Isolation and characterization of cul1-7, a recessive allele of CULLIN1 that disrupts SCF function at the C terminus of CUL1 in Arabidopsis thaliana.

Published

Journal Article

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.

Full Text

Duke Authors

Cited Authors

  • Gilkerson, J; Hu, J; Brown, J; Jones, A; Sun, T-P; Callis, J

Published Date

  • March 2009

Published In

Volume / Issue

  • 181 / 3

Start / End Page

  • 945 - 963

PubMed ID

  • 19114460

Pubmed Central ID

  • 19114460

Electronic International Standard Serial Number (EISSN)

  • 1943-2631

International Standard Serial Number (ISSN)

  • 0016-6731

Digital Object Identifier (DOI)

  • 10.1534/genetics.108.097675

Language

  • eng