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.
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.
authors.affiliation: Molecular Genetics Department, John Innes Centre, Norwich, United Kingdom.
authors.forename: D
authors.initials: D
authors.lastname: Albani
authors.forename: M C
authors.initials: MC
authors.lastname: Hammond-Kosack
authors.forename: C
authors.initials: C
authors.lastname: Smith
authors.forename: S
authors.initials: S
authors.lastname: Conlan
authors.forename: V
authors.initials: V
authors.lastname: Colot
authors.forename: M
authors.initials: M
authors.lastname: Holdsworth
authors.forename: M W
authors.initials: MW
authors.lastname: Bevan
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism*; D051790:G-Box Binding Factors; D016350:Leucine Zippers; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics*; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D055315:Prolamins; D011401:Promoter Regions, Genetic; D011494:Protein Kinases / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D012639:Seeds; D014026:Nicotiana / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics*; D014157:Transcription Factors / Q000378:metabolism*; D014908:Triticum
chemical_list: D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D051790:G-Box Binding Factors; D010940:Plant Proteins; D055315:Prolamins; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C105777:storage protein activator; C038234:storage protein, Triticum aestivum; D011494:Protein Kinases