1
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Rredhi A, Petersen J, Wagner V, Vuong T, Li W, Li W, Schrader L, Mittag M. The UV-A Receptor CRY-DASH1 Up- and Downregulates Proteins Involved in Different Plastidial Pathways. J Mol Biol 2024; 436:168271. [PMID: 37699454 DOI: 10.1016/j.jmb.2023.168271] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Revised: 08/18/2023] [Accepted: 09/06/2023] [Indexed: 09/14/2023]
Abstract
Algae encode up to five different types of cryptochrome photoreceptors. So far, relatively little is known about the biological functions of the DASH (Drosophila, Arabidopsis, Synechocystis and Homo)-type cryptochromes. The green alga Chlamydomonas reinhardtii encodes two of them. CRY-DASH1 also called DCRY1 has its maximal absorption peak in the UV-A range. It is localized in the chloroplast and plays an important role in balancing the photosynthetic machinery. Here, we performed a comparative analysis of chloroplast proteins from wild type and a knockout mutant of CRY-DASH1 named cry-dash1mut, using label-free quantitative proteomics as well as immunoblotting. Our results show upregulation of enzymes involved in specific pathways in the mutant including key enzymes of chlorophyll and carotenoid biosynthesis consistent with increased levels of photosynthetic pigments in cry-dash1mut. There is also an increase in certain redox as well as photosystem I and II proteins, including D1. Strikingly, CRY-DASH1 is coregulated in a D1 deletion mutant, where its amount is increased. In contrast, key proteins of the central carbon metabolism, including glycolysis/gluconeogenesis, dark fermentation and the oxidative pentose phosphate pathway are downregulated in cry-dash1mut. Similarly, enzymes of histidine biosynthesis are downregulated in cry-dash1mut leading to a reduction in the amount of free histidine. Yet, transcripts encoding for several of these proteins are at a similar level in the wild type and cry-dash1mut or even opposite. We show that CRY-DASH1 can bind to RNA, taking the psbA RNA encoding D1 as target. These data suggest that CRY-DASH1 regulates plastidial metabolic pathways at the posttranscriptional level.
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Affiliation(s)
- Anxhela Rredhi
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Jan Petersen
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, 07743 Jena, Germany. https://twitter.com/1anPetersen
| | - Volker Wagner
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Trang Vuong
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, 07743 Jena, Germany. https://twitter.com/trangha593
| | - Wenshuang Li
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Wei Li
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Laura Schrader
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Maria Mittag
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, 07743 Jena, Germany.
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2
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McKnight BM, Kang S, Le TH, Fang M, Carbonel G, Rodriguez E, Govindarajan S, Albocher-Kedem N, Tran AL, Duncan NR, Amster-Choder O, Golden SS, Cohen SE. Roles for the Synechococcus elongatus RNA-Binding Protein Rbp2 in Regulating the Circadian Clock. J Biol Rhythms 2023; 38:447-460. [PMID: 37515350 PMCID: PMC10528358 DOI: 10.1177/07487304231188761] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2023]
Abstract
The cyanobacterial circadian oscillator, consisting of KaiA, KaiB, and KaiC proteins, drives global rhythms of gene expression and compaction of the chromosome and regulates the timing of cell division and natural transformation. While the KaiABC posttranslational oscillator can be reconstituted in vitro, the Kai-based oscillator is subject to several layers of regulation in vivo. Specifically, the oscillator proteins undergo changes in their subcellular localization patterns, where KaiA and KaiC are diffuse throughout the cell during the day and localized as a focus at or near the pole of the cell at night. Here, we report that the CI domain of KaiC, when in a hexameric state, is sufficient to target KaiC to the pole. Moreover, increased ATPase activity of KaiC correlates with enhanced polar localization. We identified proteins associated with KaiC in either a localized or diffuse state. We found that loss of Rbp2, found to be associated with localized KaiC, results in decreased incidence of KaiC localization and long-period circadian phenotypes. Rbp2 is an RNA-binding protein, and it appears that RNA-binding activity of Rbp2 is required to execute clock functions. These findings uncover previously unrecognized roles for Rbp2 in regulating the circadian clock and suggest that the proper localization of KaiC is required for a fully functional clock in vivo.
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Affiliation(s)
- Briana M. McKnight
- Department of Molecular Biology, University of California, San Diego, La Jolla, CA 92093
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA 92093
| | - Shannon Kang
- Department of Molecular Biology, University of California, San Diego, La Jolla, CA 92093
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA 92093
| | - Tam H. Le
- Department of Biological Sciences, California State University, Los Angeles, Los Angeles, CA 90032
| | - Mingxu Fang
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA 92093
| | - Genelyn Carbonel
- Department of Biological Sciences, California State University, Los Angeles, Los Angeles, CA 90032
| | - Esbeydi Rodriguez
- Department of Biological Sciences, California State University, Los Angeles, Los Angeles, CA 90032
| | - Sutharsan Govindarajan
- Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University Faculty of Medicine, Jerusalem 91120, Israel
- Department of Biological Sciences, SRM University AP, Amaravati, India
| | - Nitsan Albocher-Kedem
- Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University Faculty of Medicine, Jerusalem 91120, Israel
| | - Amanda L. Tran
- Department of Biological Sciences, California State University, Los Angeles, Los Angeles, CA 90032
| | - Nicholas R. Duncan
- Department of Biological Sciences, California State University, Los Angeles, Los Angeles, CA 90032
| | - Orna Amster-Choder
- Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University Faculty of Medicine, Jerusalem 91120, Israel
| | - Susan S. Golden
- Department of Molecular Biology, University of California, San Diego, La Jolla, CA 92093
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA 92093
| | - Susan E. Cohen
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA 92093
- Department of Biological Sciences, California State University, Los Angeles, Los Angeles, CA 90032
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3
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Jadhav DB, Sriramkumar Y, Roy S. The enigmatic clock of dinoflagellates, is it unique? Front Microbiol 2022; 13:1004074. [PMID: 36338102 PMCID: PMC9627503 DOI: 10.3389/fmicb.2022.1004074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 09/29/2022] [Indexed: 12/01/2022] Open
Abstract
Dinoflagellate clocks are unique as they show no resemblance to any known model eukaryotic or prokaryotic clock architecture. Dinoflagellates are unicellular, photosynthetic, primarily marine eukaryotes are known for their unique biology and rhythmic physiology. Their physiological rhythms are driven by an internal oscillator whose molecular underpinnings are yet unknown. One of the primary reasons that slowed the progression of their molecular studies is their extremely large and repetitive genomes. Dinoflagellates are primary contributors to the global carbon cycle and oxygen levels, therefore, comprehending their internal clock architecture and its interaction with their physiology becomes a subject of utmost importance. The advent of high throughput Omics technology provided the momentum to understand the molecular architecture and functioning of the dinoflagellate clocks. We use these extensive databases to perform meta-analysis to reveal the status of clock components in dinoflagellates. In this article, we will delve deep into the various “Omics” studies that catered to various breakthroughs in the field of circadian biology in these organisms that were not possible earlier. The overall inference from these omics studies points toward an uncommon eukaryotic clock model, which can provide promising leads to understand the evolution of molecular clocks.
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Petersen J, Rredhi A, Szyttenholm J, Mittag M. Evolution of circadian clocks along the green lineage. PLANT PHYSIOLOGY 2022; 190:924-937. [PMID: 35325228 PMCID: PMC9516769 DOI: 10.1093/plphys/kiac141] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 03/04/2022] [Indexed: 05/10/2023]
Abstract
Circadian clocks govern temporal programs in the green lineage (Chloroplastida) as they do in other photosynthetic pro- and eukaryotes, bacteria, fungi, animals, and humans. Their physiological properties, including entrainment, phase responses, and temperature compensation, are well conserved. The involvement of transcriptional/translational feedback loops in the oscillatory machinery and reversible phosphorylation events are also maintained. Circadian clocks control a large variety of output rhythms in green algae and terrestrial plants, adjusting their metabolism and behavior to the day-night cycle. The angiosperm Arabidopsis (Arabidopsis thaliana) represents a well-studied circadian clock model. Several molecular components of its oscillatory machinery are conserved in other Chloroplastida, but their functions may differ. Conserved clock components include at least one member of the CIRCADIAN CLOCK ASSOCIATED1/REVEILLE and one of the PSEUDO RESPONSE REGULATOR family. The Arabidopsis evening complex members EARLY FLOWERING3 (ELF3), ELF4, and LUX ARRHYTHMO are found in the moss Physcomitrium patens and in the liverwort Marchantia polymorpha. In the flagellate chlorophyte alga Chlamydomonas reinhardtii, only homologs of ELF4 and LUX (named RHYTHM OF CHLOROPLAST ROC75) are present. Temporal ROC75 expression in C. reinhardtii is opposite to that of the angiosperm LUX, suggesting different clock mechanisms. In the picoalga Ostreococcus tauri, both ELF genes are missing, suggesting that it has a progenitor circadian "green" clock. Clock-relevant photoreceptors and thermosensors vary within the green lineage, except for the CRYPTOCHROMEs, whose variety and functions may differ. More genetically tractable models of Chloroplastida are needed to draw final conclusions about the gradual evolution of circadian clocks within the green lineage.
