The C-Terminal Domain of Sin1 Interacts with the SWI-SNF Complex in Yeast

Pérez-Martı́n, José; Johnson, Alexander D.

doi:10.1128/mcb.18.7.4157

Cited by 26 publications

(26 citation statements)

References 55 publications

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“…That interpretation is consistent with another observation that overexpression of the C-terminal of Sin1p (where the sin1-2 mutation is found) is toxic (8), but that this toxicity is suppressed in spt4, spt5, and spt6 strains. Each of these proteins, like Hpr1p, has been implicated in modification of chromatin structure.…”

Section: Discussionsupporting

confidence: 91%

“…Later, Perez-Martin and Johnson (8) showed that the C terminus of Sin1p physically associates with components of the SWI͞SNF complex and that this interaction is blocked in the full-length Sin1p protein by the Nterminal half of the protein. Recently, it has been reported that SWI͞SNF can stimulate transcription even after promoter clearance (34) during elongation.…”

Section: Discussionmentioning

confidence: 99%

“…Sin1 (also known as spt2 in this context) mutants were identified as suppressors of Ty and insertions in the 5Ј noncoding region of the HIS4 gene (5). Because the negative regulation of these genes is overcome by the SW1͞SNF chromatin-remodeling complex (4,6,7) and the C-terminal domain of Sin1p interacts with Swi1p (8), it was suggested that a function of SIN1p is to somehow maintain chromatin compaction at specific loci in the chromatin. Peterson et al (2) found a functional relationship between the C-terminal domain (CTD) of RNA polymerase II and Sin1p, but these data were not pursued further.…”

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confidence: 99%

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Recruitment of mRNA cleavage/polyadenylation machinery by the yeast chromatin protein Sin1p/Spt2p

Hershkovits

Bangio²,

Cohen³

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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The yeast chromatin protein Sin1p͞Spt2p has long been studied, but the understanding of its function has remained elusive. The protein has sequence similarity to HMG1, specifically binds crossing DNA structures, and serves as a negative transcriptional regulator of a small family of genes that are activated by the SWI͞SNF chromatin-remodeling complex. Recently, it has been implicated in maintaining the integrity of chromatin during transcription elongation. Here we present experiments whose results indicate that Sin1p͞Spt2 is required for, and is directly involved in, the efficient recruitment of the mRNA cleavage͞polyadenylation complex. This conclusion is based on the following findings: Sin1p͞Spt2 frequently binds specifically downstream of many ORFs but almost always upstream of the first polyadenylation site. It directly interacts with Fir1p, a component of the cleavage͞polyadenylation complex. Disruption of Sin1p͞Spt2p results in foreshortened poly(A) tracts on mRNA. It is synthetically lethal with Cdc73p, which is involved in the recruitment of the complex. This report shows that a chromatin component is involved in 3 end processing of RNA. S in1p is a yeast chromatin nonhistone protein that has beenshown to function as a negative transcriptional regulator of several genes, including Suc2 (1), Ino1 (2), and SSA3 (3). Activity of the HO promoter, as measured from an HO promoter driving a lacZ gene (4), is also affected by Sin1. Sin1 (also known as spt2 in this context) mutants were identified as suppressors of Ty and insertions in the 5Ј noncoding region of the HIS4 gene (5). Because the negative regulation of these genes is overcome by the SW1͞SNF chromatin-remodeling complex (4, 6, 7) and the C-terminal domain of Sin1p interacts with Swi1p (8), it was suggested that a function of SIN1p is to somehow maintain chromatin compaction at specific loci in the chromatin. Peterson et al. (2) found a functional relationship between the C-terminal domain (CTD) of RNA polymerase II and Sin1p, but these data were not pursued further. Sequence analysis of Sin1p showed sequence similarity in two domains to HMG1 (6, 7), a known chromatin protein. Work from our laboratory showed that Sin1p can bind four-way junction and crossing DNA structures (9), supporting the idea that Sin1p binds DNA as it enters and exits the nucleosome.In the context of a global mapping project, Tong et al. (10) reported that there is a synthetic lethal interaction between sin1 and cdc73, a member of the PAF complex. The PAF complex, which accompanies RNA polymerase II during elongation, was shown to have an important function in 3Ј end formation and in polyadenylation (11-13). In addition, a functional interaction was demonstrated between Sin1p and Hpr1p, which is associated with the PAF complex (14).Most recently, evidence has been presented indicating that Sin1p͞Spt2p plays roles in transcription elongation, chromatin structure and genome stability (15). In that study, synthetic lethal interactions were reported between sin1 and paf1, and betwe...

