Self-Perpetuating Structural States in Biology, Disease, and Genetics (2002) / Chapter Skim
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RNA-directed DNA methylation in Arabidopsis
RNA-directed DNA methylation in Arabidopsis
Pages 123-134
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From page 123... ...
Abbreviations: cisRNA, double-stranclec] RNA; Kan, kanamycin; Hyg, hygromycin; Kanr, Kan resistant; IR, invertecl DNA repeat; MTase, DNA cytosine methyltransferase; NOSpro, nopaline synthase promoter; PTGS, posttranscriptional gene silencing; RclDM, RNA-clirected DNA methylation; RNAi, RNA interference; TGS, transcriptional gene silencing; 35Spro, 35S promoter of cauliflower mosaic virus.
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From page 124... ...
Fortyeight F3 seedlings were homozygous for the ddml-S allele and were further subjected to PCR-genotyping for the presence of target NOSpro-NPTII sequences by using NOSpro-NPTII primers: 5'-GAGAATTAAGGGAGTCACG-3'and 5'-TCGTCCTGCAGTTCATTC-3'. Two of the 48 ddml-S/ddml-S plants were hemizygous for the target locus indicating a recombination event between the ddml-S allele and the NOSpro target locus during meiosis of the parental F2 plant.
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From page 125... ...
In the absence of the silencing locus, the target locus was stably expressed over multiple homozygous generations. The moderate structural complexity probably enhanced its susceptibility to silencing, as has been observed in a NOSpro silencing system in tobacco (38~.
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From page 126... ...
. Consequently, the target NOSpro-NPTII gene is active in the presence of the nontranscribed NOSpro IR, as indicated by the KanR phenotype of seedlings that are doubly homozygous for the target locus and Cre-modified silencing locus (Fig.
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From page 127... ...
and weak resistance of some of these seedlings on medium containing both Kan and Hyg (11% Kan-HygR, n = 912~. Because the ddml mutation is linked to the target locus on chromosome 5, it had to be introgressed into the double homozygous target/silencer line.
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From page 128... ...
A NOSpro dsRNA transcribed from a NOSpro IR at the silencing locus is processed to short RNAs 21-24 nt in length. Either the dsRNA or the short RNAs can locate and interact with the homologous NOSpro at the unlinked 16504 1 www.pnas.org/cgi/doi/10.1073/pnas.162371499 target locus and trigger TGS and promoter methylation.
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From page 129... ...
Overall, the results from the mutant analysis indicate that efficient maintenance of methylation triggered by RdDM requires MET1 and the activity of DDM1, perhaps as part of a chromatin remodeling complex. Despite the continued presence of NOSpro dsRNA, significant losses of target NOSpro methylation were observed after several generations in metl and ddml mutants.
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From page 130... ...
F., van der Winden, J., Matzke, M & Matzke, A
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From page 131... ...
Is a Heritable Amyloid of Ure2p: Genetics and Mechanisms Susan Liebman, University of Illinois Prion-Prion Interactions, Predisposing Factors Eric Kandel and Kausik Si, Columbia University Self-Perpetuating Protein Conformations and Memory Session Il. Protein Conformation Changes, Amyloid and Disease Erich Wanker, Max Delbruck Center for Molecular Medicine Huntington Protein Assembly, Trafficking and Drug Interactions Nancy Bonini, University of Pennsylvania Drosophila Model for Neurodegenerative Disease, Protein-Protein Interactions Ulrich Hartl, Max Planck Institute for Biochemistry Amyloid Disease Proteins and Chaperone Interactions Chris Dobson, University of Cambridge Links Between Protein Folding and Human Disease Jeffrey W
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From page 132... ...
Self-Perpetuating Genetic interactions David Low, University of California, Santa Barbara Epigenetic Pill Switches in Bacteria Steve Henikoff, Fred Hutchinson Cancer Research Center Replication-lndependent Assembly of Chromatin Utilizes Variant H3 Histones Eric Selker, University of Oregon Control of DNA Methylation: Lessons from Fungi Steve Jacobsen, University of California, Los Angeles Genetics of DNA Methylation in Arabidopsis Marjori Matzke, Austrian Academy of Sciences RNA-Based Epigenetic Silencing in Plants
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From page 133... ...
Sackler Colloquia of the National Academy of Sciences address scientific topics of broad and current interest, cutting across the boundaries of traditional disciplines. Each year, five or six such colloquia are scheduled, typically two days in length and international in scope.
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From page 134... ...
i -:K ~rthur M Sack/er C~ I I ~ ~ I I I A OF THE NATIONAL ACADEMY OF SCIENCES National Academy of Sciences 500 Fifth Street, NW Washington, DC 20001
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