DNA methylation and chromatin structure affect transcriptional and post-transcriptional transgene silencing in Arabidopsis

Curr Biol. 2000 Dec 14-28;10(24):1591-4. doi: 10.1016/s0960-9822(00)00862-9.

Abstract

In plants, transgenes can be silenced at both the transcriptional [1] and post-transcriptional levels [2]. Methylation of the transgene promoter correlates with transcriptional gene silencing (TGS) [3] whereas methylation of the coding sequence is associated with post-transcriptional gene silencing (PTGS) [4]. In animals, TGS requires methylation and changes in chromatin conformation [5]. The involvement of methylation during PTGS in plants is unclear and organisms with non-methylated genomes such as Caenorhabditis elegans or Drosophila can display RNA interference (RNAi), a silencing process mechanistically related to PTGS [6]. Here, we crossed Arabidopsis mutants impaired in a SWI2/SNF2 chromatin component (ddm1 [7]) or in the major DNA methyltransferase (met1 [8] and E. Richards, personal communication) with transgenic lines in which a reporter consisting of the cauliflower mosaic virus 35S promoter fused to the beta-glucuronidase (GUS) gene (35S-GUS) was silenced by TGS or PTGS. We observed an efficient release of 35S-GUS TGS by both the ddm1 and met1 mutations and stochastic release of 35S-GUS PTGS by these two mutations during development. These results show that DNA methylation and chromatin structure are common regulators of TGS and PTGS.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arabidopsis / genetics*
  • Arabidopsis / growth & development
  • Arabidopsis Proteins
  • Chromatin / metabolism*
  • DNA Methylation*
  • DNA-Binding Proteins / metabolism
  • Gene Silencing*
  • Genes, Plant
  • Plants, Genetically Modified
  • Promoter Regions, Genetic / genetics
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Seeds / physiology
  • Transcription Factors / metabolism
  • Transcription, Genetic
  • Transgenes*

Substances

  • Arabidopsis Proteins
  • Chromatin
  • DDM1 protein, Arabidopsis
  • DNA-Binding Proteins
  • Recombinant Fusion Proteins
  • Transcription Factors