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Heintz VJ, Wang L, LaCount DJ. NanoLuc luciferase as a quantitative yeast two-hybrid reporter. FEMS Yeast Res 2021; 21:6481623. [PMID: 34940882 PMCID: PMC8755890 DOI: 10.1093/femsyr/foab069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 12/21/2021] [Indexed: 12/25/2022] Open
Abstract
The yeast two-hybrid (Y2H) assay is a powerful technique to identify protein-protein interactions. However, the auxotrophic markers that are the most common Y2H reporters take several days to yield data and require subjective assessment of semiquantitative data to identify interactions. Several reporters have been developed to overcome these disadvantages, but there is still a need for a Y2H reporter that is objective, fast and able to be performed with common laboratory equipment. In this report, we replaced the ADE2 reporter in BK100 with NanoLuc luciferase to yield BK100Nano. We developed an optimized assay to measure NanoLuc activity in 96-well plates and analyzed a set of 74 pairs identified in Y2H library screens, which revealed 44 positive interactions using an unbiased cutoff based on the mean luminescence of negative control samples. The same set was also tested for growth on Y2H selection medium via expression of the HIS3 reporter. We found 91% agreement between the two assays, with discrepancies attributed to weak interactions that displayed variable growth on Y2H medium. Overall, the new BK100Nano strain establishes a quantitative and convenient method to identify Y2H interactions and has potential to be applied to a high throughput manner.
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Affiliation(s)
- Veronica J Heintz
- Department of Medicinal Chemistry and Molecular Pharmacology, 207 South Martin Jischke Drive, West Lafayette, IN 47907, USA
- Purdue Institute of Inflammation, Immunology and Infectious Disease Purdue University, 207 South Martin Jischke Drive, West Lafayette, IN 47907, USA
| | - Ling Wang
- Department of Medicinal Chemistry and Molecular Pharmacology, 207 South Martin Jischke Drive, West Lafayette, IN 47907, USA
- Purdue Institute of Inflammation, Immunology and Infectious Disease Purdue University, 207 South Martin Jischke Drive, West Lafayette, IN 47907, USA
| | - Douglas J LaCount
- Corresponding author: Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, DLR 442, 207 South Martin Jischke Drive, West Lafayette, IN 47907, USA. Tel: 765-496-7835; E-mail:
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Wang P, Nolan TM, Clark NM, Jiang H, Montes-Serey C, Guo H, Bassham DC, Walley JW, Yin Y. The F-box E3 ubiquitin ligase BAF1 mediates the degradation of the brassinosteroid-activated transcription factor BES1 through selective autophagy in Arabidopsis. THE PLANT CELL 2021; 33:3532-3554. [PMID: 34436598 PMCID: PMC8566207 DOI: 10.1093/plcell/koab210] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 08/14/2021] [Indexed: 05/02/2023]
Abstract
Brassinosteroids (BRs) regulate plant growth, development, and stress responses by activating the core transcription factor BRI1-EMS-SUPPRESSOR1 (BES1), whose degradation occurs through the proteasome and autophagy pathways. The E3 ubiquitin ligase(s) that modify BES1 for autophagy-mediated degradation remain to be fully defined. Here, we identified an F-box family E3 ubiquitin ligase named BES1-ASSOCIATED F-BOX1 (BAF1) in Arabidopsis thaliana. BAF1 interacts with BES1 and mediates its ubiquitination and degradation. Our genetic data demonstrated that BAF1 inhibits BR signaling in a BES1-dependent manner. Moreover, BAF1 targets BES1 for autophagic degradation in a selective manner. BAF1-triggered selective autophagy of BES1 depends on the ubiquitin binding receptor DOMINANT SUPPRESSOR OF KAR2 (DSK2). Sucrose starvation-induced selective autophagy of BES1, but not bulk autophagy, was significantly compromised in baf1 mutant and BAF1-ΔF (BAF1 F-box decoy) overexpression plants, but clearly increased by BAF1 overexpression. The baf1 and BAF1-ΔF overexpression plants had increased BR-regulated growth but were sensitive to long-term sucrose starvation, while BAF1 overexpression plants had decreased BR-regulated growth but were highly tolerant of sucrose starvation. Our results not only established BAF1 as an E3 ubiquitin ligase that targets BES1 for degradation through selective autophagy pathway, but also revealed a mechanism for plants to reduce growth during sucrose starvation.
