AAR1/TUP1 protein, with a structure similar to that of the beta subunit of G proteins, is required for a1-alpha 2 and alpha 2 repression in cell type control of Saccharomyces cerevisiae.

Mukai, Yoshihiko; Harashima, Satoshi; Oshima, Y

doi:10.1128/mcb.11.7.3773

Cited by 81 publications

(60 citation statements)

References 37 publications

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“…Both ssn6 and tupl mutations have pleiotropic effects, including flocculence and derepression of the glucose-repressible genes in addition to the mating type defects (Carlson et al 1984;Trumbly 1986;Schultz and Carlson 1987;Mukai et al 1991); effects on chromatin structure could provide a unifying mechanism for these diverse phenotypes. Both SSN6 and TUP1 are homologous to proteins associated with other systems.…”

mentioning

confidence: 99%

The global transcriptional regulators, SSN6 and TUP1, play distinct roles in the establishment of a repressive chromatin structure.

Cooper¹,

Roth²,

Simpson³

1994

Genes Dev.

184

161

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Repression of a-cell specific gene expression in yeast ~ cells requires MATch2 and MCM1, as well as two global repressors, SSN6 and TUP1. Previous studies demonstrated that nucleosomes positioned adjacent to the a2/MCM1 operator in c~ cells directly contribute to repression. To investigate the possibility that SSN6 and TUP1 provide a link between MAT~2/MCM1 and neighboring histones, nucleosome locations were examined in ssn6 and t u p l ot cells. In both cases, nucleosome positions downstream of the operator were disrupted, and the severity of the disruption correlated with the degree of derepression. Nevertheless, the observed changes in chromatin structure were not dependent on transcription. Our data strongly indicate that SSN6 and TUP1 directly organize repressive regions of chromatin.

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mentioning

confidence: 99%

The global transcriptional regulators, SSN6 and TUP1, play distinct roles in the establishment of a repressive chromatin structure.

Cooper¹,

Roth²,

Simpson³

1994

Genes Dev.

184

161

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“…Tup1 along with another protein, Ssn6, is required for the repression of at least five sets of genes in yeast, including the glucose-repressed genes, genes regulated by the presence of oxygen (hypoxic genes), the a-specific and haploidspecific genes, and a set of genes induced by DNA damage (12)(13)(14)(15)(16). A deletion of SSN6 or TUP1 results in the constitutive expression of all of these genes sets.…”

mentioning

confidence: 99%

A Complex Composed of Tup1 and Ssn6 Represses Transcription in Vitro

Redd¹,

Arnaud²,

Johnson

1997

Journal of Biological Chemistry

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The Saccharomyces cerevisiae Tup1 protein is a member of a family of WD repeat containing proteins that are involved in repression of transcription. Tup1, along with the Ssn6 protein, represses a wide variety of genes in yeast including cell type-specific and glucose-repressed genes. Tup1 and Ssn6 are recruited to these specific gene sets by interaction with sequence-specific DNA binding proteins. In this work, a protein complex containing Ssn6 and Tup1 was purified to determine its composition. The size of the complex is estimated to be 440 kDa. Tup1 and Ssn6, which are both phosphoproteins, are the only proteins present in stoichiometric amounts in the complex. We also demonstrate that this purified complex represses transcription in an in vitro assay.The Tup1 protein of Saccharomyces cerevisiae is one of a family of repressor proteins that contain ␤-transducin or WD repeats. The majority of the WD repeat containing proteins are homologs of ␤-transducin and are known to function in signal transduction pathways within the cytoplasm. However, an increasing number of WD repeat proteins have been identified that are nuclear localized and function in the repression of transcription. These include Tup1, Hir1, and Met30 in S. cerevisiae; SCON2 in Neurospora crassa; extra sex combs and groucho in Drosophila; COP1 in Arabidopsis thaliana; and HIRA and the family of TLE proteins in humans (1-10). These WD repeat repressor proteins turn off a wide variety of genes, including those involved in segmentation, sex determination, and neurogenesis (controlled by groucho) and those involved in photomorphogenesis (controlled by COP1) (7, 11). The HIRA protein has been implicated in the human developmental disease DiGeorge syndrome (8,9).Of these WD repeat repressor proteins, Tup1 is the best characterized. Tup1 along with another protein, Ssn6, is required for the repression of at least five sets of genes in yeast, including the glucose-repressed genes, genes regulated by the presence of oxygen (hypoxic genes), the a-specific and haploidspecific genes, and a set of genes induced by DNA damage (12-16). A deletion of SSN6 or TUP1 results in the constitutive expression of all of these genes sets. Tup1 and Ssn6 are recruited to these specific gene sets by interaction with sequencespecific DNA binding proteins. In the case of the a-specific and haploid-specific genes in yeast, the homeodomain protein ␣2 binds to sequences (operators) located upstream of each gene in the set and recruits Ssn6 and Tup1 by direct interaction with each of these proteins (for review, see Ref. 17).Tup1 and Ssn6 interact directly in vitro and are found associated in a large complex in yeast extracts estimated at 1.2 MDa (18). The size of this complex suggests that it consists of many protein subunits. Genetic experiments have implicated a number of additional proteins in the Ssn6-Tup1 repression pathway including Rox3, Sin4, Srb8, Srb9, Srb10,. Each of these proteins is required for full repression of transcription by Tup1 and Ssn6 in vivo. To determine the...

