title: Rice gibberellin-insensitive gene homolog, OsGAI, encodes a nuclear-localized protein capable of gene activation at transcriptional level.
abstract: This paper reports isolation and properties of a rice gene, OsGAI, a putative homolog of the GAI of Arabidopsis thaliana. OsGAI encodes a polypeptide of 625 amino acids, which shows 53-55% identity to GAI and RGA from A. thaliana, and 85% identity to wheat rht-D1a and maize d8. Genomic DNA blot analysis indicated the OsGAI to be a single-copy gene in the rice genome. RNA blot hybridization showed that OsGAI transcripts increased within 6h upon GA(3) but not ABA application. This GA-induced increment in OsGAI transcripts did not require de novo protein synthesis. High levels of OsGAI transcripts were detected in nodes, internodes, leaf sheaths and ears of adult plants and leaf sheaths of young seedlings, where GA enhances cell elongation and division. Transiently expressed OsGAI-GFP fusion protein located to the nucleus in onion epidermal cells. Transactivation assays clearly indicated that OsGAI protein is a transcriptional activator or a coactivator.
authors.affiliation: Nara Institute of Science and Technology, Nara, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Ogawa
authors.forename: T
authors.initials: T
authors.lastname: Kusano
authors.forename: M
authors.initials: M
authors.lastname: Katsumi
authors.forename: H
authors.initials: H
authors.lastname: Sano
mesh_terms: D000595:Amino Acid Sequence; D029681:Arabidopsis Proteins; D002467:Cell Nucleus / Q000378:metabolism; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D018744:DNA, Plant / Q000235:genetics; D018628:Gene Dosage; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005875:Gibberellins / Q000494:pharmacology*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics*; D012275:Oryza / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics*; D012313:RNA / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D014158:Transcription, Genetic / Q000187:drug effects; D015533:Transcriptional Activation
chemical_list: D029681:Arabidopsis Proteins; D018076:DNA, Complementary; D018744:DNA, Plant; C109555:GAI protein, Arabidopsis; D005875:Gibberellins; D009687:Nuclear Proteins; D010940:Plant Proteins; D012313:RNA