scholarly journals Molecular Mechanisms of Nonphotochemical Quenching in the LHCSR3 Protein of Chlamydomonas reinhardtii

2019 ◽  
Vol 10 (10) ◽  
pp. 2500-2505 ◽  
Author(s):  
Gabriel de la Cruz Valbuena ◽  
Franco V. A. Camargo ◽  
Rocio Borrego-Varillas ◽  
Federico Perozeni ◽  
Cosimo D’Andrea ◽  
...  
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Molecular Mechanisms ◽  
Nonphotochemical Quenching

scholarly journals Electron Cryo-Tomography Provides Insight into Procentriole Architecture and Assembly Mechanism

2018 ◽  
Author(s):  
Sam Li ◽  
Jose-Jesus Fernandez ◽  
Wallace F. Marshall ◽  
David A. Agard
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Molecular Mechanisms ◽  
Longitudinal Direction ◽  
Multiple Functions ◽  
Iris Diaphragm ◽  
Cellular Processes ◽  
Structural Framework ◽  
Integral Component ◽  
Assembly Mechanism ◽  
Insight Into

SummaryCentriole is an essential structure with multiple functions in cellular processes. Centriole biogenesis and homeostasis is tightly regulated. Using electron cryo-tomography (cryoET) we present the structure of procentrioles from Chlamydomonas reinhardtii. We identified a set of non-tubulin components attached to the triplet microtubule (MT), many are at the junctions of tubules likely to reinforce the triplet. We describe structure of the A-C linker that bridges neighboring triplets. We find that POC1 is an integral component of the A-C linker. Its conserved WD40 β-propeller domain provides sites for attachment to other A-C linker components. The twist of A-C linker results in an iris diaphragm-like motion of the triplets in the longitudinal direction of procentriole. Finally, we identified two assembly intermediates at the growing ends of procentriole allowing us to propose a model for the procentriole assembly. Our results provide a comprehensive structural framework for understanding the molecular mechanisms underpinning procentriole biogenesis and assembly.

scholarly journals MicroRNA Expression Profile Analysis of Chlamydomonas reinhardtii during Lipid Accumulation Process under Nitrogen Deprivation Stresses

2021 ◽  
Vol 9 (1) ◽  
pp. 6
Author(s):  
Jingxian Zhang ◽  
Jiping Shi ◽  
Chenyang Yuan ◽  
Xiangcen Liu ◽  
Guilin Du ◽  
...  
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Lipid Accumulation ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Profile Analysis ◽  
Critical Role ◽  
Lipid Transport ◽  
Nitrogen Deprivation ◽  
Sequencing Platform ◽  
Novel Mirna

Lipid accumulation in various microalgae has been found induced by nitrogen deprivation, and it controls many different genes expression. Yet, the underlying molecular mechanisms still remain largely unknown. MicroRNA (miRNAs) play a critical role in post-transcriptional gene regulation. In this study, miRNAs were hypothesized involved in lipid accumulation by nitrogen deprivation. A deep-sequencing platform was used to explore miRNAs-mediated responses induced by nitrogen deprivation in Chlamydomonas reinhardtii. The eukaryotic orthologous groups of proteins (KOG) function in the predicted target genes of miRNA with response to nitrogen deprivation were mainly involved in signal transduction mechanisms, including transcription, lipid transport, and metabolism. A total of 109 miRNA were predicted, including 79 known miRNA and 30 novel miRNA. A total of 29 miRNAs showed significantly differential expressions after nitrogen deprivation, and most of them were upregulated. A total of 10 miRNAs and their targeting genes might involve in lipid transport and metabolism biological process. This study first investigates nitrogen deprivation-regulated miRNAs in microalgae and broadens perspectives on miRNAs importance in microalgae lipid accumulation via nitrogen deprivation. This study provides theoretical guidance for the application of microalgae in bio-oil engineering production.

scholarly journals Structural and functional insights into nitrosoglutathione reductase from Chlamydomonas reinhardtii

