The ability to perceive and respond to the changing environment of solar radiation is a fundamental feature of most living organisms. Flavin-type blue light receptors known as cryptochrome is a major group of photosensory receptors which mediate various blue light responses in higher plants. Despite the recent progress made in the identification of this type of photoreceptors, our understanding with respect to the molecular mechanisms by which a cryptochrome mediates plant response to blue light is very limited. The proposed research is based on our recent isolation and characterization of the Arabidopsis gene CRY2, the second member of the Arabidopsis cryptochrome gene family. CRY2 is unique not only because it appears to mediate different blue light responses from that regulated by CRY1, but also in that its own expression is regulated by blue light. The long term goal of our study is to understand how plants respond to blue light, and we will take the combined approaches of biochemistry, molecular biology, and genetics to achieve the specific aims of this proposal. We propose to characterize the biochemical properties of the CRY2 protein purified from either homologous- or heterologous- expression systems. We will also identify the mechanism(s) responsible for the blue light-induced regulation of CRY2 expression. The biological function of CRY2 will be investigated by isolation and characterization of Arabidopsis cry2 mutants impaired in the CRY2 structure gene using different genetic methods. Accomplishment of these specific aims will allow experimental dissection of the molecular mechanisms underlying the ability of CRY2 to mediate blue light responses, and it will make it possible to gain further understanding of a vital signal transduction process in eucaryotic organisms.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
5R29GM056265-04
Application #
6181110
Study Section
Biological Sciences 2 (BIOL)
Program Officer
Anderson, James J
Project Start
1997-08-01
Project End
2001-07-31
Budget Start
2000-08-01
Budget End
2001-07-31
Support Year
4
Fiscal Year
2000
Total Cost
$133,875
Indirect Cost
Name
University of California Los Angeles
Department
Biochemistry
Type
Schools of Arts and Sciences
DUNS #
119132785
City
Los Angeles
State
CA
Country
United States
Zip Code
90095
Wang, Qin; Zuo, Zecheng; Wang, Xu et al. (2018) Beyond the photocycle-how cryptochromes regulate photoresponses in plants? Curr Opin Plant Biol 45:120-126
Liu, Qing; Wang, Qin; Deng, Weixian et al. (2017) Molecular basis for blue light-dependent phosphorylation of Arabidopsis cryptochrome 2. Nat Commun 8:15234
Wang, Qin; Zuo, Zecheng; Wang, Xu et al. (2016) Photoactivation and inactivation of Arabidopsis cryptochrome 2. Science 354:343-347
Gao, Jie; Wang, Xu; Zhang, Meng et al. (2015) Trp triad-dependent rapid photoreduction is not required for the function of Arabidopsis CRY1. Proc Natl Acad Sci U S A 112:9135-40
Wang, Qin; Barshop, William D; Bian, Mingdi et al. (2015) The blue light-dependent phosphorylation of the CCE domain determines the photosensitivity of Arabidopsis CRY2. Mol Plant 8:631-43
Wang, Xu; Wang, Qin; Nguyen, Paula et al. (2014) Cryptochrome-mediated light responses in plants. Enzymes 35:167-89
Liu, Yawen; Li, Xu; Li, Kunwu et al. (2013) Multiple bHLH proteins form heterodimers to mediate CRY2-dependent regulation of flowering-time in Arabidopsis. PLoS Genet 9:e1003861
Liu, Hongtao; Wang, Qin; Liu, Yawen et al. (2013) Arabidopsis CRY2 and ZTL mediate blue-light regulation of the transcription factor CIB1 by distinct mechanisms. Proc Natl Acad Sci U S A 110:17582-7
Wang, Qin; Zhu, Ziqiang; Ozkardesh, Kara et al. (2013) Phytochromes and phytohormones: the shrinking degree of separation. Mol Plant 6:5-7
Meng, Yingying; Li, Hongyu; Wang, Qin et al. (2013) Blue light-dependent interaction between cryptochrome2 and CIB1 regulates transcription and leaf senescence in soybean. Plant Cell 25:4405-20

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