Drug-induced hypomethylation of a posttranscriptionally silenced transgene locus of tobacco leads to partial release of silencing.
The effect of DNA methylation upon posttranscriptional gene silencing (PTGS) has been investigated in transgenic tobacco lines showing PTGS and methylation of the neomycin phosphotransferase II (nptII) reporter genes. Application of the hypomethylation drugs dihydroxypropyladenine or 5-azacytidine resulted in approximately 30% reduced methylation of cytosines located in a non-symmetrical context in the 3' untranslated region of the nptII transgenes. The hypomethylation was accompanied by up to 12-fold increase in NPTII protein levels, suggesting that methylation of non-symmetrical motifs may account for an increased degree of PTGS. Models for the possible role of DNA methylation in PTGS are discussed.
Kovarík
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Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65, Brno, Czech Republic. kovarik@ibp.cz
Van Houdt
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Holý
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Depicker
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D020413:3' Untranslated Regions / Q000235:genetics; D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D001374:Azacitidine / Q000494:pharmacology; D002478:Cells, Cultured; D003596:Cytosine / Q000378:metabolism; D019175:DNA Methylation / Q000187:drug effects*; D004269:DNA, Bacterial / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D020868:Gene Silencing / Q000187:drug effects*; D017930:Genes, Reporter / Q000235:genetics; D019868:Kanamycin Kinase / Q000235:genetics / Q000378:metabolism; D016366:Open Reading Frames / Q000235:genetics; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D014026:Nicotiana / Q000166:cytology / Q000187:drug effects* / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects* / Q000235:genetics; D019076:Transgenes / Q000235:genetics*
D020413:3' Untranslated Regions; D004269:DNA, Bacterial; C036483:T-DNA; C016391:9-(2,3-dihydroxypropyl)adenine; D003596:Cytosine; D019868:Kanamycin Kinase; D000225:Adenine; D001374:Azacitidine