scholarly journals New Insights on the Regulation of Glucosinolate Biosynthesis via COP1 and DELLA Proteins in Arabidopsis Thaliana

2021 ◽  
Vol 12 ◽  
Author(s):  
Henning Frerigmann ◽  
Ute Hoecker ◽  
Tamara Gigolashvili
Keyword(s):  
Light Signaling ◽  
Phytochrome A ◽  
Yeast Two Hybrid ◽  
Protein Levels ◽  
Della Proteins ◽  
Crucial Component ◽  
Ja Signaling ◽  
Biosynthesis Regulation ◽  
Two Hybrid ◽  
Low Expression

The biosynthesis of defensive secondary metabolites, such as glucosinolates (GSLs), is a costly process, which requires nutrients, ATP, and reduction equivalents, and, therefore, needs well-orchestrated machinery while coordinating defense and growth. We discovered that the key repressor of light signaling, the CONSTITUTIVE PHOTOMORPHOGENIC 1/SUPPRESSOR OF PHYTOCHROME A-105 (COP1/SPA) complex, is a crucial component of GSL biosynthesis regulation. Various mutants in this COP1/SPA complex exhibited a strongly reduced level of GSL and a low expression of jasmonate (JA)-dependent genes. Furthermore, cop1, which is known to accumulate DELLA proteins in the dark, shows reduced gibberellin (GA) and JA signaling, thereby phenocopying other DELLA-accumulating mutants. This phenotype can be complemented by a dominant gain-of-function allele of MYC3 and by crossing with a mutant having low DELLA protein levels. Hence, SPA1 interacts with DELLA proteins in a yeast two-hybrid screen, whereas high levels of DELLA inhibit MYC function and suppress JA signaling. DELLA accumulation leads to reduced synthesis of GSL and inhibited growth. Thus, the COP1/SPA-mediated degradation of DELLA not only affects growth but also regulates the biosynthesis of GSLs.

scholarly journals Novel DnaJ Protein Facilitates Thermotolerance of Transgenic Tomatoes

2019 ◽  
Vol 20 (2) ◽  
pp. 367 ◽  
Author(s):  
Guodong Wang ◽  
Guohua Cai ◽  
Na Xu ◽  
Litao Zhang ◽  
Xiuling Sun ◽  
...  
Keyword(s):  
Heat Stress ◽  
D1 Protein ◽  
Heat Sensitivity ◽  
Yeast Two Hybrid ◽  
Protein Levels ◽  
Dnaj Protein ◽  
Yeast Two Hybrid System ◽  
Ros Accumulation ◽  
Transgenic Tomatoes ◽  
Two Hybrid

DnaJ proteins, which are molecular chaperones that are widely present in plants, can respond to various environmental stresses. At present, the function of DnaJ proteins was studied in many plant species, but only a few studies were conducted in tomato. Here, we examined the functions of a novel tomato (Solanum lycopersicum) DnaJ protein (SlDnaJ20) in heat tolerance using sense and antisense transgenic tomatoes. Transient conversion assays of Arabidopsis protoplasts showed that SlDnaJ20 was targeted to chloroplasts. Expression analysis showed that SlDnaJ20 expression was induced by chilling, NaCl, polyethylene glycol, and H2O2, especially via heat stress. Under heat stress, sense plants showed higher fresh weights, chlorophyll content, fluorescence (Fv/Fm), and D1 protein levels, and a lower accumulation of reactive oxygen species (ROS) than antisense plants. These results suggest that SlDnaJ20 overexpression can reduce the photoinhibition of photosystem II (PSII) by relieving ROS accumulation. Moreover, higher expression levels of HsfA1 and HsfB1 were observed under heat stress in sense plants, indicating that SlDnaJ20 overexpression contributes to HSF expression. The yeast two-hybrid system proved that SlDnaJ20 can interact with the chloroplast heat-shock protein 70. Our results indicate that SlDnaJ20 overexpression enhances the thermotolerance of transgenic tomatoes, whereas suppression of SlDnaJ20 increases the heat sensitivity of transgenic tomatoes.