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Recruitment of mRNA cleavage/polyadenylation machinery by the yeast chromatin protein Sin1p/Spt2p

Hershkovits

Bangio²,

Cohen³

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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“…However, when we examined GAL10-MEL1 expression in a yeast strain carrying the hhf2-13 mutation in histone H4, we did not see any increase in stimulation by GAL4-TBP (Ryan and Morse, unpublished). Thus, although this sin mutation alleviates the requirement for SWI-SNF for transcriptional activation of an HO-lacZ reporter gene (58,75) and increases accessibility of nucleosomal DNA to MNase and Escherichia coli Dam methyltransferase in yeast (75), it evidently does not sufficiently perturb the local chromatin structure of the GAL10 promoter to allow activation by GAL4-TBP. We also employed an altered GAL10-MEL1 reporter having a LexA binding site between the GAL4 binding sites and the TATA element to ask whether artificial depletion of histone H4 would allow activation by LexATBP.…”

Section: Discussionmentioning

confidence: 94%

Artificially Recruited TATA-Binding Protein Fails To Remodel Chromatin and Does Not Activate Three Promoters That Require Chromatin Remodeling

Ryan

Stafford

et al. 2000

Molecular and Cellular Biology

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Transcriptional activators are believed to work in part by recruiting general transcription factors, such as TATA-binding protein (TBP) and the RNA polymerase II holoenzyme. Activation domains also contribute to remodeling of chromatin in vivo. To determine whether these two activities represent distinct functions of activation domains, we have examined transcriptional activation and chromatin remodeling accompanying artificial recruitment of TBP in yeast (Saccharomyces cerevisiae). We measured transcription of reporter genes with defined chromatin structure by artificial recruitment of TBP and found that a reporter gene whose TATA element was relatively accessible could be activated by artificially recruited TBP, whereas two promoters, GAL10 and CHA1, that have accessible activator binding sites, but nucleosomal TATA elements, could not. A third reporter gene containing the HIS4 promoter could be activated by GAL4-TBP only when a RAP1 binding site was present, although RAP1 alone could not activate the reporter, suggesting that RAP1 was needed to open the chromatin structure to allow activation. Consistent with this interpretation, artificially recruited TBP was unable to perturb nucleosome positioning via a nucleosomal binding site, in contrast to a true activator such as GAL4, or to perturb the TATA-containing nucleosome at the CHA1 promoter. Finally, we show that activation of the GAL10 promoter by GAL4, which requires chromatin remodeling, can occur even in swi gcn5 yeast, implying that remodeling pathways independent of GCN5, the SWI-SNF complex, and TFIID can operate during transcriptional activation in vivo.Transcriptional activators are thought to stimulate transcription of TATA-containing promoters in part by recruiting TFIID, a multiprotein complex consisting of the TATA-binding protein (TBP) and TBP-associated factors (TAFs), to the TATA box (25,60). Several in vitro and in vivo studies support this model. For example, transcription initiated at a mutated TATA element by induced synthesis of TBP with altered specificity was enhanced in both rate and extent in the presence of an activator that could bind upstream of the relevant promoter, consistent with activator-mediated recruitment (40). Recruitment has also been inferred from the results of "activator bypass" experiments in which artificial recruitment of TBP to promoter sites near the TATA element resulted in transcriptional activation, implying that TBP recruitment is a rate-limiting step in transcriptional activation in vivo (10,39,79). Most convincingly, chromatin immunoprecipitation experiments revealed TBP to be physically associated with promoters of numerous genes under activated, but not nonactivated, conditions, implying that recruitment accompanies activation (43,46).A potential obstacle to recruitment of TBP in vivo is posed by chromatin. Binding of TBP to nucleosomal TATA elements is greatly impeded in vitro (23, 32). Transcription is also strongly repressed by chromatin, but this repression can be largely alleviated by binding of act...

