Neither inverted repeat T‐DNA configurations nor arrangements of tandemly repeated transgenes are sufficient to trigger transgene silencing

Lechtenberg B, Schubert D, Forsbach A, Gils M, Schmidt R – 2003

Transgene expression was analysed in Arabidopsis T‐DNA transformants carrying defined numbers and arrangement of different reporter genes. All transgenes were placed under the control of the strong constitutive CaMV 35S promoter. High, stable transgene expression was observed in plants containing two copies of the β‐glucuronidase (GUS) gene, two or four copies of the green fluorescent protein (GFP) gene and two, four or six copies of the streptomycin phosphotransferase (SPT) gene. Thus, the mere presence of multiple promoter and/or transgene sequences did not result in gene silencing. In none of the cases analysed were tandem repeat arrangements of transgenes and/or inverted repeat (IR) T‐DNA structures sufficient to trigger silencing of the different reporter genes. Instead, post‐transcriptional gene silencing (PTGS) correlated with the copy number of the highly expressed transgenes. Twelve copies of the SPT and four copies of the GUS gene triggered silencing. Silencing is frequently associated with repetitive T‐DNA structures. We favour the idea that in many cases this may be attributed to the high transgene doses rather than the repeat arrangements themselves.

Title
Neither inverted repeat T‐DNA configurations nor arrangements of tandemly repeated transgenes are sufficient to trigger transgene silencing
Author
Lechtenberg B, Schubert D, Forsbach A, Gils M, Schmidt R
Publisher
Wiley Blackwell
Date
2003-05-09
Identifier
doi: 10.1046/j.1365-313X.2003.01746.x
Appeared in
The Plant Journal, 34(4): 507-517
Language
eng
Type
Text
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