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Tanida I, Yamaguchi J, Kakuta S, Uchiyama Y. Osmium-Resistant Fluorescent Proteins and In-Resin Correlative Light-Electron Microscopy of Epon-Embedded Mammalian Cultured Cells. Methods Mol Biol 2023; 2564:287-297. [PMID: 36107349 DOI: 10.1007/978-1-0716-2667-2_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Postfixation with osmium tetroxide and Epon embedding are essential for the preservation and visualization of subcellular ultrastructures via electron microscopy. These chemical treatments diminish the fluorescent intensity of most fluorescent proteins in cells, creating a problem for the in-resin correlative light-electron microscopy (CLEM) of Epon-embedded mammalian cultured cells. We found that two green and two far-red fluorescent proteins retain their fluorescence after chemical fixation with glutaraldehyde, osmium tetroxide-staining, dehydration, and polymerization of Epon resins. Consequently, we could observe the fluorescence of fluorescent proteins in ultrathin sections of Epon-embedded cells via fluorescence microscopy, investigate ultrastructures of the cells in the same sections via electron microscopy, and correlate the fluorescent image with the electron microscopic image without chemical or physical distortion of the cells. In other words, referred as "in-resin CLEM" of Epon-embedded samples. This technique also improves the Z-axis resolution of fluorescent images. In this chapter, we introduce the detailed protocol for in-resin CLEM of Epon-embedded mammalian cultured cells using these fluorescent proteins.
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Affiliation(s)
- Isei Tanida
- Department of Cellular and Molecular Neuropathology, Juntendo University Graduate School of Medicine, Tokyo, Japan.
| | - Junji Yamaguchi
- Department of Cellular and Molecular Neuropathology, Juntendo University Graduate School of Medicine, Tokyo, Japan
- Laboratory of Morphology and Image Analysis, Biomedical Research Core Facilities, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Soichiro Kakuta
- Department of Cellular and Molecular Neuropathology, Juntendo University Graduate School of Medicine, Tokyo, Japan
- Laboratory of Morphology and Image Analysis, Biomedical Research Core Facilities, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Yasuo Uchiyama
- Department of Cellular and Molecular Neuropathology, Juntendo University Graduate School of Medicine, Tokyo, Japan.
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Li R, Cai Y, Lin H, Dong L, Tang M, Lang Y, Qi Y, Peng Y, Zhou B, Yang G, Teng Y, Yang X. Generation of an Ihh- mKate2-Dre knock-in mouse line. Genesis 2022; 60:e23488. [PMID: 35765931 DOI: 10.1002/dvg.23488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 05/16/2022] [Accepted: 05/25/2022] [Indexed: 11/06/2022]
Abstract
Indian hedgehog (Ihh), a member of the Hh family, plays important roles in vertebrate development and homeostasis. To improve our understanding of the function of Ihh-expressing cells and their progeny as well, we generate an Ihh-mKate2tomm20 -Dre knock-in mouse line that can label Ihh-positive cells with a fluorescence protein mKate2 and trace Ihh-positive cells and their progeny via Dre-mediated recombination. Consistent with previous reports, we verified Ihh expression in hypertrophic chondrocytes of growth plate and granulosa cells of ovarian follicles by mKate2 immunostaining, and meanwhile confirmed Dre activity in these cells via a Dre reporter mouse line Rosa26-confetti2. We also found, for the first time, that Ihh can mark some cell types, including retinal ganglion cells, Purkinje cells, and gallbladder epithelial cells. Taken together, the Ihh-mKate2tomm20 -Dre mouse is a genetic tool for examining the precise expression profile of Ihh and tracing Ihh-expressing cells and their progeny.