2020 ◽  
Author(s):  
Andrea Tagliani ◽  
Jacopo Rossi ◽  
Christophe H. Marchand ◽  
Marcello De Mia ◽  
Daniele Tedesco ◽  
...  
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Molecular Mechanisms ◽  
Three Dimensional ◽  
Protein S ◽  
Structural Features ◽  
Zinc Ion ◽  
Kinetic Properties ◽  
Coordination Environment ◽  
Enzymatic Systems ◽  
Catalytic Zinc

ABSTRACTProtein S-nitrosylation plays a fundamental role in cell signaling and nitrosoglutathione (GSNO) is considered as the main nitrosylating signaling molecule. Enzymatic systems controlling GSNO homeostasis are thus crucial to indirectly control the formation of protein S-nitrosothiols. GSNO reductase (GSNOR) is the key enzyme controlling GSNO levels by catalyzing its degradation in the presence of NADH. Here, we found that protein extracts from the microalga Chlamydomonas reinhardtii catabolize GSNO via two enzymatic systems having specific reliance on NADPH or NADH and different biochemical features. Scoring the Chlamydomonas genome for orthologs of known plant GSNORs, we found two genes encoding for putative and almost identical GSNOR isoenzymes. One of the two, here named CrGSNOR1, was heterologously expressed and purified. The kinetic properties of CrGSNOR1 were determined and the high-resolution three-dimensional structures of the apo and NAD+-bound forms of the enzyme were solved. These analyses revealed that CrGSNOR1 has a strict specificity towards GSNO and NADH, and a conserved 3D-folding with respect to other plant GSNORs. The catalytic zinc ion, however, showed an unexpected variability of the coordination environment. Furthermore, we evaluated the catalytic response of CrGSNOR1 to thermal denaturation, thiol-modifying agents and oxidative modifications as well as the reactivity and position of accessible cysteines. Despite being a cysteine-rich protein, CrGSNOR1 contains only two solvent-exposed/reactive cysteines. Oxidizing and nitrosylating treatments have null or limited effects on CrGSNOR1 activity, highlighting a certain resistance of the algal enzyme to redox modifications. The molecular mechanisms and structural features underlying the response to thiol-based modifications are discussed.One-sentence summaryGSNOR1 from Chlamydomonas reinhardtii displays an unusual variability of the catalytic zinc coordination environment and an unexpected resistance to thiol-based redox modifications

scholarly journals Rapid and high efficiency transformation of Chlamydomonas reinhardtii by square-wave electroporation

2019 ◽  
Vol 39 (1) ◽  
Author(s):  
Liang Wang ◽  
Lijing Yang ◽  
Xin Wen ◽  
Zhuoya Chen ◽  
Qiaoying Liang ◽  
...  
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Insertional Mutagenesis ◽  
Molecular Mechanisms ◽  
High Efficiency ◽  
Model Organism ◽  
Dependent Manner ◽  
Exogenous Dna ◽  
Square Wave ◽  
Physiological Processes ◽  
Final Yield

Abstract Chlamydomonas reinhardtii, the unicellular green algae, is the model organism for studies in various physiological processes and for bioindustrial applications. To explore the molecular mechanisms underlying physiological processes or to establish engineered cell lines, the exogenous DNA needs to be integrated into the genome for the insertional mutagenesis or transgene expression. However, the amount of selected marker DNA is not seriously considered in the existing electroporation methods for mutants library construction. Here, we reported a rapid-and-high-efficiency transformation technique for cell-walled strains using square-wave electroporation system. The final yield with this electroporation method was 2–6 × 103 transformants per μg exogenous DNA for cell-walled strains in a strain-dependent manner. In general, this electroporation technique was the easy and applicable way to build a mutant library for screening phenotypes of interest.

scholarly journals Photosystem II antenna complexes CP26 and CP29 are essential for nonphotochemical quenching in Chlamydomonas reinhardtii

2019 ◽  
Vol 43 (2) ◽  
pp. 496-509 ◽  
Author(s):  
Stefano Cazzaniga ◽  
Minjae Kim ◽  
Francesco Bellamoli ◽  
Jooyoen Jeong ◽  
Sangmuk Lee ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Chlamydomonas Reinhardtii ◽  
Nonphotochemical Quenching

scholarly journals Ascorbate Deficiency Does Not Limit Nonphotochemical Quenching in Chlamydomonas reinhardtii

