Molecular and General Genetics MGG

, Volume 257, Issue 1, pp 1–13

Condensation of chromatin in transcriptional regions of an inactivated plant transgene: evidence for an active role of transcription in gene silencing

  • R. van Blokland
  • M. ten Lohuis
  • P. Meyer
ORIGINAL PAPER

DOI: 10.1007/s004380050617

Cite this article as:
van Blokland, R., ten Lohuis, M. & Meyer, P. Mol Gen Genet (1997) 257: 1. doi:10.1007/s004380050617

Abstract

The chromatin structures of two epigenetic alleles of a transgene were investigated by measuring the local accessibility of transgene chromatin to endonucleases. The two epialleles represented the active, hypomethylated state of a transgene in line 17-I of Petunia hybrida, and a transcriptionally inactive, hypermethylated derivative of the same transgene in line 17-IV. In nuclear preparations the inactive epiallele was significantly less sensitive to DNaseI digestion and nuclease S7 digestion than the transcriptionally active epiallele, whereas no significant differences in accessibility were observed between naked DNA samples of the two epialleles. Our data suggest that a condensed chromatin structure is specifically imposed on transcribed regions of the construct in line 17-IV. In contrast, in both epialleles the plasmid region of the transgene, which is not transcriptionally active in plants, retains the same accessibility to endonucleases as the chromosomal integration site. These data suggest that transcriptional inactivation is linked to the process of transcription, and imply that control of transgene expression via the use of inducible or tissue-specific promoters might prevent transgene silencing and conserve the active state of transgenes during sexual propagation.

Key words Gene silencing Chromatin structure Transgene stability DNA methylation 

Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • R. van Blokland
    • 1
  • M. ten Lohuis
    • 2
  • P. Meyer
    • 1
  1. 1.University of Leeds, Department of Biology, Leeds LS2 9JT, UKGB
  2. 2.James Cook University of Northern Queensland, Department of Molecular Sciences, Townsville, Queensland 4811, AustraliaAU

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