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Li ZY, Ma N, Zhang FJ, Li LZ, Li HJ, Wang XF, Zhang Z, You CX. Functions of Phytochrome Interacting Factors (PIFs) in Adapting Plants to Biotic and Abiotic Stresses. Int J Mol Sci 2024; 25:2198. [PMID: 38396875 PMCID: PMC10888771 DOI: 10.3390/ijms25042198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2024] [Revised: 02/03/2024] [Accepted: 02/04/2024] [Indexed: 02/25/2024] Open
Abstract
Plants possess the remarkable ability to sense detrimental environmental stimuli and launch sophisticated signal cascades that culminate in tailored responses to facilitate their survival, and transcription factors (TFs) are closely involved in these processes. Phytochrome interacting factors (PIFs) are among these TFs and belong to the basic helix-loop-helix family. PIFs are initially identified and have now been well established as core regulators of phytochrome-associated pathways in response to the light signal in plants. However, a growing body of evidence has unraveled that PIFs also play a crucial role in adapting plants to various biological and environmental pressures. In this review, we summarize and highlight that PIFs function as a signal hub that integrates multiple environmental cues, including abiotic (i.e., drought, temperature, and salinity) and biotic stresses to optimize plant growth and development. PIFs not only function as transcription factors to reprogram the expression of related genes, but also interact with various factors to adapt plants to harsh environments. This review will contribute to understanding the multifaceted functions of PIFs in response to different stress conditions, which will shed light on efforts to further dissect the novel functions of PIFs, especially in adaption to detrimental environments for a better survival of plants.
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Affiliation(s)
- Zhao-Yang Li
- College of Horticulture Science and Engineering, State Key Laboratory of Wheat Improvement, Shandong Agricultural University, Tai’an 271000, China; (Z.-Y.L.); (N.M.); (F.-J.Z.); (L.-Z.L.); (H.-J.L.); (X.-F.W.)
| | - Ning Ma
- College of Horticulture Science and Engineering, State Key Laboratory of Wheat Improvement, Shandong Agricultural University, Tai’an 271000, China; (Z.-Y.L.); (N.M.); (F.-J.Z.); (L.-Z.L.); (H.-J.L.); (X.-F.W.)
| | - Fu-Jun Zhang
- College of Horticulture Science and Engineering, State Key Laboratory of Wheat Improvement, Shandong Agricultural University, Tai’an 271000, China; (Z.-Y.L.); (N.M.); (F.-J.Z.); (L.-Z.L.); (H.-J.L.); (X.-F.W.)
- Department of Horticulture, College of Agriculture, Shihezi University, Shihezi 832003, China
| | - Lian-Zhen Li
- College of Horticulture Science and Engineering, State Key Laboratory of Wheat Improvement, Shandong Agricultural University, Tai’an 271000, China; (Z.-Y.L.); (N.M.); (F.-J.Z.); (L.-Z.L.); (H.-J.L.); (X.-F.W.)
| | - Hao-Jian Li
- College of Horticulture Science and Engineering, State Key Laboratory of Wheat Improvement, Shandong Agricultural University, Tai’an 271000, China; (Z.-Y.L.); (N.M.); (F.-J.Z.); (L.-Z.L.); (H.-J.L.); (X.-F.W.)
| | - Xiao-Fei Wang
- College of Horticulture Science and Engineering, State Key Laboratory of Wheat Improvement, Shandong Agricultural University, Tai’an 271000, China; (Z.-Y.L.); (N.M.); (F.-J.Z.); (L.-Z.L.); (H.-J.L.); (X.-F.W.)
| | - Zhenlu Zhang
- College of Horticulture Science and Engineering, State Key Laboratory of Wheat Improvement, Shandong Agricultural University, Tai’an 271000, China; (Z.-Y.L.); (N.M.); (F.-J.Z.); (L.-Z.L.); (H.-J.L.); (X.-F.W.)
| | - Chun-Xiang You
- College of Horticulture Science and Engineering, State Key Laboratory of Wheat Improvement, Shandong Agricultural University, Tai’an 271000, China; (Z.-Y.L.); (N.M.); (F.-J.Z.); (L.-Z.L.); (H.-J.L.); (X.-F.W.)
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Kaeser G, Krauß N, Roughan C, Sauthof L, Scheerer P, Lamparter T. Phytochrome-Interacting Proteins. Biomolecules 2023; 14:9. [PMID: 38275750 PMCID: PMC10813442 DOI: 10.3390/biom14010009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 12/15/2023] [Accepted: 12/19/2023] [Indexed: 01/27/2024] Open
Abstract
Phytochromes are photoreceptors of plants, fungi, slime molds bacteria and heterokonts. These biliproteins sense red and far-red light and undergo light-induced changes between the two spectral forms, Pr and Pfr. Photoconversion triggered by light induces conformational changes in the bilin chromophore around the ring C-D-connecting methine bridge and is followed by conformational changes in the protein. For plant phytochromes, multiple phytochrome interacting proteins that mediate signal transduction, nuclear translocation or protein degradation have been identified. Few interacting proteins are known as bacterial or fungal phytochromes. Here, we describe how the interacting partners were identified, what is known about the different interactions and in which context of signal transduction these interactions are to be seen. The three-dimensional arrangement of these interacting partners is not known. Using an artificial intelligence system-based modeling software, a few predicted and modulated examples of interactions of bacterial phytochromes with their interaction partners are interpreted.
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Affiliation(s)
- Gero Kaeser
- Karlsruhe Institute of Technology (KIT), Joseph Gottlieb Kölreuter Institut für Pflanzenwissenschaften (JKIP), Fritz-Haber-Weg 4, D-76131 Karlsruhe, Germany; (G.K.); (N.K.); (C.R.)
| | - Norbert Krauß
- Karlsruhe Institute of Technology (KIT), Joseph Gottlieb Kölreuter Institut für Pflanzenwissenschaften (JKIP), Fritz-Haber-Weg 4, D-76131 Karlsruhe, Germany; (G.K.); (N.K.); (C.R.)
| | - Clare Roughan
- Karlsruhe Institute of Technology (KIT), Joseph Gottlieb Kölreuter Institut für Pflanzenwissenschaften (JKIP), Fritz-Haber-Weg 4, D-76131 Karlsruhe, Germany; (G.K.); (N.K.); (C.R.)
| | - Luisa Sauthof
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Structural Biology of Cellular Signaling, Charitéplatz 1, D-10117 Berlin, Germany; (L.S.); (P.S.)
| | - Patrick Scheerer
- Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Physics and Biophysics, Group Structural Biology of Cellular Signaling, Charitéplatz 1, D-10117 Berlin, Germany; (L.S.); (P.S.)
| | - Tilman Lamparter
- Karlsruhe Institute of Technology (KIT), Joseph Gottlieb Kölreuter Institut für Pflanzenwissenschaften (JKIP), Fritz-Haber-Weg 4, D-76131 Karlsruhe, Germany; (G.K.); (N.K.); (C.R.)
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Liu Y, Wang Q, Abbas F, Zhou Y, He J, Fan Y, Yu R. Light Regulation of LoCOP1 and Its Role in Floral Scent Biosynthesis in Lilium 'Siberia'. PLANTS (BASEL, SWITZERLAND) 2023; 12:2004. [PMID: 37653921 PMCID: PMC10223427 DOI: 10.3390/plants12102004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 05/10/2023] [Accepted: 05/12/2023] [Indexed: 09/02/2023]
Abstract
Light is an important environmental signal that governs plant growth, development, and metabolism. Constitutive photomorphogenic 1 (COP1) is a light signaling component that plays a vital role in plant light responses. We isolated the COP1 gene (LoCOP1) from the petals of Lilium 'Siberia' and investigated its function. The LoCOP1 protein was found to be the most similar to Apostasia shenzhenica COP1. LoCOP1 was found to be an important factor located in the nucleus and played a negative regulatory role in floral scent production and emission using the virus-induced gene silencing (VIGS) approach. The yeast two-hybrid, β-galactosidase, and bimolecular fluorescence complementation (BiFC) assays revealed that LoCOP1 interacts with LoMYB1 and LoMYB3. Furthermore, light modified both the subcellular distribution of LoCOP1 and its interactions with LoMYB1 and MYB3 in onion cells. The findings highlighted an important regulatory mechanism in the light signaling system that governs scent emission in Lilium 'Siberia' by the ubiquitination and degradation of transcription factors via the proteasome pathway.
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Affiliation(s)
- Yang Liu
- The Research Center for Ornamental Plants, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China; (Y.L.); (Q.W.); (F.A.); (Y.Z.); (J.H.)
| | - Qin Wang
- The Research Center for Ornamental Plants, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China; (Y.L.); (Q.W.); (F.A.); (Y.Z.); (J.H.)
| | - Farhat Abbas
- The Research Center for Ornamental Plants, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China; (Y.L.); (Q.W.); (F.A.); (Y.Z.); (J.H.)
| | - Yiwei Zhou
- The Research Center for Ornamental Plants, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China; (Y.L.); (Q.W.); (F.A.); (Y.Z.); (J.H.)
| | - Jingjuan He
- The Research Center for Ornamental Plants, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China; (Y.L.); (Q.W.); (F.A.); (Y.Z.); (J.H.)
| | - Yanping Fan
- The Research Center for Ornamental Plants, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China; (Y.L.); (Q.W.); (F.A.); (Y.Z.); (J.H.)
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, South China Agricultural University, Guangzhou 510642, China
| | - Rangcai Yu
- College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
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Liu LY, Jia MZ, Wang SN, Han S, Jiang J. Identification and characterization of cotton PHYTOCHROME-INTERACTING FACTORs in temperature-dependent flowering. JOURNAL OF EXPERIMENTAL BOTANY 2023:erad119. [PMID: 36988239 DOI: 10.1093/jxb/erad119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Indexed: 06/19/2023]
Abstract
PHYTOCHROME INTERACTING FACTORs (PIFs) assimilate with light and temperature signs to control plant growth and development. However, little is known about PIFs in crop plants such as cotton. Here, we identified 68 PIF proteins and their coding genes from an allotetraploid and three diploid ancestors. Cotton PIFs contain typical APA and APB motifs by means of which they bind to phytochrome phyA and phyB, respectively, and have a bHLH domain and a nuclear localization sequence necessary for bHLH-type transcription factors. Bioinformatics analysis showed that the promoter of each PIF gene contains multiple cis-acting elements and that the evolution of cotton genomes likely underwent loss, recombination, and tandem replication. Further observations indicated that the sensitivity of cotton PIF expression to low or high temperature was significantly different, of which allotetraploid Gossypium hirsutum PIF4a (GhPIF4a) was induced by high temperature. GhPIF4a promotes flowering in cotton and Arabidopsis and binds to the promoter of GhFT (FLOWERING LOCUS T) increasing with temperature rise. In conclusion, our work identifies the evolutionary and structural characteristics and functions of PIF family members in cotton.
