14 results match your criteria isw1p

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Roles of chromatin remodeling factors in the formation and maintenance of heterochromatin structure.

J Biol Chem 2011 Apr 9;286(16):14659-69. Epub 2011 Mar 9.

Department of Biology, University of Rochester, Rochester, New York 14627, USA.

Heterochromatin consists of highly ordered nucleosomes with characteristic histone modifications. There is evidence implicating chromatin remodeling proteins in heterochromatin formation, but their exact roles are not clear. We demonstrate in Saccharomyces cerevisiae that the Fun30p and Isw1p chromatin remodeling factors are similarly required for transcriptional silencing at the HML locus, but they differentially contribute to the structure and stability of HML heterochromatin. Read More

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RNA polymerase I in yeast transcribes dynamic nucleosomal rDNA.

Nat Struct Mol Biol 2007 Feb 28;14(2):123-30. Epub 2007 Jan 28.

Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.

RNA polymerase (Pol) I-transcribed ribosomal genes of budding yeast exist as a tandem array (about 150 repeats) with transcription units separated by spacer sequences. Half of these rDNAs are inactivated by repressive chromatin structure, whereas the rest exist in an open conformation transcribed by closely spaced Pol I elongation complexes. Whereas previous studies have suggested that active rDNA is devoid of nucleosomal structure, we demonstrate that active rDNA has nucleosomal structure, according to chromatin immunoprecipitation and biochemical fractionation. Read More

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February 2007

Methylation of H3 lysine 4 at euchromatin promotes Sir3p association with heterochromatin.

J Biol Chem 2004 Nov 27;279(46):47506-12. Epub 2004 Jul 27.

Wellcome Trust/Cancer Research United Kingdom Gurdon Institute and Department of Pathology, Tennis Court Road, Cambridge, CB2 1QR, United Kingdom.

Set1p methylates lysine 4 of histone H3 and can activate transcription by recruiting the chromatin-remodeling factor Isw1p. In addition, Lys-4-methylated H3 is required for maintenance of silencing at the telomeres, rDNA, and HML locus in Saccharomyces cerevisiae. The molecular mechanism underlying the role of Set1p in silencing is not known. Read More

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November 2004

Cbf1p is required for chromatin remodeling at promoter-proximal CACGTG motifs in yeast.

J Biol Chem 2004 Jun 24;279(26):27116-23. Epub 2004 Apr 24.

Genetics Unit, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom.

Cbf1p is a basic-helix-loop-helix-zipper protein of Saccharomyces cerevisiae required for the function of centromeres and MET gene promoters, where it binds DNA via the consensus core motif CACRTG (R = A or G). At MET genes Cbf1p appears to function in both activator recruitment and chromatin-remodeling. Cbf1p has been implicated in the regulation of other genes, and CACRTG motifs are common in potential gene regulatory DNA. Read More

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ISWI complexes in Saccharomyces cerevisiae.

Biochim Biophys Acta 2004 Mar;1677(1-3):100-12

Department of Biochemistry, Microbiology Unit, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.

The imitation switch (ISWI) class of chromatin remodeling ATPase is ubiquitous in eukaryotes. It is becoming clear that these enzymes exist as part of larger complexes and the nature of the associated proteins dictate the function associated with a complex both in biochemical assays and in the cell. Much progress has been made in understanding these relationships in the budding yeast Saccharomyces cerevisiae, containing two ATPases, Isw1p and Isw2p. Read More

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Methylation of histone H3 K4 mediates association of the Isw1p ATPase with chromatin.

Mol Cell 2003 Nov;12(5):1325-32

Wellcome Trust/Cancer Research UK Institute and Department of Pathology, Tennis Court Road, Cambridge CB2 1QR, United Kingdom.

Set1p methylates lysine 4 (K4) of histone H3 and regulates the expression of many genes in yeast. Here we use a biochemical approach to identify a protein, Isw1p, which recognizes chromatin preferentially when it is di- and trimethylated at K4 H3. We show that on certain actively transcribed genes, the Isw1p chromatin remodeling ATPase requires K4 H3 methylation to associate with chromatin in vivo. Read More

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November 2003

Isw1 chromatin remodeling ATPase coordinates transcription elongation and termination by RNA polymerase II.

Cell 2003 Nov;115(4):425-35

Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom.

