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An Arabidopsis mutant defective in UV‐B light‐mediated responses
Author(s) -
Suesslin Christina,
Frohnmeyer Hanns
Publication year - 2003
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.2003.01649.x
Subject(s) - arabidopsis , mutant , biology , etiolation , microbiology and biotechnology , transcription (linguistics) , green fluorescent protein , hypocotyl , fusion protein , ultraviolet light , cytoplasm , reporter gene , transcription factor , gene expression , gene , chemistry , biochemistry , botany , enzyme , recombinant dna , linguistics , philosophy , photochemistry
Summary In plants, low fluences of ultraviolet‐B radiation (UV‐B; 280–320 nm) trigger the activation of protection mechanisms and various photomorphogenic responses. We established a novel screen to isolate Arabidopsis T‐DNA mutants ( uli , UV‐B light insensitive) with reduced sensitivity towards UV‐B light‐mediated inhibition of hypocotyl growth. One of the mutants, uli3 , shows also a reduced sensitivity of UV‐B‐induced gene expression events and was, therefore, chosen for further investigation. The ULI3 gene encodes an 80‐kDa protein with potential domains for heme‐ and diacylglycerol‐binding. In transiently transfected protoplasts, the ULI3:GFP fusion protein is localised in the cytoplasm but also adjacent to membranes. In etiolated Arabidopsis seedlings irradiated by UV‐B, ULI3 mRNA expression is strongly up‐regulated. This is caused by elevated transcription as demonstrated using stable transformants where a GUS‐reporter was driven by the ULI3 ‐promoter. ULI3 is preferentially expressed in the outer cell layers in leaves, stems and flowers, but not in roots. There is evidence that ULI3 represents a specific component involved in UV‐B‐mediated signal transduction in higher plants.