Figure 7.

Effects of wild-type B.t.-toxin sequences on synthetic B.t.-toxin mRNA accumulation. A, Schematic diagram of chimeric gene constructs used to test the effects of wild-type B.t.-toxin sequences on mRNA accumulation. The synthetic B.t.-toxin-coding region was divided into four segments using restriction sites conserved between the wild-type and synthetic coding regions. Each segment of the wild-type gene was substituted individually for the corresponding segment of the synthetic gene. B, Histogram summarizing the results of RNA gel-blot analysis of chimeric B.t.-toxin gene expression relative to the synthetic B.t.-toxin gene in pools of stably transformed tobacco BY-2 cell lines (white bars) and Arabidopsis plants (black bars). Hybridization signals for full-length B.t.-toxin mRNAs were quantitated and normalized using GUS-hybridization signals as an internal standard. Hybridization signals of the synthetic B.t.-toxin transcripts in tobacco and Arabidopsis were set equal to one to allow comparison of relative expression levels between tobacco and Arabidopsis. Data are presented as means and ses for three sets of tobacco and four sets of Arabidopsis pools.