Qx. Shen et al., HORMONE RESPONSE COMPLEX IN A NOVEL ABSCISIC-ACID AND CYCLOHEXIMIDE-INDUCIBLE BARLEY GENE, The Journal of biological chemistry, 268(31), 1993, pp. 23652-23660
The phytohormone, abscisic acid (ABA), plays a variety of roles during
, seed development and, in the plant's response to environmental stres
ses. To study the molecular action of ABA, we have isolated a single c
opy ABA-induced gene, HVA22, which is mapped to barley chromosome 1. T
he HVA22 gene can be induced by either ABA or the protein synthesis in
hibitor, cycloheximide, and addition of both inducers to barley aleuro
ne layers has a synergistic effect on the expression of this gene. Seq
uence comparison indicates that the HVA22 gene product is highly homol
ogous to the product of human DP1 gene, which is likely to contribute
to colorectal tumorigenesis. The hormonal regulation of HVA22 expressi
on has been studied, and there appear to be at least three elements, t
wo located in the promoter and one in the first intron, which are esse
ntial for the high level of ABA induction of HVA22 expression. Among t
he promoter elements is a homolog of ABA response element, which has b
een shown to be important in the expression of other ABA-induced genes
in plants. We suggest that the barley HVA22 gene product is likely a
regulatory protein, and the ABA induction of this gene requires the ac
tion of a complex set of hormone response elements.