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Affiliation(s)
- Rongyu Li
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, China
| | - Yunting Cai
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, China
| | - Huisang Lin
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, China
| | - Lei Dong
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, China
| | - Mingchuan Tang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, China
| | - Yiming Lang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, China
| | - Yini Qi
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, China
| | - Yanli Peng
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, China
| | - Bin Zhou
- The State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Guan Yang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, China
| | - Yan Teng
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, China
| | - Xiao Yang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, China
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Kjos M. Construction of Fluorescent Pneumococci for In Vivo Imaging and Labeling of the Chromosome. Methods Mol Biol 2019; 1968:41-51. [PMID: 30929204 DOI: 10.1007/978-1-4939-9199-0_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Advances in fluorescence imaging techniques and development and optimization of fluorescent proteins recent years have made major impacts on different fields of pneumococcal research. This chapter provides methodology for construction of fluorescent pneumococcal strains using fusions to DNA-binding proteins. By expressing fluorescent proteins fused to HlpA, a pneumococcal nucleoid binding protein, brightly fluorescent pneumococci are generated. HlpA fusions may be used both for in vivo imaging of pneumococci as well as for marking the nucleoid in cell biology studies. Furthermore, it also explains how to construct strains for imaging of specific chromosomal loci in pneumococci, using a heterologous ParBS system.
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Zhou K, Ding Y, Vuletic I, Tian Y, Li J, Liu J, Huang Y, Sun H, Li C, Ren Q, Lu Y. In vivo long-term investigation of tumor bearing mKate2 by an in-house fluorescence molecular imaging system. Biomed Eng Online 2018; 17:187. [PMID: 30594200 PMCID: PMC6310933 DOI: 10.1186/s12938-018-0615-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 12/05/2018] [Indexed: 11/10/2022] Open
Abstract
Background Optical imaging is one of the most common, low-cost imaging tools used for investigating the tumor biological behavior in vivo. This study explores the feasibility and sensitivity of a near infrared fluorescent protein mKate2 for a long-term non-invasive tumor imaging in BALB/c nude mice, by using a low-power optical imaging system. Methods In this study, breast cancer cell line MDA-MB-435s expressing mKate2 and MDA-MB-231 expressing a dual reporter gene firefly luciferase (fLuc)-GFP were used as cell models. Tumor cells were implanted in different animal body compartments including subcutaneous, abdominal and deep tissue area and closely monitored in real-time. A simple and low-power optical imaging system was set up to image both fluorescence and bioluminescence in live animals. Results The presence of malignant tissue was further confirmed by histopathological assay. Considering its lower exposure time and no need of substrate injection, mKate2 is considered a superior choice for subcutaneous imaging compared with fLuc. On the contrary, fLuc has shown to be a better option when monitoring the tumor in a diffusive area such as abdominal cavity. Furthermore, both reporter genes have shown good stability and sensitivity for deep tissue imaging, i.e. tumor within the liver. In addition, fLuc has shown to be an excellent method for detecting tumor cells in the lung. Conclusions The combination of mKate2 and fLuc offers a superior choice for long-term non-invasive real-time investigation of tumor biological behavior in vivo.
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Affiliation(s)
- Kedi Zhou
- Department of Biomedical Engineering, College of Engineering, Peking University, No. 5 Yiheyuan Road, Beijing, 100871, China
| | - Yichen Ding
- Department of Biomedical Engineering, College of Engineering, Peking University, No. 5 Yiheyuan Road, Beijing, 100871, China
| | - Ivan Vuletic
- Department of Biomedical Engineering, College of Engineering, Peking University, No. 5 Yiheyuan Road, Beijing, 100871, China
| | - Yonglu Tian
- Laboratory Animal Centre, Peking University, No. 5 Yiheyuan Road, Beijing, 100871, China
| | - Jun Li
- Laboratory Animal Centre, Peking University, No. 5 Yiheyuan Road, Beijing, 100871, China
| | - Jinghao Liu
- Laboratory Animal Centre, Peking University, No. 5 Yiheyuan Road, Beijing, 100871, China
| | - Yixing Huang
- Department of Biomedical Engineering, College of Engineering, Peking University, No. 5 Yiheyuan Road, Beijing, 100871, China
| | - Hongfang Sun
- Department of Biomedical Engineering, College of Engineering, Peking University, No. 5 Yiheyuan Road, Beijing, 100871, China.
| | - Changhui Li
- Department of Biomedical Engineering, College of Engineering, Peking University, No. 5 Yiheyuan Road, Beijing, 100871, China
| | - Qiushi Ren
- Department of Biomedical Engineering, College of Engineering, Peking University, No. 5 Yiheyuan Road, Beijing, 100871, China
| | - Yanye Lu
- Department of Biomedical Engineering, College of Engineering, Peking University, No. 5 Yiheyuan Road, Beijing, 100871, China.
