DNA methylation inhibits transcription by RNA polymerase III of a tRNA gene, but not of a 5S rRNA gene.
Methylation of cytosine in the DNA inhibits the transcription by RNA polymerase II in higher eukaryotes, but has no influence on RNA polymerase I transcription. The effect on RNA polymerase III was unknown, so far. Two polymerase III genes: a type 1 5S rRNA gene and a type 2 tRNA gene were methylated in vitro with a purified eukaryotic DNA methyltransferase (EC2.1.1.37) and their transcription was analyzed in Xenopus oocytes. The 5S rRNA gene, an oocyte 5S rRNA gene from X. laevis which is subject to developmental inactivation, was not affected by methylation. Conversely, transcription of the tRNA gene was 80% inhibited by methylation with the eukaryotic methyltransferase. HhaI and HpaII methylation left its transcription unaffected.
Robert Koch-Institut, Abteilung Biochemie, Berlin, Germany.
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Besser
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Götz
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Schulze-Forster
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Wagner
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Kröger
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Simon
D000818:Animals; D004247:DNA / Q000235:genetics* / Q000378:metabolism; D004275:DNA, Ribosomal / Q000235:genetics* / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000037:antagonists & inhibitors*; D005796:Genes; D008099:Liver / Q000201:enzymology; D008115:Liver Regeneration; D008745:Methylation; D010957:Plasmids; D012320:RNA Polymerase III / Q000037:antagonists & inhibitors*; D012335:RNA, Ribosomal / Q000235:genetics*; D012341:RNA, Ribosomal, 5S / Q000235:genetics*; D012343:RNA, Transfer / Q000235:genetics*; D012357:RNA, Transfer, Lys / Q000235:genetics; D051381:Rats; D013728:Terminator Regions, Genetic; D035582:Transcription Factor TFIIIA; D014157:Transcription Factors / Q000378:metabolism; D019474:Transcription Factors, TFIII; D014158:Transcription, Genetic; D000098832:Transcription Factor TFIIIC
D004275:DNA, Ribosomal; D012335:RNA, Ribosomal; D012341:RNA, Ribosomal, 5S; D012357:RNA, Transfer, Lys; D035582:Transcription Factor TFIIIA; D014157:Transcription Factors; D019474:Transcription Factors, TFIII; D000098832:Transcription Factor TFIIIC; D004247:DNA; D012343:RNA, Transfer; D012321:DNA-Directed RNA Polymerases; D012320:RNA Polymerase III