Expression of transgene on the different chromosomal positions in Arabidopsis thaliana

Abstract

Transgene expression is notoriously variable between different, independently generated, transgenic plants. The eukaryotic genome, organized in a complex, heterogeneous structure termed chromatin, is not homogeneous for transcriptional activity. The variation of transgene expression is due to random integration into the chromosome. We have analyzed several Arabidopsis transformants of which CaMV (cauliflower mosaic virus) 35S-GUS (β-glucuronidase) is integrated in single copy. We have sequenced PCR amplified junctions of T-DNA insertions and determined their position in the Arabidopsis gemone. Transgenes were equally expressed in all transformants, suggesting that the variation of transgene expression is not due to integrated chromosomal position in Arabidopsis.