scholarly journals Regulation of Thermotolerance by Stress-Induced Transcription Factors in Saccharomyces cerevisiae

2008 ◽  
Vol 7 (5) ◽  
pp. 783-790 ◽  
Author(s):  
Noritaka Yamamoto ◽  
Yuka Maeda ◽  
Aya Ikeda ◽  
Hiroshi Sakurai
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Transcription Factors ◽  
High Temperature ◽  
Heat Shock ◽  
Cell Growth ◽  
Rna Polymerase Ii ◽  
Transcriptional Activation ◽  
Target Genes ◽  
Recovery Period ◽  
Before And After

ABSTRACT The heat shock transcription factor Hsf1 and the general stress transcription factors Msn2 and Msn4 (Msn2/4) are major regulators of the heat shock response in Saccharomyces cerevisiae. Here, we show that transcriptional activation of their target genes, including HSP104, an antistress chaperone gene, is obligatory for thermotolerance. Although Hsf1 activity might be necessary before the exposure of cells to high temperature, severe heat shock induced the binding of hyperphosphorylated Hsf1 to its target promoters. However, promoter-bound, phosphorylated Hsf1 was inactive for transcription because RNA polymerase II was inactive at high temperatures. Rather, our results suggest that Hsf1 activates the transcription of most of its target genes during the recovery period following severe heat shock. This delayed upregulation by Hsf1, which would be induced by misfolded proteins that accumulate in severely heat-shocked cells, is required for the resumption of normal cell growth. In contrast, the factors Msn2/4 were not involved in the delayed upregulation of genes and were dispensable for cell growth during the recovery period, suggesting that they play a role before the exposure to high temperature. These results show that Hsf1 and Msn2/4 act differentially before and after exposure to extreme temperatures to ensure cell survival and growth.

Activation Functions 1 and 2 of Nuclear Receptors: Molecular Strategies for Transcriptional Activation

2003 ◽  
Vol 17 (10) ◽  
pp. 1901-1909 ◽  
Author(s):  
Anette Wärnmark ◽  
Eckardt Treuter ◽  
Anthony P. H. Wright ◽  
Jan-Åke Gustafsson
Keyword(s):  
Transcription Factors ◽  
Rna Polymerase Ii ◽  
Nuclear Receptors ◽  
Transcriptional Activation ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Current Knowledge ◽  
Preinitiation Complex ◽  
Activation Domains ◽  
Terminal Domain

Abstract Nuclear receptors (NRs) comprise a family of ligand inducible transcription factors. To achieve transcriptional activation of target genes, DNA-bound NRs directly recruit general transcription factors (GTFs) to the preinitiation complex or bind intermediary factors, so-called coactivators. These coactivators often constitute subunits of larger multiprotein complexes that act at several functional levels, such as chromatin remodeling, enzymatic modification of histone tails, or modulation of the preinitiation complex via interactions with RNA polymerase II and GTFs. The binding of NR to coactivators is often mediated through one of its activation domains. Many NRs have at least two activation domains, the ligand-independent activation function (AF)-1, which resides in the N-terminal domain, and the ligand-dependent AF-2, which is localized in the C-terminal domain. In this review, we summarize and discuss current knowledge regarding the molecular mechanisms of AF-1- and AF-2-mediated gene activation, focusing on AF-1 and AF-2 conformation and coactivator binding.

scholarly journals A common intermediary factor (p52/54) recognizing "acidic blob"-type domains is required for transcriptional activation by the Jun proteins.

