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Stupak A, Gęca T, Kwaśniewska A, Mlak R, Piwowarczyk P, Nawrot R, Goździcka-Józefiak A, Kwaśniewski W. Comparative Analysis of the Placental Microbiome in Pregnancies with Late Fetal Growth Restriction versus Physiological Pregnancies. Int J Mol Sci 2023; 24:ijms24086922. [PMID: 37108086 PMCID: PMC10139004 DOI: 10.3390/ijms24086922] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 04/03/2023] [Accepted: 04/06/2023] [Indexed: 04/29/2023] Open
Abstract
A comparative analysis of the placental microbiome in pregnancies with late fetal growth restriction (FGR) was performed with normal pregnancies to assess the impact of bacteria on placental development and function. The presence of microorganisms in the placenta, amniotic fluid, fetal membranes and umbilical cord blood throughout pregnancy disproves the theory of the "sterile uterus". FGR occurs when the fetus is unable to follow a biophysically determined growth path. Bacterial infections have been linked to maternal overproduction of pro-inflammatory cytokines, as well as various short- and long-term problems. Proteomics and bioinformatics studies of placental biomass allowed the development of new diagnostic options. In this study, the microbiome of normal and FGR placentas was analyzed by LC-ESI-MS/MS mass spectrometry, and the bacteria present in both placentas were identified by analysis of a set of bacterial proteins. Thirty-six pregnant Caucasian women participated in the study, including 18 women with normal pregnancy and eutrophic fetuses (EFW > 10th percentile) and 18 women with late FGR diagnosed after 32 weeks of gestation. Based on the analysis of the proteinogram, 166 bacterial proteins were detected in the material taken from the placentas in the study group. Of these, 21 proteins had an exponentially modified protein abundance index (emPAI) value of 0 and were not included in further analysis. Of the remaining 145 proteins, 52 were also present in the material from the control group. The remaining 93 proteins were present only in the material collected from the study group. Based on the proteinogram analysis, 732 bacterial proteins were detected in the material taken from the control group. Of these, 104 proteins had an emPAI value of 0 and were not included in further analysis. Of the remaining 628 proteins, 52 were also present in the material from the study group. The remaining 576 proteins were present only in the material taken from the control group. In both groups, we considered the result of ns prot ≥ 60 as the cut-off value for the agreement of the detected protein with its theoretical counterpart. Our study found significantly higher emPAI values of proteins representative of the following bacteria: Actinopolyspora erythraea, Listeria costaricensis, E. coli, Methylobacterium, Acidobacteria bacterium, Bacteroidetes bacterium, Paenisporsarcina sp., Thiodiazotropha endol oripes and Clostridiales bacterium. On the other hand, in the control group statistically more frequently, based on proteomic data, the following were found: Flavobacterial bacterium, Aureimonas sp. and Bacillus cereus. Our study showed that placental dysbiosis may be an important factor in the etiology of FGR. The presence of numerous bacterial proteins present in the control material may indicate their protective role, while the presence of bacterial proteins detected only in the material taken from the placentas of the study group may indicate their potentially pathogenic nature. This phenomenon is probably important in the development of the immune system in early life, and the placental microbiota and its metabolites may have great potential in the screening, prevention, diagnosis and treatment of FGR.
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Affiliation(s)
- Aleksandra Stupak
- Chair and Department of Obstetrics and Pathology of Pregnancy, Medical University of Lublin, 20-059 Lublin, Poland
| | - Tomasz Gęca
- Chair and Department of Obstetrics and Pathology of Pregnancy, Medical University of Lublin, 20-059 Lublin, Poland
| | - Anna Kwaśniewska
- Chair and Department of Obstetrics and Pathology of Pregnancy, Medical University of Lublin, 20-059 Lublin, Poland
| | - Radosław Mlak
- Body Composition Research Laboratory, Department of Preclinical Science, Medical University of Lublin, 20-059 Lublin, Poland
| | - Paweł Piwowarczyk
- 2nd Department of Anesthesiology and Intensive Care Unit, Medical University of Lublin, 20-059 Lublin, Poland
| | - Robert Nawrot
- Department of Molecular Virology, Institute of Experimental Biology, Adam Mickiewicz University in Poznan, 61-712 Poznań, Poland
| | - Anna Goździcka-Józefiak
- Department of Molecular Virology, Institute of Experimental Biology, Adam Mickiewicz University in Poznan, 61-712 Poznań, Poland
| | - Wojciech Kwaśniewski
- Department of Gynecologic Oncology and Gynecology, Medical University of Lublin, 20-059 Lublin, Poland
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Nawrot R, Musidlak O, Barylski J, Nowicki G, Bałdysz S, Czerwoniec A, Goździcka-Józefiak A. Characterization and expression of a novel thaumatin-like protein (CcTLP1) from papaveraceous plant Corydalis cava. Int J Biol Macromol 2021; 189:678-689. [PMID: 34390750 DOI: 10.1016/j.ijbiomac.2021.08.067] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 08/01/2021] [Accepted: 08/08/2021] [Indexed: 10/20/2022]
Abstract
Thaumatin-like proteins (TLPs, osmotins) form a protein family which shares a significant sequence homology to the sweet-tasting thaumatin from the plant Thaumatococcus daniellii. TLPs are not sweet-tasting and are involved in response to biotic stresses and developmental processes. Recently it has been shown using a proteomic approach that the tuber extract from Corydalis cava (Papaveraceae) contains a TLP protein. The aim of this work was to characterize the structure and expression of TLP from C. cava tubers. The results obtained using a PCR approach with degenerate primers demonstrated a coding sequence of a novel protein, named CcTLP1. It consists of 225 aa, has a predicted molecular weight of 24.2 kDa (NCBI GenBank accession no. KJ513303) and has 16 strictly conserved cysteine residues, which form 8 disulfide bridges and stabilize the 3D structure. CcTLP1 may be classified into class IX of plant TLPs. The highest CcTLP1 expression levels were shown by qPCR in the stem of the plant compared to other organs and in the medium-size plants compared to other growth phases. The results confirm that CcTLP1 is expressed during plant growth and development until flowering, with a possible defensive function against different stress conditions.
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Affiliation(s)
- Robert Nawrot
- Molecular Virology Research Unit, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Poznań, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland.
| | - Oskar Musidlak
- Molecular Virology Research Unit, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Poznań, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland.
| | - Jakub Barylski
- Molecular Virology Research Unit, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Poznań, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland
| | - Grzegorz Nowicki
- Molecular Virology Research Unit, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Poznań, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland
| | - Sophia Bałdysz
- Molecular Virology Research Unit, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Poznań, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland
| | - Anna Czerwoniec
- Zylia Sp. z o. o., Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland; INNO-GENE S.A.- Vita in Silica, ul. Inflancka 25, 61-132 Poznań, Poland
| | - Anna Goździcka-Józefiak
- Molecular Virology Research Unit, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Poznań, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland.
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Vozáriková V, Kunová N, Bauer JA, Frankovský J, Kotrasová V, Procházková K, Džugasová V, Kutejová E, Pevala V, Nosek J, Tomáška Ľ. Mitochondrial HMG-Box Containing Proteins: From Biochemical Properties to the Roles in Human Diseases. Biomolecules 2020; 10:biom10081193. [PMID: 32824374 PMCID: PMC7463775 DOI: 10.3390/biom10081193] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 08/11/2020] [Accepted: 08/13/2020] [Indexed: 12/14/2022] Open
Abstract
Mitochondrial DNA (mtDNA) molecules are packaged into compact nucleo-protein structures called mitochondrial nucleoids (mt-nucleoids). Their compaction is mediated in part by high-mobility group (HMG)-box containing proteins (mtHMG proteins), whose additional roles include the protection of mtDNA against damage, the regulation of gene expression and the segregation of mtDNA into daughter organelles. The molecular mechanisms underlying these functions have been identified through extensive biochemical, genetic, and structural studies, particularly on yeast (Abf2) and mammalian mitochondrial transcription factor A (TFAM) mtHMG proteins. The aim of this paper is to provide a comprehensive overview of the biochemical properties of mtHMG proteins, the structural basis of their interaction with DNA, their roles in various mtDNA transactions, and the evolutionary trajectories leading to their rapid diversification. We also describe how defects in the maintenance of mtDNA in cells with dysfunctional mtHMG proteins lead to different pathologies at the cellular and organismal level.
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Affiliation(s)
- Veronika Vozáriková
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, Mlynská dolina B-1, 842 15 Bratislava, Slovakia; (V.V.); (J.F.); (K.P.); (V.D.)
| | - Nina Kunová
- Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia; (N.K.); (J.A.B.); (V.K.); (E.K.); (V.P.)
| | - Jacob A. Bauer
- Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia; (N.K.); (J.A.B.); (V.K.); (E.K.); (V.P.)
| | - Ján Frankovský
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, Mlynská dolina B-1, 842 15 Bratislava, Slovakia; (V.V.); (J.F.); (K.P.); (V.D.)
| | - Veronika Kotrasová
- Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia; (N.K.); (J.A.B.); (V.K.); (E.K.); (V.P.)
| | - Katarína Procházková
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, Mlynská dolina B-1, 842 15 Bratislava, Slovakia; (V.V.); (J.F.); (K.P.); (V.D.)
| | - Vladimíra Džugasová
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, Mlynská dolina B-1, 842 15 Bratislava, Slovakia; (V.V.); (J.F.); (K.P.); (V.D.)
| | - Eva Kutejová
- Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia; (N.K.); (J.A.B.); (V.K.); (E.K.); (V.P.)
| | - Vladimír Pevala
- Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia; (N.K.); (J.A.B.); (V.K.); (E.K.); (V.P.)
| | - Jozef Nosek
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, Mlynská dolina CH-1, 842 15 Bratislava, Slovakia;
| | - Ľubomír Tomáška
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, Mlynská dolina B-1, 842 15 Bratislava, Slovakia; (V.V.); (J.F.); (K.P.); (V.D.)