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Affiliation(s)
- Jan Petersen
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Jena 07743, Germany
| | - Anxhela Rredhi
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Jena 07743, Germany
| | - Julie Szyttenholm
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Jena 07743, Germany
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5
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Rredhi A, Petersen J, Schubert M, Li W, Oldemeyer S, Li W, Westermann M, Wagner V, Kottke T, Mittag M. DASH cryptochrome 1, a UV-A receptor, balances the photosynthetic machinery of Chlamydomonas reinhardtii. THE NEW PHYTOLOGIST 2021; 232:610-624. [PMID: 34235760 DOI: 10.1111/nph.17603] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Accepted: 06/29/2021] [Indexed: 06/13/2023]
Abstract
Drosophila, Arabidopsis, Synechocystis, Homo (DASH) cryptochromes belong to the cryptochrome/photolyase family and can act as DNA repair enzymes. In bacteria and fungi, they also can play regulatory roles, but in plants their biological functions remain elusive. Here, we characterize CRY-DASH1 from the green alga Chlamydomonas reinhardtii. We perform biochemical and in vitro photochemical analysis. For functional characterization, a knock-out mutant of cry-dash1 is used. CRY-DASH1 protein is localized in the chloroplast and accumulates at midday. Although the photoautotrophic growth of the mutant is significantly reduced compared to the wild-type (WT), the mutant has increased levels of photosynthetic pigments and a higher maximum photochemical efficiency of photosystem II (PS II). Hyper-stacking of thylakoid membranes occurs together with an increase in proteins of the PS II reaction center, D1 and its antenna CP43, but not of their transcripts. CRY-DASH1 binds fully reduced flavin adenine dinucleotide and the antenna 5,10-methenyltetrahydrofolate, leading to an absorption peak in the UV-A range. Supplementation of white light with UV-A increases photoautotrophic growth of the WT but not of the cry-dash1 mutant. These results suggest a balancing function of CRY-DASH1 in the photosynthetic machinery and point to its role as a photoreceptor for the UV-A range separated from the absorption of photosynthetic pigments.
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Affiliation(s)
- Anxhela Rredhi
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Jena, 07743, Germany
| | - Jan Petersen
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Jena, 07743, Germany
| | - Melvin Schubert
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Jena, 07743, Germany
| | - Wei Li
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Jena, 07743, Germany
| | - Sabine Oldemeyer
- Physical and Biophysical Chemistry, Department of Chemistry, Bielefeld University, Bielefeld, 33615, Germany
| | - Wenshuang Li
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Jena, 07743, Germany
| | - Martin Westermann
- Electron Microscopy Center, Jena University Hospital, Jena, 07743, Germany
| | - Volker Wagner
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Jena, 07743, Germany
| | - Tilman Kottke
- Physical and Biophysical Chemistry, Department of Chemistry, Bielefeld University, Bielefeld, 33615, Germany
- Medical School OWL, Bielefeld University, Bielefeld, 33615, Germany
| | - Maria Mittag
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Jena, 07743, Germany
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6
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Carrasco Flores D, Fricke M, Wesp V, Desirò D, Kniewasser A, Hölzer M, Marz M, Mittag M. A marine Chlamydomonas sp. emerging as an algal model. JOURNAL OF PHYCOLOGY 2021; 57:54-69. [PMID: 33043442 DOI: 10.1111/jpy.13083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 08/25/2020] [Accepted: 08/26/2020] [Indexed: 06/11/2023]
Abstract
The freshwater microalga Chlamydomonas reinhardtii, which lives in wet soil, has served for decades as a model for numerous biological processes, and many tools have been introduced for this organism. Here, we have established a stable nuclear transformation for its marine counterpart, Chlamydomonas sp. SAG25.89, by fusing specific cis-acting elements from its Actin gene with the gene providing hygromycin resistance and using an elaborated electroporation protocol. Like C. reinhardtii, Chlamydomonas sp. has a high GC content, allowing reporter genes and selection markers to be applicable in both organisms. Chlamydomonas sp. grows purely photoautotrophically and requires ammonia as a nitrogen source because its nuclear genome lacks some of the genes required for nitrogen metabolism. Interestingly, it can grow well under both low and very high salinities (up to 50 g · L-1 ) rendering it as a model for osmotolerance. We further show that Chlamydomonas sp. grows well from 15 to 28°C, but halts its growth at 32°C. The genome of Chlamydomonas sp. contains some gene homologs the expression of which is regulated according to the ambient temperatures and/or confer thermal acclimation in C. reinhardtii. Thus, knowledge of temperature acclimation can now be compared to the marine species. Furthermore, Chlamydomonas sp. can serve as a model for studying marine microbial interactions and for comparing mechanisms in freshwater and marine environments. Chlamydomonas sp. was previously shown to be immobilized rapidly by a cyclic lipopeptide secreted from the antagonistic bacterium Pseudomonas protegens PF-5, which deflagellates C. reinhardtii.
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Affiliation(s)
- David Carrasco Flores
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University, Jena, 07743, Germany
| | - Markus Fricke
- RNA Bioinformatics and High-Throughput Analysis, Friedrich Schiller University, Jena, 07743, Germany
| | - Valentin Wesp
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University, Jena, 07743, Germany
| | - Daniel Desirò
- RNA Bioinformatics and High-Throughput Analysis, Friedrich Schiller University, Jena, 07743, Germany
| | - Anja Kniewasser
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University, Jena, 07743, Germany
| | - Martin Hölzer
- RNA Bioinformatics and High-Throughput Analysis, Friedrich Schiller University, Jena, 07743, Germany
| | - Manja Marz
- RNA Bioinformatics and High-Throughput Analysis, Friedrich Schiller University, Jena, 07743, Germany
- FLI, Leibniz Institute for Age Research, Beutenbergstr. 11, Jena, 07745, Germany
| | - Maria Mittag
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University, Jena, 07743, Germany
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7
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Li W, Flores DC, Füßel J, Euteneuer J, Dathe H, Zou Y, Weisheit W, Wagner V, Petersen J, Mittag M. A Musashi Splice Variant and Its Interaction Partners Influence Temperature Acclimation in Chlamydomonas. PLANT PHYSIOLOGY 2018; 178:1489-1506. [PMID: 30301774 PMCID: PMC6288751 DOI: 10.1104/pp.18.00972] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 09/30/2018] [Indexed: 05/09/2023]
Abstract
Microalgae contribute significantly to carbon fixation on Earth. Global warming influences their physiology and growth rates. To understand algal short-term acclimation and adaptation to changes in ambient temperature, it is essential to identify and characterize the molecular components that sense small temperature changes as well as the downstream signaling networks and physiological responses. Here, we used the green biflagellate alga Chlamydomonas reinhardtii as a model system in which to study responses to temperature. We report that an RNA recognition motif (RRM)-containing RNA-binding protein, Musashi, occurs in 25 putative splice variants. These variants bear one, two, and three RRM domains or even lack RRM domains. The most abundant Musashi variant, 12, with a molecular mass of 60 kD, interacts with two clock-relevant members of RNA metabolism, the subunit C3 of the RNA-binding protein CHLAMY1 and the 5'-3' exoribonuclease XRN1. These proteins are able to integrate temperature information by up- or down-regulation of their protein levels in cells grown at low (18°C) or high (28°C) temperature. We further show that the 60-kD Musashi variants with three RRM domains can bind to (UG)7 repeat-containing RNAs and are up-regulated in cells grown at a higher temperature during early night. Intriguingly, the 60-kD Musashi variant 12, as well as C3 and XRN1, confer thermal acclimation to C. reinhardtii, as shown with mutant lines. Our data suggest that these three proteins of the RNA metabolism machinery are key members of the thermal signaling network in C. reinhardtii.
