THE PLANT CELL, Vol 4, Issue 4 389-395, Copyright © 1992 by American Society of Plant Biologists
Both Internal and External Regulatory Elements Control Expression of the Pea Fed-1 Gene in Transgenic Tobacco Seedlings
M. Gallo-Meagher, D. A. Sowinski, R. C. Elliott and W. F. Thompson
Department of Genetics, North Carolina State University, Raleigh, North Carolina 27695
In previous studies using leaves of light-grown transgenic tobacco plants,
we have shown that sequences located within the transcribed region of the
pea Fed-1 gene (encoding ferredoxin I) are major cis-acting determinants of
light-regulated mRNA accumulation. However, we show here that these
internal sequences are less important for the Fed-1 light response in
etiolated tobacco seedlings than they are in green leaves and that upstream
elements confer organ specificity and contribute significantly to Fed-1
light responses in etiolated material. Light effects mediated by upstream
response elements are thus most pronounced during the initial induction of
gene activity, whereas internal elements play a more prominent role in
modulating Fed-1 expression once the gene is already active.