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“…The Tup1-Ssn6 corepressor is required for repression and nucleosome positioning in a-cellspecific genes [26,27], and a tup1 mutation causes the loss of nucleosome positioning in TALS minichromosomes [28]. The Isw2 chromatin remodeling complex positions nucleosomes in Tup1-regulated genes, such as a-cell-specific genes [15,[28][29][30][31].…”

Section: Hap1p Binding Is Restored By An Isw2 or Tup1 Mutation In Matmentioning

confidence: 99%

“…In a cells, nucleosomes were not positioned in these TALS minichromosomes. We also analyzed the chromatin structure of TRP1ARS1-UAS1 (lanes [25][26][27][28][29][30]. The HSR B region, where the UAS1 was inserted, was hypersensitive to MNase digestion in chromatin, as compared to naked DNA samples.…”

Section: Chromatin Structures Of Tals and Trp1ars1 Minichromosomes Comentioning

confidence: 99%

A nucleosome positioned by α2/Mcm1 prevents Hap1 activator binding in vivo

Morohashi

Nakajima

Kurihara

et al. 2007

Biochemical and Biophysical Research Communications

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Nucleosome positioning has been proposed as a mechanism of transcriptional repression. Here, we examined whether nucleosome positioning affects activator binding in living yeast cells. We introduced the cognate Hap1 binding site (UAS1) at a location 24-43 bp, 29-48 bp or 61-80 bp interior to the edge of a nucleosome positioned by α2/Mcm1 in yeast minichromosomes. Hap1 binding to the UAS1 was severely inhibited, not only at the pseudo-dyad but also in the peripheral region of the positioned nucleosome in α cells, while it was detectable in a cells, in which the nucleosomes were not positioned. Hap1 binding was restored in α cells with tup1 or isw2 mutations, which caused the loss of nucleosome positioning. These results support the mechanism in which α2/Mcm1-dependent nucleosome positioning has a regulatory function to limit the access of transcription factors.Keywords nucleosome positioning; chromatin; activator binding; in vivo footprinting; yeast In a general view of the process of transcriptional activation, activators have to gain access to an array of nucleosomes, and chromatin remodeling complexes and/or histone modification enzymes change the structural features of chromatin to recruit transcriptional machinery to the promoter regions [reviewed in 1,2]. Regarding activator binding, several regulatory factors such as steroid hormone receptor, Gal4-derivatives, USF and Sp1, bind to reconstituted nucleosomes in vitro under some circumstances, although their affinities for nucleosomal DNA decrease by one to three orders of magnitude, relative to those for naked DNA [see reviews, 2-4]. Positioned nucleosomes assembled with Drosophila embryo extracts preclude NF1 binding to its cognate site [5]. In contrast, NF-κB binds to its recognition sites within a positioned nucleosome with an affinity close to that for free DNA in vitro [6]. Yeast Gal4 is one of the best characterized activators binding to nucleosomes in vivo. Gal4 can bind to its cognate site within a positioned nucleosome to perturb the nucleosome in yeast cells [7][8][9][10][11]. Also, the Pho4 activator can reportedly bind its nucleosome-occupied site before nucleosome disassembly in vivo [12]. However, only a few activators have been examined for their access *Corresponding author. Mitsuhiro Shimizu, Department of Chemistry, Meisei University, 2-1-1 Hodokubo, Hino, Tokyo 191-8506, Japan, Phone: +81-42-591-7483, Fax: +81-42-591-7419, E-mail: shimizum@chem.meisei-u.ac.jp. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. to DNA within the nucleosome in vivo. Although nucleosome positioning has been observ...

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AAR1/TUP1 protein, with a structure similar to that of the beta subunit of G proteins, is required for a1-alpha 2 and alpha 2 repression in cell type control of Saccharomyces cerevisiae.

Cited by 81 publications

References 37 publications

The global transcriptional regulators, SSN6 and TUP1, play distinct roles in the establishment of a repressive chromatin structure.

The global transcriptional regulators, SSN6 and TUP1, play distinct roles in the establishment of a repressive chromatin structure.

A Complex Composed of Tup1 and Ssn6 Represses Transcription in Vitro

A nucleosome positioned by α2/Mcm1 prevents Hap1 activator binding in vivo

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