1992 ◽  
Vol 12 (12) ◽  
pp. 5508-5515 ◽  
Author(s):  
T Oehler ◽  
P Angel
Keyword(s):  
Transcription Factors ◽  
Rna Polymerase Ii ◽  
Transcriptional Activation ◽  
Target Genes ◽  
Serum Response Factor ◽  
Limiting Factor ◽  
Regulation Of Transcription ◽  
Physical Interaction ◽  
Main Component

The ability of the c-Jun protein, the main component of the transcription factor AP1, to interact directly or indirectly with the RNA polymerase II-initiation complex to activate transcription was investigated by in vivo transcription interference ("squelching") experiments. Coexpression of a Jun mutant lacking its DNA binding domain strongly represses the activity of wild-type c-Jun. Repression depends on the presence of the transactivation domains (TADs), suggesting that a limiting factor interacting with the TADs is essential to link Jun and the components of the transcriptional machinery. The activity of this intermediary factor(s) is restricted to TADs characterized by an abundance of negatively charged amino acids, as demonstrated by the abilities of the TADs of JunB, GAL4, and VP16 to repress c-Jun activity. Depending on the presence of the TADs of Jun, we found physical interaction between Jun and a cluster of three proteins with molecular masses of 52, 53, and 54 kDa (p52/54). Association between Jun and p52/54 is strongly reduced in the presence of VP16, suggesting that the two proteins compete for binding to p52/54. Transcription factors containing a different type of TAD (e.g., GHF1, estrogen receptor, or serum response factor) fail to inhibit Jun activity, suggesting that these proteins act through a different mechanism. We consider the requirement of Jun to interact with p52/54 utilized by other transcription factors a new mechanism in the regulation of transcription of Jun-dependent target genes.

A common intermediary factor (p52/54) recognizing "acidic blob"-type domains is required for transcriptional activation by the Jun proteins

1992 ◽  
Vol 12 (12) ◽  
pp. 5508-5515
Author(s):  
T Oehler ◽  
P Angel
Keyword(s):  
Transcription Factors ◽  
Rna Polymerase Ii ◽  
Transcriptional Activation ◽  
Target Genes ◽  
Serum Response Factor ◽  
Limiting Factor ◽  
Regulation Of Transcription ◽  
Physical Interaction ◽  
Main Component

The ability of the c-Jun protein, the main component of the transcription factor AP1, to interact directly or indirectly with the RNA polymerase II-initiation complex to activate transcription was investigated by in vivo transcription interference ("squelching") experiments. Coexpression of a Jun mutant lacking its DNA binding domain strongly represses the activity of wild-type c-Jun. Repression depends on the presence of the transactivation domains (TADs), suggesting that a limiting factor interacting with the TADs is essential to link Jun and the components of the transcriptional machinery. The activity of this intermediary factor(s) is restricted to TADs characterized by an abundance of negatively charged amino acids, as demonstrated by the abilities of the TADs of JunB, GAL4, and VP16 to repress c-Jun activity. Depending on the presence of the TADs of Jun, we found physical interaction between Jun and a cluster of three proteins with molecular masses of 52, 53, and 54 kDa (p52/54). Association between Jun and p52/54 is strongly reduced in the presence of VP16, suggesting that the two proteins compete for binding to p52/54. Transcription factors containing a different type of TAD (e.g., GHF1, estrogen receptor, or serum response factor) fail to inhibit Jun activity, suggesting that these proteins act through a different mechanism. We consider the requirement of Jun to interact with p52/54 utilized by other transcription factors a new mechanism in the regulation of transcription of Jun-dependent target genes.

scholarly journals The Non-Canonical Aspects of MicroRNAs: Many Roads to Gene Regulation

Cells ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 1465 ◽  
Author(s):  
Christiaan J. Stavast ◽  
Stefan J. Erkeland
Keyword(s):  
Rna Polymerase Ii ◽  
Transcriptional Activation ◽  
Small Rnas ◽  
Target Genes ◽  
Biological Functions ◽  
Rnase Iii ◽  
Mrna Targets ◽  
Argonaute Proteins ◽  
Epigenetic Modifiers ◽  
Encoding Genes