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Affiliation(s)
- Wenshuang Li
- Matthias Schleiden Institute of Genetics, Bioinformatics, and Molecular Botany, Friedrich Schiller University, 07743 Jena, Germany
| | - David Carrasco Flores
- Matthias Schleiden Institute of Genetics, Bioinformatics, and Molecular Botany, Friedrich Schiller University, 07743 Jena, Germany
| | - Juliane Füßel
- Matthias Schleiden Institute of Genetics, Bioinformatics, and Molecular Botany, Friedrich Schiller University, 07743 Jena, Germany
| | - Jan Euteneuer
- Matthias Schleiden Institute of Genetics, Bioinformatics, and Molecular Botany, Friedrich Schiller University, 07743 Jena, Germany
| | - Hannes Dathe
- Matthias Schleiden Institute of Genetics, Bioinformatics, and Molecular Botany, Friedrich Schiller University, 07743 Jena, Germany
| | - Yong Zou
- Matthias Schleiden Institute of Genetics, Bioinformatics, and Molecular Botany, Friedrich Schiller University, 07743 Jena, Germany
| | - Wolfram Weisheit
- Matthias Schleiden Institute of Genetics, Bioinformatics, and Molecular Botany, Friedrich Schiller University, 07743 Jena, Germany
| | - Volker Wagner
- Matthias Schleiden Institute of Genetics, Bioinformatics, and Molecular Botany, Friedrich Schiller University, 07743 Jena, Germany
| | - Jan Petersen
- Matthias Schleiden Institute of Genetics, Bioinformatics, and Molecular Botany, Friedrich Schiller University, 07743 Jena, Germany
| | - Maria Mittag
- Matthias Schleiden Institute of Genetics, Bioinformatics, and Molecular Botany, Friedrich Schiller University, 07743 Jena, Germany
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8
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Butler N. Alternative Splice Variant Sheds Light on Temperature Acclimation in Algae. PLANT PHYSIOLOGY 2018; 178:1430-1431. [PMID: 30530759 PMCID: PMC6288746 DOI: 10.1104/pp.18.01340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Affiliation(s)
- Nathaniel Butler
- Department of Horticulture, University of Wisconsin-Madison, 1575 Linden Drive, Madison, Wisconsin 53706
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9
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Zou Y, Wenzel S, Müller N, Prager K, Jung EM, Kothe E, Kottke T, Mittag M. An Animal-Like Cryptochrome Controls the Chlamydomonas Sexual Cycle. PLANT PHYSIOLOGY 2017; 174:1334-1347. [PMID: 28468769 PMCID: PMC5490917 DOI: 10.1104/pp.17.00493] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 04/28/2017] [Indexed: 05/26/2023]
Abstract
Cryptochromes are known as flavin-binding blue light receptors in bacteria, fungi, plants, and insects. The animal-like cryptochrome (aCRY) of the green alga Chlamydomonas reinhardtii has extended our view on cryptochromes, because it responds also to other wavelengths of the visible spectrum, including red light. Here, we have investigated if aCRY is involved in the regulation of the sexual life cycle of C. reinhardtii, which is controlled by blue and red light at the steps of gametogenesis along with its restoration and germination. We show that aCRY is differentially expressed not only during the life cycle but also within the cell as part of the soluble and/or membrane-associated protein fraction. Moreover, localization of aCRY within the algal cell body varies between vegetative cells and the different cell types of gametogenesis. aCRY is significantly (early day) or to a small extent (late night) enriched in the nucleus in vegetative cells. In pregametes, gametes and dark-inactivated gametes, aCRY is localized over the cell body. aCRY plays an important role in the sexual life cycle of C. reinhardtii: It controls the germination of the alga, under which the zygote undergoes meiosis, in a positive manner, similar to the regulation by the blue light receptors phototropin and plant cryptochrome (pCRY). However, aCRY acts in combination with pCRY as a negative regulator for mating ability as well as for mating maintenance, opposite to the function of phototropin in these processes.
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Affiliation(s)
- Yong Zou
- Institute of General Botany and Plant Physiology, Friedrich Schiller University, 07743 Jena, Germany
| | - Sandra Wenzel
- Institute of General Botany and Plant Physiology, Friedrich Schiller University, 07743 Jena, Germany
| | - Nico Müller
- Institute of General Botany and Plant Physiology, Friedrich Schiller University, 07743 Jena, Germany
| | - Katja Prager
- Institute of General Botany and Plant Physiology, Friedrich Schiller University, 07743 Jena, Germany
| | - Elke-Martina Jung
- Institute of Microbiology, Friedrich Schiller University, 07743 Jena, Germany
| | - Erika Kothe
- Institute of Microbiology, Friedrich Schiller University, 07743 Jena, Germany
| | - Tilman Kottke
- Physical and Biophysical Chemistry, Department of Chemistry, Bielefeld University, 33615 Bielefeld, Germany
| | - Maria Mittag
- Institute of General Botany and Plant Physiology, Friedrich Schiller University, 07743 Jena, Germany
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10
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Müller N, Wenzel S, Zou Y, Künzel S, Sasso S, Weiß D, Prager K, Grossman A, Kottke T, Mittag M. A Plant Cryptochrome Controls Key Features of the Chlamydomonas Circadian Clock and Its Life Cycle. PLANT PHYSIOLOGY 2017; 174:185-201. [PMID: 28360233 PMCID: PMC5411161 DOI: 10.1104/pp.17.00349] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 03/28/2017] [Indexed: 05/25/2023]
Abstract
Cryptochromes are flavin-binding proteins that act as blue light receptors in bacteria, fungi, plants, and insects and are components of the circadian oscillator in mammals. Animal and plant cryptochromes are evolutionarily divergent, although the unicellular alga Chlamydomonas reinhardtii (Chlamydomonas throughout) has both an animal-like cryptochrome and a plant cryptochrome (pCRY; formerly designated CPH1). Here, we show that the pCRY protein accumulates at night as part of a complex. Functional characterization of pCRY was performed based on an insertional mutant that expresses only 11% of the wild-type pCRY level. The pcry mutant is defective for central properties of the circadian clock. In the mutant, the period is lengthened significantly, ultimately resulting in arrhythmicity, while blue light-based phase shifts show large deviations from what is observed in wild-type cells. We also show that pCRY is involved in gametogenesis in Chlamydomonas pCRY is down-regulated in pregametes and gametes, and in the pcry mutant, there is altered transcript accumulation under blue light of the strictly light-dependent, gamete-specific gene GAS28 pCRY acts as a negative regulator for the induction of mating ability in the light and for the loss of mating ability in the dark. Moreover, pCRY is necessary for light-dependent germination, during which the zygote undergoes meiosis that gives rise to four vegetative cells. In sum, our data demonstrate that pCRY is a key blue light receptor in Chlamydomonas that is involved in both circadian timing and life cycle progression.
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Affiliation(s)
- Nico Müller
- Institute of General Botany and Plant Physiology, Friedrich Schiller University, 07743 Jena, Germany (N.M., S.W., Y.Z., S.K., S.S., D.W., K.P., M.M.)
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305 (A.G.)
- Physical and Biophysical Chemistry, Department of Chemistry, Bielefeld University, 33615 Bielefeld, Germany (T.K.); and
- Leibniz Institute for Natural Product Research and Infection Biology, 07745 Jena, Germany (S.S.)
| | - Sandra Wenzel
- Institute of General Botany and Plant Physiology, Friedrich Schiller University, 07743 Jena, Germany (N.M., S.W., Y.Z., S.K., S.S., D.W., K.P., M.M.)
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305 (A.G.)
- Physical and Biophysical Chemistry, Department of Chemistry, Bielefeld University, 33615 Bielefeld, Germany (T.K.); and
- Leibniz Institute for Natural Product Research and Infection Biology, 07745 Jena, Germany (S.S.)
| | - Yong Zou
- Institute of General Botany and Plant Physiology, Friedrich Schiller University, 07743 Jena, Germany (N.M., S.W., Y.Z., S.K., S.S., D.W., K.P., M.M.)
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305 (A.G.)
- Physical and Biophysical Chemistry, Department of Chemistry, Bielefeld University, 33615 Bielefeld, Germany (T.K.); and
- Leibniz Institute for Natural Product Research and Infection Biology, 07745 Jena, Germany (S.S.)
| | - Sandra Künzel
- Institute of General Botany and Plant Physiology, Friedrich Schiller University, 07743 Jena, Germany (N.M., S.W., Y.Z., S.K., S.S., D.W., K.P., M.M.)
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305 (A.G.)
- Physical and Biophysical Chemistry, Department of Chemistry, Bielefeld University, 33615 Bielefeld, Germany (T.K.); and
- Leibniz Institute for Natural Product Research and Infection Biology, 07745 Jena, Germany (S.S.)
| | - Severin Sasso
- Institute of General Botany and Plant Physiology, Friedrich Schiller University, 07743 Jena, Germany (N.M., S.W., Y.Z., S.K., S.S., D.W., K.P., M.M.)
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305 (A.G.)
- Physical and Biophysical Chemistry, Department of Chemistry, Bielefeld University, 33615 Bielefeld, Germany (T.K.); and
- Leibniz Institute for Natural Product Research and Infection Biology, 07745 Jena, Germany (S.S.)
| | - Daniel Weiß
- Institute of General Botany and Plant Physiology, Friedrich Schiller University, 07743 Jena, Germany (N.M., S.W., Y.Z., S.K., S.S., D.W., K.P., M.M.)
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305 (A.G.)
- Physical and Biophysical Chemistry, Department of Chemistry, Bielefeld University, 33615 Bielefeld, Germany (T.K.); and
- Leibniz Institute for Natural Product Research and Infection Biology, 07745 Jena, Germany (S.S.)
| | - Katja Prager
- Institute of General Botany and Plant Physiology, Friedrich Schiller University, 07743 Jena, Germany (N.M., S.W., Y.Z., S.K., S.S., D.W., K.P., M.M.)