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Affiliation(s)
- Ling-Yun Liu
- State Key Laboratory of Cotton Biology, State Key Laboratory of Crop Stress Adaptation and Improvement, College of Life Sciences, Henan University, Kaifeng 475004, Henan Province, China
| | - Ming-Zhu Jia
- State Key Laboratory of Cotton Biology, State Key Laboratory of Crop Stress Adaptation and Improvement, College of Life Sciences, Henan University, Kaifeng 475004, Henan Province, China
| | - Sheng-Nan Wang
- State Key Laboratory of Cotton Biology, State Key Laboratory of Crop Stress Adaptation and Improvement, College of Life Sciences, Henan University, Kaifeng 475004, Henan Province, China
| | - Shuan Han
- State Key Laboratory of Cotton Biology, State Key Laboratory of Crop Stress Adaptation and Improvement, College of Life Sciences, Henan University, Kaifeng 475004, Henan Province, China
| | - Jing Jiang
- State Key Laboratory of Cotton Biology, State Key Laboratory of Crop Stress Adaptation and Improvement, College of Life Sciences, Henan University, Kaifeng 475004, Henan Province, China
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Wang X, Liu Y, Huai D, Chen Y, Jiang Y, Ding Y, Kang Y, Wang Z, Yan L, Jiang H, Lei Y, Liao B. Genome-wide identification of peanut PIF family genes and their potential roles in early pod development. Gene 2021; 781:145539. [PMID: 33631242 DOI: 10.1016/j.gene.2021.145539] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 02/09/2021] [Accepted: 02/16/2021] [Indexed: 10/22/2022]
Abstract
Peanut is typically a geocarpic plant. The developing gynophore ('peg') in air could not swell normally until it buries into soil, indicating light-to-dark conversion is necessary for early pod development in peanut. As the subfamily of basic helix-loop-helix (bHLH) transcription factors, phytochrome interacting factors (PIFs) are key regulators involved in light signaling pathways, and play crucial roles in plant growth and development. In the current study, a total of 14 AhPIFs were identified in cultivated peanut genome (Arachis hypogaea L., AABB), while seven AdPIFs and six AiPIFs were discovered in the two wild diploids (A. duranensis (AA), A. ipaensis (BB)) respectively. Phylogenetic analysis revealed that peanut PIFs were clustered into four distinct clades, and members within the same subgroup had conserved motifs and displayed similar exon-intron distribution patterns. Gene synteny analysis indicated most of the PIFs exhibit one-to-one homology relationship between AA and BB subgenome in A. hypogaea, as well as among the three peanut species. Gene duplication detection showed that segmental duplication and purifying selection contributed to the expansion and evolution of peanut PIF gene family. Transcript profiles combined with subcellular localization analysis suggested AhPIF3A4 and AhPIF3B4 may possibly be involved in regulation of peanut early pod development. This study could further facilitate functional characterization of PIFs in peanut and other legumes.
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Affiliation(s)
- Xin Wang
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, PR China
| | - Yue Liu
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, PR China
| | - Dongxin Huai
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, PR China
| | - Yuning Chen
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, PR China
| | - Yifei Jiang
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, PR China
| | - Yingbin Ding
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, PR China
| | - Yanping Kang
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, PR China
| | - Zhihui Wang
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, PR China
| | - Liying Yan
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, PR China
| | - Huifang Jiang
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, PR China
| | - Yong Lei
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, PR China
| | - Boshou Liao
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, PR China.
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Di Marzo M, Roig-Villanova I, Zanchetti E, Caselli F, Gregis V, Bardetti P, Chiara M, Guazzotti A, Caporali E, Mendes MA, Colombo L, Kater MM. MADS-Box and bHLH Transcription Factors Coordinate Transmitting Tract Development in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2020; 11:526. [PMID: 32435255 PMCID: PMC7219087 DOI: 10.3389/fpls.2020.00526] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 04/07/2020] [Indexed: 05/14/2023]
Abstract
The MADS-domain transcription factor SEEDSTICK (STK) controls several aspects of plant reproduction. STK is co-expressed with CESTA (CES), a basic Helix-Loop-Helix (bHLH) transcription factor-encoding gene. CES was reported to control redundantly with the brassinosteroid positive signaling factors BRASSINOSTEROID ENHANCED EXPRESSION1 (BEE1) and BEE3 the development of the transmitting tract. Combining the stk ces-4 mutants led to a reduction in ovule fertilization due to a defect in carpel fusion which, caused the formation of holes at the center of the septum where the transmitting tract differentiates. Combining the stk mutant with the bee1 bee3 ces-4 triple mutant showed an increased number of unfertilized ovules and septum defects. The transcriptome profile of this quadruple mutant revealed a small subset of differentially expressed genes which are mainly involved in cell death, extracellular matrix and cell wall development. Our data evidence a regulatory gene network controlling transmitting tract development regulated directly or indirectly by a STK-CES containing complex and reveal new insights in the regulation of transmitting tract development by bHLH and MADS-domain transcription factors.
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Takeshima R, Nishio T, Komatsu S, Kurauchi N, Matsui K. Identification of a gene encoding polygalacturonase expressed specifically in short styles in distylous common buckwheat (Fagopyrum esculentum). Heredity (Edinb) 2019; 123:492-502. [PMID: 31076649 PMCID: PMC6781162 DOI: 10.1038/s41437-019-0227-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 04/11/2019] [Indexed: 11/09/2022] Open
Abstract
Common buckwheat (Fagopyrum esculentum) is a heteromorphic self-incompatible (SI) species with two types of floral architecture: thrum (short style) and pin (long style). The floral morphology and intra-morph incompatibility are controlled by a single genetic locus, S. However, the molecular mechanisms underlying the heteromorphic self-incompatibility of common buckwheat remain unclear. To identify these mechanisms, we performed proteomic, quantitative reverse-transcription PCR, and linkage analyses. Comparison of protein profiles between the long and short styles revealed a protein unique to the short style. Amino-acid sequencing revealed that it was a truncated form of polygalacturonase (PG); we designated the gene encoding this protein FePG1. Phylogenetic analysis classified FePG1 into the same clade as PGs that function in pollen development and floral morphology. FePG1 expression was significantly higher in short styles than in long styles. It was expressed in flowers of a short-homostyle line but not in flowers of a long-homostyle line. Linkage analysis indicated that FePG1 was not linked to the S locus; it could be a factor downstream of this locus. Our finding of a gene putatively working under the regulation of the S locus provides useful information for elucidation of the mechanism of heteromorphic self-incompatibility.
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Affiliation(s)
- Ryoma Takeshima
- Institute of Crop Science, National Agriculture and Food Research Organization (NARO), Kannondai 2-1-2, Tsukuba, Ibaraki, 305-8518, Japan
| | | | - Setsuko Komatsu
- Institute of Crop Science, National Agriculture and Food Research Organization (NARO), Kannondai 2-1-2, Tsukuba, Ibaraki, 305-8518, Japan
- Department of Environmental and Food Sciences, Fukui University of Technology, Gakuen 3-6-1, Fukui, 910-8505, Japan
| | - Nobuyuki Kurauchi
- College of Bioresource Sciences, Nihon University, 1866, Kameino, Fujisawa, Kanagawa, 252-0880, Japan
| | - Katsuhiro Matsui
- Institute of Crop Science, National Agriculture and Food Research Organization (NARO), Kannondai 2-1-2, Tsukuba, Ibaraki, 305-8518, Japan.
- Graduate School of Life and Environmental Science, University of Tsukuba, Kannondai 2-1-2, Tsukuba, Ibaraki, 305-8518, Japan.
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Dirk LMA, Kumar S, Majee M, Downie AB. PHYTOCHROME INTERACTING FACTOR1 interactions leading to the completion or prolongation of seed germination. PLANT SIGNALING & BEHAVIOR 2018; 13:e1525999. [PMID: 30296201 PMCID: PMC6204810 DOI: 10.1080/15592324.2018.1525999] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 08/29/2018] [Accepted: 09/06/2018] [Indexed: 05/31/2023]
Abstract
In Arabidopsis thaliana, the basic Helix Loop Helix transcription factor, PHYTOCHROME INTERACTING FACTOR1 (PIF1) is known to orchestrate the seed transcriptome such that, ultimately, proteins repressing the completion of germination are produced in darkness. While PIF1-mediated control of abscisic acid (ABA) and gibberellic acid (GA) anabolism/catabolism is indirect, PIF1 action favors ABA while discriminating against GA, firmly establishing ABA's repressive influence on the completion of germination. The result is tissue that is more sensitive to and producing more ABA; and is less responsive to and deficient in GA. Illumination of the appropriate wavelength activates phytochrome which enters the nucleus, and binds to PIF1, initiating PIF1's phosphorylation by diverse kinases, subsequent polyubiquitination, and hydrolysis. One mechanism by which phosphorylated PIF1 is eliminated from the cells of the seed upon illumination involves an F-BOX protein, COLD TEMPERATURE GERMINATING10 (CTG10). Discovered in an unbiased screen of activation tagged lines hastening the completion of seed germination at 10°C, one indirect consequence of CTG10 action in reducing PIF1 titer, should be to enhance the transcription of genes whose products work to increase bioactive GA titer, shifting the intracellular milieu from one that is repressive to, toward one conducive to, the completion of seed germination. We have tested this hypothesis using a variety of Arabidopsis lines altered in CTG10 amounts. Here we demonstrate using bimolecular fluorescence complementation that PIF1 interacts with CTG10 and show that, in light exposed seeds, PIF1 is more persistent in ctg10 relative to WT seeds while it is less stable in seeds over-expressing CTG10. These results are congruent with the relative transcript abundance from three genes whose products are involved in bioactive GA accumulation. We put forth a model of how PIF1 interactions in imbibed seeds change during germination and how a permissive light signal influences these changes, leading to the completion of germination of these positively photoblastic propagules.
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Affiliation(s)
- Lynnette M. A. Dirk
- Department of Horticulture, Seed Biology Group, University of Kentucky, Lexington, KY, USA
| | - Santosh Kumar
- Department of Biochemistry, 243 Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | - Manoj Majee
- National Institute of Plant Genome Research, New Delhi, India
| | - A. Bruce Downie
- Department of Horticulture, Seed Biology Group, University of Kentucky, Lexington, KY, USA
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Ahmad A, Niwa Y, Goto S, Ogawa T, Shimizu M, Suzuki A, Kobayashi K, Kobayashi H. bHLH106 Integrates Functions of Multiple Genes through Their G-Box to Confer Salt Tolerance on Arabidopsis. PLoS One 2015; 10:e0126872. [PMID: 25978450 PMCID: PMC4433118 DOI: 10.1371/journal.pone.0126872] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 04/08/2015] [Indexed: 12/16/2022] Open
Abstract
An activation-tagging methodology was applied to dedifferentiated calli of Arabidopsis to identify new genes involved in salt tolerance. This identified salt tolerant callus 8 (stc8) as a gene encoding the basic helix-loop-helix transcription factor bHLH106. bHLH106-knockout (KO) lines were more sensitive to NaCl, KCl, LiCl, ABA, and low temperatures than the wild-type. Back-transformation of the KO line rescued its phenotype, and over-expression (OX) of bHLH106 in differentiated plants exhibited tolerance to NaCl. Green fluorescent protein (GFP) fused with bHLH106 revealed that it was localized to the nucleus. Prepared bHLH106 protein was subjected to electrophoresis mobility shift assays against E-box sequences (5'-CANNTG-3'). The G-box sequence 5'-CACGTG-3' had the strongest interaction with bHLH106. bHLH106-OX lines were transcriptomically analyzed, and resultant up- and down-regulated genes selected on the criterion of presence of a G-box sequence. There were 198 genes positively regulated by bHLH106 and 36 genes negatively regulated; these genes possessed one or more G-box sequences in their promoter regions. Many of these genes are known to be involved in abiotic stress response. It is concluded that bHLH106 locates at a branching point in the abiotic stress response network by interacting directly to the G-box in genes conferring salt tolerance on plants.