- Correspondence: ; Tel.: +421-2-90149-433
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Swygert SG, Senapati S, Bolukbasi MF, Wolfe SA, Lindsay S, Peterson CL. SIR proteins create compact heterochromatin fibers. Proc Natl Acad Sci U S A 2018; 115:12447-12452. [PMID: 30455303 PMCID: PMC6298083 DOI: 10.1073/pnas.1810647115] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Heterochromatin is a silenced chromatin region essential for maintaining genomic stability and driving developmental processes. The complicated structure and dynamics of heterochromatin have rendered it difficult to characterize. In budding yeast, heterochromatin assembly requires the SIR proteins-Sir3, believed to be the primary structural component of SIR heterochromatin, and the Sir2-4 complex, responsible for the targeted recruitment of SIR proteins and the deacetylation of lysine 16 of histone H4. Previously, we found that Sir3 binds but does not compact nucleosomal arrays. Here we reconstitute chromatin fibers with the complete complement of SIR proteins and use sedimentation velocity, molecular modeling, and atomic force microscopy to characterize the stoichiometry and conformation of SIR chromatin fibers. In contrast to fibers with Sir3 alone, our results demonstrate that SIR arrays are highly compact. Strikingly, the condensed structure of SIR heterochromatin fibers requires both the integrity of H4K16 and an interaction between Sir3 and Sir4. We propose a model in which a dimer of Sir3 bridges and stabilizes two adjacent nucleosomes, while a Sir2-4 heterotetramer interacts with Sir3 associated with a nucleosomal trimer, driving fiber compaction.
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Affiliation(s)
- Sarah G Swygert
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605
| | - Subhadip Senapati
- Center for Single Molecule Biophysics, Biodesign Institute, Arizona State University, Tempe, AZ 85287
| | - Mehmet F Bolukbasi
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655
| | - Scot A Wolfe
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655
| | - Stuart Lindsay
- Center for Single Molecule Biophysics, Biodesign Institute, Arizona State University, Tempe, AZ 85287
| | - Craig L Peterson
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605;
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Nawrot R, Józefiak D, Sip A, Kuźma D, Musidlak O, Goździcka-Józefiak A. Isolation and characterization of a non-specific lipid transfer protein from Chelidonium majus L. latex. Int J Biol Macromol 2017; 104:554-563. [DOI: 10.1016/j.ijbiomac.2017.06.057] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 06/09/2017] [Accepted: 06/10/2017] [Indexed: 01/01/2023]
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Soriano I, Morafraile EC, Vázquez E, Antequera F, Segurado M. Different nucleosomal architectures at early and late replicating origins in Saccharomyces cerevisiae. BMC Genomics 2014; 15:791. [PMID: 25218085 PMCID: PMC4176565 DOI: 10.1186/1471-2164-15-791] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 09/10/2014] [Indexed: 11/10/2022] Open
Abstract
Background Eukaryotic genomes are replicated during S phase according to a temporal program. Several determinants control the timing of origin firing, including the chromatin environment and epigenetic modifications. However, how chromatin structure influences the timing of the activation of specific origins is still poorly understood. Results By performing high-resolution analysis of genome-wide nucleosome positioning we have identified different chromatin architectures at early and late replication origins. These different patterns are already established in G1 and are tightly correlated with the organization of adjacent transcription units. Moreover, specific early and late nucleosomal patterns are fixed robustly, even in rpd3 mutants in which histone acetylation and origin timing have been significantly altered. Nevertheless, higher histone acetylation levels correlate with the local modulation of chromatin structure, leading to increased origin accessibility. In addition, we conducted parallel analyses of replication and nucleosome dynamics that revealed that chromatin structure at origins is modulated during origin activation. Conclusions Our results show that early and late replication origins present distinctive nucleosomal configurations, which are preferentially associated to different genomic regions. Our data also reveal that origin structure is dynamic and can be locally modulated by histone deacetylation, as well as by origin activation. These data offer novel insight into the contribution of chromatin structure to origin selection and firing in budding yeast. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-791) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | - Mónica Segurado
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas/ Universidad de Salamanca (CSIC/USAL), Campus Miguel de Unamuno, Salamanca 37007, Spain.
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Structural context of disease-associated mutations and putative mechanism of autoinhibition revealed by X-ray crystallographic analysis of the EZH2-SET domain. PLoS One 2013; 8:e84147. [PMID: 24367637 PMCID: PMC3868555 DOI: 10.1371/journal.pone.0084147] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 11/12/2013] [Indexed: 01/16/2023] Open
Abstract
The enhancer-of-zeste homolog 2 (EZH2) gene product is an 87 kDa polycomb group (PcG) protein containing a C-terminal methyltransferase SET domain. EZH2, along with binding partners, i.e., EED and SUZ12, upon which it is dependent for activity forms the core of the polycomb repressive complex 2 (PRC2). PRC2 regulates gene silencing by catalyzing the methylation of histone H3 at lysine 27. Both overexpression and mutation of EZH2 are associated with the incidence and aggressiveness of various cancers. The novel crystal structure of the SET domain was determined in order to understand disease-associated EZH2 mutations and derive an explanation for its inactivity independent of complex formation. The 2.00 Å crystal structure reveals that, in its uncomplexed form, the EZH2 C-terminus folds back into the active site blocking engagement with substrate. Furthermore, the S-adenosyl-L-methionine (SAM) binding pocket observed in the crystal structure of homologous SET domains is notably absent. This suggests that a conformational change in the EZH2 SET domain, dependent upon complex formation, must take place for cofactor and substrate binding activities to be recapitulated. In addition, the data provide a structural context for clinically significant mutations found in the EZH2 SET domain.
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Kueng S, Oppikofer M, Gasser SM. SIR proteins and the assembly of silent chromatin in budding yeast. Annu Rev Genet 2013; 47:275-306. [PMID: 24016189 DOI: 10.1146/annurev-genet-021313-173730] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Saccharomyces cerevisiae provides a well-studied model system for heritable silent chromatin in which a histone-binding protein complex [the SIR (silent information regulator) complex] represses gene transcription in a sequence-independent manner by spreading along nucleosomes, much like heterochromatin in higher eukaryotes. Recent advances in the biochemistry and structural biology of the SIR-chromatin system bring us much closer to a molecular understanding of yeast silent chromatin. Simultaneously, genome-wide approaches have shed light on the biological importance of this form of epigenetic repression. Here, we integrate genetic, structural, and cell biological data into an updated overview of yeast silent chromatin assembly.
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Affiliation(s)
- Stephanie Kueng
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
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Abstract
Although distinct chromatin types have been long known to replicate at different timepoints of S phase, fine replication control has only recently become considered as an epigenetic phenomenon. It is now clear that in course of differentiation significant changes in genome replication timing occur, and these changes are intimately linked with the changes in transcriptional activity and nuclear architecture. Temporally coordinate replication is organized spatially into discrete units having specific chromosomal organization and function. Even though the functional aspects of such tight control of replication timing remain to be explored, one can confidently consider the replication program as yet another fundamental feature characteristic of the given differentiation state. The present review touches upon the molecular mechanisms of spatial and temporal control of replication timing, involving individual replication origins as well as large chromatin domains.
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Kim SC, Choi JK. Controlling transcriptional programs for cellular adaptation by chromatin regulation. MOLECULAR BIOSYSTEMS 2011; 7:1713-9. [PMID: 21412562 DOI: 10.1039/c0mb00319k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Gene expression is dynamically reprogrammed during growth control and stress responses, which are two key processes of cellular adaptation. Single-gene studies suggest that gene regulatory patterns of the two processes commonly show high environmental responsiveness, but contrast in terms of regulatory flexibility. Our whole-genome analysis shows that the growth and stress genes are associated with activated and repressed chromatin, respectively, which can modulate the responsiveness of promoters and help balance regulatory flexibility and fidelity. Stochastic modeling of critical nucleosomes at specific promoter regions enables rapid induction of genes during stress responses by activating repressed chromatin. Conversely, activating histone modifications may contribute to regulatory fidelity for precise growth control by common transcription factors. Nucleosome eviction and modification loss lead to an intermediate chromatin state. The combinatorial role of nucleosome organization and modification is central to the balanced control of gene expression programs for stress responses and efficient growth. These regulatory mechanisms can also contribute to evolutionary adaptation.
