Reference "The wheat transcriptional activator SPA: a seed-specific bZIP protein that recognizes the GCN4-like motif in the bifactorial endosperm box of prolamin genes"

Reference ID

9225

Title

The wheat transcriptional activator SPA: a seed-specific bZIP protein that recognizes the GCN4-like motif in the bifactorial endosperm box of prolamin genes

Source

The Plant cell, 1997, vol. 9, pp. 171-184

Authors (7)

Albani-D	Hammond-Kosack-M-C
Smith-C	Conlan-S
Colot-V	Holdsworth-M
Bevan-M-W

Abstract

The conserved bifactorial endosperm box found in the promoter of wheat storage
protein genes comprises two different cis elements that are thought to be
involved in regulating endosperm-specific gene expression. Endosperm nuclear
extracts contain binding activities. One is called ESBF-I, which binds to the
endosperm motif (EM), and the other is called ESBF-II, which binds to the GCN4-
like motif(GLM). Here, we present a functional analysis of the endosperm box of
a low-molecular-weight glutenin gene found on the 1D1 chromosome of hexaploid
wheat (LMWG-1D1) in transgenic tobacco plants. Our analysis demonstrates the
necessity of the EM and GLM for endosperm-specific gene expression and suggests
the presence in tobacco of functional counterparts of wheat ESBF-I and ESBF-II.
Furthermore, we describe the isolation and characterization of cDNA clones
encoding SPA, a seed-specific basic leucine zipper protein from wheat that can
activate transcription from the GLMs of the -326-bp LMWG-1D1 promoter in both
maize and tobacco leaf protoplasts. This activation is also partially dependent
on the presence of functional EMs, suggesting interactions between SPA with ESBF-I-
like activities.