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Affiliation(s)
- Aftab Ahmad
- Laboratory of Plant Molecular Improvement, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 1–52 Yada, Suruga, Shizuoka 422–8526, Japan
| | - Yasuo Niwa
- Laboratory of Plant Molecular Improvement, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 1–52 Yada, Suruga, Shizuoka 422–8526, Japan
| | - Shingo Goto
- Laboratory of Plant Molecular Improvement, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 1–52 Yada, Suruga, Shizuoka 422–8526, Japan
| | - Takeshi Ogawa
- Laboratory of Plant Molecular Improvement, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 1–52 Yada, Suruga, Shizuoka 422–8526, Japan
| | - Masanori Shimizu
- Laboratory of Plant Molecular Improvement, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 1–52 Yada, Suruga, Shizuoka 422–8526, Japan
| | - Akane Suzuki
- Laboratory of Plant Molecular Improvement, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 1–52 Yada, Suruga, Shizuoka 422–8526, Japan
| | - Kyoko Kobayashi
- Laboratory of Plant Molecular Improvement, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 1–52 Yada, Suruga, Shizuoka 422–8526, Japan
| | - Hirokazu Kobayashi
- Laboratory of Plant Molecular Improvement, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 1–52 Yada, Suruga, Shizuoka 422–8526, Japan
- * E-mail:
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Xu X, Paik I, Zhu L, Bu Q, Huang X, Deng XW, Huq E. PHYTOCHROME INTERACTING FACTOR1 Enhances the E3 Ligase Activity of CONSTITUTIVE PHOTOMORPHOGENIC1 to Synergistically Repress Photomorphogenesis in Arabidopsis. THE PLANT CELL 2014; 26:1992-2006. [PMID: 24858936 PMCID: PMC4079364 DOI: 10.1105/tpc.114.125591] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Revised: 04/11/2014] [Accepted: 04/22/2014] [Indexed: 05/20/2023]
Abstract
CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1) is a RING/WD40 repeat-containing ubiquitin E3 ligase that is conserved from plants to humans. COP1 forms complexes with SUPPRESSOR OF PHYTOCHROME A (SPA) proteins, and these complexes degrade positively acting transcription factors in the dark to repress photomorphogenesis. Phytochrome-interacting basic helix-loop-helix transcription factors (PIFs) also repress photomorphogenesis in the dark. In response to light, the phytochrome family of sensory photoreceptors simultaneously inactivates COP1-SPA complexes and induces the rapid degradation of PIFs to promote photomorphogenesis. However, the functional relationship between PIFs and COP1-SPA complexes is still unknown. Here, we present genetic evidence that the pif and cop1/spa Arabidopsis thaliana mutants synergistically promote photomorphogenesis in the dark. LONG HYPOCOTYL5 (HY5) is stabilized in the cop1 pif1, spa123 pif1, and pif double, triple, and quadruple mutants in the dark. Moreover, the hy5 mutant suppresses the constitutive photomorphogenic phenotypes of the pifq mutant in the dark. PIF1 forms complexes with COP1, HY5, and SPA1 and enhances the substrate recruitment and autoubiquitylation and transubiquitylation activities of COP1. These data uncover a novel function of PIFs as the potential cofactors of COP1 and provide a genetic and biochemical model of how PIFs and COP1-SPA complexes synergistically repress photomorphogenesis in the dark.
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Affiliation(s)
- Xiaosa Xu
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas 78712
| | - Inyup Paik
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas 78712
| | - Ling Zhu
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas 78712
| | - Qingyun Bu
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas 78712
| | - Xi Huang
- Peking-Yale Joint Center for Plant Molecular Genetics and Agro-Biotechnology, State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, College of Life Sciences, Peking University, Beijing 100871, China Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06520
| | - Xing Wang Deng
- Peking-Yale Joint Center for Plant Molecular Genetics and Agro-Biotechnology, State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, College of Life Sciences, Peking University, Beijing 100871, China Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06520
| | - Enamul Huq
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas 78712
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11
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Choi H, Jeong S, Kim DS, Na HJ, Ryu JS, Lee SS, Nam HG, Lim PO, Woo HR. The homeodomain-leucine zipper ATHB23, a phytochrome B-interacting protein, is important for phytochrome B-mediated red light signaling. PHYSIOLOGIA PLANTARUM 2014; 150:308-320. [PMID: 23964902 DOI: 10.1111/ppl.12087] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 06/14/2013] [Accepted: 06/19/2013] [Indexed: 06/02/2023]
Abstract
Phytochromes are red (R)/far-red (FR) photoreceptors that are central to the regulation of plant growth and development. Although it is well known that photoactivated phytochromes are translocated into the nucleus where they interact with a variety of nuclear proteins and ultimately regulate genome-wide transcription, the mechanisms by which these photoreceptors function are not completely understood. In an effort to enhance our understanding of phytochrome-mediated light signaling networks, we attempted to identify novel proteins interacting with phytochrome B (phyB). Using affinity purification in Arabidopsis phyB overexpressor, coupled with mass spectrometry analysis, 16 proteins that interact with phyB in vivo were identified. Interactions between phyB and six putative phyB-interacting proteins were confirmed by bimolecular fluorescence complementation (BiFC) analysis. Involvement of these proteins in phyB-mediated signaling pathways was also revealed by physiological analysis of the mutants defective in each phyB-interacting protein. We further characterized the athb23 mutant impaired in the homeobox protein 23 (ATHB23) gene. The athb23 mutant displayed altered hypocotyl growth under R light, as well as defects in phyB-dependent seed germination and phyB-mediated cotyledon expansion. Taken together, these results suggest that the ATHB23 transcription factor is a novel component of the phyB-mediated R light signaling pathway.
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Affiliation(s)
- Hyunmo Choi
- Academy of New Biology for Plant Senescence and Life History, Institute for Basic Science, DGIST, Daegu, Republic of Korea; Department of Life Sciences, POSTECH, Pohang, Republic of Korea
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12
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Segura MM, Mangion M, Gaillet B, Garnier A. New developments in lentiviral vector design, production and purification. Expert Opin Biol Ther 2013; 13:987-1011. [PMID: 23590247 DOI: 10.1517/14712598.2013.779249] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Lentiviruses are a very potent class of viral vectors for which there is presently a rapidly growing interest for a number of gene therapy. However, their construction, production and purification need to be performed according to state-of-the-art techniques in order to obtain sufficient quantities of high purity material of any usefulness and safety. AREAS COVERED The recent advances in the field of recombinant lentivirus vector design, production and purification will be reviewed with an eye toward its utilization for gene therapy. Such a review should be helpful for the potential user of this technology. EXPERT OPINION The principal hurdles toward the use of recombinant lentivirus as a gene therapy vector are the low titer at which it is produced as well as the difficulty to purify it at an acceptable level without degrading it. The recent advances in the bioproduction of this vector suggest these issues are about to be resolved, making the retrovirus gene therapy a mature technology.
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Affiliation(s)
- Maria Mercedes Segura
- Chemical Engineering Department, Universitat Autònoma de Barcelona, Campus Bellaterra, Cerdanyola del Vallès (08193), Barcelona, Spain
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13
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Hong SY, Seo PJ, Ryu JY, Cho SH, Woo JC, Park CM. A competitive peptide inhibitor KIDARI negatively regulates HFR1 by forming nonfunctional heterodimers in Arabidopsis photomorphogenesis. Mol Cells 2013; 35:25-31. [PMID: 23224238 PMCID: PMC3887847 DOI: 10.1007/s10059-013-2159-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 08/06/2012] [Accepted: 11/14/2012] [Indexed: 01/09/2023] Open
Abstract
Dynamic dimer formation is an elaborate means of modulating transcription factor activities in diverse cellular processes. The basic helix-loop-helix (bHLH) transcription factor LONG HYPOCOTYL IN FAR-RED 1 (HFR1), for example, plays a role in plant photomorphogenesis by forming non-DNA binding heterodimers with PHYTOCHROMEINTERACTING FACTORS (PIFs). Recent studies have shown that a small HLH protein KIDARI (KDR) negatively regulates the HFR1 activity in the process. However, molecular mechanisms underlying the KDR control of the HFR1 activity are unknown. Here, we demonstrate that KDR attenuates the HFR1 activity by competitively forming nonfunctional heterodimers, causing liberation of PIF4 from the transcriptionally inactive HFR1-PIF4 complex. Accordingly, the photomorphogenic hypocotyl growth of the HFR1-overexpressing plants can be suppressed by KDR coexpression, as observed in the HFR1-deficient hfr1-201 mutant. These results indicate that the PIF4 activity is modulated through a double layer of competitive inhibition by HFR1 and KDR, which could in turn ensure fine-tuning of the PIF4 activity under fluctuating light conditions.
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Affiliation(s)
- Shin-Young Hong
- Department of Chemistry, Seoul National University, Seoul 151-742,
Korea
| | - Pil Joon Seo
- Department of Chemistry, Seoul National University, Seoul 151-742,
Korea
- Department of Chemistry, Chonbuk National University, Jeonju 561-756,
Korea
| | - Jae Yong Ryu
- Department of Chemistry, Seoul National University, Seoul 151-742,
Korea
| | - Shin-Hae Cho
- Department of Chemistry, Seoul National University, Seoul 151-742,
Korea
| | - Je-Chang Woo
- Department of Biological Science, Mokpo National University, Muan 534-729,
Korea
| | - Chung-Mo Park
- Department of Chemistry, Seoul National University, Seoul 151-742,
Korea
- Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-742,
Korea
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14
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Sineshchekov VA. Fluorescence and Photochemical Investigations of Phytochrome in Higher Plants. JOURNAL OF BOTANY 2010; 2010:1-15. [DOI: 10.1155/2010/358372] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2023]
Abstract
In higher plants, photoreceptor phytochrome (phy)—photoisomerizing biliprotein working as a light-driven molecular switch—is represented by a small family of phytochrome gene products with phyA and phyB as major species. phyA is unique among other phytochromes mediating photoresponse modes specific only for this pigment (far-red light induced) and also photoresponses characteristic of phyB and other minor phys (red light induced). In our group,in vivofluorescence investigations of phytochrome were initiated and two native phyA pools—posttranslationally modifiedPHYAgene products designated phyA′and phyA″—were detected in dicots and monocots. They differ by spectroscopic and photochemical parameters, by abundance and distribution in etiolated plant tissues, by light stability, and other phenomenological characteristics, and, most importantly, by their functional properties. This may explain, at least partially, the nature of the uniqueness of the phyA action. In this paper, the data on the phyA polymorphism are summarized with attention to the applied experimental approach.
