Schematic diagrams of the Ac/Ds -derived constructs used for generation of gene trap lines. a The two cwAc constructs express a full-length 807 amino acids TPase and a N-terminally truncated 705 amino acids TPase103–807, respectively, under control of the native Ac promoter. Both elements were immobilized by disruption of the 5' terminal inverted repeat (gray arrowhead). The intact 3' terminal inverted repeat is shown as a black arrowhead. A small arrow indicates the transcription start. TPase protein coding sequences are indicated by dark-gray boxes. b The Ds-based gene trap construct GTDs B contains the uidA coding region (GUS), the 3' sequences of the first Act1 intron from rice and a synthetic triple splice acceptor site (I).Ac sequences are depicted as an open box and the terminal inverted repeats are shown as filled arrowheads at the outer ends. The sequences of the putative splice donors (D1-D4), the synthetic splice acceptor sites (A1-A3) and the Act1 intron (boxed sequence) existing in the GTDs B 5' subterminal region are shown. The branchpoint sequences and T-tract are bold typed.