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305 (A.G.)
- Physical and Biophysical Chemistry, Department of Chemistry, Bielefeld University, 33615 Bielefeld, Germany (T.K.); and
- Leibniz Institute for Natural Product Research and Infection Biology, 07745 Jena, Germany (S.S.)
| | - Arthur Grossman
- Institute of General Botany and Plant Physiology, Friedrich Schiller University, 07743 Jena, Germany (N.M., S.W., Y.Z., S.K., S.S., D.W., K.P., M.M.)
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305 (A.G.)
- Physical and Biophysical Chemistry, Department of Chemistry, Bielefeld University, 33615 Bielefeld, Germany (T.K.); and
- Leibniz Institute for Natural Product Research and Infection Biology, 07745 Jena, Germany (S.S.)
| | - Tilman Kottke
- Institute of General Botany and Plant Physiology, Friedrich Schiller University, 07743 Jena, Germany (N.M., S.W., Y.Z., S.K., S.S., D.W., K.P., M.M.)
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305 (A.G.)
- Physical and Biophysical Chemistry, Department of Chemistry, Bielefeld University, 33615 Bielefeld, Germany (T.K.); and
- Leibniz Institute for Natural Product Research and Infection Biology, 07745 Jena, Germany (S.S.)
| | - Maria Mittag
- Institute of General Botany and Plant Physiology, Friedrich Schiller University, 07743 Jena, Germany (N.M., S.W., Y.Z., S.K., S.S., D.W., K.P., M.M.);
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305 (A.G.);
- Physical and Biophysical Chemistry, Department of Chemistry, Bielefeld University, 33615 Bielefeld, Germany (T.K.); and
- Leibniz Institute for Natural Product Research and Infection Biology, 07745 Jena, Germany (S.S.)
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11
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Ryo M, Matsuo T, Yamashino T, Ichinose M, Sugita M, Aoki S. Diversity of plant circadian clocks: Insights from studies of Chlamydomonas reinhardtii and Physcomitrella patens. PLANT SIGNALING & BEHAVIOR 2016; 11:e1116661. [PMID: 26645746 PMCID: PMC4871632 DOI: 10.1080/15592324.2015.1116661] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Arabidopsis thaliana has long been the model plant of choice for elucidating the mechanisms of the circadian clock. Recently, relevant results have accumulated in other species of green plant lineages, including green algae. This mini-review describes a comparison of the mechanism of the A. thaliana clock to those of the green alga Chlamydomonas reinhardtii and the moss Physcomitrella patens, focusing on commonalities and divergences of subsystems of the clock. The potential of such an approach from an evolutionary viewpoint is discussed.
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Affiliation(s)
- Masashi Ryo
- Graduate School of Information Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Takuya Matsuo
- Center for Gene Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Takafumi Yamashino
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Mizuho Ichinose
- Center for Gene Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
- Institute of Transformative Bio-Molecules, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Mamoru Sugita
- Center for Gene Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Setsuyuki Aoki
- Graduate School of Information Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
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12
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Romanowski A, Yanovsky MJ. Circadian rhythms and post-transcriptional regulation in higher plants. FRONTIERS IN PLANT SCIENCE 2015; 6:437. [PMID: 26124767 PMCID: PMC4464108 DOI: 10.3389/fpls.2015.00437] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 05/28/2015] [Indexed: 05/06/2023]
Abstract
The circadian clock of plants allows them to cope with daily changes in their environment. This is accomplished by the rhythmic regulation of gene expression, in a process that involves many regulatory steps. One of the key steps involved at the RNA level is post-transcriptional regulation, which ensures a correct control on the different amounts and types of mRNA that will ultimately define the current physiological state of the plant cell. Recent advances in the study of the processes of regulation of pre-mRNA processing, RNA turn-over and surveillance, regulation of translation, function of lncRNAs, biogenesis and function of small RNAs, and the development of bioinformatics tools have helped to vastly expand our understanding of how this regulatory step performs its role. In this work we review the current progress in circadian regulation at the post-transcriptional level research in plants. It is the continuous interaction of all the information flow control post-transcriptional processes that allow a plant to precisely time and predict daily environmental changes.
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Affiliation(s)
| | - Marcelo J. Yanovsky
- *Correspondence: Marcelo J. Yanovsky, Laboratorio de Genómica Comparativa del Desarrollo Vegetal, Fundación Instituto Leloir, IIBBA-CONICET, Avenida Patricias Argentinas 435, Buenos Aires C1405BWE, Argentina,
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13
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Nolte C, Staiger D. RNA around the clock - regulation at the RNA level in biological timing. FRONTIERS IN PLANT SCIENCE 2015; 6:311. [PMID: 25999975 PMCID: PMC4419606 DOI: 10.3389/fpls.2015.00311] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 04/19/2015] [Indexed: 05/21/2023]
Abstract
The circadian timing system in plants synchronizes their physiological functions with the environment. This is achieved by a global control of gene expression programs with a considerable part of the transcriptome undergoing 24-h oscillations in steady-state abundance. These circadian oscillations are driven by a set of core clock proteins that generate their own 24-h rhythm through periodic feedback on their own transcription. Additionally, post-transcriptional events are instrumental for oscillations of core clock genes and genes in clock output. Here we provide an update on molecular events at the RNA level that contribute to the 24-h rhythm of the core clock proteins and shape the circadian transcriptome. We focus on the circadian system of the model plant Arabidopsis thaliana but also discuss selected regulatory principles in other organisms.
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Affiliation(s)
| | - Dorothee Staiger
- *Correspondence: Dorothee Staiger, Molecular Cell Physiology, Faculty of Biology, Bielefeld University, Universitaetsstrasse 25, Bielefeld D-33615, Germany
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14
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Kianianmomeni A. Cell-type specific light-mediated transcript regulation in the multicellular alga Volvox carteri. BMC Genomics 2014; 15:764. [PMID: 25194509 PMCID: PMC4167131 DOI: 10.1186/1471-2164-15-764] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 09/03/2014] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The multicellular green alga Volvox carteri makes use of none less than 13 photoreceptors, which are mostly expressed in a cell-type specific manner. This gives reason to believe that trasncriptome pattern of each cell type could change differentially in response to environmental light. Here, the cell-type specific changes of various transcripts from different pathways in response to blue, red and far-red light were analyzed. RESULTS In response to different light qualities, distinct changes in transcript accumulation of genes encoding proteins involved in chlorophyll and carotenoid biosynthesis, light-harvesting complexes, circadian clock and cell cycle control were observed. Namely, blue light tends to be effective to accumulate transcripts in the somatic cells; while red light leads to accumulate transcripts predominantly in the reproductive cells. Blue light also induced marked accumulation of two components of circadian rhythms only in the somatic cells, indicating that these clock-relevant components are affected by blue light in a cell-type specific manner. Further, we show that photosynthetic associated genes are regulated distinctly among cell types by different light qualities. CONCLUSION Our results suggest that Volvox uses different sophisticated cell-type specific light signaling pathways to modulate expression of genes involved in various cellular and metabolic pathways including circadian rhythms and photosynthesis in response to environmental light.
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Affiliation(s)
- Arash Kianianmomeni
- Department of Cellular and Developmental Biology of Plants, University of Bielefeld, Universitätsstr, 25, D-33615 Bielefeld, Germany.
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15
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Köster T, Haas M, Staiger D. The RIPper case: identification of RNA-binding protein targets by RNA immunoprecipitation. Methods Mol Biol 2014; 1158:107-121. [PMID: 24792047 DOI: 10.1007/978-1-4939-0700-7_7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Control at the posttranscriptional level emerges as an important layer of regulation in the circadian timing system. RNA-binding proteins that specifically interact with cis-regulatory motifs within pre-mRNAs are key elements of this regulation. While the ability to interact with RNA in vitro has been demonstrated for numerous Arabidopsis RNA-binding proteins, a full understanding of posttranscriptional networks controlled by an RNA-binding protein requires the identification of its immediate in vivo targets. Here we describe differential RNA immunoprecipitation in transgenic Arabidopsis thaliana plants expressing RNA-binding protein variants epitope-tagged with green fluorescent protein. To control for RNAs that nonspecifically co-purify with the RNA-binding protein, transgenic plants are generated with a mutated version of the RNA-binding protein that is not capable of binding to its target RNAs. The RNA-binding protein variants are expressed under the control of their authentic promoter and cis-regulatory motifs. Incubation of the plants with formaldehyde in vivo cross-links the proteins to their RNA targets. A whole-cell extract is then prepared and subjected to immunoprecipitation with an antibody against the GFP tag and to mock precipitation with an antibody against the unrelated red fluorescent protein. The RNAs coprecipitating with the proteins are eluted from the immunoprecipitate and identified via reverse transcription-PCR.
