The Arabidopsis GAI gene defines a signaling pathway that negatively regulates gibberellin responses.

Journal article

The Arabidopsis gai mutant allele confers a reduction in gibberellin (GA) responsiveness. Here we report the molecular cloning of GAI and a closely related gene GRS. The predicted GAI (wild-type) and gai (mutant) proteins differ only by the deletion of a 17-amino-acid segment from within the amino-terminal region. GAI and GRS contain nuclear localization signals, a region of homology to a putative transcription factor, and motifs characteristic of transcriptional coactivators. Genetic analysis indicates that GAI is a repressor of GA responses, that GA can release this repression, and that gai is a mutant repressor that is relatively resistant to the effects of GA. Mutations at SPY and GAR2 suppress the gai phenotype, indicating the involvement of GAI, SPY, and GAR2 in a signaling pathway that regulates GA responses negatively. The existence of this pathway suggests that GA modulates plant growth through derepression rather than through simple stimulation.

Authors: Peng, J; Carol, P; Richards, D; King, K; Cowling, R

• Publication status: Published
• Journal: Genes and development
• Volume: 11
• Issue: 23
• Pages: 3194-3205
• Publication date: 1997-12-01
• DOI: 10.1101/gad.11.23.3194
• EISSN: 1549-5477
• ISSN: 0890-9369
• Language: English
• Keywords: Nuclear Localization Signals; Plant Proteins; Signal Transduction; RNA, Plant; Mixed Function Oxygenases; Suppression, Genetic; Molecular Sequence Data; Cloning, Molecular; Arabidopsis; Genes, Plant; Alleles; Mutagenesis, Insertional; Plant Growth Regulators; Triazoles; Consensus Sequence; DNA, Plant; Base Sequence; Arabidopsis Proteins; Amino Acid Sequence; Gibberellins; Sequence Homology, Amino Acid; Open Reading Frames