MicroRNAs (miRNAs) are critical regulators of gene expression. As miRNAs are frequently deregulated in many human diseases, including cancer and immunological disorders, it is important to understand their biological functions. Typically, miRNA-encoding genes are transcribed by RNA Polymerase II and generate primary transcripts that are processed by RNase III-endonucleases DROSHA and DICER into small RNAs of approximately 21 nucleotides. All miRNAs are loaded into Argonaute proteins in the RNA-induced silencing complex (RISC) and act as post-transcriptional regulators by binding to the 3′- untranslated region (UTR) of mRNAs. This seed-dependent miRNA binding inhibits the translation and/or promotes the degradation of mRNA targets. Surprisingly, recent data presents evidence for a target-mediated decay mechanism that controls the level of specific miRNAs. In addition, several non-canonical miRNA-containing genes have been recently described and unexpected functions of miRNAs have been identified. For instance, several miRNAs are located in the nucleus, where they are involved in the transcriptional activation or silencing of target genes. These epigenetic modifiers are recruited by RISC and guided by miRNAs to specific loci in the genome. Here, we will review non-canonical aspects of miRNA biology, including novel regulators of miRNA expression and functions of miRNAs in the nucleus.

scholarly journals The rye Mutants Identify a Role for Ssn/Srb Proteins of the RNA Polymerase II Holoenzyme During Stationary Phase Entry in Saccharomyces cerevisiae

Genetics ◽  
2001 ◽  
Vol 157 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Ya-Wen Chang ◽  
Susie C Howard ◽  
Yelena V Budovskaya ◽  
Jasper Rine ◽  
Paul K Herman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Growth ◽  
Rna Polymerase ◽  
Stationary Phase ◽  
Yeast Cell ◽  
Rna Polymerase Ii ◽  
Transcriptional Response ◽  
Nutrient Deprivation ◽  
Ras Signaling ◽  
Rna Polymerase Ii Holoenzyme

Abstract Saccharomyces cerevisiae cells enter into a distinct resting state, known as stationary phase, in response to specific types of nutrient deprivation. We have identified a collection of mutants that exhibited a defective transcriptional response to nutrient limitation and failed to enter into a normal stationary phase. These rye mutants were isolated on the basis of defects in the regulation of YGP1 expression. In wild-type cells, YGP1 levels increased during the growth arrest caused by nutrient deprivation or inactivation of the Ras signaling pathway. In contrast, the levels of YGP1 and related genes were significantly elevated in the rye mutants during log phase growth. The rye defects were not specific to this YGP1 response as these mutants also exhibited multiple defects in stationary phase properties, including an inability to survive periods of prolonged starvation. These data indicated that the RYE genes might encode important regulators of yeast cell growth. Interestingly, three of the RYE genes encoded the Ssn/Srb proteins, Srb9p, Srb10p, and Srb11p, which are associated with the RNA polymerase II holoenzyme. Thus, the RNA polymerase II holoenzyme may be a target of the signaling pathways responsible for coordinating yeast cell growth with nutrient availability.

scholarly journals The Ras/PKA Signaling Pathway May Control RNA Polymerase II Elongation via the Spt4p/Spt5p Complex in Saccharomyces cerevisiae

Genetics ◽  
2003 ◽  
Vol 165 (3) ◽  
pp. 1059-1070
Author(s):  
Susie C Howard ◽  
Arelis Hester ◽  
Paul K Herman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Growth ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Signaling Pathway ◽  
Elongation Factor ◽  
Ras Signaling ◽  
Elongation Step ◽  
Rna Polymerase Ii Transcription

