Transgene silencing by the host genome defense: implications for the evolution of epigenetic control mechanisms in plants and vertebrates (original) (raw)

References

• Amir, R.E., Van den Veyver, I.B., Wan, M., Tran, C.Q., Franke, U. and Zoghbi, H.Y. et al. 1999. Rett syndrome is caused by mutations in X-linked MECP2, encoding methyl-CpG-binding protein 2. Nature Genet. 23: 185–188.
  PubMed Google Scholar
• Bender, J. 1998. Cytosine methylation of repeated sequences in eukaryotes: the role of DNA pairing. Trends Biochem. 23: 252–256.
  PubMed Google Scholar
• Bender, J. and Fink, G.R. 1995. Epigenetic control of an endogenous gene family is revealed by a novel blue fluorescent mutant of Arabidopsis. Cell 83: 725–734.
  PubMed Google Scholar
• Bennetzen, J.L. 2000. Transposable element contributions to plant gene and genome evolution. Plant Mol. Biol. 42: 251–269.
  PubMed Google Scholar
• Bestor, T.H., Laudano, A., Mattaliano, R. and Ingram, V. 1988. Cloning and sequencing of a cDNA encoding DNA methyltransferase of mouse cells. J. Mol. Biol. 203: 971–983.
  PubMed Google Scholar
• Bestor, T.H. 1990. DNA methylation: evolution of a bacterial immune function into a regulator of gene expression and genome structure in higher eukaryotes. Phil. Trans. R. Soc. Lond. B 326: 179–187.
  Google Scholar
• Bestor, T.H. and Tycko, B. 1996. Creation of genomic methylation patterns. Nature Genet. 12: 363–367.
  PubMed Google Scholar
• Bird, A.P. and Wolffe, A.P. 1999. Methylation-induced repression: belts, braces, and chromatin. Cell 99: 451–454.
  PubMed Google Scholar
• Bollman, J., Carpenter, R. and Coen, E.S. 1991. Allelic interactions at the nivea locus of Antirrhinum. Plant Cell 3: 1327–1336.
  Article PubMed Google Scholar
• Britten, R.J. 1996. DNA sequence insertion and evolutionary variation in gene regulation. Proc. Natl. Acad. Sci. USA 93: 9374–9377.
  PubMed Google Scholar
• Britten, R.J. 1997. Mobile elements inserted in the distant past have taken on important functions. Gene 205: 177–182.
  PubMed Google Scholar
• Bureau, T.E., Ronald, P.C. and Wessler, S.R. 1996. A computerbased systematic survey reveals the predominance of small inverted. repeat elements in wild-type rice genes. Proc. Natl. Acad. Sci. USA 93: 8524–8529.
  PubMed Google Scholar
• Casacuberta, E., Casacuberta, J.M., Puigdomènech, P. and Monfort, A. 1998. Presence of miniature inverted-repeat transposable elements (MITEs) in the genome of Arabidopsis thaliana: characterisation of the Emigrant family of elements. Plant J. 16: 79–85.
  PubMed Google Scholar
• Cogoni, C. and Macino, G. 1997a. Conservation of transgeneinduced post-transcriptional gene silencing in plants and fungi. Trends Plant Sci. 2: 438–443.
  Google Scholar
• Cogoni, C. and Macino, G. 1997b. Isolation of quelling-defective (qde) mutants impaired in posttranscriptional transgene-induced gene silencing in Neurospora crassa. Proc. Natl. Acad. Sci. USA 94: 10233–10238.
  PubMed Google Scholar
• Cogoni, C. and Macino, G. 1999a. Gene silencing in Neurospora crassa requires a protein homologous to RNA-dependent RNA polymerase. Nature 399: 166–169.
  PubMed Google Scholar
• Cogoni, C. and Macino, G. 1999b. Posttranscriptional gene silencing in Neurospora by a RecQ DNA helicase. Science 286: 2342–2344.
  PubMed Google Scholar
• Cogoni, C. and Macino, G. 1999c. Homology-dependent gene silencing in plants and fungi: a number of variations on the same theme. Curr. Opin. Microbiol. 6: 657–662.