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Affiliation(s)
- Tino Köster
- Department of Molecular Cell Physiology, University of Bielefeld, Universitätsstraße 25, 33615, Bielefeld, Germany
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16
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Filonova A, Haemsch P, Gebauer C, Weisheit W, Wagner V. Protein disulfide isomerase 2 of Chlamydomonas reinhardtii is involved in circadian rhythm regulation. MOLECULAR PLANT 2013; 6:1503-17. [PMID: 23475997 DOI: 10.1093/mp/sst048] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Protein disulfide isomerases (PDIs) are known to play important roles in the folding of nascent proteins and in the formation of disulfide bonds. Recently, we identified a PDI from Chlamydomonas reinhardtii (CrPDI2) by a mass spectrometry approach that is specifically enriched by heparin affinity chromatography in samples taken during the night phase. Here, we show that the recombinant CrPDI2 is a redox-active protein. It is reduced by thioredoxin reductase and catalyzes itself the reduction of insulin chains and the oxidative refolding of scrambled RNase A. By immunoblots, we confirm a high-amplitude change in abundance of the heparin-bound CrPDI2 during subjective night. Interestingly, we find that CrPDI2 is present in protein complexes of different sizes at both day and night. Among three identified interaction partners, one (a 2-cys peroxiredoxin) is present only during the night phase. To study a potential function of CrPDI2 within the circadian system, we have overexpressed its gene. Two transgenic lines were used to measure the rhythm of phototaxis. In the transgenic strains, a change in the acrophase was observed. This indicates that CrPDI2 is involved in the circadian signaling pathway and, together with the night phase-specific interaction of CrPDI2 and a peroxiredoxin, these findings suggest a close coupling of redox processes and the circadian clock in C. reinhardtii.
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Affiliation(s)
- Anna Filonova
- Institute of General Botany and Plant Physiology, Friedrich-Schiller-Universität Jena, 07743 Jena, Germany
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17
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Schulze T, Schreiber S, Iliev D, Boesger J, Trippens J, Kreimer G, Mittag M. The heme-binding protein SOUL3 of Chlamydomonas reinhardtii influences size and position of the eyespot. MOLECULAR PLANT 2013; 6:931-944. [PMID: 23180671 DOI: 10.1093/mp/sss137] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The flagellated green alga Chlamydomonas reinhardtii has a primitive visual system, the eyespot. It is situated at the cells equator and allows the cell to phototax. In a previous proteomic analysis of the eyespot, the SOUL3 protein was identified among 202 proteins. Here, we investigate the properties and functions of SOUL3. Heterologously expressed SOUL3 is able to bind specifically to hemin. In C. reinhardtii, SOUL3 is expressed at a constant level over the diurnal cycle, but forms protein complexes that differ in size during day and night phases. SOUL3 is primarily localized in the eyespot and it is situated in the pigment globule layer thereof. This is in contrast to the channelrhodopsin photoreceptors, which are localized in the plasma membrane region of the eyespot. Knockdown lines with a significantly reduced SOUL3 level are characterized by mislocalized eyespots, a decreased eyespot size, and alterations in phototactic behavior. Mislocalizations were either anterior or posterior and did not affect association with acetylated microtubules of the daughter four-membered rootlet. Our data suggest that SOUL3 is involved in the organization and placement of the eyespot within the cell.
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Affiliation(s)
- Thomas Schulze
- Institute of General Botany and Plant Physiology, Friedrich Schiller University Jena, 07743 Jena, Germany
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18
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McClung CR. Beyond Arabidopsis: the circadian clock in non-model plant species. Semin Cell Dev Biol 2013; 24:430-6. [PMID: 23466287 DOI: 10.1016/j.semcdb.2013.02.007] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2012] [Revised: 02/13/2013] [Accepted: 02/15/2013] [Indexed: 01/26/2023]
Abstract
Circadian clocks allow plants to temporally coordinate many aspects of their biology with the diurnal cycle derived from the rotation of Earth on its axis. Although there is a rich history of the study of clocks in many plant species, in recent years much progress in elucidating the architecture and function of the plant clock has emerged from studies of the model plant, Arabidopsis thaliana. There is considerable interest in extending this knowledge of the circadian clock into diverse plant species in order to address its role in topics as varied as agricultural productivity and the responses of individual species and plant communities to global climate change and environmental degradation. The analysis of circadian clocks in the green lineage provides insight into evolutionary processes in plants and throughout the eukaryotes.
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Affiliation(s)
- C Robertson McClung
- Department of Biological Sciences, Dartmouth College, Class of 1978 Life Sciences Center, Hanover, NH 03755, USA.
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19
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Novel interaction of two clock-relevant RNA-binding proteins C3 and XRN1 in Chlamydomonas reinhardtii. FEBS Lett 2012; 586:3969-73. [PMID: 23068615 DOI: 10.1016/j.febslet.2012.09.046] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2012] [Revised: 09/23/2012] [Accepted: 09/26/2012] [Indexed: 12/18/2022]
Abstract
The RNA-binding protein CHLAMY1 of the green alga Chlamydomonas reinhardtii consists of two subunits, named C1 and C3 that maintain the period and phase of the circadian clock. Here, we investigated if any of its subunits interact with other clock components involved in RNA metabolism. We found that C3, but not C1 strongly interacts with exoribonuclease XRN1 whose knockout results in low amplitude rhythms. XRN1 is subject to degradation by the proteasome pathway. Its level increases in cells grown at lower ambient temperature simulating night, which was also observed for C3. Our data indicate a network of clock-relevant RNA-binding proteins.
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20
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Heiland I, Bodenstein C, Hinze T, Weisheit O, Ebenhoeh O, Mittag M, Schuster S. Modeling temperature entrainment of circadian clocks using the Arrhenius equation and a reconstructed model from Chlamydomonas reinhardtii. J Biol Phys 2012; 38:449-64. [PMID: 23729908 DOI: 10.1007/s10867-012-9264-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Accepted: 01/17/2012] [Indexed: 10/28/2022] Open
Abstract
Endogenous circadian rhythms allow living organisms to anticipate daily variations in their natural environment. Temperature regulation and entrainment mechanisms of circadian clocks are still poorly understood. To better understand the molecular basis of these processes, we built a mathematical model based on experimental data examining temperature regulation of the circadian RNA-binding protein CHLAMY1 from the unicellular green alga Chlamydomonas reinhardtii, simulating the effect of temperature on the rates by applying the Arrhenius equation. Using numerical simulations, we demonstrate that our model is temperature-compensated and can be entrained to temperature cycles of various length and amplitude. The range of periods that allow entrainment of the model depends on the shape of the temperature cycles and is larger for sinusoidal compared to rectangular temperature curves. We show that the response to temperature of protein (de)phosphorylation rates play a key role in facilitating temperature entrainment of the oscillator in Chlamydomonas reinhardtii. We systematically investigated the response of our model to single temperature pulses to explain experimentally observed phase response curves.
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Affiliation(s)
- Ines Heiland
- Department of Bioinformatics, School of Biology and Pharmacy, Friedrich-Schiller University Jena, E.-Abbe-Platz 2, 07743 Jena, Germany
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21
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Staiger D, Green R. RNA-based regulation in the plant circadian clock. TRENDS IN PLANT SCIENCE 2011; 16:517-523. [PMID: 21782493 DOI: 10.1016/j.tplants.2011.06.002] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 06/03/2011] [Accepted: 06/14/2011] [Indexed: 05/31/2023]
Abstract
The circadian clock is an endogenous, approximately 24-h timer that enables plants to anticipate daily changes in their environment and regulates a considerable fraction of the transcriptome. At the core of the circadian system is the oscillator, made up of interconnected feedback loops, involving transcriptional regulation of clock genes and post-translational modification of clock proteins. Recently, it has become clear that post-transcriptional events are also critical for shaping rhythmic mRNA and protein profiles. This review covers regulation at the RNA level of both the core clock and output genes in Arabidopsis (Arabidopsis thaliana), with comparisons with other model organisms. We discuss the role of splicing, mRNA decay and translational regulation as well as recent insights into rhythms of noncoding regulatory RNAs.
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Affiliation(s)
- Dorothee Staiger
- Molecular Cell Physiology, Bielefeld University, D-33501 Bielefeld, Germany.
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22
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Schäuble S, Heiland I, Voytsekh O, Mittag M, Schuster S. Predicting the physiological role of circadian metabolic regulation in the green alga Chlamydomonas reinhardtii. PLoS One 2011; 6:e23026. [PMID: 21887226 PMCID: PMC3161734 DOI: 10.1371/journal.pone.0023026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Accepted: 07/09/2011] [Indexed: 11/23/2022] Open
Abstract
Although the number of reconstructed metabolic networks is steadily growing, experimental data integration into these networks is still challenging. Based on elementary flux mode analysis, we combine sequence information with metabolic pathway analysis and include, as a novel aspect, circadian regulation. While minimizing the need of assumptions, we are able to predict changes in the metabolic state and can hypothesise on the physiological role of circadian control in nitrogen metabolism of the green alga Chlamydomonas reinhardtii.