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Affiliation(s)
- Vitaly A. Sineshchekov
- Physico-Chemical Biology, Biology Faculty, M. V. Lomonosov Moscow State University, Moscow 119992, Russia
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15
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Zhou J, Li F, Wang JL, Ma Y, Chong K, Xu YY. Basic helix-loop-helix transcription factor from wild rice (OrbHLH2) improves tolerance to salt- and osmotic stress in Arabidopsis. JOURNAL OF PLANT PHYSIOLOGY 2009; 166:1296-1306. [PMID: 19324458 DOI: 10.1016/j.jplph.2009.02.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2008] [Revised: 02/05/2009] [Accepted: 02/05/2009] [Indexed: 05/02/2023]
Abstract
Salt stress adversely affects plant growth and development. Some plants reduce the damage of high-salt stress by expressing a series of salt-responsive genes. Studies of the molecular mechanism of the salt-stress response have focused on the characterization of components involved in signal perception and transduction. In the present work, we cloned and characterized a basic helix-loop-helix (bHLH) encoding gene, OrbHLH2, from wild rice (Oryza rufipogon), which encodes a homologue protein of ICE1 in Arabidopsis. OrbHLH2 protein localized in the nucleus. Overexpression of OrbHLH2 in Arabidopsis conferred increased tolerance to salt and osmotic stress, and the stress-responsive genes DREB1A/CBF3, RD29A, COR15A and KIN1 were upregulated in transgenic plants. Abscisic acid (ABA) treatment showed a similar effect on the seed germination or transcriptional expression of stress-responsive genes in both wild type and OrbHLH2-overexpressed plants, which implies that OrbHLH2 does not depend on ABA in responding to salt stress. OrbHLH2 may function as a transcription factor and positively regulate salt-stress signals independent of ABA in Arabidopsis, which provides some useful data for improving salt tolerance in crops.
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Affiliation(s)
- Jing Zhou
- Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, The Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Beijing 100093, China; Graduate School of the Chinese Academy of Sciences, Beijing 100049, China
| | - Fei Li
- Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, The Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Beijing 100093, China; Graduate School of the Chinese Academy of Sciences, Beijing 100049, China
| | - Jin-Lan Wang
- Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, The Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Beijing 100093, China; Graduate School of the Chinese Academy of Sciences, Beijing 100049, China
| | - Yun Ma
- Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, The Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Beijing 100093, China
| | - Kang Chong
- Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, The Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Beijing 100093, China
| | - Yun-Yuan Xu
- Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, The Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Beijing 100093, China.
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16
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A novel protein phosphatase indirectly regulates phytochrome-interacting factor 3 via phytochrome. Biochem J 2009; 415:247-55. [PMID: 18564962 DOI: 10.1042/bj20071555] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Light signal transduction in plants involves an intricate series of pathways which is finely regulated by interactions between specific signalling proteins, as well as by protein modifications such as phosphorylation and ubiquitination. The identification of novel phytochrome-interacting proteins and the precise signalling mechanisms that they mediate is still ongoing. In our present study, we show that the newly identified putative phytochrome-associated protein, PAPP2C (phytochrome-associated protein phosphatase type 2C), interacts in the nucleus with phyA (phytochrome A) and phyB, both in vitro and in vivo. Moreover, the phosphatase activity of PAPP2C and its association with phytochromes were found to be enhanced by red light, indicating that it plays a role in mediating phytochrome signalling. In particular, PAPP2C specifically binds to the N-terminal PHY domain of the phytochromes. We thus speculate that this interaction reflects a unique regulatory function of this phosphatase toward established phytochrome-associated proteins. We also show that PAPP2C effectively dephosphorylates phytochromes in vitro. Interestingly, PAPP2C indirectly mediates the dephosphorylation of PIF3 (phytochrome-interacting factor 3) in vitro. Taken together, we suggest that PAPP2C functions as a regulator of PIF3 by dephosphorylating phytochromes in the nucleus.
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17
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Kodama Y, Sano H. Functional diversification of a basic helix-loop-helix protein due to alternative transcription during generation of amphidiploidy in tobacco plants. Biochem J 2007; 403:493-9. [PMID: 17288537 PMCID: PMC1876378 DOI: 10.1042/bj20070011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2007] [Revised: 02/05/2007] [Accepted: 02/08/2007] [Indexed: 12/18/2022]
Abstract
A plastid-resident basic helix-loop-helix protein, previously identified in Nicotiana tabacum and designated as NtWIN4 (N. tabacum wound-induced clone 4), has been converted from a nuclear transcription repressor into a plastid-resident regulatory factor through replacement of the DNA-binding domain with a plastid transit sequence during evolution. N. tabacum is a natural amphidiploid plant derived from Nicotiana tomentosiformis and Nicotiana sylvestris and immunoblot staining using anti-NtWIN4 antibodies identified two protein species, a 26 kDa form and a 17 kDa form, in N. sylvestris, whereas only the 17 kDa form was found in N. tabacum. The 26 kDa protein is produced when translation starts from the first AUG codon of the mRNA and is predominantly localized in the cytoplasm and nucleus, whereas the 17 kDa protein is derived from a 24 kDa precursor protein, synthesized from the second AUG codon, and localizes only to plastids. Subsequent analyses revealed that the lengths of the mRNAs vary in the two plant species. One major form lacks the first AUG, while minor populations possess variable 5'-untranslated regions prior to the first AUG codon. Translation of the two types produces the 24 kDa and 26 kDa proteins respectively. In vitro translation assays indicated that initiation frequency from the first AUG codon is higher in mRNAs from N. sylvestris than from N. tabacum. In contrast, initiation from the second AUG codon was found to be equally efficient in mRNAs from both species. These results suggest that both mRNA populations and translation efficiency changed during the amphidiploidization responsible for generation of N. tabacum. This scheme could reflect a molecular mechanism of protein evolution in plants.
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Affiliation(s)
- Yutaka Kodama
- Research and Education Center for Genetic Information, Nara Institute of Science and Technology, Nara 630-0192, Japan
| | - Hiroshi Sano
- Research and Education Center for Genetic Information, Nara Institute of Science and Technology, Nara 630-0192, Japan
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18
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Kodama Y, Sano H. Evolution of a basic helix-loop-helix protein from a transcriptional repressor to a plastid-resident regulatory factor: involvement in hypersensitive cell death in tobacco plants. J Biol Chem 2006; 281:35369-80. [PMID: 16966334 DOI: 10.1074/jbc.m604140200] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The tobacco gene NtWIN4 (Nicotiana tabacum wound-induced clone 4) is transiently up-regulated in response not only to wounding but also to pathogen attack. NtWIN4 encodes a putative basic helix-loop-helix protein with an apparent molecular mass of 28 kDa that exhibited clear nuclear transcription repression activity in Dual-Luciferase assays. However, immunoblotting indicated the existence of a 17-kDa form of NtWIN4 localized exclusively in tobacco leaf chloroplasts. Subsequent peptide dissection analyses with green fluorescent protein fusions revealed that a polypeptide of 81 amino acids starting at position 13 from the N terminus is maximally necessary for this localization. Further fine dissection analysis strongly suggested that the protein actually begins at the second Met located at position 27, yielding a signal peptide of 67 amino acids. However, the last C-terminal 15 amino acids overlap with the conserved basic region critical for DNA binding, so NtWIN4 presumably does not function as a transcription factor in planta. Transgenic tobacco plants constitutively overexpressing NtWIN4 demonstrated mortality with abnormal features, including albinism, and transient expression upon agroinfiltration resulted in distinct necrosis with a sharp decrease in chlorophyll content, consistent with the phenomenon known as chlorosis. Transgenic RNA interference tobacco plants exhibited reduced hypersensitive cell death, showing delayed tissue necrosis upon pathogen infection. These results suggest that NtWIN4 arose by divergence, becoming a chloroplast-resident factor from a nuclear transcriptional repressor by obtaining a transit peptide sequence, and that, upon translocation, it interacts with chloroplast components to induce hypersensitive cell death through chloroplast disruption, thereby contributing to plant stress responses.
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Affiliation(s)
- Yutaka Kodama
- Research and Education Center for Genetic Information, Nara Institute of Science and Technology, Nara 630-0192, Japan
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19
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Phee BK, Shin DH, Cho JH, Kim SH, Kim JI, Lee YH, Jeon JS, Bhoo SH, Hahn TR. Identification of phytochrome-interacting protein candidates in Arabidopsis thaliana by co-immunoprecipitation coupled with MALDI-TOF MS. Proteomics 2006; 6:3671-80. [PMID: 16705748 DOI: 10.1002/pmic.200500222] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Phytochrome-interacting proteins have been extensively studied to elucidate light-signaling pathway in plants. However, most of these proteins have been identified by yeast two-hybrid screening using the C-terminal domain of phytochromes. We used co-immunoprecipitation followed by proteomic analysis in plant cell extracts in an attempt to screen for proteins interacting either directly or indirectly with native holophytochromes including the N-terminal domain as well as C-terminal domain. A total of 16 protein candidates were identified, and were selected from 2-DE experiments. Using MALDI-TOF MS analysis, 7 of these candidates were predicted to be putative phytochrome A-interacting proteins and the remaining ones to be phytochrome B-interacting proteins. Among these putative interacting proteins, protein phosphatase type 2C (PP2C) and a 66-kDa protein were strong candidates as novel phytochrome-interacting proteins, as knockout mutants for the genes encoding these two proteins had impaired light-signaling functions. A transgenic knockout Arabidopsis study showed that a 66-kDa protein candidate regulates hypocotyl elongation in a light-specific manner, and altered cotyledon development under white light during early developmental stages. The PP2C knockout plants also displayed light-specific changes in hypocotyl elongation. These results suggest that co-immunoprecipitation, followed by proteomic analysis, is a useful method for identifying novel interacting proteins and determining real protein-protein interactions in the cell.