Abstract The Ras signaling pathway in Saccharomyces cerevisiae controls cell growth via the cAMP-dependent protein kinase, PKA. Recent work has indicated that these effects on growth are due, in part, to the regulation of activities associated with the C-terminal domain (CTD) of the largest subunit of RNA polymerase II. However, the precise target of these Ras effects has remained unknown. This study suggests that Ras/PKA activity regulates the elongation step of the RNA polymerase II transcription process. Several lines of evidence indicate that Spt5p in the Spt4p/Spt5p elongation factor is the likely target of this control. First, the growth of spt4 and spt5 mutants was found to be very sensitive to changes in Ras/PKA signaling activity. Second, mutants with elevated levels of Ras activity shared a number of specific phenotypes with spt5 mutants and vice versa. Finally, Spt5p was efficiently phosphorylated by PKA in vitro. Altogether, the data suggest that the Ras/PKA pathway might be directly targeting a component of the elongating polymerase complex and that this regulation is important for the normal control of yeast cell growth. These data point out the interesting possibility that signal transduction pathways might directly influence the elongation step of RNA polymerase II transcription.

scholarly journals The Swi/Snf Chromatin Remodeling Complex Is Required for Ribosomal DNA and Telomeric Silencing in Saccharomyces cerevisiae

2004 ◽  
Vol 24 (18) ◽  
pp. 8227-8235 ◽  
Author(s):  
Vardit Dror ◽  
Fred Winston
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Chromatin Remodeling ◽  
Ribosomal Dna ◽  
Transcriptional Activation ◽  
Rdna Locus ◽  
Detectable Effect ◽  
Chromatin Remodeling Complex ◽  
Two Factors

ABSTRACT The Swi/Snf chromatin remodeling complex has been previously demonstrated to be required for transcriptional activation and repression of a subset of genes in Saccharomyces cerevisiae. In this work we demonstrate that Swi/Snf is also required for repression of RNA polymerase II-dependent transcription in the ribosomal DNA (rDNA) locus (rDNA silencing). This repression appears to be independent of both Sir2 and Set1, two factors known to be required for rDNA silencing. In contrast to many other rDNA silencing mutants that have elevated levels of rDNA recombination, snf2Δ mutants have a significantly decreased level of rDNA recombination. Additional studies have demonstrated that Swi/Snf is also required for silencing of genes near telomeres while having no detectable effect on silencing of HML or HMR.

scholarly journals Mediator subunit MED1 is required for E2A-PBX1–mediated oncogenic transcription and leukemic cell growth

2021 ◽  
Vol 118 (6) ◽  
pp. e1922864118 ◽  
Author(s):  
Yu-Ling Lee ◽  
Keiichi Ito ◽  
Wen-Chieh Pi ◽  
I-Hsuan Lin ◽  
Chi-Shuen Chu ◽  
...  
Keyword(s):  
Cell Growth ◽  
Rna Polymerase Ii ◽  
Transcriptional Activation ◽  
Critical Role ◽  
Gene Activation ◽  
Leukemic Cell ◽  
Leukemic Cells ◽  
Specific Gene ◽  
Aberrant Expression ◽  
Transcriptional Machinery

The chimeric transcription factor E2A-PBX1, containing the N-terminal activation domains of E2A fused to the C-terminal DNA-binding domain of PBX1, results in 5% of pediatric acute lymphoblastic leukemias (ALL). We recently have reported a mechanism for RUNX1-dependent recruitment of E2A-PBX1 to chromatin in pre-B leukemic cells; but the subsequent E2A-PBX1 functions through various coactivators and the general transcriptional machinery remain unclear. The Mediator complex plays a critical role in cell-specific gene activation by serving as a key coactivator for gene-specific transcription factors that facilitates their function through the RNA polymerase II transcriptional machinery, but whether Mediator contributes to aberrant expression of E2A-PBX1 target genes remains largely unexplored. Here we show that Mediator interacts directly with E2A-PBX1 through an interaction of the MED1 subunit with an E2A activation domain. Results of MED1 depletion by CRISPR/Cas9 further indicate that MED1 is specifically required for E2A-PBX1–dependent gene activation and leukemic cell growth. Integrated transcriptome and cistrome analyses identify pre-B cell receptor and cell cycle regulatory genes as direct cotargets of MED1 and E2A-PBX1. Notably, complementary biochemical analyses also demonstrate that recruitment of E2A-PBX1 to a target DNA template involves a direct interaction with DNA-bound RUNX1 that can be further stabilized by EBF1. These findings suggest that E2A-PBX1 interactions with RUNX1 and MED1/Mediator are of functional importance for both gene-specific transcriptional activation and maintenance of E2A-PBX1–driven leukemia. The MED1 dependency for E2A-PBX1–mediated gene activation and leukemogenesis may provide a potential therapeutic opportunity by targeting MED1 in E2A-PBX1+ pre-B leukemia.