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Affiliation(s)
- Sang Cheol Kim
- Korean Bioinformation Center, KRIBB, Daejeon 305-701, Korea
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Flueck C, Bartfai R, Niederwieser I, Witmer K, Alako BTF, Moes S, Bozdech Z, Jenoe P, Stunnenberg HG, Voss TS. A major role for the Plasmodium falciparum ApiAP2 protein PfSIP2 in chromosome end biology. PLoS Pathog 2010; 6:e1000784. [PMID: 20195509 PMCID: PMC2829057 DOI: 10.1371/journal.ppat.1000784] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Accepted: 01/20/2010] [Indexed: 12/30/2022] Open
Abstract
The heterochromatic environment and physical clustering of chromosome ends at the nuclear periphery provide a functional and structural framework for antigenic variation and evolution of subtelomeric virulence gene families in the malaria parasite Plasmodium falciparum. While recent studies assigned important roles for reversible histone modifications, silent information regulator 2 and heterochromatin protein 1 (PfHP1) in epigenetic control of variegated expression, factors involved in the recruitment and organization of subtelomeric heterochromatin remain unknown. Here, we describe the purification and characterization of PfSIP2, a member of the ApiAP2 family of putative transcription factors, as the unknown nuclear factor interacting specifically with cis-acting SPE2 motif arrays in subtelomeric domains. Interestingly, SPE2 is not bound by the full-length protein but rather by a 60kDa N-terminal domain, PfSIP2-N, which is released during schizogony. Our experimental re-definition of the SPE2/PfSIP2-N interaction highlights the strict requirement of both adjacent AP2 domains and a conserved bipartite SPE2 consensus motif for high-affinity binding. Genome-wide in silico mapping identified 777 putative binding sites, 94% of which cluster in heterochromatic domains upstream of subtelomeric var genes and in telomere-associated repeat elements. Immunofluorescence and chromatin immunoprecipitation (ChIP) assays revealed co-localization of PfSIP2-N with PfHP1 at chromosome ends. Genome-wide ChIP demonstrated the exclusive binding of PfSIP2-N to subtelomeric SPE2 landmarks in vivo but not to single chromosome-internal sites. Consistent with this specialized distribution pattern, PfSIP2-N over-expression has no effect on global gene transcription. Hence, contrary to the previously proposed role for this factor in gene activation, our results provide strong evidence for the first time for the involvement of an ApiAP2 factor in heterochromatin formation and genome integrity. These findings are highly relevant for our understanding of chromosome end biology and variegated expression in P. falciparum and other eukaryotes, and for the future analysis of the role of ApiAP2-DNA interactions in parasite biology.
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Affiliation(s)
- Christian Flueck
- Department of Medical Parasitology and Infection Biology, Swiss Tropical Institute, University of Basel, Basel, Switzerland
| | - Richard Bartfai
- Department of Molecular Biology, Nijmegen Center of Molecular Life Sciences, Radboud University, Nijmegen, The Netherlands
| | - Igor Niederwieser
- Department of Medical Parasitology and Infection Biology, Swiss Tropical Institute, University of Basel, Basel, Switzerland
| | - Kathrin Witmer
- Department of Medical Parasitology and Infection Biology, Swiss Tropical Institute, University of Basel, Basel, Switzerland
| | - Blaise T. F. Alako
- Department of Molecular Biology, Nijmegen Center of Molecular Life Sciences, Radboud University, Nijmegen, The Netherlands
| | - Suzette Moes
- Biozentrum, University of Basel, Basel, Switzerland
| | - Zbynek Bozdech
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Paul Jenoe
- Biozentrum, University of Basel, Basel, Switzerland
| | - Hendrik G. Stunnenberg
- Department of Molecular Biology, Nijmegen Center of Molecular Life Sciences, Radboud University, Nijmegen, The Netherlands
| | - Till S. Voss
- Department of Medical Parasitology and Infection Biology, Swiss Tropical Institute, University of Basel, Basel, Switzerland
- * E-mail:
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13
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Yu S, Smirnova JB, Friedberg EC, Stillman B, Akiyama M, Owen-Hughes T, Waters R, Reed SH. ABF1-binding sites promote efficient global genome nucleotide excision repair. J Biol Chem 2008; 284:966-73. [PMID: 18996839 DOI: 10.1074/jbc.m806830200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Global genome nucleotide excision repair (GG-NER) removes DNA damage from nontranscribing DNA. In Saccharomyces cerevisiae, the RAD7 and RAD16 genes are specifically required for GG-NER. We have reported that autonomously replicating sequence-binding factor 1 (ABF1) protein forms a stable complex with Rad7 and Rad16 proteins. ABF1 functions in transcription, replication, gene silencing, and NER in yeast. Here we show that binding of ABF1 to its DNA recognition sequence found at multiple genomic locations promotes efficient GG-NER in yeast. Mutation of the I silencer ABF1-binding site at the HMLalpha locus caused loss of ABF1 binding, which resulted in a domain of reduced GG-NER efficiency on one side of the ABF1-binding site. During GG-NER, nucleosome positioning at this site was not altered, and this correlated with an inability of the GG-NER complex to reposition nucleosomes in vitro.We discuss how the GG-NER complex might facilitate GG-NER while preventing unregulated gene transcription during this process.
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Affiliation(s)
- Shirong Yu
- Department of Pathology, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, United Kingdom
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Subtelomeric elements influence but do not determine silencing levels at Saccharomyces cerevisiae telomeres. Genetics 2008; 177:2541-6. [PMID: 18073447 DOI: 10.1534/genetics.107.079806] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In Saccharomyces cerevisiae, genes placed near telomeres are transcriptionally repressed (telomere position effect, TPE). Although telomeric DNA sequence is the same at all chromosome ends, the subtelomeric elements (STEs) and level of TPE vary from telomere to telomere. We tested whether STEs determine TPE levels. STEs contributed to TPE, as deleting the X element from the VI-R telomere modestly decreased silencing at this telomere. However, STEs were not the major determinant of TPE levels, as inserting the VI-R X element at the truncated VII-L telomere did not increase TPE. These data suggest that the TPE levels of individual telomeres are dependent on some aspect of chromosome context.
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van Vugt JJFA, Ranes M, Campsteijn C, Logie C. The ins and outs of ATP-dependent chromatin remodeling in budding yeast: biophysical and proteomic perspectives. ACTA ACUST UNITED AC 2007; 1769:153-71. [PMID: 17395283 DOI: 10.1016/j.bbaexp.2007.01.013] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2006] [Revised: 01/22/2007] [Accepted: 01/29/2007] [Indexed: 11/30/2022]
Abstract
ATP-dependent chromatin remodeling is performed by multi-subunit protein complexes. Over the last years, the identity of these factors has been unveiled in yeast and many parallels have been drawn with animal and plant systems, indicating that sophisticated chromatin transactions evolved prior to their divergence. Here we review current knowledge pertaining to the molecular mode of action of ATP-dependent chromatin remodeling, from single molecule studies to genome-wide genetic and proteomic studies. We focus on the budding yeast versions of SWI/SNF, RSC, DDM1, ISWI, CHD1, INO80 and SWR1.
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Affiliation(s)
- Joke J F A van Vugt
- Department of Molecular Biology, NCMLS, Radboud University, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
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16
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Yang L, Mullen JR, Brill SJ. Purification of the yeast Slx5-Slx8 protein complex and characterization of its DNA-binding activity. Nucleic Acids Res 2006; 34:5541-51. [PMID: 17020915 PMCID: PMC1635298 DOI: 10.1093/nar/gkl685] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
SLX5 and SLX8 encode RING-finger proteins that were previously identified based on their requirement for viability in yeast cells lacking Sgs1 DNA helicase. Slx5 and Slx8 proteins are known to be required for genome stability and to physically interact in yeast extracts; however, their biochemical functions are unknown. To address this question we purified and characterized recombinant Slx5 and Slx8 proteins. Here we show that Slx5 and Slx8 form a heterodimeric complex with double-stranded DNA (dsDNA)-binding activity. Individually, only the Slx8 subunit displays this activity. Structure–function studies indicate that the DNA-binding activity requires only the N-terminal 160 amino acids of Slx8, but not its C-terminal RING-finger domain. Alleles of SLX8 that express the RING-finger domain alone show almost complete complementation in yeast indicating that this DNA-binding domain is not essential for this in vivo function. Consistent with these findings we show that Slx5 immunolocalizes to the nucleus and that a portion of the Slx8 protein co-fractionates with chromatin. These results suggest that Slx5–Slx8 may act directly on DNA to promote genome stability.
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Affiliation(s)
| | | | - Steven J. Brill
- To whom correspondence should be addressed at Department of Molecular Biology and Biochemistry, 679 Hoes Lane, CABM, Rutgers University, Piscataway, NJ 08854, USA. Tel: +1 732 235 4197; Fax: +1 732 235 4880;
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17
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Hediger F, Berthiau AS, van Houwe G, Gilson E, Gasser SM. Subtelomeric factors antagonize telomere anchoring and Tel1-independent telomere length regulation. EMBO J 2006; 25:857-67. [PMID: 16467853 PMCID: PMC1383557 DOI: 10.1038/sj.emboj.7600976] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2005] [Accepted: 01/09/2006] [Indexed: 11/09/2022] Open
Abstract
Yeast telomeres are anchored at the nuclear envelope (NE) through redundant pathways that require the telomere-binding factors yKu and Sir4. Significant variation is observed in the efficiency with which different telomeres are anchored, however, suggesting that other forces influence this interaction. Here, we show that subtelomeric elements and the insulator factors that bind them antagonize the association of telomeres with the NE. This is detectable when the redundancy in anchoring pathways is compromised. Remarkably, these same conditions lead to a reduction in steady-state telomere length in the absence of the ATM-kinase homologue Tel1. Both the delocalization of telomeres and reduction in telomere length can be induced by targeting of Tbf1 or Reb1, or the viral transactivator VP16, to a site 23 kb away from the TG repeat. This correlation suggests that telomere anchoring and a Tel1-independent pathway of telomere length regulation are linked, lending a functional significance to the association of yeast telomeres with the NE.