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Affiliation(s)
- Bong-Kwan Phee
- Graduate School of Biotechnology and Plant Metabolism Research Center, Kyung Hee University, Suwon, Korea
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20
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Li X, Duan X, Jiang H, Sun Y, Tang Y, Yuan Z, Guo J, Liang W, Chen L, Yin J, Ma H, Wang J, Zhang D. Genome-wide analysis of basic/helix-loop-helix transcription factor family in rice and Arabidopsis. PLANT PHYSIOLOGY 2006; 141:1167-84. [PMID: 16896230 PMCID: PMC1533929 DOI: 10.1104/pp.106.080580] [Citation(s) in RCA: 399] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The basic/helix-loop-helix (bHLH) transcription factors and their homologs form a large family in plant and animal genomes. They are known to play important roles in the specification of tissue types in animals. On the other hand, few plant bHLH proteins have been studied functionally. Recent completion of whole genome sequences of model plants Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa) allows genome-wide analysis and comparison of the bHLH family in flowering plants. We have identified 167 bHLH genes in the rice genome, and their phylogenetic analysis indicates that they form well-supported clades, which are defined as subfamilies. In addition, sequence analysis of potential DNA-binding activity, the sequence motifs outside the bHLH domain, and the conservation of intron/exon structural patterns further support the evolutionary relationships among these proteins. The genome distribution of rice bHLH genes strongly supports the hypothesis that genome-wide and tandem duplication contributed to the expansion of the bHLH gene family, consistent with the birth-and-death theory of gene family evolution. Bioinformatics analysis suggests that rice bHLH proteins can potentially participate in a variety of combinatorial interactions, endowing them with the capacity to regulate a multitude of transcriptional programs. In addition, similar expression patterns suggest functional conservation between some rice bHLH genes and their close Arabidopsis homologs.
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Affiliation(s)
- Xiaoxing Li
- Shanghai Jiao Tong University-Shanghai Institutes for Biological Sciences-Pennsylvania State University Joint Center for Life Sciences, Shanghai Jiao Tong University, Shanghai, People's Republic of China, 200240
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21
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Shen H, Moon J, Huq E. PIF1 is regulated by light-mediated degradation through the ubiquitin-26S proteasome pathway to optimize photomorphogenesis of seedlings in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2005; 44:1023-35. [PMID: 16359394 DOI: 10.1111/j.1365-313x.2005.02606.x] [Citation(s) in RCA: 183] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Light signals perceived by the phytochrome (phy) family of sensory photoreceptors control multiple aspects of plant development. Recently, PIF1, a phy-interacting basic helix-loop-helix (bHLH) transcription factor, has been shown to negatively regulate facets of the photomorphogenesis of seedlings. Moreover, the transcriptional activation activity of PIF1 is reduced in a phy-dependent manner. In this study we use the luciferase (LUC) activity of the LUC-PIF1 fusion protein as an indicator of the stability of PIF1 in various light conditions. We found that the activity of LUC-PIF1 in both transient and stable transgenic lines is rapidly reduced in light, while the LUC-only control is stable under the same conditions, suggesting that PIF1 is degraded in response to light. Fluence-rate response curves indicate that PIF1 degradation is very sensitive to the quality and quantity of light. The half-life of PIF1 is about 16 min under 10 micromol m-2 sec-1 red light. PIF1 reaccumulates in the subsequent dark period after light-induced degradation, signifying that PIF1 not only functions in the dark and during the transition from etiolated to de-etiolated growth, but may also function during diurnal cycles. Inhibitors of the 26S proteasome increased the stability of PIF1, indicating that degradation of PIF1 is mediated by the ubiquitin-26S proteasome pathway. Further, de novo protein synthesis is not required for degradation of PIF1, as the presence of cycloheximide does not prevent degradation of PIF1 in the light. Taken together, these results suggest that the light signals perceived by phys induce the degradation of PIF1 and other phy-interacting factors to optimize photomorphogenesis.
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Affiliation(s)
- Hui Shen
- Section of Molecular Cell and Developmental Biology and The Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA
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22
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Devos KM, Beales J, Ogihara Y, Doust AN. Comparative sequence analysis of the phytochrome C gene and its upstream region in allohexaploid wheat reveals new data on the evolution of its three constituent genomes. PLANT MOLECULAR BIOLOGY 2005; 58:625-41. [PMID: 16158239 DOI: 10.1007/s11103-005-6801-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2004] [Accepted: 04/29/2005] [Indexed: 05/04/2023]
Abstract
Bread wheat is an allohexaploid with genome composition AABBDD. Phytochrome C is a gene involved in photomorphogenesis that has been used extensively for phylogenetic analyses. In wheat, the PhyC genes are single copy in each of the three homoeologous genomes and map to orthologous positions on the long arms of the group 5 chromosomes. Comparative sequence analysis of the three homoeologous copies of the wheat PhyC gene and of some 5 kb of upstream region has demonstrated a high level of conservation of PhyC, but frequent interruption of the upstream regions by the insertion of retroelements and other repeats. One of the repeats in the region under investigation appeared to have inserted before the divergence of the diploid wheat genomes, but was degraded to the extent that similarity between the A and D copies could only be observed at the amino acid level. Evidence was found for the differential presence of a foldback element and a miniature inverted-repeat transposable element (MITE) 5' to PhyC in different wheat cultivars. The latter may represent the first example of an active MITE family in the wheat genome. Several conserved non-coding sequences were also identified that may represent functional regulatory elements. The level of sequence divergence (Ks) between the three wheat PhyC homoeologs suggests that the divergence of the diploid wheat ancestors occurred some 6.9 Mya, which is considerably earlier than the previously estimated 2.5-4.5 Mya. Ka/Ks ratios were <0.15 indicating that all three homoeologs are under purifying selection and presumably represent functional PhyC genes. RT-PCR confirmed expression of the A, B and D copies. The discrepancy in evolutionary age of the wheat genomes estimated using sequences from different parts of the genome may reflect a mosaic origin of some of the Triticeae genomes.
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Affiliation(s)
- Katrien M Devos
- John Innes Centre, Norwich Research Park, Colney, Norwich, NR4 7UH, UK.
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23
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Stone BB, Esmon CA, Liscum E. Phototropins, other photoreceptors, and associated signaling: the lead and supporting cast in the control of plant movement responses. Curr Top Dev Biol 2005; 66:215-38. [PMID: 15797455 DOI: 10.1016/s0070-2153(05)66007-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Bethany B Stone
- University of Missouri-Columbia, Columbia, Missouri 65211, USA
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Im YJ, Kim JI, Shen Y, Na Y, Han YJ, Kim SH, Song PS, Eom SH. Structural analysis of Arabidopsis thaliana nucleoside diphosphate kinase-2 for phytochrome-mediated light signaling. J Mol Biol 2004; 343:659-70. [PMID: 15465053 DOI: 10.1016/j.jmb.2004.08.054] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2004] [Revised: 08/17/2004] [Accepted: 08/18/2004] [Indexed: 12/14/2022]
Abstract
In plants, nucleoside diphosphate kinases (NDPKs) play a key role in the signaling of both stress and light. However, little is known about the structural elements involved in their function. Of the three NDPKs (NDPK1-NDPK3) expressed in Arabidopsis thaliana, NDPK2 is involved in phytochrome-mediated signal transduction. In this study, we found that the binding of dNDP or NTP to NDPK2 strengthens the interaction significantly between activated phytochrome and NDPK2. To better understand the structural basis of the phytochrome-NDPK2 interaction, we determined the X-ray structures of NDPK1, NDPK2, and dGTP-bound NDPK2 from A.thaliana at 1.8A, 2.6A, and 2.4A, respectively. The structures showed that nucleotide binding caused a slight conformational change in NDPK2 that was confined to helices alphaA and alpha2. This suggests that the presence of nucleotide in the active site and/or the evoked conformational change contributes to the recognition of NDPK2 by activated phytochrome. In vitro binding assays showed that only NDPK2 interacted specifically with the phytochrome and the C-terminal regulatory domain of phytochrome is involved in the interaction. A domain swap experiment between NDPK1 and NDPK2 showed that the variable C-terminal region of NDPK2 is important for the activation by phytochrome. The structure of Arabidopsis NDPK1 and NDPK2 showed that the isoforms share common electrostatic surfaces at the nucleotide-binding site, but the variable C-terminal regions have distinct electrostatic charge distributions. These findings suggest that the binding of nucleotide to NDPK2 plays a regulatory role in phytochrome signaling and that the C-terminal extension of NDPK2 provides a potential binding surface for the specific interaction with phytochromes.
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Affiliation(s)
- Young Jun Im
- Department of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712, South Korea
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25
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Huq E, Al-Sady B, Hudson M, Kim C, Apel K, Quail PH. Phytochrome-interacting factor 1 is a critical bHLH regulator of chlorophyll biosynthesis. Science 2004; 305:1937-41. [PMID: 15448264 DOI: 10.1126/science.1099728] [Citation(s) in RCA: 303] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Photosynthetic organisms must achieve a delicate balance between the light energy absorbed by chlorophyll and their capacity to channel that energy into productive photochemical reactions. Release of excess absorbed energy in the cell can cause lethal photooxidative damage. We identified a basic helix-loop-helix (bHLH) transcription factor, designated PHYTOCHROME-INTERACTING FACTOR 1 (PIF1), that negatively regulates chlorophyll biosynthesis. pif1 mutant seedlings accumulate excess free protochlorophyllide when grown in the dark, with consequent lethal bleaching upon exposure to light. PIF1 interacts specifically with the photoactivated conformer of phytochromes A and B, suggesting a signaling pathway by which chlorophyll biosynthetic rates are tightly controlled during the critical initial emergence of seedlings from subterranean darkness into sunlight.
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Affiliation(s)
- Enamul Huq
- Section of Molecular Cell and Developmental Biology and Institute of Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
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26
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Park E, Kim J, Lee Y, Shin J, Oh E, Chung WI, Liu JR, Choi G. Degradation of Phytochrome Interacting Factor 3 in Phytochrome-Mediated Light Signaling. ACTA ACUST UNITED AC 2004; 45:968-75. [PMID: 15356322 DOI: 10.1093/pcp/pch125] [Citation(s) in RCA: 146] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Plant photoreceptors regulate various developmental processes. Among the photoreceptors, phytochromes, red and far-red light receptors, regulate light responses through many signaling components, including phytochrome-interacting proteins. The functional relationships among phytochromes and their interacting proteins, however, have not been clearly established. Here, we sought to identify a functional relationship between phytochromes and phytochrome interacting factor 3 (PIF3). We demonstrate that PIF3 is polyubiquitinated rapidly and subsequently degraded in PHYA and PHYB-mediated light signaling. We also show that the degradation of PIF3 is mediated by the 26S proteasome. Our data indicate that light-stimulated phytochromes cause the degradation of their interacting protein, PIF3, by the 26S proteasome.