  Google Scholar
• Colot, V. and Rossignol, J.-L. 1999. Eukaryotic DNA methylation as an evolutionary device. BioEssays 15: 3153–3163.
  Google Scholar
• Colot, V., Maloisel, L. and Rossignol, J.-L. 1997. Interchromosomal transfer of epigenetic states in Ascobolus: transfer of DNA methylation is mechanistically related to homologous recombination. Cell 86: 855–864.
  Google Scholar
• Coppin-Raynal, E., Picard, M. and Arnaise, S. 1989. Transformation by integration in Podospora anserina. Mol. Gen. Genet. 219: 270–276.
  PubMed Google Scholar
• Craig, N.L 1997. Target site selection in transposition. Annu. Rev. Biochem. 66: 437–474.
  PubMed Google Scholar
• Ding, D. and Lipschutz, H.D. 1994. Spatially regulated expression of retrovirus-like transposons during Drosophila melanogaster embryogenesis. Genet. Res. Camb. 64: 167–181.
  Google Scholar
• Elmayan, T., Balzergue, S., Béon, F., Bourdon, V., Daubremet, J., Guénet, Y., Mourrain, P., Palauqui, J.-C., Vernhettes, S., Vialle, T., Wostrikoff, K. and Vaucheret, H. 1998. Arabidopsis mutants impaired in cosuppression. Plant Cell 10: 1747–1757.
  PubMed Google Scholar
• Finnegan, E.J., Genger, R.K., Peacock, W.J. and Dennis, E.S. 1998. DNA methylation in plants. Annu. Rev. Plant Physiol. Plant Mol. Biol. 49: 223-248. Fire, A. 1999. RNA-triggered gene silencing. Trends Genet. 15: 358–363.
  Google Scholar
• Fuks, F., Burgers, W.A., Brehm, A., Hughes-Davies, L. and Kouzarides. 2000. DNA methyltransferase Dnmt1 associates with histone deacetylase activity. Nature Genet. 24: 88–91.
  PubMed Google Scholar
• Genger, R.K., Kovac, K.A., Dennis, E.S., Peacock, W.J. and Finnegan, E.J. 1999. Multiple DNA methyltransferase genes in Arabidopsis thaliana. Plant Mol. Biol. 41: 269–278.
  PubMed Google Scholar
• Girard, L. and Freeling, M. 1999. Regulatory changes as a consequence of transposon insertion. Dev. Genet. 25: 291–296.
  PubMed Google Scholar
• Gonzalgo, M.L. and Jones, P.A. 1997. Mutagenic and epigenetic effects of DNA methylation. Mut. Res. 386: 107–118.
  Google Scholar
• Hamilton, A.J., Brown, S., Yuanhai, H., Ishizuka, M., Lowe, A., Alpuche Solis, A. and Grierson, D. 1998. A transgene with repeated DNA causes high frequency, post-transcriptional suppression of ACC-oxidase gene expression in tomato. Plant J. 15: 737–746.
  Google Scholar
• Hansen, R.S., Wijmenga, C., Luo, P., Stanek, A.M., Canfield, T.K., Weemaes, C.M.R. and Gartler, S.M. 1999. The DNMT3B DNA methyltransferase gene is mutated in the ICF immunodeficiency syndrome. Proc. Natl. Acad. Sci. USA 96: 14412–14417.
  PubMed Google Scholar
• Hendrich, B., Hardeland, U., Ng, H.-H., Jiricny, J. and Bird, A. 1999. The thymine glycosylase MBD4 can bind to the product of deamination at methylated CpG sites. Nature 401: 301–304.
  PubMed Google Scholar
• Henikoff, S. and Comai, L. 1998. A DNA methyltransferase homolog with a chromodomain exists in multiple polymorphic forms in Arabidopsis. Genetics 149: 307–318.
  PubMed Google Scholar
• Holland, P.W.H. 1999. The future of evolutionary developmental biology. Nature 402: C41–C44.
