Characterization of a short unique sequence in the yeast HO gene promoter that regulates HO transcription in a SIN1 dependent manner

Yona, Eyal; Bangio, Haim; Friedman, Yael; Shpungin, Sally; Katcoff, Don J.

doi:10.1016/0014-5793(96)00159-7

Cited by 6 publications

(5 citation statements)

References 11 publications

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“…We think it unlikely that DNA could serve as an intermediate, because the ability of Sin1 to bind DNA is located in the Nt domain of Sin1 (14,48) and the interaction with SWI-SNF was seen in the absence of this domain. In addition, the finding that full-length Sin1 and the Nt half of Sin1 (both of which contain the DNA binding domain) do not interact with the SWI-SNF complex supports the view that the interaction is not mediated just through DNA.…”

Section: Discussionmentioning

confidence: 99%

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

Pérez-Martı́n

Johnson

1998

Molecular and Cellular Biology

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In the yeast Saccharomyces cerevisiae, the SWI-SNF complex has been proposed to antagonize the repressive effects of chromatin by disrupting nucleosomes. The SIN genes were identified as suppressors of defects in the SWI-SNF complex, and the SIN1 gene encodes an HMG1-like protein that has been proposed to be a component of chromatin. Specific mutations (sin mutations) in both histone H3 and H4 genes produce the same phenotypic effects as do mutations in the SIN1 gene. In this study, we demonstrate that Sin1 and the H3 and H4 histones interact genetically and that the C terminus of Sin1 physically associates with components of the SWI-SNF complex. In addition, we demonstrate that this interaction is blocked in the full-length Sin1 protein by the N-terminal half of the protein. Based on these and additional results, we propose that Sin1 acts as a regulatable bridge between the SWI-SNF complex and the nucleosome.Genetic studies have shown that chromatin structure in the yeast Saccharomyces cerevisiae affects gene expression (11,47). The study of mutations that suppress transcriptional defects caused by Ty or ␦ insertion mutations at HIS4 or LYS2 (named SPT for suppressor of Ty [46]) identified a group of genes whose products are involved in chromatin structure and its regulation. These include histones H2A and H2B (SPT11 and SPT12) (8), the SPT2 gene, which encodes an HMG1-like protein (14, 31), and genes whose activity has been proposed to affect nucleosome assembly (SPT4, SPT5, and SPT6) (7,20,43). The ability of this group of genes to affect transcription suggested an important role for chromatin in the control of gene expression.A second group of genetic screens, which identified SWI-SNF components, were obtained from an analysis of the HO gene (required for mating type switching; SWI stands for switching [39]) and the SUC2 gene (encoding an invertase required for growth on sucrose and raffinose; SNF stands for sucrose nonfermenting [24]). Genetic and biochemical studies (reviewed in reference 29) have shown that the SWI-SNF products form a complex composed of at least 11 polypeptides, including SWI1-ADR6, SW13, SNF5, SNF6, SNF11, TFG3, and SWP73 (5,6,16,17,27,44). The link between the SWI-SNF complex and chromatin was identified by the study of suppressors of defects in components of this complex. Deletion of one of the two loci that encode histones H2A and H2B suppresses transcriptional defects caused by loss of the SWI-SNF complex (12). The SIN (for switch independent) genes were identified as suppressors of the swi phenotype (23, 40). Two of them, sin1 and sin2, partially suppress mutants of the SWI1, SWI2, and SWI3 genes (14,15,40). The sin2-1 mutation was found to lie in the HHT1 gene, which encodes histone H3. Five additional point mutations, two in histone H3 and three in histone H4, also displayed a Sin Ϫ phenotype in that they partially suppress the requirements for SWI genes in transcriptional activation (15,20). These mutations change residues believed to contact DNA or to be involved in histone-h...

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Section: Discussionmentioning

confidence: 99%

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

Pérez-Martı́n

Johnson

1998

Molecular and Cellular Biology

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“…Previous work has defined several hypothetical functional domains in SIN1 based on genetic, structural and biochemical considerations (Fig. 2a) (2,6,7,12,13). We therefore synthesized GST/sinl fusions that contain portions of the SIN1 molecule based on the functional domains that have been suggested, bound them to glutathione-agarose beads, and asked whether the radiolabeled CDC23 molecule would bind the partial SIN1 molecule.…”

Section: Resultsmentioning

confidence: 99%

Association of yeast SIN1 with the tetratrico peptide repeats of CDC23.

Shpungin

Liberzon²,

Bangio³

et al. 1996

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

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The yeast SINI protein is a nuclear protein that together with other proteins behaves as a transcriptional repressor of a family of genes. In addition, sinl mutants are defective in proper mitotic chromosome segregation. In an effort to understand the basis for these phenotypes, we employed the yeast two-hybrid system to identify proteins that interact with SINI in vivo. Here we demonstrate that CDC23, a protein known to be involved in sister chromatid separation during mitosis, is able to directly interact with SINM. Furthermore, using recombinant molecules in vitro, we show that the N terminal of SINI is sufficient to bind a portion of CDC23 consisting solely of tetratrico peptide repeats. Earlier experiments identified the C-terminal domain of SINM to be responsible for interaction with a protein that binds the regulatory region of HO, a gene whose transcription is repressed by SINM. Taken together with the results presented here, we suggest that SINM is a chromatin protein having at least a dual function: The N terminal of SINM interacts with the tetratrico peptide repeat domains of CDC23, a protein involved in chromosome segregation, whereas the C terminal of SINM binds proteins involved in transcriptional regulation.

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“…Several hypothetical functional domains in Sin1p have been defined based on genetic, structural, and biochemical considerations (6,9,21,(23)(24)(25). These domains include two HMG1-like domains, (amino acids 26-88 and 98-159), an acidic domain (amino acids 224-304), and a basic C-terminal domain (amino acids 303-333).…”

Section: Sin1p Binds Downstream Of Many Genes Just Upstream Of a Majormentioning

confidence: 99%

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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Characterization of a short unique sequence in the yeast HO gene promoter that regulates HO transcription in a SIN1 dependent manner

Cited by 6 publications

References 11 publications

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

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

Association of yeast SIN1 with the tetratrico peptide repeats of CDC23.

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

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