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Affiliation(s)
- Ping Wang
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa 50011
| | - Trevor M Nolan
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa 50011
| | - Natalie M Clark
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, Iowa 50011
| | - Hao Jiang
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa 50011
| | | | - Hongqing Guo
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa 50011
| | - Diane C Bassham
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa 50011
| | - Justin W Walley
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, Iowa 50011
- Plant Sciences Institutes, Iowa State University, Ames, Iowa 50011
| | - Yanhai Yin
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa 50011
- Plant Sciences Institutes, Iowa State University, Ames, Iowa 50011
- Author for correspondence:
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Wang P, Nolan TM, Yin Y, Bassham DC. Identification of transcription factors that regulate ATG8 expression and autophagy in Arabidopsis. Autophagy 2019; 16:123-139. [PMID: 30909785 DOI: 10.1080/15548627.2019.1598753] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Autophagy is a conserved catabolic process in eukaryotes that contributes to cell survival in response to multiple stresses and is important for organism fitness. In Arabidopsis thaliana, the core machinery of autophagy is well defined, but its transcriptional regulation is largely unknown. The ATG8 (autophagy-related 8) protein plays central roles in decorating autophagosomes and binding to specific cargo receptors to recruit cargo to autophagosomes. We propose that the transcriptional control of ATG8 genes is important during the formation of autophagosomes and therefore contributes to survival during stress. Here, we describe a yeast one-hybrid (Y1H) screen for transcription factors (TFs) that regulate ATG8 gene expression in Arabidopsis, using the promoters of 4 ATG8 genes. We identified a total of 225 TFs from 35 families that bind these promoters. The TF-ATG8 promoter interactions revealed a wide array of diverse TF families for different promoters, as well as enrichment for families of TFs that bound to specific fragments. These TFs are not only involved in plant developmental processes but also in the response to environmental stresses. TGA9 (TGACG (TGA) motif-binding protein 9)/AT1G08320 was confirmed as a positive regulator of autophagy. TGA9 overexpression activated autophagy under both control and stress conditions and transcriptionally up-regulated expression of ATG8B, ATG8E and additional ATG genes via binding to their promoters. Our results provide a comprehensive resource of TFs that regulate ATG8 gene expression and lay a foundation for understanding the transcriptional regulation of plant autophagy.Abbreviations: ABRC: Arabidopsis biological resource center; AP2-EREBP: APETALA2/Ethylene-responsive element binding protein; ARF: auxin response factor; ATF4: activating transcription factor 4; ATG: autophagy-related; ChIP: chromatin immunoprecipitation; DAP-seq: DNA affinity purification sequencing; FOXO: forkhead box O; GFP: green fluorescent protein; GO: gene ontologies; HB: homeobox; LD: long-day; LUC: firefly luciferase; MAP1LC3: microtubule associated protein 1 light chain 3; MDC: monodansylcadaverine; 3-MA: 3-methyladenine; OE: overexpressing; PCD: programmed cell death; qPCR: quantitative polymerase chain reaction; REN: renilla luciferase; RT: room temperature; SD: standard deviation; TF: transcription factor; TFEB: transcription factor EB; TGA: TGACG motif; TOR: target of rapamycin; TSS: transcription start site; WT: wild-type; Y1H: yeast one-hybrid.