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Affiliation(s)
- Florence Hediger
- Department of Molecular Biology and NCCR Frontiers in Genetics, University of Geneva, Geneva, Switzerland
| | - Anne-Sophie Berthiau
- Laboratoire de Biologie Moléculaire de la Cellule de l'Ecole Normale Supérieure de Lyon, CNRS UMR5161, Lyon, France
| | - Griet van Houwe
- Department of Molecular Biology and NCCR Frontiers in Genetics, University of Geneva, Geneva, Switzerland
| | - Eric Gilson
- Laboratoire de Biologie Moléculaire de la Cellule de l'Ecole Normale Supérieure de Lyon, CNRS UMR5161, Lyon, France
| | - Susan M Gasser
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, Basel CH-4058, Switzerland. Tel.: +41 61 697 7255; Fax: +41 61 697 3976; E-mail:
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18
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Abstract
There has been remarkable progress in the last 20 years in defining the molecular mechanisms that regulate initiation of DNA synthesis in eukaryotic cells. Replication origins in the DNA nucleate the ordered assembly of protein factors to form a prereplication complex (preRC) that is poised for DNA synthesis. Transition of the preRC to an active initiation complex is regulated by cyclin-dependent kinases and other signaling molecules, which promote further protein assembly and activate the mini chromosome maintenance helicase. We will review these mechanisms and describe the state of knowledge about the proteins involved. However, we will also consider an additional layer of complexity. The DNA in the cell is packaged with histone proteins into chromatin. Chromatin structure provides an additional layer of heritable information with associated epigenetic modifications. Thus, we will begin by describing chromatin structure, and how the cell generally controls access to the DNA. Access to the DNA requires active chromatin remodeling, specific histone modifications, and regulated histone deposition. Studies in transcription have revealed a variety of mechanisms that regulate DNA access, and some of these are likely to be shared with DNA replication. We will briefly describe heterochromatin as a model for an epigenetically inherited chromatin state. Next, we will describe the mechanisms of replication initiation and how these are affected by constraints of chromatin. Finally, chromatin must be reassembled with appropriate modifications following passage of the replication fork, and our third major topic will be the reassembly of chromatin and its associated epigenetic marks. Thus, in this chapter, we seek to bring together the studies of replication initiation and the studies of chromatin into a single holistic narrative.
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Affiliation(s)
- Angel P Tabancay
- Molecular and Computational Biology Section University of Southern California Los Angeles, California 90089, USA
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19
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Wintersberger E. Biochemical events controlling initiation and propagation of the S phase of the cell cycle. Rev Physiol Biochem Pharmacol 2005; 118:49-95. [PMID: 1754800 DOI: 10.1007/bfb0031481] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- E Wintersberger
- Institut für Molekularbiologie der Universität Wien, Austria
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20
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Hsu HC, Stillman B, Xu RM. Structural basis for origin recognition complex 1 protein-silence information regulator 1 protein interaction in epigenetic silencing. Proc Natl Acad Sci U S A 2005; 102:8519-24. [PMID: 15937111 PMCID: PMC1150838 DOI: 10.1073/pnas.0502946102] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The interaction between silence information regulator 1 protein (Sir1p) and origin recognition complex 1 protein (Orc1p), the largest subunit of the origin recognition complex, plays an important role in the establishment of transcriptional silencing at the cryptic mating-type gene loci in Saccharomyces cerevisiae. Sir1p binds the N-terminal region of Orc1p encompassing a Bromo-adjacent homology (BAH) domain found in various chromatin-associated proteins. To understand the molecular mechanism of Sir protein recruitment, we have determined a 2.5-A cocrystal structure of the N-terminal domain of Orc1p in complex with the Orc1p-interacting domain of Sir1p. The structure reveals that Sir1p Orc1p-interacting domain has a bilobal structure: an alpha/beta N-terminal lobe and a C-terminal lobe resembling the Tudor domain royal family fold. The N-terminal lobe of Sir1p binds in a shallow groove between a helical subdomain and the BAH domain of Orc1p. The structure provides a mechanistic understanding of Orc1p-Sir1p interaction specificity, as well as insights into protein-protein interactions involving BAH domains in general.
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Affiliation(s)
- Hao-Chi Hsu
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
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21
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Nieduszynski CA, Blow JJ, Donaldson AD. The requirement of yeast replication origins for pre-replication complex proteins is modulated by transcription. Nucleic Acids Res 2005; 33:2410-20. [PMID: 15860777 PMCID: PMC1087785 DOI: 10.1093/nar/gki539] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The mini-chromosome maintenance proteins Mcm2–7 are essential for DNA replication. They are loaded onto replication origins during G1 phase of the cell cycle to form a pre-replication complex (pre-RC) that licenses each origin for subsequent initiation. We have investigated the DNA elements that determine the dependence of yeast replication origins on Mcm2–7 activity, i.e. the sensitivity of an origin to mcm mutations. Using chimaeric constructs from mcm sensitive and mcm insensitive origins, we have identified two main elements affecting the requirement for Mcm2–7 function. First, transcription into an origin increases its dependence on Mcm2–7 function, revealing a conflict between pre-RC assembly and transcription. Second, sequence elements within the minimal origin influence its mcm sensitivity. Replication origins show similar differences in sensitivity to mutations in other pre-RC proteins (such as Origin Recognition Complex and Cdc6), but not to mutations in initiation and elongation factors, demonstrating that the mcm sensitivity of an origin is determined by its ability to establish a pre-RC. We propose that there is a hierarchy of replication origins with respect to the range of pre-RC protein concentrations under which they will function. This hierarchy is both ‘hard-wired’ by the minimal origin sequences and ‘soft-wired’ by local transcriptional context.
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Affiliation(s)
| | - J. Julian Blow
- Cancer Research UK Chromosome Replication Research Group, Wellcome Trust Biocentre, University of DundeeDow Street, Dundee DD1 5EH, Scotland, UK
| | - Anne D. Donaldson
- To whom correspondence should be addressed. Tel: +44 0 1224 550975; Fax: +44 0 1224 555844;
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22
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Yarragudi A, Miyake T, Li R, Morse RH. Comparison of ABF1 and RAP1 in chromatin opening and transactivator potentiation in the budding yeast Saccharomyces cerevisiae. Mol Cell Biol 2004; 24:9152-64. [PMID: 15456886 PMCID: PMC517901 DOI: 10.1128/mcb.24.20.9152-9164.2004] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Autonomously replicating sequence binding factor 1 (ABF1) and repressor/activator protein 1 (RAP1) from budding yeast are multifunctional, site-specific DNA-binding proteins, with roles in gene activation and repression, replication, and telomere structure and function. Previously we have shown that RAP1 can prevent nucleosome positioning in the vicinity of its binding site and have provided evidence that this ability to create a local region of "open" chromatin contributes to RAP1 function at the HIS4 promoter by facilitating binding and activation by GCN4. Here we examine and directly compare to that of RAP1 the ability of ABF1 to create a region of open chromatin near its binding site and to contribute to activated transcription at the HIS4, ADE5,7, and HIS7 promoters. ABF1 behaves similarly to RAP1 in these assays, but it shows some subtle differences from RAP1 in the character of the open chromatin region near its binding site. Furthermore, although the two factors can similarly enhance activated transcription at the promoters tested, RAP1 binding is continuously required for this enhancement, but ABF1 binding is not. These results indicate that ABF1 and RAP1 achieve functional similarity in part via mechanistically distinct pathways.
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23
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Loch CM, Mosammaparast N, Miyake T, Pemberton LF, Li R. Functional and Physical Interactions between Autonomously Replicating Sequence-Binding Factor 1 and the Nuclear Transport Machinery. Traffic 2004; 5:925-35. [PMID: 15522095 DOI: 10.1111/j.1600-0854.2004.00233.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Autonomously replicating sequence-binding factor 1 (Abf1p) is a site-specific DNA binding protein in Saccharomyces cerevisiae that functions to regulate multiple nuclear events including DNA replication, transcriptional activation, and gene silencing. Previous work indicates that the multiple functions of Abf1p are conferred by the carboxy-terminus of the protein, which can be further dissected into two important clusters of amino acid residues (CS1 and CS2). Here we present genetic and cell biological evidence for a critical role of CS1 in proper nuclear localization of Abf1p. Mutations in CS1 cause severe defects in cell growth, nuclear translocation, and Abf1p-mediated gene regulation, which can be rescued by a heterologous nuclear localization sequence (NLS). In addition, the CS1-domain can mediate the import of a CS1-GFP fusion protein. Importantly, the CS1-mediated nuclear import depends on the Ran guanine nucleotide exchange factor Prp20p. Interestingly, a single amino acid change in CS1 (K625I) also causes the protein to be exported out of the nucleus via the Crm1p-dependent pathway. The temperature-sensitive growth phenotype of this particular mutant can be overcome by overexpression of Kap121p/Pse1p, a well-established nuclear transport receptor. Biochemical studies indicate that Pse1p binds to a region of Abf1p upstream of CS1 in a RanGTP-sensitive manner, suggesting that Abf1p has a second distinct NLS and can be imported into the nucleus by several overlapping pathways. We propose that the link between Abf1p and the nuclear transport machinery may also be important for partitioning multiple Abf1p-mediated nuclear processes.
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Affiliation(s)
- Christian M Loch
- Department of Biochemistry and Molecular Genetics, School of Medicine, PO Box 800733, University of Virginia, Charlottesville, VA 22908-0733, USA
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24
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Miyake T, Reese J, Loch CM, Auble DT, Li R. Genome-wide Analysis of ARS (Autonomously Replicating Sequence) Binding Factor 1 (Abf1p)-mediated Transcriptional Regulation in Saccharomyces cerevisiae. J Biol Chem 2004; 279:34865-72. [PMID: 15192094 DOI: 10.1074/jbc.m405156200] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Autonomously replicating sequence-binding factor-1 (Abf1p) is an essential sequence-specific transcription factor in Saccharomyces cerevisiae that participates in multiple nuclear events including DNA replication, transcription activation, and gene silencing. Numerous gene-specific analyses have implicated Abf1p in the transcriptional control of genes involved in a diverse range of cellular functions, leading to the notion that Abf1p acts as a global transcriptional regulator. Here we report findings from a genome-wide comparison of the gene expression profiles in the wild-type and abf1-1 temperature-sensitive mutant. The study identifies a total of 86 Abf1p-regulated genes (1.4% of the genome) of which 50 are activated and 36 are repressed by Abf1p. Interestingly, Abf1p binds to its own promoter in vivo and strongly represses its own transcription, suggesting a potential negative regulatory loop in Abf1p-mediated gene regulation. A comparison of our microarray data with the available databases reveals a significant overlap of genes regulated by Abf1p and those by several general transcription factors such as Mot1p and TAFs (TATA-binding protein-associated factors). Different mutant alleles of abf1 affect Abf1p-mediated transcription in a gene-dependent manner. Furthermore, Abf1p in vivo is associated with the promoter region of most Abf1p-activated but not with that of most Abf1p-repressed genes. Taken together, these results strongly suggest distinct underlying mechanisms by which Abf1p regulates gene expression.
