How environmental signals are perceived by living organisms and integrated to modulate their key developmental regulators to control gene expression and development program is a fundamental question of biology. The long-term goal of this research is to dissect the molecular and cellular basis of how light signals are integrated to achieve the control of the development mode switch, employing the light-regulated seedling development of Arabidopsis thaliana as an experimental system. A multidisciplinary approach in our past effort have established working model that in darkness, COP1 (constitutively photomorphogenic 1) acts inside the nucleus to suppress the photomorphogenic development, via directly interacting with and negatively regulating specific transcription factors whose activities are responsible for promoting photomorphogenesis. While light abolishes COP1 nuclear accumulation and abrogates its repressive action. Here I propose to extend our current investigation through a combination of molecular genetic, cell biological, and biochemical approaches. To confirm our working model and reveal the molecular insights of COP1 action, we will further examine the regulatory role of the best defined COP1 and HY5 interaction in vivo, and to illuminate how this interaction translates into the regulation of HY5 stability, and its ability to interact with its target promoters and regulate their expression. To illustrate the molecular basis and mechanism of COP1's ability to interact with multiple targets and regulate pleiotropic development processes, we shall further analyze the role of four new putative downstream targets which specifically interact with the WD-40 repeats domain of COP1 and reveal how they specifically contact the distinct interactive surfaces defined by those seven WD-40-repeats. As a first step to understand how light regulate COP1 activity, we will further characterize a recently cloned signaling component which play a key role in phyA inactivation of COP1 and whose expression is also regulated by hormone auxin. To achieve a more comprehensive picture of this regulatory switch, we will pursue molecular cloning and characterization of two additional key regulatory components that defined by two separate genetic screens. If time permits, in vitro reconstitution system will be developed using our defined components and further genetic screens will be carried to reveal additional regulatory components. Those studies will provide novel insights into the mechanism of how an environmental signal achieves its control of an organism's development program. Since all the COP proteins defined so far are highly conserved among all multicellular eukaryotic organisms including human, the fundamental mechanism gained in this Arabidopsis model system will provide a guidance for understanding the function of those conserved regulators in human and thus enhance our ability to combat human health problems.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM047850-10
Application #
6351193
Study Section
Cell Development and Function Integrated Review Group (CDF)
Program Officer
Anderson, James J
Project Start
1992-08-01
Project End
2004-01-31
Budget Start
2001-02-01
Budget End
2002-01-31
Support Year
10
Fiscal Year
2001
Total Cost
$480,993
Indirect Cost
Name
Yale University
Department
Physiology
Type
Schools of Arts and Sciences
DUNS #
082359691
City
New Haven
State
CT
Country
United States
Zip Code
06520
Zhou, Yangyang; Yang, Li; Duan, Jie et al. (2018) Hinge region of Arabidopsis phyA plays an important role in regulating phyA function. Proc Natl Acad Sci U S A 115:E11864-E11873
Zhao, Xianhai; Jiang, Yan; Li, Jian et al. (2018) COP1 SUPPRESSOR 4 promotes seedling photomorphogenesis by repressing CCA1 and PIF4 expression in Arabidopsis. Proc Natl Acad Sci U S A 115:11631-11636
Shi, Hui; Lyu, Mohan; Luo, Yiwen et al. (2018) Genome-wide regulation of light-controlled seedling morphogenesis by three families of transcription factors. Proc Natl Acad Sci U S A 115:6482-6487
Lin, Fang; Jiang, Yan; Li, Jian et al. (2018) B-BOX DOMAIN PROTEIN28 Negatively Regulates Photomorphogenesis by Repressing the Activity of Transcription Factor HY5 and Undergoes COP1-Mediated Degradation. Plant Cell 30:2006-2019
Lin, Fang; Xu, Dongqing; Jiang, Yan et al. (2017) Phosphorylation and negative regulation of CONSTITUTIVELY PHOTOMORPHOGENIC 1 by PINOID in Arabidopsis. Proc Natl Acad Sci U S A 114:6617-6622
Dong, Jie; Ni, Weimin; Yu, Renbo et al. (2017) Light-Dependent Degradation of PIF3 by SCFEBF1/2 Promotes a Photomorphogenic Response in Arabidopsis. Curr Biol 27:2420-2430.e6
Ling, Jun-Jie; Li, Jian; Zhu, Danmeng et al. (2017) Noncanonical role of Arabidopsis COP1/SPA complex in repressing BIN2-mediated PIF3 phosphorylation and degradation in darkness. Proc Natl Acad Sci U S A 114:3539-3544
Shi, Hui; Liu, Renlu; Xue, Chang et al. (2016) Seedlings Transduce the Depth and Mechanical Pressure of Covering Soil Using COP1 and Ethylene to Regulate EBF1/EBF2 for Soil Emergence. Curr Biol 26:139-149
Shi, Hui; Shen, Xing; Liu, Renlu et al. (2016) The Red Light Receptor Phytochrome B Directly Enhances Substrate-E3 Ligase Interactions to Attenuate Ethylene Responses. Dev Cell 39:597-610
Li, Kunlun; Yu, Renbo; Fan, Liu-Min et al. (2016) DELLA-mediated PIF degradation contributes to coordination of light and gibberellin signalling in Arabidopsis. Nat Commun 7:11868

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