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Affiliation(s)
- Ping Wang
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA.,State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, China
| | - Trevor M Nolan
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA
| | - Yanhai Yin
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA
| | - Diane C Bassham
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA
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Ioka S, Saitoh T, Maki SA, Imoto M, Nishiyama S. Development of a luminescence-controllable firefly luciferin analogue using selective enzymatic cyclization. Tetrahedron 2016. [DOI: 10.1016/j.tet.2016.09.069] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Watanabe K, Yabe M, Kasahara K, Kokubo T. A Random Screen Using a Novel Reporter Assay System Reveals a Set of Sequences That Are Preferred as the TATA or TATA-Like Elements in the CYC1 Promoter of Saccharomyces cerevisiae. PLoS One 2015; 10:e0129357. [PMID: 26046838 PMCID: PMC4457894 DOI: 10.1371/journal.pone.0129357] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 05/08/2015] [Indexed: 12/11/2022] Open
Abstract
In Saccharomyces cerevisiae, the core promoters of class II genes contain either TATA or TATA-like elements to direct accurate transcriptional initiation. Genome-wide analyses show that the consensus sequence of the TATA element is TATAWAWR (8 bp), whereas TATA-like elements carry one or two mismatches to this consensus. The fact that several functionally distinct TATA sequences have been identified indicates that these elements may function, at least to some extent, in a gene-specific manner. The purpose of the present study was to identify functional TATA sequences enriched in one particular core promoter and compare them with the TATA or TATA-like elements that serve as the pre-initiation complex (PIC) assembly sites on the yeast genome. For this purpose, we conducted a randomized screen of the TATA element in the CYC1 promoter by using a novel reporter assay system and identified several hundreds of unique sequences that were tentatively classified into nine groups. The results indicated that the 7 bp TATA element (i.e., TATAWAD) and several sets of TATA-like sequences are preferred specifically by this promoter. Furthermore, we find that the most frequently isolated TATA-like sequence, i.e., TATTTAAA, is actually utilized as a functional core promoter element for the endogenous genes, e.g., ADE5,7 and ADE6. Collectively, these results indicate that the sequence requirements for the functional TATA or TATA-like elements in one particular core promoter are not as stringent. However, the variation of these sequences differs significantly from that of the PIC assembly sites on the genome, presumably depending on promoter structures and reflecting the gene-specific function of these sequences.
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Affiliation(s)
- Kiyoshi Watanabe
- Molecular and Cellular Biology Laboratory, Graduate School of Medical Life Science, Yokohama City University, Yokohama, Kanagawa, Japan
| | - Makoto Yabe
- Molecular and Cellular Biology Laboratory, Graduate School of Medical Life Science, Yokohama City University, Yokohama, Kanagawa, Japan
| | - Koji Kasahara
- Molecular and Cellular Biology Laboratory, Graduate School of Medical Life Science, Yokohama City University, Yokohama, Kanagawa, Japan
| | - Tetsuro Kokubo
- Molecular and Cellular Biology Laboratory, Graduate School of Medical Life Science, Yokohama City University, Yokohama, Kanagawa, Japan
- * E-mail:
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Richter I, Fidler AE. Marine invertebrate xenobiotic-activated nuclear receptors: their application as sensor elements in high-throughput bioassays for marine bioactive compounds. Mar Drugs 2014; 12:5590-618. [PMID: 25421319 PMCID: PMC4245547 DOI: 10.3390/md12115590] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 10/31/2014] [Accepted: 11/11/2014] [Indexed: 02/07/2023] Open
Abstract
Developing high-throughput assays to screen marine extracts for bioactive compounds presents both conceptual and technical challenges. One major challenge is to develop assays that have well-grounded ecological and evolutionary rationales. In this review we propose that a specific group of ligand-activated transcription factors are particularly well-suited to act as sensors in such bioassays. More specifically, xenobiotic-activated nuclear receptors (XANRs) regulate transcription of genes involved in xenobiotic detoxification. XANR ligand-binding domains (LBDs) may adaptively evolve to bind those bioactive, and potentially toxic, compounds to which organisms are normally exposed to through their specific diets. A brief overview of the function and taxonomic distribution of both vertebrate and invertebrate XANRs is first provided. Proof-of-concept experiments are then described which confirm that a filter-feeding marine invertebrate XANR LBD is activated by marine bioactive compounds. We speculate that increasing access to marine invertebrate genome sequence data, in combination with the expression of functional recombinant marine invertebrate XANR LBDs, will facilitate the generation of high-throughput bioassays/biosensors of widely differing specificities, but all based on activation of XANR LBDs. Such assays may find application in screening marine extracts for bioactive compounds that could act as drug lead compounds.
