XVI International Botanical Congess

The detailed mechanism of maize Ac/Ds element transposition and excision site repair remain poorly understood. As the study of these reactions in plants is tedious, we have developed a system in which Ds transposition occurs in S. cerevisiae. Ds excision from the yeast ADE2 locus requires expression of the Ac transposase fused to a yeast NLS. Mutations in the transposase and in the Ds inverted repeats eliminate activity in yeast. Interestingly, the footprints left behind by Ds differ from those in maize. Our data suggest the yeast transposition system will be extremely valuable for dissecting transposition features intrinsic to Ac/Ds elements. In addition, as in yeast a wide variety of DNA repair mutants are available, the system should also provide insight into the host-encoded factors that can influence transposition and excision site repair.