PROMOTER LEADER DELETION ANALYSIS AND PLANT EXPRESSION VECTORS WITH THE FIGWORT MOSAIC-VIRUS (FMV) FULL-LENGTH TRANSCRIPT (FLT) PROMOTER CONTAINING SINGLE OR DOUBLE ENHANCER DOMAINS/

The boundaries required for maximal expression from the promoter/leade r region of the full length transcript of figwort mosaic virus (FLt pr omoter) coupled to reporter genes were defined by 5' and 3' deletion a nalyses. In transient expression assays using protoplasts of Nicotiana edwardsonii, a 314 bp FLt promoter fragment sequence (-249 to +65 fro m the transcription start site) was sufficient for strong expression a ctivity. Plant expression vectors developed with modified FLt promoter s were tested with GUS or CAT as reporter genes in transgenic plants. The FLt promoter is a strong constitutive promoter, with strength comp arable to or greater than that of the CaMV 35S promoter. The FLt promo ter with its double enhancer domain linked to GUS or CAT reporter gene s provides an average 4-fold greater activity than the FLt promoter wi th a single enhancer domain (-55 to -249 bp upstream fragment) in test s with transgenic plants and in protoplast transient expression assays .