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Son JB, Kim S, Yang S, Ahn Y, Lee NK. Analysis of Fluorescent Proteins for Observing Single Gene Locus in a Live and Fixed Escherichia coli Cell. J Phys Chem B 2024; 128:6730-6741. [PMID: 38968413 PMCID: PMC11264270 DOI: 10.1021/acs.jpcb.4c01816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 06/21/2024] [Accepted: 06/27/2024] [Indexed: 07/07/2024]
Abstract
Fluorescent proteins (FPs) are essential tools for advanced microscopy techniques such as super-resolution imaging, single-particle tracking, and quantitative single-molecule counting. Various FPs fused to DNA-binding proteins have been used to observe the subcellular location and movement of specific gene loci in living and fixed bacterial cells. However, quantitative assessments of the properties of FPs for gene locus measurements are still lacking. Here, we assessed various FPs to observe specific gene loci in live and fixed Escherichia coli cells using a fluorescent repressor-operator binding system (FROS), tet operator-Tet repressor proteins (TetR). Tsr-fused FPs were used to assess the intensity and photostability of various FPs (five red FPs: mCherry2, FusionRed, mRFP, mCrimson3, and dKatushka; and seven yellow FPs: SYFP2, Venus, mCitrine, YPet, mClover3, mTopaz, and EYFP) at the single-molecule level in living cells. These FPs were then used for gene locus measurements using FROS. Our results indicate that TetR-mCrimson3 (red) and TetR-EYFP (yellow) had better properties for visualizing gene loci than the other TetR-FPs. Furthermore, fixation procedures affected the clustering of diffusing TetR-FPs and altered the locations of the TetR-FP foci. Fixation with formaldehyde consistently disrupted proper DNA locus observations using TetR-FPs. Notably, the foci measured using TetR-mCrimson3 remained close to their original positions in live cells after glyoxal fixation. This in vivo study provides a cell-imaging guide for the use of FPs for gene-locus observation in E. coli and a scheme for evaluating the use of FPs for other cell-imaging purposes.
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Affiliation(s)
| | | | | | - Youmin Ahn
- Department of Chemistry, Seoul
National University, 08826 Seoul, South
Korea
| | - Nam Ki Lee
- Department of Chemistry, Seoul
National University, 08826 Seoul, South
Korea
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2
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Senft RA, Diaz-Rohrer B, Colarusso P, Swift L, Jamali N, Jambor H, Pengo T, Brideau C, Llopis PM, Uhlmann V, Kirk J, Gonzales KA, Bankhead P, Evans EL, Eliceiri KW, Cimini BA. A biologist's guide to planning and performing quantitative bioimaging experiments. PLoS Biol 2023; 21:e3002167. [PMID: 37368874 PMCID: PMC10298797 DOI: 10.1371/journal.pbio.3002167] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2023] Open
Abstract
Technological advancements in biology and microscopy have empowered a transition from bioimaging as an observational method to a quantitative one. However, as biologists are adopting quantitative bioimaging and these experiments become more complex, researchers need additional expertise to carry out this work in a rigorous and reproducible manner. This Essay provides a navigational guide for experimental biologists to aid understanding of quantitative bioimaging from sample preparation through to image acquisition, image analysis, and data interpretation. We discuss the interconnectedness of these steps, and for each, we provide general recommendations, key questions to consider, and links to high-quality open-access resources for further learning. This synthesis of information will empower biologists to plan and execute rigorous quantitative bioimaging experiments efficiently.
