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CRY1 inhibits COP1-mediated degradation of BIT1, a MYB transcription factor, to activate blue light-dependent gene expression in Arabidopsis.

Authors :
Sung Hyun Hong
Hyo Jung Kim
Jong Sang Ryu
Hyunmo Choi
Suyeong Jeong
Jieun Shin
Giltsu Choi
Hong Gil Nam
Source :
Plant Journal. Aug2008, Vol. 55 Issue 3, p361-371. 11p. 5 Graphs.
Publication Year :
2008

Abstract

Cryptochromes (CRY) are one of the two major classes of photoreceptors that perceive light stimuli in the UV-A to blue light region and they are involved in multiple aspects of plant growth and development. However, knowledge regarding their signaling transduction components and mechanisms remains limited. Here, we report that a MYB transcription factor Blue Insensitive Trait 1 (BIT1), plays an important role in controlling blue light responses. Hypocotyl growth responses indicate that BIT1 functions as a positive element in blue light signaling, since BIT1 antisense and knock-out lines show a reduced light response in blue light. BIT1 controls blue light-dependent expression of various genes such as PsbS, a member of the light-harvesting complex gene family. A transactivation assay showed that BIT1 regulates promoter activity of PsbS in a blue light-dependent manner and that it requires CRY1 for activation of the PsbS promoter. BIT1 undergoes degradation in darkness and CRY1 functions to stabilize BIT1 in a blue light-dependent manner. In contrast, COP1 binds to BIT1 and mediates its degradation. We propose that the PsbS promoter is activated in blue light via the blue light-dependent stabilization of BIT1 by CRY1, while in darkness BIT1 is degraded by COP1-mediated proteolysis. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
09607412
Volume :
55
Issue :
3
Database :
Academic Search Index
Journal :
Plant Journal
Publication Type :
Academic Journal
Accession number :
33281149
Full Text :
https://doi.org/10.1111/j.1365-313X.2008.03508.x