Gfi1 Protein Turnover Is Regulated by the Ubiquitin Ligase Triad1.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1173-1173
Author(s):  
Laurens T. van der Meer ◽  
Jurgen A.F. Marteijn ◽  
Theo M. de Witte ◽  
Joop H. Jansen ◽  
Bert A. van der Reijden
Keyword(s):  
Ubiquitin Ligase ◽  
Half Life ◽  
Proteasome Inhibitors ◽  
Ring Finger ◽  
Ubiquitin Ligases ◽  
Proteasomal Degradation ◽  
Mrna Levels ◽  
Yeast Two Hybrid ◽  
Protein Levels ◽  
Two Hybrid

Abstract The transcriptional repressor Growth factor independence-1 (Gfi1) plays an essential role during various stages of hematopoiesis. It is crucial for the self-renewal and long-term reconstituting potential of stem cells, essential for neutrophilic differentiation, and it plays an important role in T-cell and dendritic cell development. Gfi1 has also been implicated in malignant hematopoeisis because the Gfi1 gene is a common proviral integration site in murine leukemia models. We recently found that Gfi1 protein levels are mainly regulated by the ubiquitin-proteasome system. Although Gfi1 mRNA levels are low in primary human monocytes, the protein levels are high due to low proteasomal degradation. Conversely, in mature granulocytes Gfi1 mRNA levels are high but protein levels are low due to strong proteasome-mediated turnover. Because Gfi1 plays an important role in normal and malignant hematopoiesis it will be of great interest to identify the ubiquitin ligases that regulate its turnover. Previously, we showed that the RING finger ubiquitin ligase Triad1 regulates myeloid cell proliferation. Using yeast-two-hybrid assays we found that Triad1 binds the zinc finger region of Gfi1. This interaction was confirmed in co-immunoprecipitation experiments. To study whether the turnover of Gfi1 is regulated by Triad1 we performed ubiquitination assays. To our suprise we found that instead of promoting ubiquitination, Triad1 inhibited Gfi1 protein ubiquitination, also in the presence of proteasome inhibitors. RNAi mediated down regulation of Triad1 protein levels stimulated Gfi1 ubiquitination. Importantly, expression of a Triad1 point mutant (H158A) that fails to bind the ubiquitin conjugating enzyme UbcH7 also inhibited Gfi1 ubiquitination. To study whether the observed diminished ubiquitination by Triad1 affected the turnover of Gfi1 we analyzed Gfi1 protein half-life using the protein synthesis inhibitor cycloheximide. This showed that Triad1 co-expression prolonged the half-life of Gfi1 significantly. We conclude that Triad1 inhibits Gfi1 ubiquitination, resulting in decreased turnover of the protein. As this inhibition also occurs in the presence of proteasome inhibitors and is independent of the ubiquitin ligase activity of Triad1, these data support a model in which Triad1 competes for Gfi1 binding with other ubiquitin ligases that do mark Gfi1 for proteasomal degradation. Currently, we are testing candidate ubiquitin ligases (RING finger and HECT proteins) that were found to associate with Gfi1 in yeast-two-hybrid assays to gain more insight in how the activity of this important transcription factor is regulated.

scholarly journals The Peptidyl Prolyl cis/trans Isomerase FKBP38 Determines Hypoxia-Inducible Transcription Factor Prolyl-4-Hydroxylase PHD2 Protein Stability

2007 ◽  
Vol 27 (10) ◽  
pp. 3758-3768 ◽  
Author(s):  
Sandra Barth ◽  
Jutta Nesper ◽  
Philippe A. Hasgall ◽  
Renato Wirthner ◽  
Katarzyna J. Nytko ◽  
...  
Keyword(s):  
Protein Stability ◽  
Transcriptional Activity ◽  
Mrna Levels ◽  
Yeast Two Hybrid ◽  
Isomerase Activity ◽  
Fk506 Binding Protein ◽  
Protein Levels ◽  
Hypoxic Conditions ◽  
Α Subunits ◽  
Two Hybrid

ABSTRACT The heterodimeric hypoxia-inducible transcription factors (HIFs) are central regulators of the response to low oxygenation. HIF-α subunits are constitutively expressed but rapidly degraded under normoxic conditions. Oxygen-dependent hydroxylation of two conserved prolyl residues by prolyl-4-hydroxylase domain-containing enzymes (PHDs) targets HIF-α for proteasomal destruction. We identified the peptidyl prolyl cis/trans isomerase FK506-binding protein 38 (FKBP38) as a novel interactor of PHD2. Yeast two-hybrid, glutathione S-transferase pull-down, coimmunoprecipitation, colocalization, and mammalian two-hybrid studies confirmed specific FKBP38 interaction with PHD2, but not with PHD1 or PHD3. PHD2 and FKBP38 associated with their N-terminal regions, which contain no known interaction motifs. Neither FKBP38 mRNA nor protein levels were regulated under hypoxic conditions or after PHD inhibition, suggesting that FKBP38 is not a HIF/PHD target. Stable RNA interference-mediated depletion of FKBP38 resulted in increased PHD hydroxylation activity and decreased HIF protein levels and transcriptional activity. Reconstitution of FKBP38 expression abolished these effects, which were independent of the peptidyl prolyl cis/trans isomerase activity. Downregulation of FKBP38 did not affect PHD2 mRNA levels but prolonged PHD2 protein stability, suggesting that FKBP38 is involved in PHD2 protein regulation.