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Affiliation(s)
- Rebecca A. Senft
- Imaging Platform, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Barbara Diaz-Rohrer
- Imaging Platform, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Pina Colarusso
- Live Cell Imaging Laboratory, University of Calgary, Calgary, Alberta, Canada
| | - Lucy Swift
- Live Cell Imaging Laboratory, University of Calgary, Calgary, Alberta, Canada
| | - Nasim Jamali
- Imaging Platform, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Helena Jambor
- National Center for Tumor Diseases, University Cancer Center, NCT-UCC, Universitätsklinikum Carl Gustav Carus an der Technischen Universität Dresden, Dresden, Germany
| | - Thomas Pengo
- Informatics Institute, University of Minnesota Twin Cities, Minneapolis, Minnesota, United States of America
| | - Craig Brideau
- Live Cell Imaging Laboratory, University of Calgary, Calgary, Alberta, Canada
| | - Paula Montero Llopis
- MicRoN Core, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Virginie Uhlmann
- European Bioinformatic Institute, European Molecular Biology Laboratory, Wellcome Genome Campus, Hinxton, United Kingdom
| | - Jason Kirk
- Optical Imaging & Vital Microscopy Core, Baylor College of Medicine, Houston, Texas, United States of America
| | - Kevin Andrew Gonzales
- Mammalian Cell Biology and Development, Rockefeller University, New York, New York, United States of America
| | - Peter Bankhead
- Edinburgh Pathology, Centre for Genomic and Experimental Medicine, and CRUK Scotland Centre, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, United Kingdom
| | - Edward L. Evans
- Morgridge Institute and University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Kevin W. Eliceiri
- Morgridge Institute and University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Beth A. Cimini
- Imaging Platform, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
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Ten Approaches That Improve Immunostaining: A Review of the Latest Advances for the Optimization of Immunofluorescence. Int J Mol Sci 2022; 23:ijms23031426. [PMID: 35163349 PMCID: PMC8836139 DOI: 10.3390/ijms23031426] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 01/03/2022] [Accepted: 01/06/2022] [Indexed: 12/04/2022] Open
Abstract
Immunostaining has emerged as one of the most common and valuable techniques that allow the localization of proteins at a quantitative level within cells and tissues using antibodies coupled to enzymes, fluorochromes, or colloidal nanogold particles. The application of fluorochromes during immunolabeling is referred to as immunofluorescence, a method coupled to widefield or confocal microscopy and extensively applied in basic research and clinical diagnosis. Notwithstanding, there are still disadvantages associated with the application of this technique due to technical challenges in the process, such as sample fixation, permeabilization, antibody incubation times, and fluid exchange, etc. These disadvantages call for continuous updates and improvements to the protocols extensively described in the literature. This review contributes to protocol optimization, outlining 10 current methods for improving sample processing in different stages of immunofluorescence, including a section with further recommendations. Additionally, we have extended our own antibody signal enhancer method, which was reported to significantly increase antibody signals and is useful for cervical cancer detection, to improve the signals of fluorochrome-conjugated staining reagents in fibrous tissues. In summary, this review is a valuable tool for experienced researchers and beginners when planning or troubleshooting the immunofluorescence assay.
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Arribas-Hernández L, Rennie S, Schon M, Porcelli C, Enugutti B, Andersson R, Nodine MD, Brodersen P. The YTHDF proteins ECT2 and ECT3 bind largely overlapping target sets and influence target mRNA abundance, not alternative polyadenylation. eLife 2021; 10:72377. [PMID: 34591013 PMCID: PMC8789314 DOI: 10.7554/elife.72377] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 09/25/2021] [Indexed: 11/18/2022] Open
Abstract
Gene regulation via N6-methyladenosine (m6A) in mRNA involves RNA-binding proteins that recognize m6A via a YT521-B homology (YTH) domain. The plant YTH domain proteins ECT2 and ECT3 act genetically redundantly in stimulating cell proliferation during organogenesis, but several fundamental questions regarding their mode of action remain unclear. Here, we use HyperTRIBE (targets of RNA-binding proteins identified by editing) to show that most ECT2 and ECT3 targets overlap, with only a few examples of preferential targeting by either of the two proteins. HyperTRIBE in different mutant backgrounds also provides direct views of redundant, ectopic, and specific target interactions of the two proteins. We also show that contrary to conclusions of previous reports, ECT2 does not accumulate in the nucleus. Accordingly, inactivation of ECT2, ECT3, and their surrogate ECT4 does not change patterns of polyadenylation site choice in ECT2/3 target mRNAs, but does lead to lower steady-state accumulation of target mRNAs. In addition, mRNA and microRNA expression profiles show indications of stress response activation in ect2/ect3/ect4 mutants, likely via indirect effects. Thus, previous suggestions of control of alternative polyadenylation by ECT2 are not supported by evidence, and ECT2 and ECT3 act largely redundantly to regulate target mRNA, including its abundance, in the cytoplasm.