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Affiliation(s)
- Tsuyoshi Miyake
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Virginia, Charlottesville, VA 22908-0733, USA
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25
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Adkins NL, Watts M, Georgel PT. To the 30-nm chromatin fiber and beyond. ACTA ACUST UNITED AC 2004; 1677:12-23. [PMID: 15020041 DOI: 10.1016/j.bbaexp.2003.09.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2003] [Revised: 09/25/2003] [Accepted: 09/25/2003] [Indexed: 10/26/2022]
Abstract
Chromatin fibers are intrinsically dynamic macromolecular complexes whose biological functions are intimately linked with their structure and interactions with chromatin-associated proteins (CAPs). Three-dimensional architectural transitions between or within the two co-existing chromatin types referred to as euchromatin and heterochromatin have been associated with activation or repression of nuclear functions. The presence of specific subsets of chromosomal proteins co-existing with the different chromatin conformations suggests a functional significance for their co-localization. The major points of emphasis of this review will assess the structure, function and recently documented exchanges amongst various members of the CAP family.
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Affiliation(s)
- Nicholas L Adkins
- Department of Biological Sciences, College of Science, Marshall University, 1 John Marshall Drive, Huntington, WV 25701, USA
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26
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Deng Z, Atanasiu C, Burg JS, Broccoli D, Lieberman PM. Telomere repeat binding factors TRF1, TRF2, and hRAP1 modulate replication of Epstein-Barr virus OriP. J Virol 2003; 77:11992-2001. [PMID: 14581536 PMCID: PMC254251 DOI: 10.1128/jvi.77.22.11992-12001.2003] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Epstein-Barr virus OriP confers cell cycle-dependent DNA replication and stable maintenance on plasmids in EBNA1-positive cells. The dyad symmetry region of OriP contains four EBNA1 binding sites that are punctuated by 9-bp repeats referred to as nonamers. Previous work has shown that the nonamers bind to cellular factors associated with human telomeres and contribute to episomal maintenance of OriP. In this work, we show that substitution mutation of all three nonamer sites reduces both DNA replication and plasmid maintenance of OriP-containing plasmids by 2.5- to 5-fold. The nonamers were required for high-affinity binding of TRF1, TRF2, and hRap1 to the dyad symmetry element but were not essential for the binding of EBNA1 as determined by DNA affinity purification from nuclear extracts. Chromatin immunoprecipitation assays indicated that TRF1, TRF2, and hRap1 bound OriP in vivo. Cell cycle studies indicate that TRF2 binding to OriP peaks in G(1)/S while TRF1 binding peaks in G(2)/M. OriP replication was inhibited by transfection of full-length TRF1 but not by deletion mutants lacking the myb DNA binding domain. In contrast, OriP replication was not affected by transfection of full-length TRF2 or hRap1 but was potently inhibited by dominant-negative TRF2 or hRap1 amino-terminal truncation mutants. Knockdown experiments with short interfering RNAs (siRNAs) directed against TRF2 and hRap1 severely reduced OriP replication, while TRF1 siRNA had a modest stimulatory effect on OriP replication. These results indicate that TRF2 and hRap1 promote, while TRF1 antagonizes, OriP-dependent DNA replication and suggest that these telomeric factors contribute to the establishment of replication competence at OriP.
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Affiliation(s)
- Zhong Deng
- The Wistar Institute, Philadelphia, Pennsylvania 19104, USA
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27
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Fricke WM, Brill SJ. Slx1-Slx4 is a second structure-specific endonuclease functionally redundant with Sgs1-Top3. Genes Dev 2003; 17:1768-78. [PMID: 12832395 PMCID: PMC196184 DOI: 10.1101/gad.1105203] [Citation(s) in RCA: 174] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The RecQ DNA helicases human BLM and yeast Sgs1 interact with DNA topoisomerase III and are thought to act on stalled replication forks to maintain genome stability. To gain insight into this mechanism, we previously identified SLX1 and SLX4 as genes that are required for viability and for completion of rDNA replication in the absence of SGS1-TOP3. Here we show that SLX1 and SLX4 encode a heteromeric structure-specific endonuclease. The Slx1-Slx4 nuclease is active on branched DNA substrates, particularly simple-Y, 5'-flap, or replication fork structures. It cleaves the strand bearing the 5' nonhomologous arm at the branch junction and generates ligatable nicked products from 5'-flap or replication fork substrates. Slx1 is the founding member of a family of proteins with a predicted URI nuclease domain and PHD-type zinc finger. This subunit displays weak structure-specific endonuclease activity on its own, is stimulated 500-fold by Slx4, and requires the PHD finger for activity in vitro and in vivo. Both subunits are required in vivo for resistance to DNA damage by methylmethane sulfonate (MMS). We propose that Sgs1-Top3 acts at the termination of rDNA replication to decatenate stalled forks, and, in its absence, Slx1-Slx4 cleaves these stalled forks.
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Affiliation(s)
- William M Fricke
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854, USA
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28
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Yan P, Mao X, Wang L, Zha X, Lu C. HBV C promoter Sp1 binding sequence functionally substitutes for the yeast ARS1 ABF1 binding site. DNA Cell Biol 2002; 21:737-42. [PMID: 12443543 DOI: 10.1089/104454902760599717] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Transcriptional factors have been implicated in eukaryotic DNA replication. We have studied the potential function of a viral promoter sequence in DNA replication. The hepatitis B virus (HBV) pregenomic promoter is regulated by two enhancers and cis-elements. The G-C rich region between 1734-1754 nt, which contains two SP1 binding sites, is necessary for transcription origin and HBV replication. We found that the Abf1-binding B3 element in yeast ARS1 can be functionally replaced by the viral Sp1-binding DNA sequence, which activates transcription from the HBV C promoter. Further, yeast RAP1 bound to the viral Sp1 binding sites in vitro. These results suggest that RAP1 binds to the Sp1 binding sites and stimulates yeast DNA replication.
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Affiliation(s)
- Peijun Yan
- Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai 200032, China
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29
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Miyake T, Loch CM, Li R. Identification of a multifunctional domain in autonomously replicating sequence-binding factor 1 required for transcriptional activation, DNA replication, and gene silencing. Mol Cell Biol 2002; 22:505-16. [PMID: 11756546 PMCID: PMC139751 DOI: 10.1128/mcb.22.2.505-516.2002] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Autonomously replicating sequence-binding factor 1 (ABF1) is a multifunctional, site-specific DNA binding protein that is essential for cell viability in Saccharomyces cerevisiae. ABF1 plays a direct role in transcriptional activation, stimulation of DNA replication, and gene silencing at the mating-type loci. Here we demonstrate that all three activities of ABF1 are conferred by the C terminus of the protein (amino acids [aa] 604 to 731). Furthermore, a detailed mutational analysis has revealed two important clusters of amino acid residues in the C terminus (C-terminal sequence 1 [CS1], aa 624 to 628; and CS2, aa 639 to 662). While both regions play a pivotal role in supporting cell viability, they make distinct contributions to ABF1 functions in various nuclear processes. CS1 specifically participates in transcriptional silencing and/or repression in a context-dependent manner, whereas CS2 is universally required for all three functions of ABF1. When tethered to specific regions of the genome, a 30-aa fragment that contains CS2 alone is sufficient for activation of transcription and chromosomal replication. In addition, CS2 is responsible for ABF1-mediated chromatin remodeling. Based on these results, we suggest that ABF1 may function as a chromatin-reorganizing factor to increase accessibility of the local chromatin structure, which in turn facilitates the action of additional factors to establish either an active or repressed chromatin state.
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Affiliation(s)
- Tsuyoshi Miyake
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Virginia, Charlottesville, Virginia 22908-0733, USA
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30
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Reed SH, Akiyama M, Stillman B, Friedberg EC. Yeast autonomously replicating sequence binding factor is involved in nucleotide excision repair. Genes Dev 1999; 13:3052-8. [PMID: 10601031 PMCID: PMC317179 DOI: 10.1101/gad.13.23.3052] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/1999] [Accepted: 10/14/1999] [Indexed: 11/25/2022]
Abstract
Nucleotide excision repair (NER) in yeast is effected by the concerted action of a large complex of proteins. Recently, we identified a stable subcomplex containing the yeast Rad7 and Rad16 proteins. Here, we report the identification of autonomously replicating sequence binding factor 1 (ABF1) as a component of the Rad7/Rad16 NER subcomplex. Yeast ABF1 protein is encoded by an essential gene required for DNA replication, transcriptional regulation, and gene silencing. We show that ABF1 plays a direct role in NER in vitro. Additionally, consistent with a role of ABF1 protein in NER in vivo, we show that certain temperature-sensitive abf1 mutant strains that are defective in DNA replication are specifically defective in the removal of photoproducts by NER and are sensitive to killing by ultraviolet (UV) radiation. These studies define a novel and unexpected role for ABF1 protein during NER in yeast.
