To generate injection constructs to assay promoter activity, we perform a two-way multisite LR reaction with the L4/R2 flanked promoter entry clone and the L1/L2 flanked reporter clone. For this reaction, we use a Tol2 based plasmid with an attR4-attR2 Destination cassette. It is also possible to generate a Destination plasmid from this injection construct that allows one-way LR transfer of promoter elements (this is sometimes preferred if generating a large number of injection constructs). Click here for tips on how to convert to a single fragment Destination vector.