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Constantin D, Dubuis G, Conde-Rubio MDC, Widmann C. APOBEC3C, a nucleolar protein induced by genotoxins, is excluded from DNA damage sites. FEBS J 2021; 289:808-831. [PMID: 34528388 PMCID: PMC9292673 DOI: 10.1111/febs.16202] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 08/22/2021] [Accepted: 09/14/2021] [Indexed: 01/23/2023]
Abstract
The human genome contains 11 APOBEC (apolipoprotein B mRNA editing catalytic polypeptide‐like) cytidine deaminases classified into four families. These proteins function mainly in innate antiviral immunity and can also restrict endogenous retrotransposable element multiplication. The present study focuses on APOBEC3C (A3C), a member of the APOBEC3 subfamily. Some APOBEC3 proteins use their enzymatic activity on genomic DNA, inducing mutations and DNA damage, while other members facilitate DNA repair. Our results show that A3C is highly expressed in cells treated with DNA‐damaging agents. Its expression is regulated by p53. Depletion of A3C slightly decreases proliferation and does not affect DNA repair via homologous recombination or nonhomologous end joining. The A3C interactomes obtained from control cells and cells exposed to the genotoxin etoposide indicated that A3C is a nucleolar protein. This was confirmed by the detection of either endogenous or ectopic A3C in nucleoli. Interestingly, we show that A3C is excluded from areas of DNA breaks in live cells. Our data also indicate that the C‐terminal part of A3C is responsible for its nucleolar localization and exclusion from DNA damage sites.
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Affiliation(s)
- Daniel Constantin
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, Switzerland
| | - Gilles Dubuis
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, Switzerland
| | | | - Christian Widmann
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, Switzerland
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HMGB1-mediated chromatin remodeling attenuates Il24 gene expression for the protection from allergic contact dermatitis. Proc Natl Acad Sci U S A 2021; 118:2022343118. [PMID: 33443188 DOI: 10.1073/pnas.2022343118] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Dysregulation of inflammatory cytokines in keratinocytes promote the pathogenesis of the skin inflammation, such as allergic contact dermatitis (ACD). High-mobility group box 1 protein (HMGB1) has been implicated in the promotion of skin inflammation upon its extracellular release as a damage-associated molecular pattern molecule. However, whether and how HMGB1 in keratinocytes contributes to ACD and other skin disorders remain elusive. In this study, we generated conditional knockout mice in which the Hmgb1 gene is specifically deleted in keratinocytes, and examined its role in ACD models. Interestingly, the mutant mice showed exacerbated skin inflammation, accompanied by increased ear thickening in 2,4-dinitrofluorobenezene-induced ACDs. The mRNA expression of interleukin-24 (IL-24), a cytokine known to critically contribute to ACD pathogenesis, was elevated in skin lesions of the mutant mice. As with constitutively expressed, IL-4-induced Il24 mRNA, expression was also augmented in the Hmgb1-deficient keratinocytes, which would account for the exacerbation of ACD in the mutant mice. Mechanistically, we observed an increased binding of trimethyl histone H3 (lys4) (H3K4me3), a hallmark of transcriptionally active genes, to the promoter region of the Il24 gene in the hmgb1-deficient cells. Thus, the nuclear HMGB1 is a critical "gate keeper" in that the dermal homeostasis is contingent to its function in chromatin remodeling. Our study revealed a facet of nuclear HMGB1, namely its antiinflammatory function in keratinocytes for the skin homeostasis.
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Li K, Wong C, Cheng C, Cheng S, Li M, Mansveld S, Bergsma A, Huang T, van Eijk MJT, Lam H. GmDNJ1, a type-I heat shock protein 40 (HSP40), is responsible for both Growth and heat tolerance in soybean. PLANT DIRECT 2021; 5:e00298. [PMID: 33532690 PMCID: PMC7833466 DOI: 10.1002/pld3.298] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 11/26/2020] [Accepted: 12/02/2020] [Indexed: 05/24/2023]
Abstract
Global warming poses severe threats to agricultural production, including soybean. One of the major mechanisms for organisms to combat heat stress is through heat shock proteins (HSPs) that stabilize protein structures at above-optimum temperatures, by assisting in the folding of nascent, misfolded, or unfolded proteins. The HSP40 subgroups, or the J-domain proteins, functions as co-chaperones. They capture proteins that require folding or refolding and pass them on to HSP70 for processing. In this study, we have identified a type-I HSP40 gene in soybean, GmDNJ1, with high basal expression under normal growth conditions and also highly inducible under abiotic stresses, especially heat. Gmdnj1-knockout mutants had diminished growth in normal conditions, and when under heat stress, exhibited more severe browning, reduced chlorophyll contents, higher reactive oxygen species (ROS) contents, and higher induction of heat stress-responsive transcription factors and ROS-scavenging enzyme-encoding genes. Under both normal and heat-stress conditions, the mutant lines accumulated more aggregated proteins involved in protein catabolism, sugar metabolism, and membrane transportation, in both roots and leaves. In summary, GmDNJ1 plays crucial roles in the overall plant growth and heat tolerance in soybean, probably through the surveillance of misfolded proteins for refolding to maintain the full capacity of cellular functions.
