Implications for the cis-requirements for Ds transposition based on the sequence of the wxB4 Ds element

Summary The nucleotide sequence of the 1494 by wxB4 Ds element is presented. A comparison with previously characterized Ds elements reveals several novel features. This element has less Ac terminal sequence than other Ac-like Ds elements. The left terminus contains 398 by of Ac sequence interrupted by a transposon-like DNA insertion, leaving only 317 by of contiguous Ac sequence. The right terminus has 259 by of Ac terminal sequence. The interior of the element contains sequences not found in other cloned members of the Ac/Ds family. We suggest that the role of this non-Ac DNA is to separate the Ac termini by a minimum distance and may be a cis requirement for Ds transposition in maize.Abbreviations Ac activator - Adh1 alcohol dehydrogenase 1 - Ds dissociation - RFLP restriction fragment length polymorphism - Spm suppressor mutator - Wx waxy