UNEXPECTEDLY HIGHER EXPRESSION LEVELS OF A CHIMERIC 2S ALBUMIN SEED PROTEIN TRANSGENE FROM A TANDEM ARRAY CONSTRUCT

In wild-type Arabidopsis seeds the 2S albumin seed protein gene family members are differentially expressed. In this work it is shown that a s predicted by the wild type situation, the at2S2 promoter is much mor e effective than that of the at2S1 gene in the expression of a transge ne. However, unexpectedly high expression levels were obtained using a construct in which the transgene was present as a tandem duplication in the T-DNA. Neither in this case nor in homozygous plants with eithe r construct was epigenetic silencing observed. While transgene mRNA le vels were of the same order of magnitude as the endogenous at2S2 gene, protein levels were much lower.