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“…The prototype of this remodeling machine is the evolutionary conserved human SWI/SNF, a multisubunit complex composed of Brm and Brg1 subunits (62,63). Recent, experimental data showed that these constituents are associated with transcriptional repressors like Sin (46,53). Chromatin remodeling by Mi-2, a member of the SWI/SNF superfamily, has also been purified with HDAC activity and shown to repress transcription in a methylation-dependent manner (59).…”

Section: Discussionmentioning

confidence: 99%

Precipitous Release of Methyl-CpG Binding Protein 2 and Histone Deacetylase 1 from the Methylated Human Multidrug Resistance Gene (MDR1) on Activation

El‐Osta

Kantharidis

Zalcberg

et al. 2002

Molecular and Cellular Biology

172

139

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Overexpression of the human multidrug resistance gene 1 (MDR1) is a negative prognostic factor in leukemia. Despite intense efforts to characterize the gene at the molecular level, little is known about the genetic events that switch on gene expression in P-glycoprotein-negative cells. Recent studies have shown that the transcriptional competence of MDR1 is often closely associated with DNA methylation. Chromatin remodeling and modification targeted by the recognition of methylated DNA provide a dominant mechanism for transcriptional repression. Consistent with this epigenetic model, interference with DNA methyltransferase and histone deacetylase activity alone or in combination can reactivate silent genes. In the present study, we used chromatin immunoprecipitation to monitor the molecular events involved in the activation and repression of MDR1. Tumors become resistant to chemotherapy by a variety of mechanisms, including altered DNA repair, alterations in scavenging enzymes, and increased drug efflux. Although clinical drug resistance may be multifactorial, understanding these various mechanisms is important and may afford a means of improving treatment regimens. One of the most extensively studied mechanisms of multidrug resistance is associated with the overexpression of the MDR1 product, P glycoprotein (Pgp) (for reviews see references 27 and 55). A transmembrane protein, Pgp acts as an efflux pump, reducing intracellular drug levels and thus cytotoxic activity. We and others have demonstrated that the human MDR1 promoter is activated by changes in CpG methylation in B-cell chronic lymphocytic leukemia (26), acute myeloid leukemia (38), and tumor cell lines (12).DNA hypermethylation is associated with transcriptional silencing and is accompanied by the accumulation of deacetylated histones on heterochromatin (13,21). Methylation is often associated with the pathological silencing of tumor suppressor genes in human cancer and neurodevelopmental syndrome (20, 23). In contrast, transcriptionally active chromatin is characterized by the enrichment of hyperacetylated histone and is generally associated with hypomethylated chromatin (2, 34). The mechanisms underlying the correlation between DNA methylation and histone deacetylation in the control of gene expression have been established by recent biochemical experiments (24,42). Evidence has emerged that a family of methylCpG binding proteins binds heterochromatin to stably repress transcription (10, 18). The transcriptional repressor methylCpG binding protein 2 (MeCP2 ) is the best-characterized family member (18,41). MeCP2 is typically associated on heterochromatin in a methylation-dependent manner by its methyl-binding domain (MBD) and can displace histone H1 for nucleosome binding, indicating that it can dynamically interact with assembled chromatin (30,40). The transcriptional-repression domain of MeCP2 recruits the corepressors mSin3 and histone deacetylases (HDACs) (24, 42), causing transcriptional repression (41). Moreover, repression by MeCP2 is partial...

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The C-Terminal Domain of Sin1 Interacts with the SWI-SNF Complex in Yeast

Cited by 26 publications

References 55 publications

Recruitment of mRNA cleavage/polyadenylation machinery by the yeast chromatin protein Sin1p/Spt2p

Recruitment of mRNA cleavage/polyadenylation machinery by the yeast chromatin protein Sin1p/Spt2p

Artificially Recruited TATA-Binding Protein Fails To Remodel Chromatin and Does Not Activate Three Promoters That Require Chromatin Remodeling

Precipitous Release of Methyl-CpG Binding Protein 2 and Histone Deacetylase 1 from the Methylated Human Multidrug Resistance Gene (MDR1) on Activation

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