title: The activation domain of the maize transcription factor Opaque-2 resides in a single acidic region.
abstract: The maize (Zea mays L.) endosperm specific transcription factor, encoded by the Opaque-2(O2) locus, functions in vivo to activate transcription from its target promoters.O2 regulates the expression of a major storage protein class, the 22 kDa zeins, and of a type I ribosome inactivating protein, b-32, during maturation phase endosperm development. The coding sequence of O2, which indicates it to be a member of the basic region-leucine zipper (bZIP) class of DNA-binding proteins, contains a number of regions rich in either proline or acidic residues which are candidates for activation domains. In functional assays using tobacco mesophyll protoplasts, the level of transactivation conferred by a series of O2-deletion constructs was tested using as a reporter a fusion of the b-32 target promoter to beta-glucuronidase (GUS). The results indicate that O2 has a single acidic activation domain, located near the N-terminus of the protein (amino acids 41-91). The ability of a shorter part of this domain (amino acids 39-82) to confer transactivation was also demonstrated in domain swapping experiments, using fusions of the O2 polypeptide sequence to the DNA-binding domain of the parsley (Petroselinum crispum) transcription factor CPRF1.
authors.affiliation: Max-Planck-Institut für Züchtungsforschung, Köln, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Schmitz
authors.forename: S
authors.initials: S
authors.lastname: Lohmer
authors.forename: F
authors.initials: F
authors.lastname: Salamini
authors.forename: R D
authors.initials: RD
authors.lastname: Thompson
mesh_terms: D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D005966:Glucuronidase / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D010957:Plasmids; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D017384:Sequence Deletion; D014157:Transcription Factors / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics*; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D003313:Zea mays / Q000235:genetics*
chemical_list: C069384:CPRF protein, Petroselinum crispum; D004268:DNA-Binding Proteins; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; C067402:opaque-2 protein, Zea mays; D005966:Glucuronidase