2019 ◽  
Vol 182 (1) ◽  
pp. 597-611 ◽  
Author(s):  
André Vidal-Meireles ◽  
Dávid Tóth ◽  
László Kovács ◽  
Juliane Neupert ◽  
Szilvia Z. Tóth
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Nonphotochemical Quenching

scholarly journals Molecular Mechanisms Underlying the Acclimation of Chlamydomonas reinhardtii Against Nitric Oxide Stress

2021 ◽  
Vol 12 ◽  
Author(s):  
Eva YuHua Kuo ◽  
Tse-Min Lee
Keyword(s):  
Nitric Oxide ◽  
Nadph Oxidase ◽  
Chlamydomonas Reinhardtii ◽  
Protein Trafficking ◽  
Molecular Mechanisms ◽  
Antioxidant Defense System ◽  
No Donor ◽  
Dynamic Regulation ◽  
Translational Activity ◽  
Photosynthesis Inhibition

The acclimation mechanism of Chlamydomonas reinhardtii to nitric oxide (NO) was studied by exposure to S-nitroso-N-acetylpenicillamine (SNAP), a NO donor. Treatment with 0.1 or 0.3 mM SNAP transiently inhibited photosynthesis within 1 h, followed by a recovery, while 1.0 mM SNAP treatment caused irreversible photosynthesis inhibition and mortality. The SNAP effects are avoided in the presence of the NO scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-l-oxyl-3-oxide (cPTIO). RNA-seq, qPCR, and biochemical analyses were conducted to decode the metabolic shifts under NO stress by exposure to 0.3 mM SNAP in the presence or absence of 0.4 mM cPTIO. These findings revealed that the acclimation to NO stress comprises a temporally orchestrated implementation of metabolic processes: (1). modulation of NADPH oxidase (respiratory burst oxidase-like 2, RBOL2) and ROS signaling pathways for downstream mechanism regulation, (2). trigger of NO scavenging elements to reduce NO level; (3). prevention of photo-oxidative risk through photosynthesis inhibition and antioxidant defense system induction; (4). acclimation to nitrogen and sulfur shortage; (5). attenuation of transcriptional and translational activity together with degradation of damaged proteins through protein trafficking machinery (ubiquitin, SNARE, and autophagy) and molecular chaperone system for dynamic regulation of protein homeostasis. In addition, the expression of the gene encoding NADPH oxidase, RBOL2, showed a transient increase while that of RBOL1 was slightly decreased after NO challenge. It reflects that NADPH oxidase, a regulator in ROS-mediated signaling pathway, may be involved in the responses of Chlamydomonas to NO stress. In conclusion, our findings provide insight into the molecular events underlying acclimation mechanisms in Chlamydomonas to NO stress.

scholarly journals Electron cryo-tomography provides insight into procentriole architecture and assembly mechanism

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Sam Li ◽  
Jose-Jesus Fernandez ◽  
Wallace F Marshall ◽  
David A Agard
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Molecular Mechanisms ◽  
Longitudinal Direction ◽  
Multiple Functions ◽  
Iris Diaphragm ◽  
Cellular Processes ◽  
Structural Framework ◽  
Assembly Mechanism ◽  
Attachment Sites ◽  
Insight Into

Centriole is an essential structure with multiple functions in cellular processes. Centriole biogenesis and homeostasis is tightly regulated. Using electron cryo-tomography (cryoET) we present the structure of procentrioles from Chlamydomonas reinhardtii. We identified a set of non-tubulin components attached to the triplet microtubule (MT), many are at the junctions of tubules likely to reinforce the triplet. We describe structure of the A-C linker that bridges neighboring triplets. The structure infers that POC1 is likely an integral component of A-C linker. Its conserved WD40 β-propeller domain provides attachment sites for other A-C linker components. The twist of A-C linker results in an iris diaphragm-like motion of the triplets in the longitudinal direction of procentriole. Finally, we identified two assembly intermediates at the growing ends of procentriole allowing us to propose a model for the procentriole assembly. Our results provide a comprehensive structural framework for understanding the molecular mechanisms underpinning procentriole biogenesis and assembly.