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Affiliation(s)
- Kwan‐Pok Li
- School of Life Sciences and Center for Soybean Research of the State Laboratory of AgrobiotechnologyThe Chinese University of Hong KongShatinHong Kong SAR
| | - Cheuk‐Hon Wong
- School of Life Sciences and Center for Soybean Research of the State Laboratory of AgrobiotechnologyThe Chinese University of Hong KongShatinHong Kong SAR
| | - Chun‐Chiu Cheng
- School of Life Sciences and Center for Soybean Research of the State Laboratory of AgrobiotechnologyThe Chinese University of Hong KongShatinHong Kong SAR
| | - Sau‐Shan Cheng
- School of Life Sciences and Center for Soybean Research of the State Laboratory of AgrobiotechnologyThe Chinese University of Hong KongShatinHong Kong SAR
| | - Man‐Wah Li
- School of Life Sciences and Center for Soybean Research of the State Laboratory of AgrobiotechnologyThe Chinese University of Hong KongShatinHong Kong SAR
| | | | | | | | | | - Hon‐Ming Lam
- School of Life Sciences and Center for Soybean Research of the State Laboratory of AgrobiotechnologyThe Chinese University of Hong KongShatinHong Kong SAR
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Jia L, Song H, Fan W, Song Y, Wang G, Li X, He Y, Yao A. The association between high mobility group box 1 chromatin protein and mitotic chromosomes in glioma cells. Oncol Lett 2020; 19:745-752. [PMID: 31897190 PMCID: PMC6924194 DOI: 10.3892/ol.2019.11170] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 11/01/2019] [Indexed: 11/06/2022] Open
Abstract
High mobility group box 1 (HMGB1) is an abundant non-histone nuclear protein that functions as a structural protein of chromatin, regulating genome replication and recombination, mRNA transcription and DNA repair. HMGB1 has been implicated in the tumorigenesis of various cancer types, and the upregulation of HMGB1 has been demonstrated in glioma cells. However, the association between HMGB1 and the mitotic chromosomes in glioma remains uncharacterized. In the present study, the sub-cellular localization of HMGB1 in glioma tissues and cells was investigated. In addition, enhanced green fluorescent protein (EGFP)-tagging of the human HMGB1 protein and chromosome spreading were used to investigate the combination of HMGB1 with mitotic chromosomes. The results of the current study indicated that HMGB1 was localized to the nucleus and the cytoplasm, and it was determined to combine with the condensed chromosomes of proliferating cells in paraformaldehyde (PFA)-fixed glioma tissues. However, HMGB1 was also associated with interphase (but not mitotic chromosomes) when fixed with chilled methanol and 5% (v/v) acetic acid or PFA in vitro. Data from live cell imaging and chromosome spreading indicated the association of HMGB1 with mitotic chromosomes in glioma cells. The present results suggest that HMGB1 combines with mitotic chromosomes in glioma cells, and that the use of fixatives may result in the dissociation of the HMGB1-DNA interaction. Therefore, in live specimens and chromosome spreads, EGFP fusion proteins may represent an accurate indicator for the determination of the correct localization and interaction of HMGB1 in glioma cells.
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Affiliation(s)
- Liyun Jia
- Department of Medical Genetics and Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan 450001, P.R. China
| | - Huiling Song
- Department of Medical Genetics and Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan 450001, P.R. China
| | - Wange Fan
- Department of Medical Genetics and Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan 450001, P.R. China
| | - Yanan Song
- Department of Medical Genetics and Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan 450001, P.R. China
| | - Gang Wang
- Henan Eye Institute, Henan Eye Hospital, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, P.R. China
| | - Xueli Li
- Department of Medical Genetics and Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan 450001, P.R. China
| | - Ying He
- Department of Medical Genetics and Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan 450001, P.R. China
| | - Anhui Yao
- Department of Neurosurgery, The General Hospital of Chinese People's Liberation Army, Beijing 100084, P.R. China.,Department of Neurosurgery, No. 988 Hospital of Joint Logistic Support Force, Zhengzhou, Henan 450042, P.R. China
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