title: A new CULLIN 1 mutant has altered responses to hormones and light in Arabidopsis.
abstract: Regulated protein degradation contributes to plant development by mediating signaling events in many hormone, light, and developmental pathways. Ubiquitin ligases recognize and ubiquitinate target proteins for subsequent degradation by the 26S proteasome. The multisubunit SCF is the best-studied class of ubiquitin ligases in Arabidopsis (Arabidopsis thaliana). However, the extent of SCF participation in signaling networks is unclear. SCFs are composed of four subunits: CULLIN 1 (CUL1), ASK, RBX1, and an F-box protein. Null mutations in CUL1 are embryo lethal, limiting insight into the role of CUL1 and SCFs in later stages of development. Here, we describe a viable and fertile weak allele of CUL1, called cul1-6. cul1-6 plants have defects in seedling and adult morphology. In addition to reduced auxin sensitivity, cul1-6 seedlings are hyposensitive to ethylene, red, and blue light conditions. An analysis of protein interactions with the cul1-6 gene product suggests that both RUB (related to ubiquitin) modification and interaction with the SCF regulatory protein CAND1 (cullin associated and neddylation dissociated) are disrupted. These findings suggest that the morphological defects observed in cul1-6 plants are caused by defective SCF complex formation. Characterization of weak cul1 mutants provides insight into the role of SCFs throughout plant growth and development.
authors.affiliation: Department of Biology, Indiana University, Bloomington, Indiana 47405, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Moon
authors.forename: Yunde
authors.initials: Y
authors.lastname: Zhao
authors.forename: Xinhua
authors.initials: X
authors.lastname: Dai
authors.forename: Wenjing
authors.initials: W
authors.lastname: Zhang
authors.forename: William M
authors.initials: WM
authors.lastname: Gray
authors.forename: Enamul
authors.initials: E
authors.lastname: Huq
authors.forename: Mark
authors.initials: M
authors.lastname: Estelle
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D044842:Cullin Proteins / Q000235:genetics / Q000378:metabolism*; D003517:Cyclopentanes / Q000378:metabolism; D003583:Cytokinins / Q000378:metabolism; D005030:Ethylenes / Q000378:metabolism; D035264:Flowers / Q000033:anatomy & histology / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D018522:Gravitropism / Q000235:genetics; D018546:Hypocotyl / Q000033:anatomy & histology / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism; D008027:Light; D009154:Mutation; D054883:Oxylipins; D051942:Phytochrome A / Q000378:metabolism; D010937:Plant Growth Regulators / Q000494:pharmacology*; D036226:Seedlings / Q000033:anatomy & histology / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; C100318:Cullin 1; D044842:Cullin Proteins; D003517:Cyclopentanes; D003583:Cytokinins; D005030:Ethylenes; D007210:Indoleacetic Acids; D054883:Oxylipins; C497973:PHYA protein, Arabidopsis; D051942:Phytochrome A; D010937:Plant Growth Regulators; C011006:jasmonic acid; C036216:ethylene