  PubMed Google Scholar
• Holliday, R. and Pugh, J.E. 1975. DNA modification mechanisms and gene activity during development. Science 187: 226–232.
  PubMed Google Scholar
• Huang, M.-S., Karthikeyan, N., Huang, B., Koo, H.-C., Kiger, J. and Shen, C.-K. 1999. Drosophila proteins related to vertebrate DNA (5–cytosine) methyltransferases. Proc. Natl. Acad. Sci. USA 96: 11940–11945.
  PubMed Google Scholar
• Iglesias, V.A., Moscone, E.A., Papp, I., Neuhuber, F., Michalowski, S., Phelan, T., Spiker, S., Matzke, M. and Matzke, A.J.M. 1997. Molecular and cytogenetic analyses of stably and unstably expressed transgene loci in tobacco. Plant Cell 9: 1251–1264.
  PubMed Google Scholar
• Jacobsen, S.E. and Meyerowitz, E.M. 1997. Hypermethylated SUPERMAN epigenetic alleles in Arabidopsis. Science 277: 1100–1103.
  PubMed Google Scholar
• Jakowitsch, J., Papp, I., Matzke, M.A. and Matzke, A.J.M. 1998. Identification of a new family of highly repetitive DNA, NTS9, that is located predominantly on the S9 chromosome of tobacco. Chrom. Res. 6: 649–659.
  PubMed Google Scholar
• Jakowitsch, J., Mette, M.F., van der Winden, J., Matzke, M.A. and Matzke, A.J.M. 1999a. Integrated pararetroviral sequences define a unique class of dispersed repetitive DNA in plants. Proc. Natl. Acad. Sci. USA 96: 13241–13246.
  PubMed Google Scholar
• Jakowitsch, J., Papp, I., Moscone, E.A., van der Winden, J., Matzke, M. and Matzke, A.J.M. 1999b. Molecular and cytogenetic characterization of a transgene locus that induces silencing and methylation of homologous promoters in trans. Plant J. 17: 131–140.
  PubMed Google Scholar
• Jeddeloh, J.A., Stokes, T.L. and Richards, E.J. 1999. Maintenance of genomic methylation requires a SWI2/SNF2–like protein. Nature Genet. 21: 209–212.
  PubMed Google Scholar
• Jensen, S., Gassama, M.-P. and Heidmann, T. 1999. Cosuppression of I transposon activity by I-containing sense and antisense transgenes. Genetics 153: 1767–1774.
  PubMed Google Scholar
• Jones, A.L., Thomas, C.L. and Maule, A.J. 1998. De novo methylation and cosuppression induced by a cytoplasmically replicating plant RNA virus. EMBO J. 17: 6385–6393.
  PubMed Google Scholar
• Jones, L., Hamilton, A.J., Voinnet, O., Thomas, C.L., Maule, A.J. and Baulcombe, D.C. 1999. RNA-DNA interaction and DNA methylation in post-transcriptional gene silencing. Plant Cell 11: 2291–2301.
  PubMed Google Scholar
• Jones, P., Veenstra, G., Wade, P.A., Vermaak, D., Kass, S.U., Landsberger, N., Strouboulis, J. and Wolffe, A.P. 1998. Methylated DNA and MeCP2 recruit histone deacetylases to repress transcription. Nature Genet. 19: 187–191.
  PubMed Google Scholar
• Jurka, J. 1998. Repeats in genomic DNA: mining and meaning. Curr. Opin. Struct. Biol. 8: 333–337.
  PubMed Google Scholar
• Ketting, R.F., Haverkamp, T.H., van Luenen, H.G. and Plasterk, R.H. 1999. mut-7 of C. elegans, required for transposon silencing and RNA interference, is a homolog of Werner syndrome helicase and RNase D. Cell 99: 133–141.
  PubMed Google Scholar
• Kidwell, M. and Lisch, D. 1997. Transposable elements as sources of variation in animals and plants. Proc. Natl. Acad. Sci. USA 94: 7704–7711.
