Indexed on: 01 Jul '93Published on: 01 Jul '93Published in: Plant Molecular Biology
We have identified cis-regulatory elements within the 5′-upstream region of a Vicia faba non-storage seed protein gene, called usp, by studying the expression of usp-promoter deletion fragments fused to reporter genes in transgenic tobacco seeds. 0.4 kb of usp upstream sequence contain at least six, but probably more, distinct cis-regulatory elements which are responsible for seemingly all quantitative, spatial and temporal aspects of expression. Expression-increasing and-decreasing elements are interspersed and include an AT-rich sequence, a G-box element and a CATGCATG motif. The latter acts as a negative element in contrast to what has been found for the same motif in legumin-and vicilin-type seed storage protein gene promoters. Seed specificity of expression is mainly determined by the −68/+51 region which confers, however, only very low levels of expression. The data support the combinatiorial model of promoter function.