Figure 3.

Characterization of the short B.t.-toxin transcripts by hybridization with different segments of the coding region. A, The cryIA(c) B.t.-toxin-coding region was divided into four segments using convenient restriction sites. Segment 1 consists of an SphI-XbaI restriction fragment from positions 28 to 295; segment 2 is a restriction fragment extending from positions 295 to 670 and is defined by XbaI sites at each end; segment 3 is an XbaI-AccI restriction fragment from positions 670 to 1201; and segment 4 is the remainder of the coding region from the AccI site at position 1201 to the BamHI site at position 1851. B, An RNA gel blot consisting of alternating lanes of poly(A⁺) RNA from stably transformed tobacco cells (left lane) or untransformed cells (right lane) was sectioned and hybridized with a probe for the entire coding region or with the individual segments of the B.t.-toxin-coding region (designated below each panel). The arrowheads indicate the full-length transcript, and the dark circles indicate the 900- and 600-nucleotide transcripts. The box diagrams indicate the segments of the B.t.-toxin-coding region found in each transcript.