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Affiliation(s)
- Ingrid Richter
- Environmental Technology Group, Cawthron Institute, Private Bag 2, Nelson 7012, New Zealand.
| | - Andrew E Fidler
- Environmental Technology Group, Cawthron Institute, Private Bag 2, Nelson 7012, New Zealand.
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Pollock K, Sumstad D, Kadidlo D, McKenna DH, Hubel A. Clinical mesenchymal stromal cell products undergo functional changes in response to freezing. Cytotherapy 2014; 17:38-45. [PMID: 25457275 DOI: 10.1016/j.jcyt.2014.06.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 06/20/2014] [Accepted: 06/23/2014] [Indexed: 02/07/2023]
Abstract
BACKGROUND AIMS Current methods of mesenchymal stromal cell (MSC) cryopreservation result in variable post-thaw recovery and phenotypic changes caused by freezing. The objective of this investigation was to determine the influence of ex vivo cell expansion on phenotype of MSCs and the response of resulting phenotypes to freezing and thawing. METHODS Human bone marrow aspirate was used. MSCs were isolated and cells were assessed for total count, viability, apoptosis and senescence over 6 passages (8-10 doublings/passage) in ex vivo culture. One half of cells harvested at each passage were re-plated for continued culture and the other half were frozen at 1°C/min in a controlled-rate freezer. Frozen samples were stored in liquid nitrogen, thawed and reassessed for total cell count, viability and senescence immediately and 48 h after thaw. RESULTS Viability did not differ significantly between samples before freeze or after thaw. Senescence increased over time in pre-freeze culture and was significantly higher in one sample that had growth arrest both before freeze and after thaw. Freezing resulted in similar initial post-thaw recovery in all samples, but 48-h post-thaw growth arrest was observed in the sample with high senescence only. CONCLUSIONS High pre-freeze senescence appears to correlate with poor post-thaw function in MSC samples, but additional studies are necessary to obtain a sample sizes large enough to quantify results.
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Affiliation(s)
- Kathryn Pollock
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota, USA
| | - Darin Sumstad
- Molecular and Cellular Therapy Center, University of Minnesota, Minneapolis, Minnesota, USA
| | - Diane Kadidlo
- Molecular and Cellular Therapy Center, University of Minnesota, Minneapolis, Minnesota, USA
| | - David H McKenna
- Molecular and Cellular Therapy Center, University of Minnesota, Minneapolis, Minnesota, USA
| | - Allison Hubel
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota, USA.
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Yu JX, Kodibagkar VD, Hallac RR, Liu L, Mason RP. Dual 19F/1H MR gene reporter molecules for in vivo detection of β-galactosidase. Bioconjug Chem 2012; 23:596-603. [PMID: 22352428 DOI: 10.1021/bc200647q] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Increased emphasis on personalized medicine and novel therapies requires the development of noninvasive strategies for assessing biochemistry in vivo. The detection of enzyme activity and gene expression in vivo is potentially important for the characterization of diseases and gene therapy. Magnetic resonance imaging (MRI) is a particularly promising tool, since it is noninvasive and has no associated radioactivity, yet penetrates deep tissue. We now demonstrate a novel class of dual (1)H/(19)F nuclear magnetic resonance (NMR) lacZ gene reporter molecule to specifically reveal enzyme activity in human tumor xenografts growing in mice. We report the design, synthesis, and characterization of six novel molecules and evaluation of the most effective reporter in mice in vivo. Substrates show a single (19)F NMR signal and exposure to β-galactosidase induces a large (19)F NMR chemical shift response. In the presence of ferric ions, the liberated aglycone generates intense proton MRI T(2) contrast. The dual modality approach allows both the detection of substrate and the imaging of product enhancing the confidence in enzyme detection.