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Affiliation(s)
- S H Reed
- Laboratory of Molecular Pathology, Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas 75235, USA
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31
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Park HD, Scott S, Rai R, Dorrington R, Cooper TG. Synergistic operation of the CAR2 (Ornithine transaminase) promoter elements in Saccharomyces cerevisiae. J Bacteriol 1999; 181:7052-64. [PMID: 10559172 PMCID: PMC94181 DOI: 10.1128/jb.181.22.7052-7064.1999] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dal82p binds to the UIS(ALL) sites of allophanate-induced genes of the allantoin-degradative pathway and functions synergistically with the GATA family Gln3p and Gat1p transcriptional activators that are responsible for nitrogen catabolite repression-sensitive gene expression. CAR2, which encodes the arginine-degradative enzyme ornithine transaminase, is not nitrogen catabolite repression sensitive, but its expression can be modestly induced by the allantoin pathway inducer. The dominant activators of CAR2 transcription have been thought to be the ArgR and Mcm1 factors, which mediate arginine-dependent induction. These observations prompted us to investigate the structure of the CAR2 promoter with the objectives of determining whether other transcription factors were required for CAR2 expression and, if so, of ascertaining their relative contributions to CAR2's expression and control. We show that Rap1p binds upstream of CAR2 and plays a central role in its induced expression irrespective of whether the inducer is arginine or the allantoin pathway inducer analogue oxalurate (OXLU). Our data also explain the early report that ornithine transaminase production is induced when cells are grown with urea. OXLU induction derives from the Dal82p binding site, which is immediately downstream of the Rap1p site, and Dal82p functions synergistically with Rap1p. This synergism is unlike all other known instances of Dal82p synergism, namely, that with the GATA family transcription activators Gln3p and Gat1p, which occurs only in the presence of an inducer. The observations reported suggest that CAR2 gene expression results from strong constitutive transcriptional activation mediated by Rap1p and Dal82p being balanced by the down regulation of an equally strong transcriptional repressor, Ume6p. This balance is then tipped in the direction of expression by the presence of the inducer. The formal structure of the CAR2 promoter and its operation closely follow the model proposed for CAR1.
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Affiliation(s)
- H D Park
- Department of Food Science and Technology, Kyungpook National University, Taegu 702-701, Korea
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32
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Brill SJ, Bastin-Shanower S. Identification and characterization of the fourth single-stranded-DNA binding domain of replication protein A. Mol Cell Biol 1998; 18:7225-34. [PMID: 9819409 PMCID: PMC109304 DOI: 10.1128/mcb.18.12.7225] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Replication protein A (RPA), the heterotrimeric single-stranded-DNA (ssDNA) binding protein (SSB) of eukaryotes, contains two homologous ssDNA binding domains (A and B) in its largest subunit, RPA1, and a third domain in its second-largest subunit, RPA2. Here we report that Saccharomyces cerevisiae RPA1 contains a previously undetected ssDNA binding domain (domain C) lying in tandem with domains A and B. The carboxy-terminal portion of domain C shows sequence similarity to domains A and B and to the region of RPA2 that binds ssDNA (domain D). The aromatic residues in domains A and B that are known to stack with the ssDNA bases are conserved in domain C, and as in domain A, one of these is required for viability in yeast. Interestingly, the amino-terminal portion of domain C contains a putative Cys4-type zinc-binding motif similar to that of another prokaryotic SSB, T4 gp32. We demonstrate that the ssDNA binding activity of domain C is uniquely sensitive to cysteine modification but that, as with gp32, ssDNA binding is not strictly dependent on zinc. The RPA heterotrimer is thus composed of at least four ssDNA binding domains and exhibits features of both bacterial and phage SSBs.
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Affiliation(s)
- S J Brill
- Department of Molecular Biology, Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, New Jersey 08855, USA.
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33
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Abstract
Accurate replication and segregation of chromosomal DNA is essential for high-fidelity transmission of genetic information from generation to generation. Eukaryotic cells typically replicate by first duplicating their chromosomes during the S phase followed by their segregation between two daughter cells during the M phase. Over recent years, advances in our understanding of this process at the molecular level have been incredibly rapid. The present review will focus on molecular control of DNA replication and the mechanisms which operate to ensure that once replicated, chromosomes are not rereplicated in the same cell cycle.
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Affiliation(s)
- S Dalton
- Department of Biochemistry, University of Adelaide, South Australia, Australia
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34
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Pierce M, Wagner M, Xie J, Gailus-Durner V, Six J, Vershon AK, Winter E. Transcriptional regulation of the SMK1 mitogen-activated protein kinase gene during meiotic development in Saccharomyces cerevisiae. Mol Cell Biol 1998; 18:5970-80. [PMID: 9742114 PMCID: PMC109183 DOI: 10.1128/mcb.18.10.5970] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Meiotic development (sporulation) in Saccharomyces cerevisiae is characterized by an ordered pattern of gene expression, with sporulation-specific genes classified as early, middle, mid-late, or late depending on when they are expressed. SMK1 encodes a mitogen-activated protein kinase required for spore morphogenesis that is expressed as a middle sporulation-specific gene. Here, we identify the cis-acting DNA elements that regulate SMK1 transcription and characterize the phenotypes of mutants with altered expression patterns. The SMK1 promoter contains an upstream activating sequence (UASS) that specifically interacts with the transcriptional activator Abf1p. The Abf1p-binding sites from the early HOP1 and the middle SMK1 promoters are functionally interchangeable, demonstrating that these elements do not play a direct role in their differential transcriptional timing. Timing of SMK1 expression is determined by another cis-acting DNA sequence termed MSE (for middle sporulation element). The MSE is required not only for activation of SMK1 transcription during middle sporulation but also for its repression during vegetative growth and early meiosis. In addition, the SMK1 MSE can repress vegetative expression in the context of the HOP1 promoter and convert HOP1 from an early to a middle gene. SMK1 function is not contingent on its tight transcriptional regulation as a middle sporulation-specific gene. However, promoter mutants with different quantitative defects in SMK1 transcript levels during middle sporulation show distinct sporulation phenotypes.
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Affiliation(s)
- M Pierce
- Department of Biochemistry and Molecular Pharmacology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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35
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Schroeder SC, Weil PA. Genetic tests of the role of Abf1p in driving transcription of the yeast TATA box bindng protein-encoding gene, SPT15. J Biol Chem 1998; 273:19884-91. [PMID: 9677425 DOI: 10.1074/jbc.273.31.19884] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In this report we describe studies which utilized yeast strains bearing gain and loss of function alleles of ABF1 in order to attempt to directly implicate Abf1p in modulating transcription of the TBP-encoding gene, SPT15, in vivo. We found that overexpression of Abf1p in a yeast cell increased transcription of the TBP-encoding gene and that this stimulation depended upon the exact sequence of the Abf1p binding site (ABF1) present in the gene. Further, in a yeast strain expressing a temperature sensitive form of Abf1p, occupancy of the chromosomal ABF1 site in the TBP-encoding gene was immediately lost following a temperature shift. Both results suggest that Abf1p drives transcription of the TBP-encoding gene. Surprisingly though we found that continuous ABF1 cis-element occupancy by Abf1p was not acutely required for normal levels of transcription of either the TBP-encoding gene or other "Abf1p-driven" genes tested. We propose a model to explain these results and suggest mechanisms by which Abf1p could activate gene transcription.
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Affiliation(s)
- S C Schroeder
- Department of Molecular Physiology and Biophysics, Vanderbilt University, School of Medicine, Nashville, Tennessee 37232-0615, USA
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36
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Piatti S. Cell cycle regulation of S phase entry in Saccharomyces cerevisiae. PROGRESS IN CELL CYCLE RESEARCH 1998; 3:143-56. [PMID: 9552413 DOI: 10.1007/978-1-4615-5371-7_12] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Eukaryotic DNA replication is restricted to a narrow window of the cell cycle called S phase, and occurs once and only once during each cell cycle. The combination of genetic and biochemical approaches in the budding yeast Saccharomyces cerevisiae has proven extremely helpful for studying the cell cycle regulation of S phase entry. This review will try to summarise the most recent discoveries which led to a new model to explain how entry into S phase is regulated in eukaryotic cells.
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Affiliation(s)
- S Piatti
- Dipartimento di Genetica e Biologia dei Microrganismi, Università degli Studi di Milano, Italy
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37
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Wiltshire S, Raychaudhuri S, Eisenberg S. An Abf1p C-terminal region lacking transcriptional activation potential stimulates a yeast origin of replication. Nucleic Acids Res 1997; 25:4250-6. [PMID: 9336454 PMCID: PMC147049 DOI: 10.1093/nar/25.21.4250] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Although it has been demonstrated that eukaryotic cellular origins of DNA replication may harbor stimulatory elements that bind transcription factors, how these factors stimulate origin function is unknown. In Saccharomyces cerevisiae , the transcription factor Abf1p stimulates origin function of ARS121 and ARS1 . In the results presented here, an analysis of Abf1p function has been carried out utilizing LexA(BD)-Abf1p fusion proteins and an ARS 121 derivative harboring LexA DNA-binding sites. A minimal region which stimulates origin function mapped to 50 amino acids within the C-terminus of Abf1p. When tested for transcriptional activation of a LacZ reporter gene, the same LexA(BD)-Abf1p fusion protein had negligible transcriptional activation potential. Therefore, stimulation of ARS 121 may occur independently of a transcriptional activation domain. It has been previously observed that the Gal4p, Rap1p DNA-binding sites and the LexA-Gal4p fusion protein can replace the role of Abf1p in stimulating ARS 1 . Here we show that the stimulatory function of Abf1p at ARS 121 cannot be replaced by these alternative DNA-binding sites and the potent chimeric transcriptional activator LexA(BD)-Gal4(AD)p . Hence, these results strongly suggest that the Abf1p stimulation of replication may differ for ARS 121 and ARS 1 , and imply specificity in the Abf1p/ARS 121 relationship.
