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A new type of mutation in phytochrome A causes enhanced light sensitivity and alters the degradation and subcellular partitioning of the photoreceptor
Author(s) -
Dieterle Monika,
Bauer Diana,
Büche Claudia,
Krenz Martina,
Schäfer Eberhard,
Kretsch Thomas
Publication year - 2005
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 - 10.1111/j.1365-313x.2004.02286.x
Subject(s) - phytochrome , mutant , phytochrome a , biology , microbiology and biotechnology , subcellular localization , fusion protein , mutation , arabidopsis , green fluorescent protein , biophysics , biochemistry , cytoplasm , gene , red light , recombinant dna , botany
Summary A specific light program consisting of multiple treatments with alternating red and far‐red light pulses was used to isolate mutants in phytochrome A‐dependent signal transduction pathways in Arabidopsis. Because of their phenotype, the mutants were called eid for empfindlicher im dunkelroten Licht, which means hypersensitive in far‐red light. One of the isolated mutants, eid4 , is a novel semi‐dominant allele of the phytochrome A gene that carries a missense mutation in the chromophore‐binding domain. The mutation did not change the photochemical properties of the photoreceptor, but it leads to an increased stability under light conditions that induce its rapid degradation. Fusion proteins with the green fluorescent protein exhibited clear alterations in subcellular localization of the mutated photoreceptor: The fusion protein was impaired in the formation of sequestered areas of phytochrome in the cytosol, which can explain its reduced light‐dependent degradation. In contrast, the mutation stabilizes nuclear speckles (NUS) that appear late under continuous far‐red light, whereas the formation of early, transiently appearing NUS remained more or less unaltered.