  PubMed Google Scholar
• Kiefer, M.C., Owens, R.A. and Diener, T.O. 1983. Structural similarities between viroids and transposable genetic elements. Proc. Natl. Acad. Sci. USA 80: 6234–6238.
  PubMed Google Scholar
• Kooter, J., Matzke, M.A. and Meyer, P. 1999. Listening to the silent genes: transgene silencing, gene regulation and pathogen control. Trends Plant Sci. 4: 340–347.
  PubMed Google Scholar
• Leitch, I.J. and Bennett, M.D. 1997. Polyploidy in angiosperms. Trends Plant Sci. 2: 470–476.
  Google Scholar
• Li, E., Bestor, T.H. and Jaenisch, R. 1992. Targeted mutation of the DNA methyltransferase gene results in embryonic lethality. Cell 69: 915–926.
  PubMed Google Scholar
• Luff, B., Pawlowski, L. and Bender, J. 1999. An inverted repeat triggers cytosine methylation of identical sequences in Arabidopsis. Mol. Cell 3: 505–511.
  Article PubMed Google Scholar
• Lyko, F., Ramsahoye, B.H., Kaxhevsky, H., Tudor, M., Mastrangelo, M.-A., Orr-Weaver, T.L. and Jaenisch, R. 1999. Mammalian (cytosine-5) methyltransferases cause genomic DNA methylation and lethality in Drosophila. Nature Genet. 23: 363–366.
  PubMed Google Scholar
• Malagnac, F., Wendel, F., Goyon, C., Faugeron, G., Zickler, D., Rossignol, J.-L., Noyer-Weldner, M., Trautner, T. and Walter, J. 1997. A gene essential for de novo methylation and development in Ascobolus reveals a novel type of eukaryotic DNA methyltransferase structure. Cell 91: 1–20.
  PubMed Google Scholar
• Martienssen, R. 1996. Epigenetic phenomena: paramutation and gene silencing in plants. Curr. Biol. 6: 810–813.
  PubMed Google Scholar
• Masterson, J. 1994. Stomatal size in fossil plants: evidence for polyploidy in the majority of angiosperms. Science 264: 421–424.
  Google Scholar
• Matzke, A.J.M. and Matzke, M.A. 1998. Position effects and epigenetic silencing of plant transgenes. Curr. Opin. Plant Biol. 1: 142–148.
  PubMed Google Scholar
• Matzke, A.J.M., Varga, F., Gruendler, P., Unfried, I., Berger, H., Mayr, B. and Matzke, M.A. 1992. Characterization of a new repetitive sequence that is enriched on microchromosomes of turkey. Chromosoma 102: 9–14.
  PubMed Google Scholar
• Matzke, M.A., Matzke, A.J.M. and Eggleston, W. 1996. Transgene silencing and paramutation: a common response to invasive DNA? Trends Plant Sci. 1: 382–388.
  Google Scholar
• Matzke, M.A., Mette, M.F., Kunz, C., Jakowitsch, J. and Matzke, A.J.M. 2000a. Homology-dependent gene silencing in transgenic plants: links to cellular defense responses and genome evolution. In: J.P. Gustafson (Ed.) Stadler Genetics Symposium, Plenum, New York, in press.
  Google Scholar
• Matzke, M.A., Mette. M.F., Aufsatz, W., Jakowitsch, J. and Matzke, A.J.M. 2000b. Host defenses to parasitic sequences and the evolution of epigenetic control mechanisms. In: J.F. McDonald (Ed.) Transposable Elements and Evolution, Kluwer Academic Publishers, Dordrecht, Netherlands, in press.
  Google Scholar
• McDonald, J.F. 1990. Macroevolution and retroviral elements. BioScience 40: 183–191.
  Google Scholar
• McDonald, J.F. 1995. Transposable elements: possible catalysts of organismic evolution. Trends Ecol Evol. 10: 123–126.
  Google Scholar
• Melquist, S., Luff, B. and Bender, J. 1999. Arabidopsis PAI gene rearrangements, cytosine methylation and expression. Genetics 153: 401–413.