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Affiliation(s)
- Sascha Schäuble
- Department of Bioinformatics, Friedrich Schiller University Jena, Jena, Germany
| | - Ines Heiland
- Department of Bioinformatics, Friedrich Schiller University Jena, Jena, Germany
- * E-mail:
| | - Olga Voytsekh
- Institute of General Botany and Plant Physiology, Friedrich Schiller University Jena, Jena, Germany
| | - Maria Mittag
- Institute of General Botany and Plant Physiology, Friedrich Schiller University Jena, Jena, Germany
| | - Stefan Schuster
- Department of Bioinformatics, Friedrich Schiller University Jena, Jena, Germany
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23
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Matsuo T, Ishiura M. Chlamydomonas reinhardtiias a new model system for studying the molecular basis of the circadian clock. FEBS Lett 2011; 585:1495-502. [DOI: 10.1016/j.febslet.2011.02.025] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2010] [Revised: 01/31/2011] [Accepted: 02/21/2011] [Indexed: 12/31/2022]
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24
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Staiger D, Köster T. Spotlight on post-transcriptional control in the circadian system. Cell Mol Life Sci 2011; 68:71-83. [PMID: 20803230 PMCID: PMC11114774 DOI: 10.1007/s00018-010-0513-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Revised: 08/16/2010] [Accepted: 08/16/2010] [Indexed: 10/19/2022]
Abstract
An endogenous timing mechanism, the circadian clock, causes rhythmic expression of a considerable fraction of the genome of most organisms to optimally align physiology and behavior with their environment. Circadian clocks are self-sustained oscillators primarily based on transcriptional feedback loops and post-translational modification of clock proteins. It is increasingly becoming clear that regulation at the RNA level strongly impacts the cellular circadian transcriptome and proteome as well as the oscillator mechanism itself. This review focuses on posttranscriptional events, discussing RNA-binding proteins that, by influencing the timing of pre-mRNA splicing, polyadenylation and RNA decay, shape rhythmic expression profiles. Furthermore, recent findings on the contribution of microRNAs to orchestrating circadian rhythms are summarized.
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Affiliation(s)
- Dorothee Staiger
- Molecular Cell Physiology, Bielefeld University, 33501, Bielefeld, Germany.
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25
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Schulze T, Prager K, Dathe H, Kelm J, Kiessling P, Mittag M. How the green alga Chlamydomonas reinhardtii keeps time. PROTOPLASMA 2010; 244:3-14. [PMID: 20174954 DOI: 10.1007/s00709-010-0113-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Accepted: 01/18/2010] [Indexed: 05/10/2023]
Abstract
The unicellular green alga Chlamydomonas reinhardtii has two flagella and a primitive visual system, the eyespot apparatus, which allows the cell to phototax. About 40 years ago, it was shown that the circadian clock controls its phototactic movement. Since then, several circadian rhythms such as chemotaxis, cell division, UV sensitivity, adherence to glass, or starch metabolism have been characterized. The availability of its entire genome sequence along with homology studies and the analysis of several sub-proteomes render C. reinhardtii as an excellent eukaryotic model organism to study its circadian clock at different levels of organization. Previous studies point to several potential photoreceptors that may be involved in forwarding light information to entrain its clock. However, experimental data are still missing toward this end. In the past years, several components have been functionally characterized that are likely to be part of the oscillatory machinery of C. reinhardtii since alterations in their expression levels or insertional mutagenesis of the genes resulted in defects in phase, period, or amplitude of at least two independent measured rhythms. These include several RHYTHM OF CHLOROPLAST (ROC) proteins, a CONSTANS protein (CrCO) that is involved in parallel in photoperiodic control, as well as the two subunits of the circadian RNA-binding protein CHLAMY1. The latter is also tightly connected to circadian output processes. Several candidates including a significant number of ROCs, CrCO, and CASEIN KINASE1 whose alterations of expression affect the circadian clock have in parallel severe effects on the release of daughter cells, flagellar formation, and/or movement, indicating that these processes are interconnected in C. reinhardtii. The challenging task for the future will be to get insights into the clock network and to find out how the clock-related factors are functionally connected. In this respect, system biology approaches will certainly contribute in the future to improve our understanding of the C. reinhardtii clock machinery.
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Affiliation(s)
- Thomas Schulze
- Institute of General Botany and Plant Physiology, Friedrich-Schiller-University, Am Planetarium 1, 07743, Jena, Germany
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26
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Seitz SB, Weisheit W, Mittag M. Multiple roles and interaction factors of an E-box element in Chlamydomonas reinhardtii. PLANT PHYSIOLOGY 2010; 152:2243-57. [PMID: 20154097 PMCID: PMC2850036 DOI: 10.1104/pp.109.149195] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Accepted: 02/08/2010] [Indexed: 05/23/2023]
Abstract
The two subunits of the circadian RNA-binding protein CHLAMY1 from Chlamydomonas reinhardtii are involved in maintaining period (C1 subunit) and phase (C3 subunit) of the circadian clock. C1 coregulates the level of C3. Overexpression of C1 causes a parallel increase in C3. Both subunits can also integrate temperature information, resulting in hyperphosphorylation of C1 and up-regulation of C3 at low temperature. Temperature-dependent up-regulation of C3 is mediated predominantly by an E-box element and only partially by two DREB1A-boxes that are situated within the C3 promoter. The E-box element is also involved in circadian C3 expression. Here, we show that the C3 promoter region drives C3 coregulation by C1. We also found that replacement of the E-box prevents the coregulation of C3 in strains overexpressing C1. In contrast, replacement of any of the two DREB1A-boxes does not influence either the coregulation of C3 by increased levels of C1 or circadian C3 expression. Thus, the E-box has multiple key roles, including temperature-dependent up-regulation of C3, its circadian expression, and its coregulation by C1. Using mobility shift assays and DNA-affinity chromatography along with mass spectrometry, we characterized proteins binding specifically to the E-box region and identified five of them. By immunoblotting, we could further show that C3 that was detected in nuclear extracts can be found in the E-box-binding protein complex. Our data indicate a complex transcriptional mechanism of C3 up-regulation and a positive feedback of C3 on its own promoter region.
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Affiliation(s)
| | | | - Maria Mittag
- Institute of General Botany and Plant Physiology, Friedrich Schiller University, 07743 Jena, Germany
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New Insights into the Circadian Clock in Chlamydomonas. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2010; 280:281-314. [DOI: 10.1016/s1937-6448(10)80006-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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28
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Analysis of flagellar phosphoproteins from Chlamydomonas reinhardtii. EUKARYOTIC CELL 2009; 8:922-32. [PMID: 19429781 DOI: 10.1128/ec.00067-09] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Cilia and flagella are cell organelles that are highly conserved throughout evolution. For many years, the green biflagellate alga Chlamydomonas reinhardtii has served as a model for examination of the structure and function of its flagella, which are similar to certain mammalian cilia. Proteome analysis revealed the presence of several kinases and protein phosphatases in these organelles. Reversible protein phosphorylation can control ciliary beating, motility, signaling, length, and assembly. Despite the importance of this posttranslational modification, the identities of many ciliary phosphoproteins and knowledge about their in vivo phosphorylation sites are still missing. Here we used immobilized metal affinity chromatography to enrich phosphopeptides from purified flagella and analyzed them by mass spectrometry. One hundred forty-one phosphorylated peptides were identified, belonging to 32 flagellar proteins. Thereby, 126 in vivo phosphorylation sites were determined. The flagellar phosphoproteome includes different structural and motor proteins, kinases, proteins with protein interaction domains, and many proteins whose functions are still unknown. In several cases, a dynamic phosphorylation pattern and clustering of phosphorylation sites were found, indicating a complex physiological status and specific control by reversible protein phosphorylation in the flagellum.
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Lorković ZJ. Role of plant RNA-binding proteins in development, stress response and genome organization. TRENDS IN PLANT SCIENCE 2009; 14:229-36. [PMID: 19285908 DOI: 10.1016/j.tplants.2009.01.007] [Citation(s) in RCA: 215] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Revised: 12/18/2008] [Accepted: 01/08/2009] [Indexed: 05/20/2023]
Abstract
RNA-binding proteins (RBPs) in eukaryotes have crucial roles in all aspects of post-transcriptional gene regulation. They are important governors of diverse developmental processes by modulating expression of specific transcripts. The Arabidopsis (Arabidopsis thaliana) genome encodes for more than 200 different RBPs, most of which are plant specific and are therefore likely to perform plant-specific functions. Indeed, recent identification and analysis of plant RBPs clearly showed that, in addition to the important role in diverse developmental processes, they are also involved in adaptation of plants to various environmental conditions. Clearly, they act by regulating pre-mRNA splicing, polyadenylation, RNA stability and RNA export, as well as by influencing chromatin modification.
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Affiliation(s)
- Zdravko J Lorković
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Dr. Bohrgasse 9/3, A-1030 Vienna, Austria.
