The presence of a chromatin boundary appears to shield a transgene in tobacco from RNA silencing.
We present isogenic transgenic tobacco lines that carry at a given chromosomal position a beta-glucuronidase (GUS) reporter gene either with or without the presence of the matrix-associated region known as the chicken lysozyme A element. Plants were generated with the Cre-lox site-specific recombination system using heterospecific lox sites. Analysis of GUS gene expression in plant populations demonstrates that the presence of the A element can shield against RNA silencing of the GUS gene. Protection was observed in two of three independent tobacco transformants. Plants carrying an A element 5' of the GUS gene always had stable GUS activity, but upon removal of this A element, the GUS gene became silenced over time in two lines, notably when homozygous.
Mlynárová
Ludmila
L
Plant Research International, Wageningen University and Research Centre, NL-6700AA Wageningen, The Netherlands.
Hricová
Andrea
A
Loonen
Annelies
A
Nap
Jan-Peter
JP
D002843:Chromatin / Q000378:metabolism*; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D034622:RNA Interference; D020079:Terminal Repeat Sequences / Q000235:genetics; D014026:Nicotiana / Q000235:genetics*; D019076:Transgenes / Q000235:genetics*
D002843:Chromatin; D005966:Glucuronidase