  PubMed Google Scholar
• Mette, M.F., van der Winden, J., Matzke, M.A. and Matzke, A.J.M. 1999. Production of aberrant promoter transcripts contributes to methylation and silencing of unlinked homologous promoters in trans. EMBO J. 18: 241–248.
  PubMed Google Scholar
• Meyer, A. and Schartl, M. 1999. Gene and genome duplications in vertebrates: the one-to-four (-to-eight in fish) rule and the evolution of novel gene functions. Curr. Opin. Cell Biol. 11: 699–704.
  PubMed Google Scholar
• Mittelsten Scheid, O., Afsar, K. and Paszkowski, J. 1998. Release of epigenetic silencing by _trans_-acting mutations in Arabidopsis. Proc. Natl. Acad. Sci. USA 95: 632–637.
  PubMed Google Scholar
• Nan, X., Ng, H.-H., Johnson, C.A., Laherty, C.D., Turner, B.M., Eisenman, R.N. and Bird, A. 1998. Transcriptional repression by the methyl-CpG-binding protein MeCP2 involves a histone deacetylase complex. Nature 393: 386–389.
  PubMed Google Scholar
• Ng, H.-H., Zhang, Y., Hendrich, B., Johnson, C.A., Turner, B.M., Erdjument-Bromage, H., Tempst, P., Reinberg, D. and Bird, A. 1999. MBD2 is a transcriptional repressor belonging to the MeCP1 histone deacetylase complex. Nature Genet. 23: 58–61.
  PubMed Google Scholar
• Okano, M., Bell, D.W., Haber, D.A. and Li, E. 1999. DNA methyltransferases Dnmt3a and Dnmt3b are essential for de novo methylation and mammalian development. Cell 99: 247–257.
  PubMed Google Scholar
• Papp, I., Iglesias, V.A., Moscone, E.A., Michalowski, S., Spiker, S., Park, Y.-D., Matzke, M.A. and Matzke, A.J.M. 1996. Structural instability of a transgene locus in tobacco is associated with aneuploidy. Plant J. 10: 469–478.
  PubMed Google Scholar
• Pélissier, T., Tutois, S., Deragon, J.M., Tourmente, S., Genestier, S. and Picard, G. 1995. Athila, a new retroelement from Arabidopsis thaliana. Plant Mol. Biol. 29: 441–452.
  PubMed Google Scholar
• Pélissier, T., Thalmeir, S., Kempe, D., Sänger, H.-L. and Wassenegger, M. 1999. Heavy de novo methylation at symmetrical and non-symmetrical sites is a hallmark of RNA-directed DNA methylation. Nucl. Acids Res. 27: 1625–1634.
  PubMed Google Scholar
• Pélissier, T. and Wassenegger, M. 2000. A DNA target of 30 bp is sufficient for RNA-directed DNA methylation. RNA 6: 55–65.
  PubMed Google Scholar
• Pinarbasi, E., Elliot, J. and Hornby, D.P. 1996. Activation of a yeast pseudo DNA methyltransferase by deletion of a single amino acid. J. Mol. Biol. 257: 804–813.
  PubMed Google Scholar
• Pröls, F. and Meyer, P. 1992. The methylation patterns of chromosomal integration regions influence gene activity of transferred DNA in Petunia hybrida. Plant J. 2: 465–475.
  PubMed Google Scholar
• Regev, A., Lamb, M. and Jablonka, E. 1998. The role of DNA methylation in invertebrates: developmental regulation of genome defense? Mol. Biol. Evol. 15: 880–891.
  Google Scholar
• Richards, E. 1997. DNA methylation and plant development. Trends Genet. 13: 319–322.
  PubMed Google Scholar
• Riggs, A.D. 1975. X chromosome inactivation, differentiation and DNA methylation. Cytogenet. Cell Genet. 14: 9–25.
  PubMed Google Scholar
• Rossignol, J.-L. and Faugeron, G. 1994. Gene inactivation triggered by recognition between DNA repeats. Experientia 50: 307–317.
