The role of two f-box proteins, SLEEPY1 and SNEEZY, in Arabidopsis gibberellin signaling

Tohru Ariizumi; Paulraj K Lawrence; Camille M Steber

doi:10.1104/pp.110.166272

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The role of two f-box proteins, SLEEPY1 and SNEEZY, in Arabidopsis gibberellin signaling

Journal article

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The role of two f-box proteins, SLEEPY1 and SNEEZY, in Arabidopsis gibberellin signaling

Tohru Ariizumi, Paulraj K Lawrence and Camille M Steber

Plant physiology (Bethesda), Vol.155(2), pp.765-775

02/2011

DOI: https://doi.org/10.1104/pp.110.166272

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https://hdl.handle.net/2376/110242

PMID: 21163960

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Abstract

Transformation, Genetic

Arabidopsis Proteins - genetics

F-Box Proteins - metabolism

Alkyl and Aryl Transferases - metabolism

Arabidopsis - metabolism

Arabidopsis - genetics

Arabidopsis Proteins - metabolism

Sequence Homology, Amino Acid

Alkyl and Aryl Transferases - genetics

Gibberellins - metabolism

Gene Expression Regulation, Plant

Plant Growth Regulators - metabolism

F-Box Proteins - genetics

Repressor Proteins - metabolism

The SLEEPY1 (SLY1) F-box gene is a positive regulator of gibberellin (GA) signaling in Arabidopsis (Arabidopsis thaliana). Loss of SLY1 results in GA-insensitive phenotypes including dwarfism, reduced fertility, delayed flowering, and increased seed dormancy. These sly1 phenotypes are partially rescued by overexpression of the SLY1 homolog SNEEZY (SNE)/SLY2, suggesting that SNE can functionally replace SLY1. GA responses are repressed by DELLA family proteins. GA relieves DELLA repression when the SCF(SLY1) (for Skp1, Cullin, F-box) E3 ubiquitin ligase ubiquitinates DELLA protein, thereby targeting it for proteolysis. Coimmunoprecipitation experiments using constitutively expressed 35S:hemagglutinin (HA)-SLY1 and 35S:HA-SNE translational fusions in the sly1-10 background suggest that SNE can function similarly to SLY1 in GA signaling. Like HA-SLY1, HA-SNE interacted with the CULLIN1 subunit of the SCF complex, and this interaction required the F-box domain. Like HA-SLY1, HA-SNE coimmunoprecipitated with the DELLA REPRESSOR OF GA1-3 (RGA), and this interaction required the SLY1 or SNE carboxyl-terminal domain. Whereas HA-SLY1 overexpression resulted in a decrease in both DELLA RGA and RGA-LIKE2 (RGL2) protein levels, HA-SNE caused a decrease in DELLA RGA but not in RGL2 levels. This suggests that one reason HA-SLY1 is able to effect a stronger rescue of sly1-10 phenotypes than HA-SNE is because SLY1 regulates a broader spectrum of DELLA proteins. The FLAG-SLY1 fusion protein was found to coimmunoprecipitate with the GA receptor HA-GA-INSENSITIVE DWARF1b (GID1b), supporting the model that SLY1 regulates DELLA through interaction with the DELLA-GA-GID1 complex.

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Title: The role of two f-box proteins, SLEEPY1 and SNEEZY, in Arabidopsis gibberellin signaling
Creators: Tohru Ariizumi - United States Department of Agriculture-Agricultural Research Service, Wheat Genetics, Quality Physiology and Disease Research Unit, Pullman, Washington 99164-6420, USA
Paulraj K Lawrence
Camille M Steber
Publication Details: Plant physiology (Bethesda), Vol.155(2), pp.765-775
Academic Unit: Crop and Soil Sciences, Department of
Publisher: United States
Identifiers: 99900547139701842
Language: English
Resource Type: Journal article