Abstract
The SCF ubiquitin ligase complex targets the ubiquitin-mediated degradation of proteins in multiple dynamic cellular processes including flower formation, hormone and light signal transduction, and senescence in plant. The SCF ubiquitin ligase is composed of SKP1, cullin, Rbx1 and F-box protein. The genome of Arabidopsis has been shown to contain at least 19 SKP1 homologue (ASK; Arabidopsis SKP1 homologue) genes. The biochemical properties, expression, and function of the ASK genes are examined. By yeast two-hybrid analysis, ASK proteins exhibited diverse binding specificities for F-box proteins in Arabidopsis. The tissue specificity of expression of ASK genes was also varied by promoter-GUS transgenic plants. Over expression or antisense expression of ASK genes resulted in abnormal morphology in flower, leaves and stem. Our results suggest that through combinatorial arrangements between ASK proteins and F-box proteins, specific types of SCF complexes can be formed.