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Affiliation(s)
- Eunae Park
- Department of Biological Sciences, KAIST, Daejeon, 305-701 Korea
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27
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Fujimori T, Yamashino T, Kato T, Mizuno T. Circadian-controlled basic/helix-loop-helix factor, PIL6, implicated in light-signal transduction in Arabidopsis thaliana. PLANT & CELL PHYSIOLOGY 2004; 45:1078-86. [PMID: 15356333 DOI: 10.1093/pcp/pch124] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
PHYTOCHROME-INTERACTING FACTOR-LIKE 6 (PIL6) is a member of the large family of basic/helix-loop-helix (bHLH) factors in Arabidopsis thaliana. This circadian-controlled transcription factor was previously suggested to interact with the clock component, TIMING OF CAB EXPRESSION 1 (TOC1). In this study, we isolated a loss-of-function mutant of PIL6, together with a transgenic line aberrantly expressing PIL6 in a manner independent of circadian rhythm. These mutant plants were simultaneously examined with special reference to circadian rhythm and light-signal transduction. The results suggested that PIL6 appears to be not directly involved in the clock function per se. However, the loss-of-function mutant (pil6-1) showed a remarkable phenotype in that it is hypersensitive to red light in seedling de-etiolation. This phenotype was similar to that observed for transgenic lines overexpressing TOC1 (or APRR1). Conversely, transgenic plants overexpressing PIL6 (PIL6-ox) are hyposensitive to red light under the same conditions. This phenotype was very similar to that observed for phyB mutants. The developmental morphologies of PIL6-ox, including the phenotype of early flowering, were also similar to those of phyB mutants. We propose that PIL6 acts as a negative regulator for a red light-mediated morphogenic response (e.g., elongation of hypocotyls in de-etiolation). Taken together, PIL6 might function at an interface between the circadian clock and red light-signal transduction pathways.
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Affiliation(s)
- Toru Fujimori
- Laboratory of Molecular Microbiology, School of Agriculture, Nagoya University, Chikusa-ku, Nagoya, 464-8601 Japan
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28
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Lin X, Momany C, Momany M. SwoHp, a nucleoside diphosphate kinase, is essential in Aspergillus nidulans. EUKARYOTIC CELL 2004; 2:1169-77. [PMID: 14665452 PMCID: PMC326647 DOI: 10.1128/ec.2.6.1169-1177.2003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The temperature-sensitive swoH1 mutant of Aspergillus nidulans was previously identified in a screen for mutants with defects in polar growth. In the present work, we found that the swoH1 mutant swelled, lysed, and did not produce conidia during extended incubation at the restrictive temperature. When shifted from the permissive to the restrictive temperature, swoH1 showed the temperature-sensitive swelling phenotype only after 8 h at the higher temperature. The swoH gene was mapped to chromosome II and cloned by complementation of the temperature-sensitive phenotype. The sequence showed that swoH encodes a homologue of nucleoside diphosphate kinases (NDKs) from other organisms. Deletion experiments showed that the swoH gene is essential. A hemagglutinin-SwoHp fusion complemented the mutant phenotype, and the purified fusion protein possessed phosphate transferase activity in thin-layer chromatography assays. Sequencing of the mutant allele showed a predicted V83F change. Structural modeling suggested that the swoH1 mutation would lead to perturbation of the NDK active site. Crude cell extracts from the swoH1 mutant grown at the permissive temperature had approximately 20% of the NDK activity seen in the wild type and did not show any decrease in activity when assayed at higher temperatures. Though the data are not conclusive, the lack of temperature-sensitive NDK activity in the swoH1 mutant raises the intriguing possibility that the SwoH NDK is required for growth at elevated temperatures rather than for polarity maintenance.
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Affiliation(s)
- Xiaorong Lin
- Department of Plant Biology, Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia 30602
| | - Cory Momany
- Department of Plant Biology, Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia 30602
| | - Michelle Momany
- Department of Plant Biology, Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, Georgia 30602
- Corresponding author. Mailing address: Michelle Momany, Department of Plant Biology, University of Georgia, Athens, GA 30602. Phone: (706) 542-2014. Fax: (706) 542-1805. E-mail:
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29
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Affiliation(s)
- Haiyang Wang
- Boyce Thompson Institute for Plant Research, Cornell University, Ithaca, NY 14853, USA
| | - Xing Wang Deng
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8104, USA
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30
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Khanna R, Kikis EA, Quail PH. EARLY FLOWERING 4 functions in phytochrome B-regulated seedling de-etiolation. PLANT PHYSIOLOGY 2003; 133:1530-8. [PMID: 14605220 PMCID: PMC300710 DOI: 10.1104/pp.103.030007] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2003] [Revised: 08/04/2003] [Accepted: 09/10/2003] [Indexed: 05/19/2023]
Abstract
To define the functions of genes previously identified by expression profiling as being rapidly light induced under phytochrome (phy) control, we are investigating the seedling de-etiolation phenotypes of mutants carrying T-DNA insertional disruptions at these loci. Mutants at one such locus displayed reduced responsiveness to continuous red, but not continuous far-red light, suggesting a role in phyB signaling but not phyA signaling. Consistent with such a role, expression of this gene is induced by continuous red light in wild-type seedlings, but the level of induction is strongly reduced in phyB-null mutants. The locus encodes a novel protein that we show localizes to the nucleus, thus suggesting a function in light-regulated gene expression. Recently, this locus was identified as EARLY FLOWERING 4, a gene implicated in floral induction and regulating the expression of the gene CIRCADIAN CLOCK-ASSOCIATED 1. Together with these previous data, our findings suggest that EARLY FLOWERING 4 functions as a signaling intermediate in phy-regulated gene expression involved in promotion of seedling de-etiolation, circadian clock function, and photoperiod perception.
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Affiliation(s)
- Rajnish Khanna
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, USA
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31
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Ito S, Matsushika A, Yamada H, Sato S, Kato T, Tabata S, Yamashino T, Mizuno T. Characterization of the APRR9 Pseudo-Response Regulator Belonging to the APRR1/TOC1 Quintet in Arabidopsis thaliana. ACTA ACUST UNITED AC 2003; 44:1237-45. [PMID: 14634162 DOI: 10.1093/pcp/pcg136] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In Arabidopsis thaliana, a number of circadian-associated factors have been identified, including TOC1 (TIMING OF CAB EXPRESSION1) that is believed to be a component of the central oscillator. TOC1 is a member of a small family of proteins, designated as ARABIDOPSIS PSEUDO-RESPONSE REGULATORS (APRR1/TOC1, APRR3, APRR5, APRR7, and APRR9). As demonstrated previously, these APRR1/TOC1 quintet members are crucial for a better understanding of the molecular links between circadian rhythms and photosensory signal transduction. Here we focused on the light-induced quintet member, APRR9, and three critical issues with regard to this member were simultaneously addressed: (i) clarification of the mechanism underlying the light-dependent acute response of APRR9, (ii) clarification of the phenotype of a null mutant of APRR9, (iii) identification of protein(s) that interacts with APRR9. In this study, we present the results that support the following views. (i) A phytochrome-mediated signaling pathway(s) activates the transcription of APRR9, leading to the acute light response of APRR9. (ii) The severe mutational lesion of APRR9 singly, if not directly, affects the period (and/or phase) of free-running rhythms, in continuous light, of every circadian-controlled gene tested, including the clock genes, APRR1/TOC1, CCA1, and LHY. (iii) The APRR9 protein is capable of interacting with APRR1/TOC1, suggesting a hetrodimer formation between these cognate family members. These results are discussed within the context of a current consistent model of the Arabidopsis circadian oscillator.
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Affiliation(s)
- Shogo Ito
- Laboratory of Molecular Microbiology, School of Agriculture, Nagoya University, Chikusa-ku, Nagoya, 464-8601 Japan
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32
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Merkle T. Nucleo-cytoplasmic partitioning of proteins in plants: implications for the regulation of environmental and developmental signalling. Curr Genet 2003; 44:231-60. [PMID: 14523572 DOI: 10.1007/s00294-003-0444-x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2003] [Revised: 08/21/2003] [Accepted: 09/01/2003] [Indexed: 12/21/2022]
Abstract
Considerable progress has been made in the past few years in characterising Arabidopsis nuclear transport receptors and in elucidating plant signal transduction pathways that employ nucleo-cytoplasmic partitioning of a member of the signal transduction chain. This review briefly introduces the major principles of nuclear transport of macromolecules across the nuclear envelope and the proteins involved, as they have been described in vertebrates and yeast. Proteins of the plant nuclear transport machinery that have been identified to date are discussed, the focus being on Importin beta-like nuclear transport receptors. Finally, the importance of nucleo-cytoplasmic partitioning as a regulatory tool for signalling is highlighted, and different plant signal transduction pathways that make use of this regulatory potential are presented.
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Affiliation(s)
- Thomas Merkle
- Institute of Biology II, Cell Biology, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany.
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33
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Toledo-Ortiz G, Huq E, Quail PH. The Arabidopsis basic/helix-loop-helix transcription factor family. THE PLANT CELL 2003; 15:1749-70. [PMID: 12897250 PMCID: PMC167167 DOI: 10.1105/tpc.013839] [Citation(s) in RCA: 876] [Impact Index Per Article: 41.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2003] [Accepted: 06/02/2003] [Indexed: 05/18/2023]
Abstract
The basic/helix-loop-helix (bHLH) proteins are a superfamily of transcription factors that bind as dimers to specific DNA target sites and that have been well characterized in nonplant eukaryotes as important regulatory components in diverse biological processes. Based on evidence that the bHLH protein PIF3 is a direct phytochrome reaction partner in the photoreceptor's signaling network, we have undertaken a comprehensive computational analysis of the Arabidopsis genome sequence databases to define the scope and features of the bHLH family. Using a set of criteria derived from a previously defined consensus motif, we identified 147 bHLH protein-encoding genes, making this one of the largest transcription factor families in Arabidopsis. Phylogenetic analysis of the bHLH domain sequences permits classification of these genes into 21 subfamilies. The evolutionary and potential functional relationships implied by this analysis are supported by other criteria, including the chromosomal distribution of these genes relative to duplicated genome segments, the conservation of variant exon/intron structural patterns, and the predicted DNA binding activities within subfamilies. Considerable diversity in DNA binding site specificity among family members is predicted, and marked divergence in protein sequence outside of the conserved bHLH domain is observed. Together with the established propensity of bHLH factors to engage in varying degrees of homodimerization and heterodimerization, these observations suggest that the Arabidopsis bHLH proteins have the potential to participate in an extensive set of combinatorial interactions, endowing them with the capacity to be involved in the regulation of a multiplicity of transcriptional programs. We provide evidence from yeast two-hybrid and in vitro binding assays that two related phytochrome-interacting members in the Arabidopsis family, PIF3 and PIF4, can form both homodimers and heterodimers and that all three dimeric configurations can bind specifically to the G-box DNA sequence motif CACGTG. These data are consistent, in principle, with the operation of this combinatorial mechanism in Arabidopsis.
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Affiliation(s)
- Gabriela Toledo-Ortiz
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
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34
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Abstract
The basic helix-loop-helix (bHLH) family of proteins is a group of functionally diverse transcription factors found in both plants and animals. These proteins evolved early in eukaryotic cells before the split of animals and plants, but appear to function in 'plant-specific' or 'animal-specific' processes. In animals bHLH proteins are involved in regulation of a wide variety of essential developmental processes. On the contrary, bHLH proteins have not been extensively studied in plants. Those that have been characterized function in anthocyanin biosynthesis, phytochrome signaling, globulin expression, fruit dehiscence, carpel and epidermal development. We have identified 118 different bHLH genes in the completely sequenced Arabidopsis thaliana genome and 131 bHLH genes in the rice genome. Here we report a phylogenetic analysis of these genes, including 46 genes from other plant species and a classification of these proteins into 15 distinct plant clades. Results imply a polyphyletic origin for the plant bHLH proteins related only by their bHLH DNA binding motif. We suggest that plant bHLH proteins are under weaker selective constraints than their animal counterparts and that lineage specific expansions and subfunctionalization have fashioned regulatory proteins for plant specific functions.
