THE PLANT CELL, Vol 2, Issue 5 457-467, Copyright © 1990 by American Society of Plant Biologists
Interaction of Nuclear Factors with Upstream Sequences of a Lipid Body Membrane Protein Gene from Carrot
P. Hatzopoulos, G. Franz, L. Choy and R. Z. Sung
Department of Plant Biology, University of California, Berkeley, California 94720
To study the regulation of gene expression during embryo development, we
isolated a gene, DC 59, expressed in embryos but not in mature carrot
plants. Sequence and S1 analysis showed that the gene was composed of one
exon encoding a polypeptide of 19 kilodaltons and was highly homologous to
the lipid body membrane protein gene L3 from maize. The plant hormone
abscisic acid regulated the accumulation of DC 59 mRNA. To understand the
mechanism of embryo-specific and hormonal regulation of DC 59, 5[prime] DNA
fragments were incubated with nuclear proteins. Two adjacent regions (from
-706 to -235) interacted with nuclear extracts from embryos, resulting in
the formation of four complexes (C1, C2, C3, and C4). Factors involved in
the formation of the C3 and C4 complexes could be competed with sequences
upstream of DC 8, a gene that is coordinately expressed with DC 59 during
embryo development. DNase I footprinting analysis revealed that nuclear
extracts from embryos bound to four AT-rich sequences, and the protected
motifs within fragment V were located in the highly homologous upstream
regions of DC 59 and DC 8 genes.