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Affiliation(s)
- S Wiltshire
- Department of Microbiology, School of Medicine, The University of Connecticut Health Center, Farmington, CT 06030, USA
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38
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Rolfes RJ, Zhang F, Hinnebusch AG. The transcriptional activators BAS1, BAS2, and ABF1 bind positive regulatory sites as the critical elements for adenine regulation of ADE5,7. J Biol Chem 1997; 272:13343-54. [PMID: 9148957 DOI: 10.1074/jbc.272.20.13343] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Adenine repression of the purine nucleotide biosynthetic genes in Saccharomyces cerevisiae involves down-regulation of the activator protein BAS1 or BAS2 by an unknown mechanism. To determine the minimal cis-acting requirements for adenine regulation, hybrid promoter constructs were made between ADE5,7 promoter fragments and a CYC1-lacZ reporter. A 139-nucleotide fragment containing two BAS1 binding sites was sufficient to confer adenine regulation on the CYC1-lacZ reporter. Analysis of deletion and substitution mutations led to the conclusion that the proximal BAS1 binding site is both necessary and sufficient for regulation, whereas the distal site augments the function of the proximal site. By performing saturation mutagenesis, we found two essential regions that flank the proximal site. An ABF1 consensus sequence is within one of these regions, and mutations that impaired in vitro ABF1 binding impaired promoter activity in vivo. A second region is AT-rich and appears to bind BAS2. No substitution mutations led to high level constitutive promoter activity as would be expected from removal of an upstream repression sequence. Our results indicate that ABF1, BAS1, and BAS2 are required for ADE5,7 promoter function and that adenine repression most likely involves activator modification or a negative regulator that does not itself bind DNA.
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Affiliation(s)
- R J Rolfes
- Department of Biology, Georgetown University, Washington, D. C. 20057, USA.
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39
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Budd ME, Campbell JL. A yeast replicative helicase, Dna2 helicase, interacts with yeast FEN-1 nuclease in carrying out its essential function. Mol Cell Biol 1997; 17:2136-42. [PMID: 9121462 PMCID: PMC232061 DOI: 10.1128/mcb.17.4.2136] [Citation(s) in RCA: 185] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
We have recently described a new helicase, the Dna2 helicase, that is essential for yeast DNA replication. We now show that the yeast FEN-1 (yFEN-1) nuclease interacts genetically and biochemically with Dna2 helicase. FEN-1 is implicated in DNA replication and repair in yeast, and the mammalian homolog of yFEN-1 (DNase IV, FEN-1, or MF1) participates in Okazaki fragment maturation. Overproduction of yFEN-1, encoded by RAD27/RTH1, suppresses the temperature-sensitive growth of dna2-1 mutants. Overproduction of Dna2 suppresses the rad27/rth1 delta temperature-sensitive growth defect. dna2-1 rad27/rth1 delta double mutants are inviable, indicating that the mutations are synthetically lethal. The genetic interactions are likely due to direct physical interaction between the two proteins, since both epitope-tagged yFEN-1 and endogenous yFEN-1 coimmunopurify with tagged Dna2. The simplest interpretation of these data is that one of the roles of Dna2 helicase is associated with processing of Okazaki fragments.
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Affiliation(s)
- M E Budd
- Braun Laboratories, California Institute of Technology, Pasadena 91125, USA
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40
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Gailus-Durner V, Xie J, Chintamaneni C, Vershon AK. Participation of the yeast activator Abf1 in meiosis-specific expression of the HOP1 gene. Mol Cell Biol 1996; 16:2777-86. [PMID: 8649386 PMCID: PMC231269 DOI: 10.1128/mcb.16.6.2777] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The meiosis-specific gene HOP1, which encodes a component of the synaptonemal complex, is controlled through two regulatory elements, UASH and URS1H. Sites similar to URS1H have been identified in the promoter region of virtually every early meiosis-specific gene, as well as in many promoters of nonmeiotic genes, and it has been shown that the proteins that bind to this site function to regulate meiotic and nonmeiotic transcription. Sites similar to the UASH site have been found in a number of meiotic and nonmeiotic genes as well. Since it has been shown that UASH functions as an activator site in vegetative haploid cells, it seemed likely that the factors binding to this site regulate both meiotic and nonmeiotic transcription. We purified the factor binding to the UASH element of the HOP1 promoter. Sequence analysis identified the protein as Abf1 (autonomously replicating sequence-binding factor 1), a multifunctional protein involved in DNA replication, silencing, and transcriptional regulation. We show by mutational analysis of the UASH site, that positions outside of the proposed UASH consensus sequence (TNTGN[A/T]GT) are required for DNA binding in vitro and transcriptional activation in vivo. A new UASH consensus sequence derived from this mutational analysis closely matches a consensus Abf1 binding site. We also show that an Abf1 site from a nonmeiotic gene can replace the function of the UASH site in the HOP1 promoter. Taken together, these results show that Abf1 functions to regulate meiotic gene expression.
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Affiliation(s)
- V Gailus-Durner
- Waksman Institute, Rutgers University, Piscataway, New Jersey 08855-0759, USA
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41
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Packham EA, Graham IR, Chambers A. The multifunctional transcription factors Abf1p, Rap1p and Reb1p are required for full transcriptional activation of the chromosomal PGK gene in Saccharomyces cerevisiae. MOLECULAR & GENERAL GENETICS : MGG 1996; 250:348-56. [PMID: 8602150 DOI: 10.1007/bf02174393] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We have identified two new transcription factor binding sites upstream of the previously defined UAS within the phosphoglycerate kinase (PGK) gene promoter in Saccharomyces cerevisiae. These sites are bound in vitro by the multifunctional factors Cpf1p and Reb1p. We have generated targeted deletions of Rap1p, Abf1p and Reb1p binding sites in the promoter of the chromosomal copy of the PGK gene. Northern blot analysis confirmed that most PGK promoter activity is mediated through the Rap1p binding site. However, significant effects are also mediated through both the Reb1p and Abf1p sites. In contrast, when the promoter is present on a high-copy-number plasmid, both the Abf1p and Reb1p sites play no role in transcriptional activation. The role of Cpf1p was examined using a cpf1 null strain. Cpf1p was found to have little if any, effect on activation of either the chromosomal or plasmid-borne PGK gene.
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Affiliation(s)
- E A Packham
- Department of Genetics, University of Nottingham, Queen's Medical Centre, Nottingham, UK
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42
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Kang JJ, Yokoi TJ, Holland MJ. Binding sites for abundant nuclear factors modulate RNA polymerase I-dependent enhancer function in Saccharomyces cerevisiae. J Biol Chem 1995; 270:28723-32. [PMID: 7499394 DOI: 10.1074/jbc.270.48.28723] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The 190-base pair (bp) rDNA enhancer within the intergenic spacer sequences of Saccharomyces cerevisiae rRNA cistrons activates synthesis of the 35S-rRNA precursor about 20-fold in vivo (Mestel,, R., Yip, M., Holland, J. P., Wang, E., Kang, J., and Holland, M. J. (1989) Mol. Cell. Biol. 9, 1243-1254). We now report identification and analysis of transcriptional activities mediated by three cis-acting sites within a 90-bp portion of the rDNA enhancer designated the modulator region. In vivo, these sequences mediated termination of transcription by RNA polymerase I and potentiated the activity of the rDNA enhancer element. Two trans-acting factors, REB1 and REB2, bind independently to sites within the modulator region (Morrow, B. E., Johnson, S. P., and Warner, J. R. (1989) J. Biol. Chem. 264, 9061-9068). We show that REB2 is identical to the ABF1 protien. Site-directed mutagenesis of REB1 and ABF1 binding sites demonstrated uncoupling of RNA polymerase I-dependent termination from transcriptional activation in vivo. We conclude that REB1 and ABF1 are required for RNA polymerase I-dependent termination and enhancer function, respectively, Since REB1 and ABF1 proteins also regulate expression of class II genes and other nuclear functions, our results suggest further similarities between RNA polymerase I and II regulatory mechanisms. Two rDNA enhancers flanking a rDNA minigene stimulated RNA polymerase I transcription in a "multiplicative" fashion. Deletion mapping analysis showed that similar cis-acting sequences were required for enhancer function when positioned upstream or downstream from a rDNA minigene.
