THE PLANT CELL, Vol 1, Issue 9 925-936, Copyright © 1989 by American Society of Plant Biologists
Multiple Domains Exist within the Upstream Activator Sequence of the Octopine Synthase Gene
S. M. Leisner and S. B. Gelvin
Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907
It is known that a 16-base pair palindrome (ACGTAAGCGCTTACGT) located
upstream of the ocs gene can activate a maize adh1 promoter in a transient
expression system [Ellis et al. (1987). EMBO J. 6, 11-16; Ellis et al.
(1987). EMBO J. 6, 3203-3208]. We have determined that this palindrome is
also essential for ocs promoter activity in tobacco calli. In addition,
sequences immediately adjacent to this palindrome, both 5[prime] and
3[prime], modulate its activity. The palindrome is sensitive to the
differentiated state of the plant cells in which it resides; it is active
in calli and the leaves of small shoots but is inactive in the leaves of
rooted plants. We have tested upstream sequences from two other T-DNA genes
that have homology to this palindrome for their ability to activate the
octopine synthase promoter in tobacco calli. The upstream region from the
mannopine synthase gene can activate the octopine synthase promoter, but an
upstream region from the gene implicated in octopine and nopaline secretion
cannot activate the promoter.
