THE PLANT CELL, Vol 3, Issue 10 1051-1061, Copyright © 1991 by American Society of Plant Biologists
Vascular-Specific Expression of the Bean GRP 1.8 Gene Is Negatively Regulated
B. Keller and C. Baumgartner
Department of Plant Breeding, Swiss Federal Research Station for Agronomy, Reckenholzstrasse 191, CH-8046 Zurich, Switzerland
In French bean, the glycine-rich cell wall protein GRP 1.8 is specifically
synthesized in the vascular tissue. To identify cis-acting sequences
required for cell type-specific synthesis of GRP 1.8, expression patterns
of fusion gene constructs were analyzed in transgenic tobacco. In these
constructs, the uidA ([beta]-glucuronidase) gene was placed under control
of 5[prime] upstream deletions as well as internal deletions of the GRP 1.8
promoter. Four different cis-acting regulatory regions, SE1 and SE2 (stem
elements), a negative regulatory element, and a root-specific element, were
found to control the tissue-specific expression. Deletion of the negative
regulatory element resulted in expression of the uidA gene in cell types
other than vascular cells. The SE1 region was essential for expression in
several cell types in the absence of further upstream regulatory sequences.
Full-length promoters having insertions between the negative regulatory
element and SE1 strongly expressed the gene in nonvascular cell types in
stems and leaves. Thus, vascular-specific expression of the GRP 1.8
promoter is controlled by a complex set of positive and negative
interactions between cis-acting regulatory regions. The disturbance of
these interactions results in expression in additional cell types.
