title: SPINDLY's role in the gibberellin response pathway.
abstract: The SPINDLY (SPY) locus of Arabidopsis thaliana is believed to be involved in gibberellin (GA) signal transduction. The six known mutations at this locus cause a phenotype that is consistent with constitutive activation of the GA signal transduction pathway. spy alleles are epistatic to gai, a mutation conferring gibberellin-insensitivity, indicating that SPY acts as a negative regulator of GA signal transduction, downstream of GAI. SPY was cloned using a T-DNA insertion in the spy-4 allele. SPY encodes a 914 amino acid protein with an N-terminal TPR region (a likely protein-protein interaction domain) and a novel C-terminal domain. The spy mutants show that both the N- and C-terminal domains of SPY are functionally important, spy-4 is likely to be a null allele and displays some morphological defects not seen in the other alleles. A 35S:SPY construct rescues the spy mutant phenotype, but does not show any gain-of-function SPY phenotypes. Smaller constructs overexpressing different domains of the SPY protein have no effect on plant development.
authors.affiliation: Division of Biology, California Institute of Technology, Pasadena 91125, USA.
authors.forename: S E
authors.initials: SE
authors.lastname: Jacobsen
authors.forename: N E
authors.initials: NE
authors.lastname: Olszewski
authors.forename: E M
authors.initials: EM
authors.lastname: Meyerowitz
mesh_terms: D000483:Alleles; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins; D003001:Cloning, Molecular; D017343:Genes, Plant; D005875:Gibberellins / Q000378:metabolism*; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins; D015398:Signal Transduction / Q000235:genetics*
chemical_list: D029681:Arabidopsis Proteins; D005875:Gibberellins; D010940:Plant Proteins; D012097:Repressor Proteins; C101465:SPY protein, Arabidopsis