Planta

, Volume 225, Issue 2, pp 365–379

A single transgene locus triggers both transcriptional and post-transcriptional silencing through double-stranded RNA production

Authors

  • Philippe Mourrain
    • Laboratoire de Biologie CellulaireInstitut Jean-Pierre Bourgin, INRA
    • INSERM U784 Genetique Moleculaire du DeveloppementEcole Normale Supérieure
  • Rik van Blokland
    • Department of Genetics, FALW-IMCVrije Universiteit Amsterdam
    • Swammerdam Institute for Life SciencesUniversity of Amsterdam
  • Jan M. Kooter
    • Department of Genetics, FALW-IMCVrije Universiteit Amsterdam
    • Laboratoire de Biologie CellulaireInstitut Jean-Pierre Bourgin, INRA
Original Article

DOI: 10.1007/s00425-006-0366-1

Cite this article as:
Mourrain, P., van Blokland, R., Kooter, J.M. et al. Planta (2007) 225: 365. doi:10.1007/s00425-006-0366-1

Abstract

Silencing of a target locus by an unlinked silencing locus can result from transcription inhibition (transcriptional gene silencing; TGS) or mRNA degradation (post-transcriptional gene silencing; PTGS), owing to the production of double-stranded RNA (dsRNA) corresponding to promoter or transcribed sequences, respectively. The involvement of distinct cellular components in each process suggests that dsRNA-induced TGS and PTGS likely result from the diversification of an ancient common mechanism. However, a strict comparison of TGS and PTGS has been difficult to achieve because it generally relies on the analysis of distinct silencing loci. We describe a single transgene locus that triggers both TGS and PTGS, owing to the production of dsRNA corresponding to promoter and transcribed sequences of different target genes. We describe mutants and epigenetic variants derived from this locus and propose a model for the production of dsRNA. Also, we show that PTGS, but not TGS, is graft-transmissible, which together with the sensitivity of PTGS, but not TGS, to RNA viruses that replicate in the cytoplasm, suggest that the nuclear compartmentalization of TGS is responsible for cell-autonomy. In contrast, we contribute local and systemic trafficking of silencing signals and sensitivity to viruses to the cytoplasmic steps of PTGS and to amplification steps that require high levels of target mRNAs.

Keywords

Double-stranded RNAPost-transcriptional gene silencingShort interfering RNASystemic silencingTranscriptional gene silencing

Abbreviations

dsRNA

Double-stranded RNA

GUS

ß-Glucuronidase

NIR

Nitrate reductase

PTGS

Post-transcriptional gene silencing

siRNA

Short interfering RNA

ssRNA

Single stranded RNA

TGS

Transcriptional gene silencing

Copyright information

© Springer-Verlag 2006