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Affiliation(s)
- J J Kang
- Department of Biological Chemistry, School of Medicine, University of California, Davis 95616-8635, USA
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43
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Chambers A, Packham EA, Graham IR. Control of glycolytic gene expression in the budding yeast (Saccharomyces cerevisiae). Curr Genet 1995; 29:1-9. [PMID: 8595651 DOI: 10.1007/bf00313187] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- A Chambers
- Department of Genetics, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
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44
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Svetlov VV, Cooper TG. Review: compilation and characteristics of dedicated transcription factors in Saccharomyces cerevisiae. Yeast 1995; 11:1439-84. [PMID: 8750235 DOI: 10.1002/yea.320111502] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Affiliation(s)
- V V Svetlov
- Department of Microbiology and Immunology, University of Tennessee, Memphis 36163, USA
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45
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Ozsarac N, Bhattacharyya M, Dawes IW, Clancy MJ. The SPR3 gene encodes a sporulation-specific homologue of the yeast CDC3/10/11/12 family of bud neck microfilaments and is regulated by ABFI. Gene 1995; 164:157-62. [PMID: 7590307 DOI: 10.1016/0378-1119(95)00438-c] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The SPR3 gene is selectively activated only during the sporulation phase of the Saccharomyces cerevisiae (Sc) life cycle. The predicted amino acid (aa) sequence has homology to microfilament proteins that are involved in cytokinesis and other proteins of unknown function. These include the products of Sc cell division cycle (CDC) genes involved in bud formation (Cdc3p, Cdc10p, Cdc11p and Cdc12p), Candida albicans proteins that accumulate in the hyphal phase (CaCdc3p and CaCdc10p), mouse brain-specific (H5p) and lymphocyte (Diff6p) proteins, Drosophila melanogaster (Dm) protein Pnutp (which is localized to the cleavage furrow of dividing cells), a Diff6p homologue (DmDiff6p), and the Sc septin protein (Sep1hp), a homologue of the 10-nm filament proteins of Sc. One strongly conserved region contains a potential ATP-GTP-binding domain. Primer extension analysis revealed six major transcription start points (tsp) beginning at -142 relative to the ATG start codon. The sequence immediately upstream from the tsp contains consensus binding sites for the HAP2/3/4 and ABFI transcription factors, a T-rich sequence and two putative novel elements for mid to late sporulation, termed SPR3 and PAL. Electrophoretic mobility shift assay (EMSA) and footprint analyses demonstrated that the ABFI protein binds to a region containing the putative ABFI site in vitro, and site-directed mutagenesis showed that the ABFI motif is essential for expression of SPR3 at the appropriate stage in sporulating cells.
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Affiliation(s)
- N Ozsarac
- School of Biochemistry and Molecular Genetics, University of New South Wales, Sydney, Australia
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46
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Cho G, Kim J, Rho HM, Jung G. Structure-function analysis of the DNA binding domain of Saccharomyces cerevisiae ABF1. Nucleic Acids Res 1995; 23:2980-7. [PMID: 7659521 PMCID: PMC307139 DOI: 10.1093/nar/23.15.2980] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
To localize the DNA binding domain of the Saccharomyces cerevisiae Ars binding factor 1 (ABF1), a multifunctional DNA binding protein, plasmid constructs carrying point mutations and internal deletions in the ABF1 gene were generated and expressed in Escherichia coli. Normal and mutant ABF1 proteins were purified by affinity chromatography and their DNA binding activities were analyzed. The substitution of His61, Cys66 and His67 respectively, located in the zinc finger motif in the N-terminal region (amino acids 40-91), eliminated the DNA binding activity of ABF1 protein. Point mutations in the middle region of ABF1, specifically at Leu353, Leu399, Tyr403, Gly404, Phe410 and Lys434, also eliminated or reduced DNA binding activity. However, the DNA binding activity of point mutants of Ser307, Ser496 and Glu649 was the same as that of wild-type ABF1 protein and deletion mutants of amino acids 200-265, between the zinc finger region and the middle region (residues 323-496) retained DNA binding activity. As a result, we confirmed that the DNA binding domain of ABF1 appears to be bipartite and another DNA binding motif, other than the zinc finger motif, is situated between amino acid residues 323 and 496.
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Affiliation(s)
- G Cho
- Department of Biology Education, Seoul National University, Korea
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47
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Ruiz MT, Pearson CE, Nielsen T, Price GB, Zannis-Hadjopoulos M. Cofractionation of HeLa cell replication proteins with ors-binding activity. J Cell Biochem 1995; 58:221-36. [PMID: 7673329 DOI: 10.1002/jcb.240580211] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Ors (origin enriched sequence) 8 is a mammalian autonomously replicating DNA sequence previously isolated by extrusion of nascent monkey (CV-1) DNA in early S phase. A 186 bp fragment of ors 8 has been identified as the minimal sequence required for origin function, since upon its deletion the in vivo and in vitro replication activity of this ors is abolished. We have fractionated total HeLa cell extracts on a DEAE-Sephadex and then on a Affi-Gel Heparin column and identified a protein fraction that interacts with the 186 bp fragment of ors 8 in a specific manner. The same fraction is able to support the in vitro replication of ors 8 plasmid. The ors binding activity (OBA) present in this fraction sediments at approximately 150 kDa in a glycerol gradient. Band-shift elution experiments of the specific protein-DNA complex detect by silver-staining predominantly two protein bands with molecular weights of 146 kDa and 154 kDa, respectively. The fraction containing the OBA is also enriched for polymerases alpha and delta, topoisomerase II, and replication protein A, (RP-A).
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Affiliation(s)
- M T Ruiz
- McGill Cancer Centre, Department of Medicine, McGill University, Montréal, Québec, Canada
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48
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Gonçalves PM, Griffioen G, Minnee R, Bosma M, Kraakman LS, Mager WH, Planta RJ. Transcription activation of yeast ribosomal protein genes requires additional elements apart from binding sites for Abf1p or Rap1p. Nucleic Acids Res 1995; 23:1475-80. [PMID: 7784199 PMCID: PMC306885 DOI: 10.1093/nar/23.9.1475] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
All ribosomal protein (rp) gene promoters from Saccharomyces cerevisiae studied so far contain either (usually two) binding sites for the global gene regulator Rap1p or one binding site for another global factor, Abf1p. Previous analysis of the rpS33 and rpL45 gene promoters suggested that apart from the Abf1 binding site, additional cis-acting elements play a part in transcription activation of these genes. We designed a promoter reconstruction system based on the beta-glucuronidase reporter gene to examine the role of the Abf1 binding site and other putative cis-acting elements in promoting transcription. An isolated Abf1 binding site turned out to be a weak activating element. A T-rich sequence derived from the rpS33 proximal promoter was found to be stronger, but full transcription activation was only achieved by a combination of these elements. Both in the natural rpL45 promoter and in the reconstituted promoter, a Rap1 binding site could functionally replace the Abf1 binding site. Characteristic rp gene nutritional control of transcription, evoked by a carbon source upshift or by nitrogen re-feeding to nitrogen starved cells, could only be mediated by the combined Abf1 (or Rap1) binding site and T-rich element and not by the individual elements. These results demonstrate that Abf1p and Rap1p do not activate rp genes in a prototypical fashion, but rather may serve to potentiate transcription activation through the T-rich element.
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Affiliation(s)
- P M Gonçalves
- Department of Biochemistry and Molecular Biology, IMBW, BioCentrum Amsterdam, Vrije Universiteit, The Netherlands
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49
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Buck SW, Shore D. Action of a RAP1 carboxy-terminal silencing domain reveals an underlying competition between HMR and telomeres in yeast. Genes Dev 1995; 9:370-84. [PMID: 7867933 DOI: 10.1101/gad.9.3.370] [Citation(s) in RCA: 162] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
RAP1 is a sequence-specific DNA-binding protein in yeast that can either repress or activate transcription. Previous studies have demonstrated a direct role for RAP1 in silencing at HM mating-type loci and telomeres. Here, we show that a small carboxy-terminal domain of RAP1 is sufficient to establish repression when fused to the GAL4 DNA-binding domain (GBD) and targeted to mutated HMR silencers containing GAL4 DNA-binding sites. Silencing by GBD/RAP1 hybrids, like normal silencing at HMR, requires the trans-acting factors SIR2, SIR3, and SIR4. However, GBD/RAP1-mediated silencing is independent of SIR1, whose product is normally required for the establishment of repression at HMR. Targeted silencing also displays an unusual response to silencing-defective rap1s mutations. The incorporation of a rap1s missense mutation into GBD/RAP1 hybrids can improve targeted silencing, yet wild-type GBD/RAP1 hybrids fail to establish repression in strains in which the endogenous RAP1 locus carries a rap1s mutation. In addition, we find that telomeric silencing is increased in rap1s strains. We propose that the rap1s mutation creates an HMR-specific silencing defect by shifting a balance between silencing at HMR and telomeres in favor of telomeric silencing. This balance is regulated by telomere length and by interactions between the RAP1 carboxyl terminus and both RIF1 and SIR4 proteins. In support of this model, we show that abnormally long telomeres antagonize silencing at HMR and a rap1s hybrid protein displays a strengthened interaction with SIR4 in a two-hybrid assay.
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Affiliation(s)
- S W Buck
- Department of Microbiology, College of Physicians and Surgeons of Columbia University, New York, New York 10032
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Bauknecht T, Jundt F, Herr I, Oehler T, Delius H, Shi Y, Angel P, Zur Hausen H. A switch region determines the cell type-specific positive or negative action of YY1 on the activity of the human papillomavirus type 18 promoter. J Virol 1995; 69:1-12. [PMID: 7983700 PMCID: PMC188542 DOI: 10.1128/jvi.69.1.1-12.1995] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
YY1 is a zinc finger transcription factor which acts as either a repressor or an activator dependent on the promoter context. YY1 is a potent activator of the genuine human papillomavirus type 18 (HPV-18) upstream regulatory region (URR) in HeLa cells, which are known for high-level expression of the HPV-18 early genes. The activating activity of YY1 is dependent on the presence of a newly identified switch region located upstream of the YY1 binding site. Deletion of this region causes YY1 to act as a repressor of HPV-18 promoter activity. In vivo footprinting of the HPV-18 URR and an in vitro electrophoretic mobility shift assay identified proteins binding to the switch region. Site-directed mutagenesis of the switch region and YY1 binding sites suggests that these two regions work in concert to yield high-level HPV-18 URR activity in HeLa cells but not in HepG2 cells, where HPV-18 is almost inactive. These data identified a novel mode of cell type-specific regulation of HPV-18 promoter activity by positive or negative action of YY1, determined by the switch region binding factor(s).
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Affiliation(s)
- T Bauknecht
- Forschungsschwerpunkt Angewandte Tumorvirologie, Deutsches Krebsforschungszentrum Heidelberg, Germany
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