  PubMed Google Scholar
• Sandmeyer, S.B., Hansen, L.J. and Chalker, D.L. 1990. Integration specificity of retrotransposons and retroviruses. Annu. Rev. Genet. 24: 491–518.
  PubMed Google Scholar
• SanMiguel, P. Tikhonov, A., Jin, Y., Motchoulskaia, N., Zakharov, D., Melake-Berhan, A., Springer, P.S., Edwards, K.J., Lee, M., Avramova, Z. and Bennetzen, J.L. 1996. Nested retrotransposons in the intergenic regions of the maize genome. Science 274: 765–768.
  PubMed Google Scholar
• SanMiguel, P., Gaut, B.S., Tikhonov, A., Nakajima, Y. and Bennetzen, J.L. 1998. The paleontology of intergene retrotransposons of maize. Nature Genet. 20: 43–45.
  PubMed Google Scholar
• Scrable, H. and Stambrook, P.J. 1997. Activation of the lac repressor in the transgenic mouse. Genetics 147: 297–304.
  PubMed Google Scholar
• Scrable, H. and Stambrook, P.J. 1999. A genetic program for deletion of foreign DNA from the mammalian genome. Mut. Res. 429: 225–237.
  Google Scholar
• Selker, E.U. 1990. Premeiotic instability of repeated sequences in Neurospora. Annu. Rev. Genet. 24: 579–614.
  PubMed Google Scholar
• Selker, E.U. 1997. Epigenetic phenomena in filamentous fungi: useful paradigms or repeat-induced confusion? Trends Genet. 13: 296–310.
  PubMed Google Scholar
• Selker, E.U. 1999. Repeats that count. Cell 97: 157–160.
  PubMed Google Scholar
• Shimeld, S.M. 1999. Gene function, gene networks and the fate of duplicated genes. Sem. Cell Dev. Biol. 10: 549–553.
  Google Scholar
• Singer, M., Marcotte, B. and Selker, E.U. 1995. DNA methylation associated with repeat-induced point mutation in Neurospora crassa. Mol. Cell Biol. 15: 5586–5597.
  PubMed Google Scholar
• Smit, A.F. 1999. Interspersed repeats and other mementos of transposable elements in mammalian genomes. Curr. Opin. Genet. Dev. 9: 657–663.
  PubMed Google Scholar
• Soltis, D.E. and Soltis, P.S. 1999. Polyploidy: recurrent formation and genome evolution. Trends Ecol. Evol 14: 348–352.
  PubMed Google Scholar
• Spring, J. 1997. Vertebrate evolution by interspecific hybridization: are we polyploid? FEBS Lett. 400: 2–8.
  PubMed Google Scholar
• Stam, M., Viterbo, A., Mol, J.N.M. and Kooter, J.M. 1998. Position-dependent methylation and transcriptional silencing of transgenes in inverted T-DNA repeats: implications for posttranscriptional silencing of homologous host genes in plants. Mol. Cell Biol. 18: 6165–6177.
  PubMed Google Scholar
• Tabara, H., Sarkissian, M., Kelly, W.G., Fleenor, J., Grishok, A., Timmons, L., Fire, A. and Mello, C.C. 1999. The rde-1 gene, RNA interference, and transposon silencing in C. elegans. Cell 99: 123–132.
  PubMed Google Scholar
• ten Lohuis, M., Müller, A., Heidmann, I., Niedenhof, I. and Meyer, P. 1995. A repetitive DNA fragment carrying a hot spot for de novo DNA methylation enhances expression variegation in tobacco and petunia. Plant J. 8: 919–932.
  PubMed Google Scholar
• Turker, M.S. and Bestor, T.H. 1997. Formation of methylation patterns in the mammalian genome. Mut. Res. 386: 119–130.
  Google Scholar
• Tweedie, S., Ng, H.-H., Barlow, A.L., Turner, B.M., Hendrich, B. and Bird, A. 1999. Vestiges of a DNA methylation system in Drosophila melanogaster? Nature Genet. 23: 389–390.
