Regulation of flower development in Arabidopsis by SCF complexes.
SCF complexes are the largest and best studied family of E3 ubiquitin protein ligases that facilitate the ubiquitylation of proteins targeted for degradation. The SCF core components Skp1, Cul1, and Rbx1 serve in multiple SCF complexes involving different substrate-specific F-box proteins that are involved in diverse processes including cell cycle and development. In Arabidopsis, mutations in the F-box gene UNUSUAL FLORAL ORGANS (UFO) result in a number of defects in flower development. However, functions of the core components Cul1 and Rbx1 in flower development are poorly understood. In this study we analyzed floral phenotypes caused by altering function of Cul1 or Rbx1, as well as the effects of mutations in ASK1 and ASK2. Plants homozygous for a point mutation in the AtCUL1 gene showed reduced floral organ number and several defects in each of the four whorls. Similarly, plants with reduced AtRbx1 expression due to RNA interference also exhibited floral morphological defects. In addition, compared to the ask1 mutant, plants homozygous for ask1 and heterozygous for ask2 displayed enhanced reduction of B function, as well as other novel defects of flower development, including carpelloid sepals and an inhibition of petal development. Genetic analyses demonstrate that AGAMOUS (AG) is required for the novel phenotypes observed in the first and second whorls. Furthermore, the genetic interaction between UFO and AtCUL1 supports the idea that UFO regulates multiple aspects of flower development as a part of SCF complexes. These results suggest that SCF complexes regulate several aspects of floral development in Arabidopsis.
Ni
Weimin
W
Department of Biology and the Huck Institutes of Life Sciences, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Xie
Daoxin
D
Hobbie
Lawrence
L
Feng
Baomin
B
Zhao
Dazhong
D
Akkara
Joseph
J
Ma
Hong
H
D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D044842:Cullin Proteins / Q000235:genetics / Q000378:metabolism; D035264:Flowers / Q000235:genetics / Q000254:growth & development*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism; D009097:Multienzyme Complexes / Q000235:genetics* / Q000378:metabolism; D010641:Phenotype; D017354:Point Mutation; D025941:Protein Interaction Mapping; D034622:RNA Interference / Q000502:physiology; D044843:SKP Cullin F-Box Protein Ligases / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
C101342:APETALA 3 protein, Arabidopsis; C120363:ASK1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; C100318:Cullin 1; D044842:Cullin Proteins; D026161:MADS Domain Proteins; D009097:Multienzyme Complexes; D014157:Transcription Factors; C098247:UFO protein, Arabidopsis; C484058:ASK2 protein, Arabidopsis; D044843:SKP Cullin F-Box Protein Ligases