scholarly journals The GIS2 Gene Is Repressed by a Zinc-Regulated Bicistronic RNA in Saccharomyces cerevisiae

Genes ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 462 ◽  
Author(s):  
Janet Taggart ◽  
Yirong Wang ◽  
Erin Weisenhorn ◽  
Colin W. MacDiarmid ◽  
Jason Russell ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Rna Polymerase Ii ◽  
Zinc Deficiency ◽  
Transcriptional Activation ◽  
Open Reading Frames ◽  
Zinc Homeostasis ◽  
Protein Accumulation ◽  
Coding Region ◽  
Yeast Saccharomyces Cerevisiae ◽  
Short Transcript

Zinc homeostasis is essential for all organisms. The Zap1 transcriptional activator regulates these processes in the yeast Saccharomyces cerevisiae. During zinc deficiency, Zap1 increases expression of zinc transporters and proteins involved in adapting to the stress of zinc deficiency. Transcriptional activation by Zap1 can also repress expression of some genes, e.g., RTC4. In zinc-replete cells, RTC4 mRNA is produced with a short transcript leader that is efficiently translated. During deficiency, Zap1-dependent expression of an RNA with a longer transcript leader represses the RTC4 promoter. This long leader transcript (LLT) is not translated due to the presence of small open reading frames upstream of the RTC4 coding region. In this study, we show that the RTC4 LLT RNA also plays a second function, i.e., repression of the adjacent GIS2 gene. In generating the LLT transcript, RNA polymerase II transcribes RTC4 through the GIS2 promoter. Production of the LLT RNA correlates with the decreased expression of GIS2 mRNA and mutations that prevent synthesis of the LLT RNA or terminate it before the GIS2 promoter renders GIS2 mRNA expression and Gis2 protein accumulation constitutive. Thus, we have discovered an unusual regulatory mechanism that uses a bicistronic RNA to control two genes simultaneously.

Transcriptional activation in an improved whole-cell extract from Saccharomyces cerevisiae

1991 ◽  
Vol 11 (9) ◽  
pp. 4555-4560 ◽  
Author(s):  
M Woontner ◽  
P A Wade ◽  
J Bonner ◽  
J A Jaehning
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Rna Polymerase Ii ◽  
Transcriptional Activation ◽  
In Vitro Transcription ◽  
Cell Extract ◽  
Whole Cell ◽  
Transcription System ◽  
Upstream Activation Sequence ◽  
Activation Sequence

We report an improved in vitro transcription system for Saccharomyces cerevisiae. Small changes in assay and whole-cell extraction procedures increase selective initiation by RNA polymerase II up to 60-fold over previous conditions (M. Woontner and J. A. Jaehning, J. Biol. Chem. 265:8979-8982, 1990), to levels comparable to those obtained with nuclear extracts. We have found that the simultaneous use of distinguishable templates with and without an upstream activation sequence is critical to the measurement of apparent activation. Transcription from any template was very sensitive to the concentrations of template and nontemplate DNA, extract, and activator (GAL4/VP16). Alterations in reaction conditions led to proportionately greater changes from a template lacking an upstream activation sequence; thus, the apparent ratio of activation is largely dependent on the level of basal transcription. Using optimal conditions for activation, we have also demonstrated activation by a bona fide yeast activator, heat shock transcription factor.

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