  PubMed Google Scholar
• VanderWiel, P. Voytas, D.F. and Wendel, J.F. 1993. _Copia_-like retrotransposable element evolution in diploid and polyploid cotton (Gossypium L.). J. Mol. Evol. 36: 429–447.
  PubMed Google Scholar
• Vaucheret, H., Béclin, C., Elmayan, T., Feuerbach, F., Gordon, C., Morel, J.-B., Mourrain, P., Palauqui, J.-C. and Vernhettes, S. 1998. Transgene-induced gene silencing in plants. Plant J. 16: 651–659.
  PubMed Google Scholar
• Wade, P.A., Gegonne, A., Jones, P.L., Ballestar, E., Aubry, F. and Wolffe, A.P. 1999. Mi-2 complex couples DNA methylation to chromatin remodelling and histone deacetylation. Nature Genet. 23: 62–66.
  PubMed Google Scholar
• Waldman, A.S., Tran, H., Goldsmith, E.C. and Resnick, M.A. 1999. Long inverted repeats are an at-risk motif for recombination in mammalian cells. Genetics 153: 1873–1883.
  PubMed Google Scholar
• Walsh, C.P. and Bestor, T.H. 1999. Cytosine methylation and mammalian development. Genes Devel. 13: 26–34.
  PubMed Google Scholar
• Wassenegger, M., Himes, S., Riedel, L. and Sänger, H. 1994. RNAdirected de novo methylation of genomic sequences in plants. Cell 76: 567–576.
  PubMed Google Scholar
• Waterhouse, P.M., Graham, H.W. and Wang, M.B. 1998. Virus resistance and gene silencing in plants can be induced by simultaneous expression of sense and antisense RNA. Proc. Natl. Acad. Sci. USA 95: 13959–13964.
  PubMed Google Scholar
• Waterhouse, P.M., Smith, N.A. and Wang, M.-B. 1999. Virus resistance and gene silencing: killing the messenger. Trends Plant Sci. 4: 452–457.
  PubMed Google Scholar
• Wenck, A., Czakó, M., Kanevski, I. and Márton, L. 1997. Frequent collinear long transfer of DNA inclusive of the whole binary vector during _Agrobacterium_-mediated transformation. Plant Mol. Biol. 43: 913–922.
  Google Scholar
• Wendel, J.F. 2000. Genome evolution in polyploids. Plant Mol. Biol. 42: 225–249.
  Article PubMed Google Scholar
• Wessler, S. 1998. Transposable elements associated with normal plant genes. Physiol. Plant. 103: 581–586.
  Google Scholar
• White, S.E., Habera, L.F. and Wessler, S.R. 1994. Retrotranspsons in the flanking regions of normal plant genes: a role for _copia_like elements in the evoution of gene structure and expression. Proc. Natl. Acad. Sci. USA 91: 11792–11796.
  PubMed Google Scholar
• Wilkinson, C.R., Bartlett, R., Nurse, P. and Bird, A.P. 1995. The fission yeast gene pmt1 encodes a DNA methyltransferase homolog. Nucl. Acids Res. 23: 203–210.
  PubMed Google Scholar
• Wolffe, A.P. and Matzke, M.A. 1999. Epigenetics: regulation through repression. Science 286: 481–486.
  PubMed Google Scholar
• Xu, G.-L-. Bestor, T.H., Bourc'his, D., Hsieh, C.-L., Tommerup, N., Bugge, M., Hulten, M., Qu, X., Russo, J.J. and Viegas-Péquignot, E. 1999. Chromosome instability and immunodeficienty syndrome caused by mutations in a DNA methyltransferase gene. Nature 402: 187–191.
  PubMed Google Scholar
• Yoder, J.A. and Bestor, T.H. 1998. A candidate mammalian DNA methyltransferase related to pmt1p of fission yeast. Hum. Mol. Genet. 7: 279–284.
  PubMed Google Scholar
• Yoder, J.A., Walsh, C. and Bestor, T.H. 1997. Cytosine methylation and the ecology of intragenomic parasites. Trends Genet. 13: 335–339.
  PubMed Google Scholar

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