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Vuletic I, Liu J, Wu H, Ding Y, Lei Y, Li C, Zhu D, Ren Q, Sun H, Li J. Establishment of an mKate2-Expressing Cell Line for Non-Invasive Real-Time Breast Cancer In Vivo Imaging. Mol Imaging Biol 2015; 17:811-8. [PMID: 25902968 DOI: 10.1007/s11307-015-0853-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PURPOSE Non-invasive real-time in vivo imaging experiments using mice as animal models have become crucial for understanding cancer development and treatment. In this study, we have developed and validated a new breast cancer cell line MDA-MB-435s that stably express a far-red fluorescence protein (mKate2) and that could serve as a highly valuable cell model for studying breast cancer detection and therapy using in vivo fluorescence imaging in nude mice. PROCEDURES The new cell line (MDA-MB-435s-mKate2) was constructed by plasmid transfection. The stability and sensitivity of mKate2, and the cell biological activities, were tested in vitro using different experimental approaches. For its potential use in tumor growth research and drug therapy in vivo, MDA-MB-435s-mKate2 was validated using the immunocompromised Balb/c nude mice tumor model. In addition, the new cell line has been characterized as a luteinizing hormone-releasing hormone receptor (LHRHR) positive cell line. RESULTS Firstly, MDA-MB-435s-mKate2 has shown a stable chromosomal integration of the amplified mKate2 gene and good fluorescence sensitivity for detection using a fluorescence reflectance imaging (FRI) device. Compared to its parental cell line, no significant difference in cell migration, proliferation, and clone formation was observed in vitro. Secondly, using the quantification of tumor-fluorescence surface area in live animals, we were able to monitor and detect the tumor progress or tumor inhibition rate (by Paclitaxel treatment) non-invasively and in real-time. Furthermore, MDA-MB-435s-mKate2 has been positively tested for LHRHR; these findings open the possibility to use this cell line for future studies of breast cancer therapy based on LHRH analogs in vivo. CONCLUSION In the present research, we have successfully built the MDA-MB-435s-mKate2 cell line that can be used as a suitable cell model for breast cancer therapy and anti-cancer drug evaluation by non-invasive fluorescence imaging in mice.
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Abstract
The human pathogen Streptococcus pneumoniae (pneumococcus) is a bacterium that owes its success to complex gene expression regulation patterns on both the cellular and the population level. Expression of virulence factors enables a mostly hazard-free presence of the commensal, in balance with the host and niche competitors. Under specific circumstances, changes in this expression can result in a more aggressive behavior and the reversion to the invasive form as pathogen. These triggering conditions are very difficult to study due to the fact that environmental cues are often unknown or barely possible to simulate outside the host (in vitro). An alternative way of investigating expression patterns is found in synthetic biology approaches of reconstructing regulatory networks that mimic an observed behavior with orthogonal components. Here, we created a genetic platform suitable for synthetic biology approaches in S. pneumoniae and characterized a set of standardized promoters and reporters. We show that our system allows for fast and easy cloning with the BglBrick system and that reliable and robust gene expression after integration into the S. pneumoniae genome is achieved. In addition, the cloning system was extended to allow for direct linker-based assembly of ribosome binding sites, peptide tags, and fusion proteins, and we called this new generally applicable standard "BglFusion". The gene expression platform and the methods described in this study pave the way for employing synthetic biology approaches in S. pneumoniae.
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Affiliation(s)
- Robin A. Sorg
- Molecular Genetics Group,
Groningen Biomolecular Sciences and Biotechnology Institute, Centre
for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Oscar P. Kuipers
- Molecular Genetics Group,
Groningen Biomolecular Sciences and Biotechnology Institute, Centre
for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Jan-Willem Veening
- Molecular Genetics Group,
Groningen Biomolecular Sciences and Biotechnology Institute, Centre
for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
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