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RNA-protein interaction mediating post-transcriptional regulation in the circadian system. Methods Mol Biol 2009; 479:337-51. [PMID: 19083177 DOI: 10.1007/978-1-59745-289-2_21] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Post-transcriptional control makes an important contribution to shaping transcript profiles of circadianly regulated genes. In Arabidopsis thaliana, the clock-regulated glycine-rich RNA-binding protein ATGRP7 oscillates with a 24-h rhythm and transmits the rhythmicity generated by the central oscillator within the cell. ATGRP7 negatively auto-regulates its own expression at the post-transcriptional level. In response to an elevated protein level, a shift to a cryptic 5' splice site within the intron occurs, leading to an unproductively spliced transcript that rapidly vanishes due to its short half-life. This feedback regulation relies on direct binding of the RNA-binding protein to its own RNA. Here we describe the analysis of RNA-protein interaction in vitro employing recombinant RNA-binding protein and 32P-labelled in vitro transcripts or synthetic RNA oligoribonucleotides comprising the binding site under study.
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Grossman AR. In the Grip of Algal Genomics. TRANSGENIC MICROALGAE AS GREEN CELL FACTORIES 2008; 616:54-76. [DOI: 10.1007/978-0-387-75532-8_6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Voytsekh O, Seitz SB, Iliev D, Mittag M. Both subunits of the circadian RNA-binding protein CHLAMY1 can integrate temperature information. PLANT PHYSIOLOGY 2008; 147:2179-93. [PMID: 18567830 PMCID: PMC2492650 DOI: 10.1104/pp.108.118570] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The circadian RNA-binding protein CHLAMY1 from the green alga Chlamydomonas reinhardtii consists of two subunits named C1 and C3. Changes in the C1 level cause arrhythmicity of the phototaxis rhythm, while alterations in the level of C3 lead to acrophase shifts. Thus, CHLAMY1 is involved in maintaining period and phase of the circadian clock. Here, we analyzed the roles of the two subunits in the integration of temperature information, the basis for other key properties of circadian clocks, including entrainment by temperature cycles and temperature compensation. Applied temperatures (18 degrees C and 28 degrees C) were in the physiological range of C. reinhardtii. While C1 is hyperphosphorylated at low temperature, the C3 expression level is up-regulated at 18 degrees C. An inhibitor experiment showed that this up-regulation occurs at the transcriptional level. Promoter analysis studies along with single promoter element mutations revealed that individual replacement of two DREB1A-boxes lowered the amplitude of c3 up-regulation at 18 degrees C, while replacement of an E-box abolished it completely. Replacement of the E-box also caused arrhythmicity of circadian-controlled c3 expression. Thus, the E-box has a dual function for temperature-dependent up-regulation of c3 as well as for its circadian expression. We also found that the temperature-dependent regulation of C1 and C3 as well as temperature entrainment are altered in the clock mutant per1, indicating that a temperature-controlled network of C1, C3, and PER1 exists.
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Affiliation(s)
- Olga Voytsekh
- Institut für Allgemeine Botanik und Pflanzenphysiologie, Friedrich-Schiller-Universität Jena, 07743 Jena, Germany
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Wobbe L, Schwarz C, Nickelsen J, Kruse O. Translational control of photosynthetic gene expression in phototrophic eukaryotes. PHYSIOLOGIA PLANTARUM 2008; 133:507-15. [PMID: 18346070 DOI: 10.1111/j.1399-3054.2008.01091.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
It is getting more and more evident that photosynthetic gene expression is fine-tuned by translation regulation factors encoded in the nucleus of photosynthetic cells. The research of the past decades led to the identification of several nucleus-encoded protein factors that recognize cis-acting elements in plastid transcripts, thereby modulating the stoichiometry and abundance of photosynthetic multisubunit complexes. Despite of its importance for photoacclimatory processes, the investigation of pathways that regulate translation of nuclear-encoded photosynthetic genes is still in its infancy. This review summarizes the yet known paradigms of translation control in chloroplast and cytosol of photosynthetic eukaryotes.
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Affiliation(s)
- Lutz Wobbe
- Algae BioTech Group, Department of Biology, University of Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany
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35
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Lapointe M, Morse D. Reassessing the role of a 3′-UTR-binding translational inhibitor in regulation of circadian bioluminescence rhythm in the dinoflagellate Gonyaulax. Biol Chem 2008; 389:13-9. [DOI: 10.1515/bc.2008.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractThe nightly bioluminescence of the dinoflagellateGonyaulaxis a circadian rhythm caused by the presence in cells of specialized bioluminescent organelles, termed scintillons, containing the reaction catalyst luciferase, the substrate luciferin and a luciferin-binding protein (LBP). LBP levels increase at the start of the night phase because of increased protein synthesis ratesin vivo, and this regulation has been ascribed to circadian binding of an inhibitory protein factor binding to the 3′ untranslated region (UTR) oflbpmRNA at times when LBP is not normally synthesized. To purify and characterize the binding factor, the electrophoretic mobility shift assays and UV crosslinking experiments used to first characterize the factor were repeated. However, neither these protocols nor binding to biotinylated RNA probes confirmed the presence of a specific circadian RNA-binding protein. Furthermore, neither RNA probe screening of a cDNA library expressed in bacteria nor three-hybrid assays in yeast were successful in isolating a cDNA encoding a protein able to bind specifically to thelbp3′UTR. Taken together, these results suggest that alternative mechanisms for regulatinglbptranslation should now be examined.
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Schöning JC, Streitner C, Page DR, Hennig S, Uchida K, Wolf E, Furuya M, Staiger D. Auto-regulation of the circadian slave oscillator component AtGRP7 and regulation of its targets is impaired by a single RNA recognition motif point mutation. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2007; 52:1119-30. [PMID: 17924945 DOI: 10.1111/j.1365-313x.2007.03302.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The clock-regulated RNA-binding protein AtGRP7 (Arabidopsis thaliana glycine-rich RNA-binding protein) influences circadian oscillations of its transcript by negative feedback at the post-transcriptional level. Here we show that site-specific mutation of one conserved arginine to glutamine within the RNA recognition motif impairs binding of recombinant AtGRP7 to its pre-mRNA in vitro. This correlates with the loss of the negative auto-regulation in vivo: in transgenic plants constitutively overexpressing AtGRP7 (AtGRP7-ox), a shift occurs to an alternatively spliced AtGRP7 transcript that decays rapidly, and thus does not accumulate to high levels. In contrast, constitutive ectopic overexpression of the AtGRP7-RQ mutant does not lead to alternative splicing of the endogenous AtGRP7 transcript and concomitant damping of the oscillations. This highlights the importance of AtGRP7 binding to its own transcript for the negative auto-regulatory circuit. Moreover, regulation of AtGRP7 downstream targets also depends on its RNA-binding activity, as AtGRP8 and other targets identified by transcript profiling of wild-type and AtGRP7-ox plants using fluorescent differential display are negatively affected by AtGRP7 but not by AtGRP7-RQ. In mutants impaired in the nonsense-mediated decay (NMD) components UPF1 or UPF3, levels of the alternatively spliced AtGRP7 and AtGRP8 transcripts that contain premature termination codons are strongly elevated, implicating UPF1 and UPF3 in the decay of these clock-regulated transcripts.
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Affiliation(s)
- Jan C Schöning
- Department of Molecular Cell Physiology, University of Bielefeld, D-33615 Bielefeld, Germany
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Abstract
This review examines the connections between circadian and metabolic rhythms. Examples from a wide variety of well-studied organisms are used to illustrate some of the genetic and molecular pathways linking circadian timekeeping to metabolism. The principles underlying biological timekeeping by intrinsic circadian clocks are discussed briefly. Genetic and molecular studies have unambiguously identified the importance of gene expression feedback circuits to the generation of overt circadian rhythms. This is illustrated particularly well by the results of genome-wide expression studies, which have uncovered hundreds of clock-controlled genes in cyanobacteria, fungi, plants, and animals. The potential connections between circadian oscillations in gene expression and circadian oscillations in metabolic activity are a major focus of this review.
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Affiliation(s)
- Herman Wijnen
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904-4328, USA.
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Garbarino-Pico E, Green CB. Posttranscriptional regulation of mammalian circadian clock output. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2007; 72:145-156. [PMID: 18419272 DOI: 10.1101/sqb.2007.72.022] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Circadian clocks are present in many different cell types/tissues and control many aspects of physiology. This broad control is exerted, at least in part, by the circadian regulation of many genes, resulting in rhythmic expression patterns of 5-10% of the mRNAs in a given tissue. Although transcriptional regulation is certainly involved in this process, it is becoming clear that posttranscriptional mechanisms also have important roles in producing the appropriate rhythmic expression profiles. In this chapter, we review the available data about posttranscriptional regulation of circadian gene expression and highlight the potential role of Nocturnin (Noc) in such processes. NOC is a deadenylase-a ribonuclease that specifically removes poly(A) tails from mRNAs-that is expressed widely in the mouse with high-amplitude rhythmicity. Deadenylation affects the stability and translational properties of mRNAs. Mice lacking the Noc gene have metabolic defects including a resistance to diet-induced obesity, decreased fat storage, changes in lipid-related gene expression profiles in the liver, and altered glucose and insulin sensitivities. These findings suggest that NOC has a pivotal role downstream from the circadian clockwork in the post-transcriptional regulation genes involved in the circadian control of metabolism.
