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Article
Modular domain structure of Arabidopsis COP1. Reconstitution of activity by Fragment Complementation and Mutational Analysis of a nuclear localization signal in planta.
Plant Physiology (2000)
Abstract
The Arabidopsis COP1 protein functions as a developmental regulator, in part by repressing photomorphogenesis in darkness. Using complementation of a cop1loss-of-function allele with transgenes expressing fusions of cop1 mutant proteins and β-glucuronidase, it was confirmed that COP1 consists of two modules, an amino terminal module conferring a basal function during development and a carboxyl terminal module conferring repression of photomorphogenesis. The amino-terminal zinc-binding domain of COP1 was indispensable for COP1 function. In contrast, the debilitating effects of site-directed mutations in the single nuclear localization signal of COP1 were partially compensated by high-level transgene expression. The carboxyl-terminal module of COP1, though unable to substantially ameliorate a cop1 loss-of-function allele on its own, was sufficient for conferring a light-quality-dependent hyperetiolation phenotype in the presence of wild-type COP1. Moreover, partial COP1 activity could be reconstituted in vivo from two non-covalently linked, complementary polypeptides that represent the two functional modules of COP1. Evidence is presented for efficient association of the two sub-fragments of the split COP1 protein in Arabidopsis and in a yeast two-hybrid assay.
Keywords
  • COP1,
  • constitutive photomorphogenesis,
  • nuclear localization signal
Disciplines
Publication Date
2000
Citation Information
"Modular domain structure of Arabidopsis COP1. Reconstitution of activity by Fragment Complementation and Mutational Analysis of a nuclear localization signal in planta." Plant Physiology Vol. 124 Iss. 3 (2000) p. 979 - 990
Available at: http://works.bepress.com/olga-kopp/12/