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Affiliation(s)
- Jian-Xin Yu
- Department of Radiology, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
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Jessulat M, Pitre S, Gui Y, Hooshyar M, Omidi K, Samanfar B, Tan LH, Alamgir M, Green J, Dehne F, Golshani A. Recent advances in protein-protein interaction prediction: experimental and computational methods. Expert Opin Drug Discov 2011; 6:921-35. [PMID: 22646215 DOI: 10.1517/17460441.2011.603722] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Proteins within the cell act as part of complex networks, which allow pathways and processes to function. Therefore, understanding how proteins interact is a significant area of current research. AREAS COVERED This review aims to present an overview of key experimental techniques (yeast two-hybrid, tandem affinity purification and protein microarrays) used to discover protein-protein interactions (PPIs), as well as to briefly discuss certain computational methods for predicting protein interactions based on gene localization, phylogenetic information, 3D structural modeling or primary protein sequence data. Due to the large-scale applicability of primary sequence-based methods, the authors have chosen to focus on this strategy for our review. There is an emphasis on a recent algorithm called Protein Interaction Prediction Engine (PIPE) that can predict global PPIs. The readers will discover recent advances both in the practical determination of protein interaction and the strategies that are available to attempt to anticipate interactions without the time and costs of experimental work. EXPERT OPINION Global PPI maps can help understand the biology of complex diseases and facilitate the identification of novel drug target sites. This study describes different techniques used for PPI prediction that we believe will significantly impact the development of the field in a new future. We expect to see a growing number of similar techniques capable of large-scale PPI predictions.
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Affiliation(s)
- Matthew Jessulat
- Carleton University , Department of Biology , 209 Nesbitt Building, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6 , Canada
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Napper AD, Motlekar N, de Almeida RA, Pavitt GD. Parallel High-Throughput Automated Assays to Measure Cell Growth and Beta-Galactosidase Reporter Gene Expression in the Yeast Saccharomyces cerevisiae. CURRENT PROTOCOLS IN CHEMICAL BIOLOGY 2011; 3:1-14. [PMID: 23836585 DOI: 10.1002/9780470559277.ch100119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Parallel high-throughput automated assays are described for the measurement of cell growth and β-galactosidase reporter gene expression from a single culture of the yeast S. cerevisiae. The dual assay measures the effect of test compounds on expression of a specific gene of interest linked to the β-galactosidase reporter gene, and simultaneously tests for compound toxicity and other effects on cell growth. Examples of assay development and validation results are used to illustrate how this protocol may be used to screen two yeast cell lines in parallel. Yeast cells are grown overnight in V-bottom polypropylene 384-well plates, after which portions of the cell suspension are transferred to clear and to white flat-bottom 384-well plates for measurement of cell growth and reporter gene expression, respectively. Cell growth is determined by measurement of absorbance at 595 nm, and β-galactosidase expression is quantified by Beta-Glo, a commercially available luminescent β-galactosidase substrate. Curr. Protoc. Chem. Biol. 3:1-14 © 2011 by John Wiley & Sons, Inc.