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Affiliation(s)
- Michael J Buck
- Department of Genetics and The Center for Computational Biology, North Carolina State University, Campus Box 7614, Raleigh, NC 27695-7614, USA.
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35
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Yamashino T, Matsushika A, Fujimori T, Sato S, Kato T, Tabata S, Mizuno T. A Link between circadian-controlled bHLH factors and the APRR1/TOC1 quintet in Arabidopsis thaliana. PLANT & CELL PHYSIOLOGY 2003; 44:619-29. [PMID: 12826627 DOI: 10.1093/pcp/pcg078] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
APRR1 (ARABIDPSIS PSUEDO-RESPONSE REGULATOR 1) (or TOC1, TIMING OF CAB EXPRESSION 1) is believed to be a crucial component of biological clocks of Arabidopsis thaliana. Nevertheless, its molecular function remains to be fully elucidated. Based on the results of yeast two-hybrid and in vitro binding assays, we previously showed that APRR1/TOC1 interacts with certain bHLH factors (i.e. PIF3 and PIL1, which are PHYTOCHROME INTERACTING FACTOR 3 and its homolog (PIF3-LIKE 1), respectively). To critically examine the relevance of PIL1 with reference to the function of APRR1/TOC1, T-DNA insertion mutants were isolated for PIL1. No phenotype was observed for such homozygous pil1 mutants, in terms of circadian-associated events in plants. We then examined more extensively a certain set of bHLH factors, which are considerably similar to PIL1 in their structural designs. The results of extensive analyses of such bHLH factors (namely, HFR1, PIL2, PIF4, PIL5 and PIL6) in wild-type and APRR1-overexressing (APRR1-ox) transgenic lines provided us with several new insights into a link between APRR1/TOC1 and these bHLH factors. In yeast two-hybrid assays, APRR1/TOC1 showed the ability to interact with these proteins (except for HFR1), as well as PIL1 and PIF3. Among them, it was found that the expressions of PIF4 and PIL6 were regulated in a circadian-dependent manner, exhibiting free-running robust rhythms. The expressions of PIF4 and PIL6 were regulated also by light in a manner that their transcripts were rapidly accumulated upon exposure of etiolated seedlings to light. The light-induced expressions of PIF4 and PIL6 were severely impaired in APRR1-ox transgenic lines. Taken together, here we propose the novel view that these bHLH factors (PIF4 and PIL6) might play roles, in concert with APRR1/TOC1, in the integration of light-signals to control both circadian and photomorphogenic processes.
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Affiliation(s)
- Takafumi Yamashino
- Laboratory of Molecular Microbiology, School of Agriculture, Nagoya University, Chikusa-ku, Nagoya, 464-8601 Japan
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36
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Schäfer E, Bowler C. Phytochrome-mediated photoperception and signal transduction in higher plants. EMBO Rep 2002; 3:1042-8. [PMID: 12429614 PMCID: PMC1307593 DOI: 10.1093/embo-reports/kvf222] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2002] [Revised: 09/30/2002] [Accepted: 10/01/2002] [Indexed: 12/16/2022] Open
Abstract
Light provides a major source of information from the environment during plant growth and development. Light perception is mediated through the action of several photoreceptors, including the phytochromes. Recent results demonstrate that light responses involve the regulation of several thousand genes. Some of the key events controlling this gene expression are the translocation of the phytochrome photoreceptors into the nucleus followed by their binding to transcription factors. Coupled with these events, the degradation of positively acting intermediates appears to be an important process whereby photomorphogenesis is repressed in darkness. This review summarizes our current knowledge of these processes.
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Affiliation(s)
- Eberhard Schäfer
- Universitat Freiburg, Institut fur Biologie II/Botanik, Schanzlestrasse 1, D-79104 Freiburg, Germany
| | - Chris Bowler
- Molecular Plant Biology Laboratory, Stazione Zoologica 'Anton Dohrn', Villa Comunale, I-80121 Naples, Italy
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37
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Sato E, Nakamichi N, Yamashino T, Mizuno T. Aberrant expression of the Arabidopsis circadian-regulated APRR5 gene belonging to the APRR1/TOC1 quintet results in early flowering and hypersensitiveness to light in early photomorphogenesis. PLANT & CELL PHYSIOLOGY 2002; 43:1374-85. [PMID: 12461138 DOI: 10.1093/pcp/pcf166] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
In Arabidopsis thaliana, the transcripts of the APRR1/TOC1 family genes each start accumulating after dawn rhythmically and one after another at intervals in the order of APRR9-->APRR7-->APRR5-->APRR3-->APRR1/TOC1 under continuous light. Except for the well-characterized APRR1/TOC1, however, no evidence has been provided that other APRR1/TOC1 family genes are indeed implicated in the mechanisms underlying circadian rhythms. We here attempted to provide such evidence by characterizing transgenic plants that constitutively express the APRR5 gene. The resulting APRR5-overexpressing (APRR5-ox) plants showed intriguing properties with regard to not only circadian rhythms, but also control of flowering time and light response. First, the aberrant expression of APRR5 in such transgenic plants resulted in a characteristic phenotype with regard to transcriptional events, in which free-running rhythms were considerably altered for certain circadian-regulated genes, including CCA1, LHY, APRR1/TOC1, other APRR1/TOC1 members, GI and CAB2, although each rhythm was clearly sustained even after plants were transferred to continuous light. With regard to biological events, APRR5-ox plants flowered much earlier than wild-type plants, more or less, in a manner independent of photoperiodicity (or under short-day conditions). Furthermore, APRR5-ox plants showed an SRL (short-hypocotyls under red light) phenotype that is indicative of hypersensitiveness to red light in early photomorphogenesis. Both APRR1-ox and APRR9-ox plants also showed the same phenotype. Therefore, APRR5 (together with APRR1/TOC1 and APRR9) must be taken into consideration for a better understanding of the molecular links between circadian rhythms, control of flowering time through the photoperiodic long-day pathway, and also light signaling-controlled plant development.
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Affiliation(s)
- Eriko Sato
- Laboratory of Molecular Microbiology, School of Agriculture, Nagoya University, Chikusa-ku, Nagoya, 464-8601 Japan
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38
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Ma L, Gao Y, Qu L, Chen Z, Li J, Zhao H, Deng XW. Genomic evidence for COP1 as a repressor of light-regulated gene expression and development in Arabidopsis. THE PLANT CELL 2002; 14:2383-98. [PMID: 12368493 PMCID: PMC151224 DOI: 10.1105/tpc.004416] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2002] [Accepted: 06/24/2002] [Indexed: 05/18/2023]
Abstract
Microarray gene expression profiling was used to examine the role of COP1 in the light control of Arabidopsis genome expression. Qualitatively similar gene expression profiles were observed between wild-type seedlings grown in white light and multiple cop1 mutant alleles grown in the dark. Furthermore, overexpression of the dominant-negative-acting N terminus of COP1 (N282) in darkness produced a genome expression profile similar to those produced by white light and the cop1 mutations. Different cop1 mutant alleles, N282, and light treatment also resulted in distinct expression profiles in a small fraction of the genes examined. In the light, the genome expression of cop1 mutations displayed an exaggerated light response. COP1-regulated genes in the dark were estimated to account for >20% of the genome. Analysis of these COP1-regulated genes revealed that >28 cellular pathways are coordinately but antagonistically regulated by light and COP1. Interestingly, the gene expression regulation attributable to HY5 in the light is included largely within those genes regulated by COP1 in the dark. Thus, this genomic study supports the hypothesis that COP1 acts as a repressor of photomorphogenesis, possibly by controlling the degradation of transcription factors and their target gene expression. The majority of light-controlled genome expression could be accounted for by the negative regulation of COP1 activity.
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Affiliation(s)
- Ligeng Ma
- Peking-Yale Joint Center of Plant Molecular Genetics and Agrobiotechnology, College of Life Sciences, Peking University, Beijing 100871, People's Republic of China
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39
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Abstract
Phytochromes were long thought to have evolved in non-motile photosynthetic eukaryotes for adaptation to unfavorable light environments, but recent studies suggest that phytochromes evolved billions of years earlier from a tetrapyrrole sensor protein progenitor. These investigations have identified phytochromes and phytochrome-related proteins in photosynthetic bacteria (cyanobacteria and purple bacteria), nonphotosynthetic eubacteria and fungi - an observation that has opened new avenues for investigating the origins, molecular evolution and biochemical functions of this ecologically important family of plant photoreceptors.
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40
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Møller SG, Ingles PJ, Whitelam GC. The cell biology of phytochrome signalling. THE NEW PHYTOLOGIST 2002; 154:553-590. [PMID: 33873456 DOI: 10.1046/j.1469-8137.2002.00419.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Phytochrome signal transduction has in the past often been viewed as being a nonspatially separated linear chain of events. However, through a combination of molecular, genetic and cell biological approaches, it is becoming increasingly evident that phytochrome signalling constitutes a highly ordered multidimensional network of events. The discovery that some phytochromes and signalling intermediates show light-dependent nucleo-cytoplasmic partitioning has not only led to the suggestion that early signalling events take place in the nucleus, but also that subcellular localization patterns most probably represent an important signalling control point. Moreover, detailed characterization of signalling intermediates has demonstrated that various branches of the signalling network are spatially separated and take place in different cellular compartments including the nucleus, cytosol, and chloroplasts. In addition, proteasome-mediated degradation of signalling intermediates most probably act in concert with subcellular partitioning events as an integrated checkpoint. An emerging view from this is that phytochrome signalling is separated into several subcellular organelles and that these are interconnected in order to execute accurate responses to changes in the light environment. By integrating the available data, both at the cellular and subcellular level, we should be able to construct a solid foundation for further dissection of phytochrome signal transduction in plants. Contents Summary 553 I. Introduction 554 II. Nucleus vs cytoplasm 556 III. The nucleus 562 IV. The cytoplasm 571 V. Interactions with other signalling pathways 577 VI. Conclusions and the future 582 Acknowledgements 583 References 583.
