Figure 1.

Rearrangements associated with TE activity near a gene result in altered tissue specificity. (A) In the original isolate, a Tam3 element had inserted 64 bp upstream of the start of transcription of the niv gene of Antirrhinum. The result of this insertion was a reduced level of expression. (B) A derivative of the initial insertion allele carries an inversion flanked by two copies of the transposon. This allele confers an additional reduction in the level of expression. (C) Excision of the element closest to the niv gene left a short (26 bp) “footprint.” This rearrangement resulted in an increase in the level of niv gene expression as well as a novel pattern of expression, presumably due to the juxtaposition of a novel sequence with the niv gene TATA box and coding sequences [adapted from Lister et al. (20)].