scholarly journals Flagellar Elongation and Gene Expression in Chlamydomonas reinhardtii

2007 ◽  
Vol 6 (8) ◽  
pp. 1411-1420 ◽  
Author(s):  
Goran Periz ◽  
Darshita Dharia ◽  
Steven H. Miller ◽  
Laura R. Keller
Keyword(s):  
Gene Expression ◽  
Signal Transduction ◽  
Chlamydomonas Reinhardtii ◽  
Cellular Response ◽  
Molecular Mechanisms ◽  
Genetic Model ◽  
Gene Promoter ◽  
Signal Transduction Pathways ◽  
Flagellar Motility ◽  
Consensus Binding Site

ABSTRACT Lithium (Li+) affects the physiology of cells from a broad range of organisms including plants and both vertebrate and invertebrate animals. Although its effects result presumably from changes in gene expression elicited by its interaction with intracellular signal transduction pathways, the molecular mechanisms of Li+ action are not well understood. The biflagellate green alga Chlamydomonas reinhardtii is an ideal genetic model for the integration of the effects on Li+ on signal transduction, gene expression, and aspects of flagellar biogenesis. Li+ causes C. reinhardtii flagella to elongate to ∼1.4 times their normal length and blocks flagellar motility (S. Nakamura, H. Tabino, and M. K. Kojima, Cell Struct. Funct. 12:369-374, 1987). We report here that Li+ treatment increases the abundance of several flagellar mRNAs, including α- and β-tubulin and pcf3-21. Li+-induced flagellar gene expression occurs in cells pretreated with cycloheximide, suggesting that the abundance change is a response that does not require new protein synthesis. Deletion analysis of the flagellar α1-tubulin gene promoter showed that sequences necessary for Li+-induced expression differed from those for acid shock induction and contain a consensus binding site for CREB/ATF and AP-1 transcription factors. These studies suggest potential promoter elements, candidate factors, and signal transduction pathways that may coordinate the C. reinhardtii cellular response to Li+.

scholarly journals LHCSR3-Type NPQ Prevents Photoinhibition and Slowed Growth under Fluctuating Light in Chlamydomonas reinhardtii

Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1604
Author(s):  
Thomas Roach
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Nonphotochemical Quenching ◽  
Constant Light ◽  
Natural Light ◽  
Wild Type ◽  
Actinic Light ◽  
Fluctuating Light ◽  
Related Proteins ◽  
Very High

Natural light intensities can rise several orders of magnitude over subsecond time spans, posing a major challenge for photosynthesis. Fluctuating light tolerance in the green alga Chlamydomonas reinhardtii requires alternative electron pathways, but the role of nonphotochemical quenching (NPQ) is not known. Here, fluctuating light (10 min actinic light followed by 10 min darkness) led to significant increase in NPQ/qE-related proteins, LHCSR1 and LHCSR3, relative to constant light of the same subsaturating or saturating intensity. Elevated levels of LHCSR1/3 increased the ability of cells to safely dissipate excess light energy to heat (i.e., qE-type NPQ) during dark to light transition, as measured with chlorophyll fluorescence. The low qE phenotype of the npq4 mutant, which is unable to produce LHCSR3, was abolished under fluctuating light, showing that LHCSR1 alone enables very high levels of qE. Photosystem (PS) levels were also affected by light treatments; constant light led to lower PsbA levels and Fv/Fm values, while fluctuating light led to lower PsaA and maximum P700+ levels, indicating that constant and fluctuating light induced PSII and PSI photoinhibition, respectively. Under fluctuating light, npq4 suffered more PSI photoinhibition and significantly slower growth rates than parental wild type, whereas npq1 and npq2 mutants affected in xanthophyll carotenoid compositions had identical growth under fluctuating and constant light. Overall, LHCSR3 rather than total qE capacity or zeaxanthin is shown to be important in C. reinhardtii in tolerating fluctuating light, potentially via preventing PSI photoinhibition.

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