A test for transvection in plants: DNA pairing may lead to trans-activation or silencing of complex heteroalleles in tobacco

Marjori Matzke*, Michael Mette, Johannes Jakowitsch, Tatsuo Kanno, Eduardo A. Moscone, Johannes Van Der Winden, Antonius J.M. Matzke

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


To study whether DNA pairing that influences gene expression can take place in somatic plant cells, a system designed to mimic transvection was established in transgenic tobacco. Pairing was evaluated by testing whether an enhancerless GUS gene on one allele could be activated in trans by an enhancer on the second allele. The required heteroalleles were obtained at four genomic locations using Cre-lox-mediated recombination. In one transgenic line, elevated GUS activity was observed with the heteroallelic combination, suggesting that trans-activation occurred. Conversely, when the unaltered allele was homozygous, GUS activity dropped to hemizygous levels in a silencing phenomenon resembling dosage compensation. Double-stranded GUS RNAs or small GUS RNAs indicative of RNA-based silencing mechanisms were not detected in plants displaying reduced GUS activity. These results suggested that a transgene locus capable of pairing, as revealed by trans-activation, could also become silenced in an RNA-independent manner, thus linking DNA pairing and gene silencing. The transgene locus was complex and comprised an inverted repeat, which possibly potentiated allelic interactions. The locus was unable to trans-activate transgenes at ectopic sites, further implicating allelic pairing in the transvection effects.

Original languageEnglish (US)
Pages (from-to)451-461
Number of pages11
Issue number1
StatePublished - May 22 2001

ASJC Scopus subject areas

  • Genetics

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