Publications [#230874] of Tai-ping Sun

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Papers Published

  1. Gilkerson, J; Hu, J; Brown, J; Jones, A; Sun, T-P; Callis, J, Isolation and characterization of cul1-7, a recessive allele of CULLIN1 that disrupts SCF function at the C terminus of CUL1 in Arabidopsis thaliana., Genetics, vol. 181 no. 3 (March, 2009), pp. 945-963 [doi] .
    (last updated on 2026/01/16)

    Abstract:
    Many aspects of plant biology depend on the ubiquitin proteasome system for degradation of regulatory proteins. Ubiquitin E3 ligases confer substrate specificity in this pathway, and SCF-type ligases comprise a major class of E3s. SCF ligases have four subunits: SKP1, CUL1, RBX1, and an F-box protein for substrate recognition. The Aux/IAAs are a well-characterized family of SCF substrates in plants. Here, we report characterization of a mutant isolated from a genetic screen in Arabidopsis thaliana designed to identify plants defective in degradation of an Aux/IAA fusion protein, Aux/IAA1-luciferase (IAA1-LUC). This mutant exhibited fourfold slower IAA1-LUC degradation compared with the progenitor line, and seedlings displayed altered auxin responses. Experiments identified the mutant as an allele of CUL1, named cul1-7. The cul1-7 mutation affects the C terminus of the protein, results in reduced cul1-7 levels, and interferes with RBX1 interaction. cul1-7 seedlings are defective in degradation of an endogenous SCF substrate, Repressor of ga1-3 (RGA), and have altered responses to gibberellins. cul1-7 seedlings exhibit slower degradation of the light-labile red/far-red photoreceptor phytochrome A and are photomorphogenic in the dark. This mutation represents the first reported allele of CUL1 to directly affect subunit interactions at the CUL1 C terminus.