Silencing in Arabidopsis T-DNA transformants: the predominant role of a gene-specific RNA sensing mechanism versus position effects

Schubert D, Lechtenberg B, Forsbach A, Gils M, Bahadur S, Schmidt R – 2004

Pronounced variability of transgene expression and transgene silencing are commonly observed among independent plant lines transformed with the same construct. Single-copy T-DNA lines harboring reporter genes of various kind and number under the control of a strong promoter were established in Arabidopsis thaliana for a comprehensive analysis of transgene expression. Characterization of 132 independent transgenic lines revealed no case of silencing as a result of site of T-DNA integration. Below a certain number of identical transgenes in the genome, gene copy number and expression were positively correlated. Expression was high, stable over all generations analyzed, and of a comparable level among independent lines harboring the same copy number of a particular transgene. Conversely, RNA silencing was triggered if the transcript level of a transgene surpassed a gene-specific threshold. Transcript level-mediated silencing effectively accounts for the pronounced transgene expression variability seen among transformants. It is proposed that the RNA sensing mechanism described is a genome surveillance system that eliminates RNA corresponding to excessively transcribed genes, including transgenes, and so plays an important role in genome defense.

Title
Silencing in Arabidopsis T-DNA transformants: the predominant role of a gene-specific RNA sensing mechanism versus position effects
Author
Schubert D, Lechtenberg B, Forsbach A, Gils M, Bahadur S, Schmidt R
Publisher
American Society of Plant Physiologists,
Date
2004-10
Identifier
doi: 10.1105/tpc.104.024547
Appeared in
The Plant cell, 16(10): 2561-72
Language
eng
Type
Text
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