Gene Tagging with Engineered Ds Elements in Maize

We describe here protocols for isolating genes in maize using Dissociation (Ds ) transposons marked with a green fluorescent protein (GFP ) transgene. The introduced marker enables the phenotypic scoring of the nonautonomous element and the anchoring of unique primers on the element to facilitate the isolation of the adjacent DNA by PCR. Transposons such as Ds transpose preferentially to sites closely linked to the Ds -launching platform. Based on this transposition behavior, a genetic resource is being created to mobilize a modified Ds element from different starting sites in the genome. Enough transgenic lines are being generated to cover most of the maize genome, allowing the targeted tagging of most genes from a Ds-launching platform located nearby.