scholarly journals CSN-5, a Component of the COP9 Signalosome Complex, Regulates the Levels of UNC-96 and UNC-98, Two Components of M-lines in Caenorhabditis elegans Muscle

2009 ◽  
Vol 20 (15) ◽  
pp. 3608-3616 ◽  
Author(s):  
Rachel K. Miller ◽  
Hiroshi Qadota ◽  
Thomas J. Stark ◽  
Kristina B. Mercer ◽  
Tesheka S. Wortham ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Hybrid Method ◽  
Muscle Cells ◽  
Mutant Phenotype ◽  
Cop9 Signalosome ◽  
Wild Type ◽  
Yeast Two Hybrid ◽  
Protein Levels ◽  
Thick Filaments ◽  
Two Hybrid

In Caenorhabditis elegans two M-line proteins, UNC-98 and UNC-96, are involved in myofibril assembly and/or maintenance, especially myosin thick filaments. We found that CSN-5, a component of the COP9 signalosome complex, binds to UNC-98 and -96 using the yeast two-hybrid method. These interactions were confirmed by biochemical methods. The CSN-5 protein contains a Mov34 domain. Although one other COP9 signalosome component, CSN-6, also has a Mov34 domain, CSN-6 did not interact with UNC-98 or -96. Anti-CSN-5 antibody colocalized with paramyosin at A-bands in wild type and colocalized with abnormal accumulations of paramyosin found in unc-98, -96, and -15 (encodes paramyosin) mutants. Double knockdown of csn-5 and -6 could slightly suppress the unc-96 mutant phenotype. In the double knockdown of csn-5 and -6, the levels of UNC-98 protein were increased and the levels of UNC-96 protein levels were slightly reduced, suggesting that CSN-5 promotes the degradation of UNC-98 and that CSN-5 stabilizes UNC-96. In unc-15 and unc-96 mutants, CSN-5 protein was reduced, implying the existence of feed back regulation from myofibril proteins to CSN-5 protein levels. Taken together, we found that CSN-5 functions in muscle cells to regulate UNC-98 and -96, two M-line proteins.

scholarly journals CCA1 and ATAF2 differentially suppress cytochrome P450-mediated brassinosteroid inactivation in Arabidopsis

2018 ◽  
Author(s):  
Hao Peng ◽  
Michael M. Neff
Keyword(s):  
Cytochrome P450 ◽  
Binding Sites ◽  
Expression Patterns ◽  
Regulatory Protein ◽  
Cytochrome P450s ◽  
Null Mutant ◽  
Yeast Two Hybrid ◽  
Protein Levels ◽  
The Core ◽  
Two Hybrid

AbstractBrassinosteroids (BRs) are a group of steroid hormones regulating plant growth and development. Since BRs do not undergo transport among plant tissues, their metabolism is tightly regulated by transcription factors (TFs) and feedback loops. BAS1 (CYP734A1, formerly CYP72B1) and SOB7 (CYP72C1) are two BR-inactivating cytochrome P450s identified in Arabidopsis thaliana. We previously found that a TF ATAF2 (ANAC081) suppresses BAS1 and SOB7 expression by binding to the Evening Element (EE) and CCA1-binding sites (CBS) on their promoters. Both EE and CBS are known binding targets of the core circadian clock regulatory protein CCA1. Here, we confirm that CCA1 binds the EE and CBS motifs on BAS1 and SOB7 promoters, respectively. Elevated accumulations of BAS1 and SOB7 transcripts in the CCA1 null mutant cca1-1 indicate that CCA1 is a repressor of their expression. When compared to either cca1-1 or the ATAF2 null mutant ataf2-2, the cca1-1 ataf2-2 double mutant shows higher SOB7 transcript accumulations and stronger BR-insensitive phenotype of hypocotyl elongation in white light. CCA1 interacts with ATAF2 at both DNA-protein and protein-protein levels. ATAF2, BAS1 and SOB7 are all circadian-regulated with distinct expression patterns. These results demonstrate that CCA1 and ATAF2 differentially suppress BAS1- and SOB7-mediated BR inactivation.HighlightThe core circadian regulator CCA1 is a direct repressor of brassinosteroid inactivating genes BAS1 and SOB7, and interact with another repressor, ATAF2. Their differential suppressing effects are regulated by light.Abbreviations3-aminotriazole (3-AT), brassinolide (BL), brassinosteroid (BR), CCA1-binding site (CBS), cytochrome P450 (P450), Evening Element (EE), transcription factor (TF), yeast one-hybrid (Y1H), yeast two-hybrid (Y2H)