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Affiliation(s)
- E Garbarino-Pico
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904, USA
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Iliev D, Voytsekh O, Schmidt EM, Fiedler M, Nykytenko A, Mittag M. A heteromeric RNA-binding protein is involved in maintaining acrophase and period of the circadian clock. PLANT PHYSIOLOGY 2006; 142:797-806. [PMID: 16920878 PMCID: PMC1586056 DOI: 10.1104/pp.106.085944] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The RNA-binding protein CHLAMY1 from the green alga Chlamydomonas reinhardtii consists of two subunits. One (named C1) contains three lysine homology motifs and the other (named C3) has three RNA recognition motifs. CHLAMY1 binds specifically to uridine-guanine-repeat sequences and its circadian-binding activity is controlled at the posttranslational level, presumably by time-dependent formation of protein complexes consisting of C1 and C3 or C1 alone. Here we have characterized the role of the two subunits within the circadian system by measurements of a circadian rhythm of phototaxis in strains where C1 or C3 are either up- or down-regulated. Further, we have measured the rhythm of nitrite reductase activity in strains with reduced levels of C1 or C3. In case of changes in the C3 level (both increases and decreases), the acrophase of the phototaxis rhythm and of the nitrite reductase rhythm (C3 decrease) was shifted by several hours from subjective day (maximum in wild-type cells) back towards the night. In contrast, both silencing and overexpression of C1 resulted in disturbed circadian rhythms and arrhythmicity. Interestingly, the expression of C1 is interconnected with that of C3. Our data suggest that CHLAMY1 is involved in the control of the phase angle and period of the circadian clock in C. reinhardtii.
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Affiliation(s)
- Dobromir Iliev
- Institut für Allgemeine Botanik und Pflanzenphysiologie, Friedrich-Schiller-Universität Jena, 07743 Jena, Germany
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Schmidt M, Gessner G, Luff M, Heiland I, Wagner V, Kaminski M, Geimer S, Eitzinger N, Reissenweber T, Voytsekh O, Fiedler M, Mittag M, Kreimer G. Proteomic analysis of the eyespot of Chlamydomonas reinhardtii provides novel insights into its components and tactic movements. THE PLANT CELL 2006; 18:1908-30. [PMID: 16798888 PMCID: PMC1533972 DOI: 10.1105/tpc.106.041749] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Flagellate green algae have developed a visual system, the eyespot apparatus, which allows the cell to phototax. To further understand the molecular organization of the eyespot apparatus and the phototactic movement that is controlled by light and the circadian clock, a detailed understanding of all components of the eyespot apparatus is needed. We developed a procedure to purify the eyespot apparatus from the green model alga Chlamydomonas reinhardtii. Its proteomic analysis resulted in the identification of 202 different proteins with at least two different peptides (984 in total). These data provide new insights into structural components of the eyespot apparatus, photoreceptors, retina(l)-related proteins, members of putative signaling pathways for phototaxis and chemotaxis, and metabolic pathways within an algal visual system. In addition, we have performed a functional analysis of one of the identified putative components of the phototactic signaling pathway, casein kinase 1 (CK1). CK1 is also present in the flagella and thus is a promising candidate for controlling behavioral responses to light. We demonstrate that silencing CK1 by RNA interference reduces its level in both flagella and eyespot. In addition, we show that silencing of CK1 results in severe disturbances in hatching, flagellum formation, and circadian control of phototaxis.
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Affiliation(s)
- Melanie Schmidt
- Institute of Biology, Friedrich-Alexander-University, D-91058 Erlangen, Germany
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Buratti E, Brindisi A, Giombi M, Tisminetzky S, Ayala YM, Baralle FE. TDP-43 Binds Heterogeneous Nuclear Ribonucleoprotein A/B through Its C-terminal Tail. J Biol Chem 2005; 280:37572-84. [PMID: 16157593 DOI: 10.1074/jbc.m505557200] [Citation(s) in RCA: 363] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
TDP-43 is a highly conserved nuclear factor of yet unknown function that binds to ug-repeated sequences and is responsible for cystic fibrosis transmembrane conductance regulator exon 9 splicing inhibition. We have analyzed TDP-43 interactions with other splicing factors and identified the critical regions for the protein/protein recognition events that determine this biological function. We show here that the C-terminal region of TDP-43 is capable of binding directly to several proteins of the heterogeneous nuclear ribonucleoprotein (hnRNP) family with well known splicing inhibitory activity, in particular, hnRNP A2/B1 and hnRNP A1. Mutational analysis showed that TDP-43 proteins lacking the C-terminal region could not inhibit splicing probably because they were unable to form the hnRNP-rich complex involved in splicing inhibition. Finally, through splicing complex analysis, we show that splicing inhibition mediated by TDP-43 occurs at the earliest stages of spliceosomal assembly.
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Affiliation(s)
- Emanuele Buratti
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
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Kucho KI, Okamoto K, Tabata S, Fukuzawa H, Ishiura M. Identification of novel clock-controlled genes by cDNA macroarray analysis in Chlamydomonas reinhardtii. PLANT MOLECULAR BIOLOGY 2005; 57:889-906. [PMID: 15952072 DOI: 10.1007/s11103-005-3248-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2004] [Accepted: 03/05/2005] [Indexed: 05/02/2023]
Abstract
Circadian rhythms are self-sustaining oscillations whose period length under constant conditions is about 24 h. Circadian rhythms are widespread and involve functions as diverse as human sleep-wake cycles and cyanobacterial nitrogen fixation. In spite of a long research history, knowledge about clock-controlled genes is limited in Chlamydomonas reinhardtii. Using a cDNA macroarray containing 10 368 nuclear-encoded genes, we examined global circadian regulation of transcription in Chlamydomonas. We identified 269 candidates for circadianly expressed gene. Northern blot analysis confirmed reproducible and sustainable rhythmicity for 12 genes. Most genes exhibited peak expression at the transition point between day and night. One hundred and eighteen genes were assigned predicted annotations. The functions of the cycling genes were diverse and included photosynthesis, respiration, cellular structure, and various metabolic pathways. Surprisingly, 18 genes encoding chloroplast ribosomal proteins showed a coordinated circadian pattern of expression and peaked just at the beginning of subjective day. The co-regulation of genes bearing a similar function was also observed in genes involved in cellular structure. They peaked at the end of the subjective night, which is when the regeneration of cell walls and flagella in daughter cells occurs. Expression of the chlamyopsin gene, which encodes an opsin-type photoreceptor, also exhibited circadian rhythm.
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Affiliation(s)
- Ken-Ichi Kucho
- Center for Gene Research, , Nagoya University, Furo-cho, 464-8602, Nagoya, Chikusa-ku, Japan
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Affiliation(s)
- Arthur R Grossman
- The Carnegie Institution, Department of Plant Biology, Stanford, California 94305, USA.
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Mittag M, Kiaulehn S, Johnson CH. The circadian clock in Chlamydomonas reinhardtii. What is it for? What is it similar to? PLANT PHYSIOLOGY 2005; 137:399-409. [PMID: 15710681 PMCID: PMC1065344 DOI: 10.1104/pp.104.052415] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2004] [Revised: 10/04/2004] [Accepted: 10/07/2004] [Indexed: 05/17/2023]
Affiliation(s)
- Maria Mittag
- Institut für Allgemeine Botanik, Friedrich-Schiller-Universität Jena, 07743 Jena, Germany
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46
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Stauber EJ, Hippler M. Chlamydomonas reinhardtii proteomics. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2004; 42:989-1001. [PMID: 15707836 DOI: 10.1016/j.plaphy.2004.09.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2004] [Accepted: 09/27/2004] [Indexed: 05/01/2023]
Abstract
Proteomics, based on the expanding genomic resources, has begun to reveal new details of Chlamydomonas reinhardtii biology. In particular, analyses focusing on subproteomes have already provided new insight into the dynamics and composition of the photosynthetic apparatus, the chloroplast ribosome, the oxidative phosphorylation machinery of the mitochondria, and the flagellum. It assisted to discovered putative new components of the circadian clockwork as well as shed a light on thioredoxin protein-protein interactions. In the future, quantitative techniques may allow large scale comparison of protein expression levels. Advances in software algorithms will likely improve the use of genomic databases for mass spectrometry (MS) based protein identification and validation of gene models that have been predicted from the genomic DNA sequences. Although proteomics has only been recently applied for exploring C. reinhardtii biology, it will likely be utilized extensively in the near future due to the already existing genetic, genomic, and biochemical tools.
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Affiliation(s)
- Einar J Stauber
- Lehrstuhl für Pflanzenphysiologie, Friedrich-Schiller Universität Jena, Dornburger Street 159, 07743 Jena, Germany
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