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Affiliation(s)
- Simon G Møller
- Department of Biology, University of Leicester, University Road, Leicester, LE1 7RH, UK
| | - Patricia J Ingles
- Department of Biology, University of Leicester, University Road, Leicester, LE1 7RH, UK
| | - Garry C Whitelam
- Department of Biology, University of Leicester, University Road, Leicester, LE1 7RH, UK
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41
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Holm M, Ma LG, Qu LJ, Deng XW. Two interacting bZIP proteins are direct targets of COP1-mediated control of light-dependent gene expression in Arabidopsis. Genes Dev 2002; 16:1247-59. [PMID: 12023303 PMCID: PMC186273 DOI: 10.1101/gad.969702] [Citation(s) in RCA: 447] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Arabidopsis COP1 acts to repress photomorphogenesis in the absence of light. It was shown that in the dark, COP1 directly interacts with the bZIP transcription factor HY5, a positive regulator of photomorphogenesis, and promotes its proteasome-mediated degradation. Here we identify a novel bZIP protein HYH, as a new target of COP1. We identify a physical and genetic interaction between HYH and COP1 and show that this interaction results in dark-specific degradation of HYH. Genetic analysis indicates that HYH is predominantly involved in blue-light regulation of development and gene expression, and that the function of HYH in part overlaps with that of HY5. The accumulation of HYH protein, not the mRNA, is dependent on the presence of HY5. Our data suggest that HYH and HY5 can, respectively, act as heterodimers and homodimers, thus mediating light-regulated expression of overlapping as well as distinct target genes. We propose that COP1 mediates light control of gene expression through targeted degradation of multiple photomorphogenesis-promoting transcription factors in the nucleus.
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Affiliation(s)
- Magnus Holm
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06520-8104, USA
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42
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Huq E, Quail PH. PIF4, a phytochrome-interacting bHLH factor, functions as a negative regulator of phytochrome B signaling in Arabidopsis. EMBO J 2002; 21:2441-50. [PMID: 12006496 PMCID: PMC126004 DOI: 10.1093/emboj/21.10.2441] [Citation(s) in RCA: 406] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Plants sense and respond to red and far-red light using the phytochrome (phy) family of photoreceptors. However, the mechanism of light signal transduction is not well defined. Here, we report the identification of a new mutant Arabidopsis locus, srl2 (short under red-light 2), which confers selective hypersensitivity to continuous red, but not far-red, light. This hypersensitivity is eliminated in srl2phyB, but not srl2phyA, double mutants, indicating that this locus functions selectively and negatively in phyB signaling. The SRL2 gene encodes a bHLH factor, designated PIF4 (phytochrome-interacting factor 4), which binds selectively to the biologically active Pfr form of phyB, but has little affinity for phyA. Despite its hypersensitive morphological phenotype, the srl2 mutant displays no perturbation of light-induced expression of marker genes for chloroplast development. These data suggest that PIF4 may function specifically in a branch of the phyB signaling network that regulates a subset of genes involved in cell expansion. Consistent with this proposal, PIF4 localizes to the nucleus and can bind to a G-box DNA sequence motif found in various light-regulated promoters.
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Affiliation(s)
| | - Peter H. Quail
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720 and US Department of Agriculture/Agricultural Research Service, Plant Gene Expression Center, 800 Buchanan Street, Albany, CA 94710, USA
Corresponding author e-mail:
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43
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Shin B, Choi G, Yi H, Yang S, Cho I, Kim J, Lee S, Paek NC, Kim JH, Song PS, Choi G. AtMYB21, a gene encoding a flower-specific transcription factor, is regulated by COP1. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2002; 30:23-32. [PMID: 11967090 DOI: 10.1046/j.1365-313x.2002.01264.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Light is an important environmental signal that governs plant growth and development. One important light-signalling component involved in plant light responses is COP1. The pleiotropic phenotypes of the cop1 mutant suggest that COP1 regulates not only photomorphogenesis, but also other developmental processes. We investigated the role of COP1 by identifying genes that are regulated by COP1. We report that AtMYB21, a gene encoding a flower-specific transcription factor, is ectopically expressed in the cop1 mutant. Analysis shows that dark-grown transgenic seedlings expressing AtMYB21-GR fusion protein display some features of the cop1 mutant, including decreased hypocotyl cell expansion, open cotyledons in the dark, and seedling lethality in the presence of dexamethasone. Light-grown adult transgenic plants expressing AtMYB21 have shorter stems, smaller and narrower leaves, narrower petals, and malformed carpels. In addition, we show that AtMYB21 directly regulates two genes that are also expressed more abundantly in the cop1 mutant. The results indicate that COP1 is required to repress the AtMYB21 gene in seedlings, and the pleiotropic phenotypes shown in the cop1 mutant are due to the combination of misregulation of genuine light-signalling components and other tissue-specific factors.
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Affiliation(s)
- Byongchul Shin
- Kumho Life and Environmental Science Laboratory, 1 Oryong-dong, Buk-gu, Gwangju 500-712 Korea
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44
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Abstract
Plants monitor informational light signals using three sensory photoreceptor families: the phototropins, cryptochromes and phytochromes. Recent advances suggest that the phytochromes act transcriptionally by targeting light signals directly to photoresponsive promoters through binding to a transcriptional regulator. By contrast, the cryptochromes appear to act post-translationally, by disrupting extant proteosome-mediated degradation of a key transcriptional activator through direct binding to a putative E3 ubiquitin ligase, thereby elevating levels of the activator and consequently of target gene expression.
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Affiliation(s)
- Peter H Quail
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA.
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45
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Wang H, Deng XW. Arabidopsis FHY3 defines a key phytochrome A signaling component directly interacting with its homologous partner FAR1. EMBO J 2002; 21:1339-49. [PMID: 11889039 PMCID: PMC125923 DOI: 10.1093/emboj/21.6.1339] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2001] [Revised: 01/16/2002] [Accepted: 01/22/2002] [Indexed: 11/14/2022] Open
Abstract
In Arabidopsis, phytochrome A (phyA) is the primary photoreceptor mediating various plant responses to far-red (FR) light. Here we show that phyA signaling involves a combinatorial action of downstream intermediates, which controls overlapping yet distinctive sets of FR responses. FHY3 is a prominent phyA signaling intermediate sharing structural similarity to FAR1, a previously identified phyA signaling component. The fhy3 and far1 mutants display similar yet distinctive defects in phyA signaling; however, overexpression of either FHY3 or FAR1 suppresses the mutant phenotype of both genes. Moreover, overexpression of partial fragments of FHY3 can cause a dominant-negative interference phenotype on phyA signaling that is stronger than those of the fhy3 or far1 null mutants. Further, we demonstrate that FHY3 and FAR1 are capable of homo- and hetero-interaction. Our data indicate that FHY3, together with FAR1, defines a key module in a signaling network underlying phyA-mediated FR light responses.
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Affiliation(s)
- Haiyang Wang
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8104, USA
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46
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Abstract
If the last common ancestor of plants and animals was unicellular, comparison of the developmental mechanisms of plants and animals would show that development was independently invented in each lineage. And if this is the case, comparison of plant and animal developmental processes would give us a truly comparative study of development, which comparisons merely among animals, or merely among plants, do not-because in each of these lineages, the fundamental mechanisms are similar by descent. Evidence from studies of developmental mechanisms in both kingdoms, and data from genome-sequencing projects, indicate that development evolved independently in the lineages leading to plants and to animals.
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Affiliation(s)
- Elliot M Meyerowitz
- Division of Biology 156-29, California Institute of Technology, Pasadena, CA 91125, USA.
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47
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Abstract
Light is life for plants. To continuously assess and adapt to fluctuations in the quality and quantity of this essential commodity, plants deploy sensory photoreceptors, including the phytochromes. Having captured an incoming photon, the activated phytochrome molecule must relay this information to nuclear genes that are poised to respond by directing appropriate adjustments in growth and development. Defining the intricate intracellular signalling networks through which this sensory information is transduced is an area of intense research activity.
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Affiliation(s)
- Peter H Quail
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, USA.
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48
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Santelli RV, Siviero F. A search for homologues of plant photoreceptor genes and their signaling partners in the sugarcane expressed sequence tag (Sucest) database. Genet Mol Biol 2001. [DOI: 10.1590/s1415-47572001000100008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A search in the sugarcane expressed sequence tag (SUCEST) database for homologues of plant genes involved in photo-sensory mechanisms was carried out using the basic local alignment tool (BLAST). Our results shown that known elements (phytochromes, cryptochromes and phototoprin) present in Arabidopsis and other higher plants were detected with low e-values. We also searched for proteins interacting with photoreceptors in primary or downstream signaling events. One putative homologue for a protein postulated to be a primary element in phytochrome signaling pathways was identified, as were other candidates for downstream interacting factors.
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49
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Hoecker U, Quail PH. The phytochrome A-specific signaling intermediate SPA1 interacts directly with COP1, a constitutive repressor of light signaling in Arabidopsis. J Biol Chem 2001; 276:38173-8. [PMID: 11461903 DOI: 10.1074/jbc.m103140200] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
SPA1 is a phytochrome A (phyA)-specific signaling intermediate that acts as a light-dependent repressor of photomorphogenesis in Arabidopsis seedlings. It contains a WD-repeat domain that shows high sequence similarity to the WD-repeat region of the constitutive repressor of light signaling, COP1. Here, using yeast two-hybrid and in vitro interaction assays, we show that SPA1 strongly and selectively binds to COP1. Domain mapping studies indicate that the putative coiled-coil domain of SPA1 is necessary and sufficient for binding to COP1. Conversely, similar deletion analyses of the COP1 protein suggest that SPA1 interacts with the presumed coiled-coil domain of COP1. To further investigate SPA1 function in the phyA signaling pathway, we tested whether SPA1, like COP1, mediates changes in gene expression in response to light. We show that spa1 mutations increase the photoresponsiveness of certain light-regulated genes within 2 h of light treatment. Taken together, the results suggest that SPA1 may function to link the phytochrome A-specific branch of the light signaling pathway to COP1. Hence, our data provide molecular support for the hypothesis that COP1 is a convergence point for upstream signaling pathways dedicated to individual photoreceptors.
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Affiliation(s)
- U Hoecker
- Institut für Entwicklungs-und Molekularbiologie der Pflanzen, University of Düsseldorf, Building 26.03.02., D-40225 Düsseldorf, Germany.
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50
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Tepperman JM, Zhu T, Chang HS, Wang X, Quail PH. Multiple transcription-factor genes are early targets of phytochrome A signaling. Proc Natl Acad Sci U S A 2001; 98:9437-42. [PMID: 11481498 PMCID: PMC55439 DOI: 10.1073/pnas.161300998] [Citation(s) in RCA: 330] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The phytochrome family of sensory photoreceptors directs adaptational changes in gene expression in response to environmental light signals. Using oligonucleotide microarrays to measure expression profiles in wild-type and phytochrome A (phyA) null-mutant Arabidopsis seedlings, we have shown that 10% of the genes represented on the array are regulated by phyA in response to a continuous far-red light signal. Strikingly, 44% of the genes responding to the signal within 1 h are predicted to encode multiple classes of transcriptional regulators. Together with previous data, this observation suggests that phyA may regulate seedling photomorphogenesis by direct targeting of light signals to the promoters of genes encoding a master set of diverse transcriptional regulators, responsible in turn for orchestrating the expression of multiple downstream target genes in various branches of a phyA-regulated transcriptional network.
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Affiliation(s)
- J M Tepperman
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
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