Identifications of DNA Sequences Encoding Key Region of SCR Interacting with SRK Extracellular Domain by Using Yeast Two-Hybrid System

2013 ◽  
Vol 38 (9) ◽  
pp. 1583-1591
Author(s):  
Li-Yan XUE ◽  
Bing LUO ◽  
Li-Quan ZHU ◽  
Yong-Jun YANG ◽  
He-Cui ZHANG ◽  
...  
Keyword(s):  
Hybrid System ◽  
Dna Sequences ◽  
Extracellular Domain ◽  
Yeast Two Hybrid ◽  
Yeast Two Hybrid System ◽  
Two Hybrid

scholarly journals Structural Glycoprotein E2 of Classical Swine Fever Virus Interacts with Host Protein Dynactin Subunit 6 (DCTN6) during the Virus Infectious Cycle

2019 ◽  
Vol 94 (1) ◽  
Author(s):  
M. V. Borca ◽  
E. A. Vuono ◽  
E. Ramirez-Medina ◽  
P. Azzinaro ◽  
K. A. Berggren ◽  
...  
Keyword(s):  
Amino Acid ◽  
Protein Interaction ◽  
Hybrid Approach ◽  
Classical Swine Fever ◽  
Host Protein ◽  
Yeast Two Hybrid ◽  
Protein Protein Interaction ◽  
Viral Virulence ◽  
Glycoprotein E2 ◽  
Two Hybrid

ABSTRACT The E2 protein in classical swine fever (CSF) virus (CSFV) is the major virus structural glycoprotein and is an essential component of the viral particle. E2 has been shown to be involved in several functions, including virus adsorption, induction of protective immunity, and virulence in swine. Using the yeast two-hybrid system, we previously identified a swine host protein, dynactin subunit 6 (DCTN6) (a component of the cell dynactin complex), as a specific binding partner for E2. We confirmed the interaction between DCTN6 and E2 proteins in CSFV-infected swine cells by using two additional independent methodologies, i.e., coimmunoprecipitation and proximity ligation assays. E2 residues critical for mediating the protein-protein interaction with DCTN6 were mapped by a reverse yeast two-hybrid approach using a randomly mutated E2 library. A recombinant CSFV mutant, E2ΔDCTN6v, harboring specific substitutions in those critical residues was developed to assess the importance of the E2-DCTN6 protein-protein interaction for virus replication and virulence in swine. CSFV E2ΔDCTN6v showed reduced replication, compared with the parental virus, in an established swine cell line (SK6) and in primary swine macrophage cultures. Remarkably, animals infected with CSFV E2ΔDCTN6v remained clinically normal during the 21-day observation period, which suggests that the ability of CSFV E2 to bind host DCTN6 protein efficiently during infection may play a role in viral virulence. IMPORTANCE Structural glycoprotein E2 is an important component of CSFV due to its involvement in many virus activities, particularly virus-host interactions. Here, we present the description and characterization of the protein-protein interaction between E2 and the swine host protein DCTN6 during virus infection. The E2 amino acid residues mediating the interaction with DCTN6 were also identified. A recombinant CSFV harboring mutations disrupting the E2-DCTN6 interaction was created. The effect of disrupting the E2-DCTN6 protein-protein interaction was studied using reverse genetics. It was shown that the same amino acid substitutions that abrogated the E2-DCTN6 interaction in vitro constituted a critical factor in viral virulence in the natural host, domestic swine. This highlights the potential importance of the E2-DCTN6 protein-protein interaction in CSFV virulence and provides possible mechanisms of virus attenuation for the development of improved CSF vaccines.

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