We demonstrate that distinct forms of the yeast chromatin-remodeling enzyme Isw1p sequentially regulate each stage of the transcription cycle. The Isw1a complex (Iswlp/Ioc3p) represses gene expression at initiation through specific positioning of a promoter proximal dinucleosome, whereas the Isw1b complex (Iswlp/Ioc2p/Ioc4p) acts within coding regions to control the amount of RNA polymerase (RNAPII) released into productive elongation and to coordinate elongation with termination and pre-mRNA processing. These effects of Isw1b are controlled via phosphorylation of the heptad repeat carboxy-terminal domain (CTD) of RNAPII and methylation of the chromatin template. Read More

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November 2003

Regulated displacement of TBP from the PHO8 promoter in vivo requires Cbf1 and the Isw1 chromatin remodeling complex.

Mol Cell 2003 Jun;11(6):1609-20

Eukaryotic Transcription Laboratory, Marie Curie Research Institute, The Chart, Oxted, Surrey RH8 OTL, United Kingdom.

Regulated binding of TBP to a promoter is a key event in transcriptional regulation. We show here that on glucose depletion, the S. cerevisiae Isw1 chromatin remodeling complex is required for the displacement of TBP from the PHO8 promoter. Read More

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A role for chromatin remodeling in transcriptional termination by RNA polymerase II.

Mol Cell 2002 Dec;10(6):1441-52

Sir William Dunn School of Pathology, University of Oxford, South Parks Road, OX1 3RE, Oxford, United Kingdom.

Chromatin remodeling can facilitate the recruitment of RNA polymerase II (Pol II) to targeted promoters, as well as enhancing the level of transcription. Here, we describe a further key role for chromatin remodeling in transcriptional termination. Using a genetic screen in S. Read More

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December 2002

Yeast Isw1p forms two separable complexes in vivo.

Mol Cell Biol 2003 Jan;23(1):80-91

Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA.

There are several classes of ATP-dependent chromatin remodeling complexes, which modulate the structure of chromatin to regulate a variety of cellular processes. The budding yeast, Saccharomyces cerevisiae, encodes two ATPases of the ISWI class, Isw1p and Isw2p. Previously Isw1p was shown to copurify with three other proteins. Read More

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January 2003

Restoration of silencing in Saccharomyces cerevisiae by tethering of a novel Sir2-interacting protein, Esc8.

Genetics 2002 Oct;162(2):633-45

Department of Molecular Biology, University of Geneva, CH-1211 Switzerland.

We previously described two classes of SIR2 mutations specifically defective in either telomeric/HM silencing (class I) or rDNA silencing (class II) in S. cerevisiae. Here we report the identification of genes whose protein products, when either overexpressed or directly tethered to the locus in question, can establish silencing in SIR2 class I mutants. Read More

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October 2002

In vivo chromatin remodeling by yeast ISWI homologs Isw1p and Isw2p.

Genes Dev 2001 Mar;15(5):619-26

Division of Molecular Genetics, Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK.

Isw1p and Isw2p are budding yeast homologs of the Drosophila ISWI chromatin-remodeling ATPase. Using indirect-end-label and chromatin immunoprecipitation analysis, we show both independent and cooperative Isw1p- and Isw2p-mediated positioning of short nucleosome arrays in gene-regulatory elements at a variety of transcription units in vivo. We present evidence that both yeast ISWI complexes regulate developmental responses to starvation and that for Isw2p, recruitment by different DNA-binding proteins controls meiosis and haploid invasive growth. Read More

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Characterization of the imitation switch subfamily of ATP-dependent chromatin-remodeling factors in Saccharomyces cerevisiae.

Genes Dev 1999 Mar;13(6):686-97

Laboratory of Molecular Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.

We have identified and characterized two Imitation Switch genes in Saccharomyces cerevisiae, ISW1 and ISW2, which are highly related to Drosophila ISWI, encoding the putative ATPase subunit of three ATP-dependent chromatin remodeling factors. Purification of ISW1p reveals a four-subunit complex with nucleosome-stimulated ATPase activity, as well as ATP-dependent nucleosome disruption and spacing activities. Purification of ISW2p reveals a two-subunit complex also with nucleosome-stimulated ATPase and ATP-dependent nucleosome spacing activities but no detectable nucleosome disruption activity. Read More

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