Poster: Transcription Regulation

Abs # 1043: Expressional traits of the mannopine synthase gene promoter from Ri-plasmid

Presenter:	Inoguchi, Masahiko , ino@dbc.ous.ac.jp
Authors	Inoguchi, Masahiko  (A)   Kusuyama, Ei-ichi  (A)   Kondo, Hirokiyo  (A)
Affiliations:	(A): Okayama University of Science, Department of Biochemistry

The expression of the bidirectional mannopine synthase 1'2' (Ri-mas) promoter of Agrobacterium rhizogenes was analyzed in transgenic tobacco plants. The coding region of the b-glucuronidase (GUS) gene was fused to either side of the Ri-mas promoter (Ri-mas1'-GUS and Ri-mas2'-GUS). Both fusion genes showed similar expression which was highest in roots and lowest in leaves. In leaves and stems, their expression was induced about 2-fold upon wounding. Their expression was also relatively high in callus tissue, but it was not influenced by any phytohormones. These expressional traits are similar to those of agropine synthase promoter of the same bacteria (Ri-ags), except for Ri-mas promoter's much higher activity in all tissues and lower induction rate upon wounding. We previously identified a putative cis-element in the Ri-ags promoter which should be responsible for the wound-inducibility of the promoter (WRE, Wound-Responsive Element), and similar sequences were found in the Ri-mas promoter. We examined the interaction of tobacco nuclear factors with Ri-mas promoter sequences by the electrophoretic-mobility shift assay (EMSA). Two major binding sites were found in the Ri-mas promoter; one site was famous ocs-element and the other was WRE.