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Arabidopsis GIGANTEA protein is post‐transcriptionally regulated by light and dark
Author(s) -
David Karine M.,
Armbruster Ute,
Tama Nga,
Putterill Joanna
Publication year - 2006
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2006.01.016
Subject(s) - arabidopsis , gigantea , proteolysis , proteasome , circadian clock , biology , microbiology and biotechnology , regulator , function (biology) , biochemistry , gene , botany , mutant , enzyme
GIGANTEA ( GI ) is a key regulator of photoperiodic flowering in Arabidopsis and encodes a protein with no domains of known biochemical function. Expression of GI mRNA is controlled by the circadian clock, but GI protein accumulation has not been previously investigated. We generated plants that produced functional epitope‐tagged GI to enable us to track the protein through the daily cycle. Here we show that GI protein levels oscillate when either constitutively overexpressed or driven by its promoter and that its accumulation is modulated by day length as well as by phase‐specific factors. Also, we demonstrate that one of the mechanisms underlying GI protein oscillation occurs post‐translationally via dark‐induced proteolysis by the 26S proteasome.