAA triplet motif [33] characteristic of heat shock elements (HSEs) [34], while exerting its negative regulation through the recruitment of the Ssn6p-Tup1p corepressor complex [35]. ScSfl1p has dual activator/repressor functions, acting as a transcriptional repressor of flocculation-related genes and as an activator of stress-responsive genes [35,36].…”

Interaction between Heat Shock Transcription Factors (HSFs) and Divergent Binding Sequences

“…A genome-wide ScHsf1 binding analysis indicates that ScHsf1 binds to the 5Ј-upstream regions of a set of genes that participate in a broad range of biological functions (29). The heat shock-induced transcription of many of these genes is inhibited in cells containing an Schsf1 mutation, although several of the target genes lack an apparent HSE in their promoter regions (20). In the present study, we identified the ScHsf1-binding sequences in most of the target genes examined and showed that ScHsf1 binds to and activates transcription via HSEs that diverge from the canonical sequence.…”

“…The differently arranged nGAAn units are classified as follows: the perfect-type HSE consists of continuous inverted repeats of the unit (nTTCnnGAAnnTTCn), the gap-type contains one gap between the units (nTTCnnGAAn(5 bp)nGAAn), and the step-type contains two gaps (nTTCn(5 bp)nTTCn(5 bp)nTTCn) (20). Various ScHsf1 domains are involved in HSE architecture-specific transcription.…”