SEQUENCE-SPECIFIC INTERACTIONS OF WOUND-INDUCIBLE NUCLEAR FACTORS WITH MANNOPINE SYNTHASE 2'-PROMOTER WOUND-RESPONSIVE ELEMENTS

A 318 bp mannopine synthase 2' (mas2') promoter element from the T-DNA of Agrobacterium tumefaciens can direct wound-inducible and root-pref erential expression of a linked uidA gene in transgenic tobacco plants . Wound inducibility is further enhanced by sucrose in the medium. Pro moter deletion analysis indicated that the sucrose enhancement is conf erred by a region extending from -318 to -213. DNase I footprinting in dicated that an A/T-rich DNA sequence in this region is protected by t obacco nuclear factors. Regions extending from -103 to +66 and from -2 13 to -138 directed wound-inducibile expression of a linked uidA gene when placed downstream of a CaMV 35S enhancer or upstream of a truncat ed (-209) CaMV 35S promoter, respectively. DNase I footprinting analys es indicated that proteins from wounded tobacco leaves specifically bo und to three contiguous motifs downstream of the mas2' TATA box. In ad dition to a common retarded band formed by the upstream wound-responsi ve element complexed with proteins from either wounded or unwounded to bacco leaves, two unique retarded bands were observed when this elemen t was incubated with protein from wounded leaves. Methylation interfer ence analysis additionally identified an unique motif composed of prom oter elements and nuclear factors derived specifically from wounded to bacco leaves. We propose a model to describe the involvement of nuclea r factors with mas2' promoter elements in wound-inducible gene express ion.