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Affiliation(s)
- Andrew D Napper
- Penn Center for Molecular Discovery, Institute for Medicine and Engineering, and Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania
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Osipov S, Tutyaeva V, Preobrazhenskaya O, Karpov V. A rapid method for liquid β-galactosidase reporter assay in Saccharomyces cerevisiae. World J Microbiol Biotechnol 2010. [DOI: 10.1007/s11274-010-0546-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Kamiya T, Ojima T, Sugimoto K, Nakano H, Kawarasaki Y. Quantitative Y2H screening: Cloning and signal peptide engineering of a fungal secretory LacA gene and its application to yeast two-hybrid system as a quantitative reporter. J Biotechnol 2010; 146:151-9. [DOI: 10.1016/j.jbiotec.2010.02.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2009] [Revised: 02/07/2010] [Accepted: 02/11/2010] [Indexed: 10/19/2022]
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Motlekar N, de Almeida RA, Pavitt GD, Diamond SL, Napper AD. Discovery of chemical modulators of a conserved translational control pathway by parallel screening in yeast. Assay Drug Dev Technol 2010; 7:479-94. [PMID: 19715453 DOI: 10.1089/adt.2009.0198] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Eukaryotic initiation factor 2 (eIF2) B is a guanine nucleotide exchange factor that plays a central role in translation initiation and its control, especially in response to diverse cellular stresses. In addition, inherited mutations in human eIF2B subunits cause a fatal brain disorder commonly called childhood ataxia with central nervous system hypomyelination or leukoencephalopathy with vanishing white matter. In yeast, inhibiting activity of eIF2B up-regulates expression of the transcriptional activator general control nondepressible (GCN) 4. We report here evaluation of high-throughput screening (HTS) using a yeast-based reporter gene assay, in which strains containing either wild-type or a mutant eIF2B were screened in parallel to identify compounds modifying eIF2B-dependent responses. The goals of the HTS were twofold: first, to discover compounds that restore normal function to mutant eIF2B, which may have therapeutic utility for the fatal human disease; and second, to identify compounds that activate a GCN4 response, which might be useful experimental tools. The HTS assay measured cell growth by absorbance, and activation of gene expression via a beta-galactosidase reporter gene fusion. Because mutant eIF2B activates GCN4 in the absence of stress inducers, the mutant strain was screened for reduction in GCN4 activation. HTS revealed apparent mutant-selective inhibitors but did not reliably predict selectivity as these hits affected both wild-type and mutant strains equally on dose-response confirmation. Wild-type strain results from the HTS identified two GCN4 response activators, both of which were confirmed to be wild-type selective in dose-response testing, suggesting that these compounds may activate GCN4 by a mechanism that down-regulates eIF2B activity.
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Affiliation(s)
- Nuzhat Motlekar
- Penn Center for Molecular Discovery, Institute for Medicine and Engineering, and Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Orenga S, James AL, Manafi M, Perry JD, Pincus DH. Enzymatic substrates in microbiology. J Microbiol Methods 2009; 79:139-55. [PMID: 19679151 DOI: 10.1016/j.mimet.2009.08.001] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 07/24/2009] [Accepted: 08/03/2009] [Indexed: 11/15/2022]
Abstract
Enzymatic substrates are powerful tools in biochemistry. They are widely used in microbiology to study metabolic pathways, to monitor metabolism and to detect, enumerate and identify microorganisms. Synthetic enzymatic substrates have been customized for various microbial assays, to detect an expanding range of both new enzymatic activities and target microorganisms. Recent developments in synthetic enzymatic substrates with new spectral, chemical and biochemical properties allow improved detection, enumeration and identification of food-borne microorganisms, clinical pathogens and multi-resistant bacteria in various sample types. In the past 20 years, the range of synthetic enzymatic substrates used in microbiology has been markedly extended supporting the development of new multi-test systems (e.g., Microscan, Vitek 2, Phoenix) and chromogenic culture media. The use of such substrates enables an improvement in time to detection and specificity over conventional tests that employ natural substrates. In the era of intense developments in molecular biology, phenotypic tests involving enzymatic substrates remain useful to analyse both simple and complex samples. Such tests are applicable to diagnostic and research laboratories all over the world.
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Affiliation(s)
- Sylvain Orenga
- Research & Development Microbiology, bioMérieux, 3 route de Port Michaud, La Balme-les-Grottes, France.
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Current awareness on yeast. Yeast 2008. [DOI: 10.1002/yea.1563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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