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Zein-Sabatto H, Brockett JS, Jin L, Husbands CA, Lee J, Fang J, Buehler J, Bullock SL, Lerit DA. Centrocortin potentiates co-translational localization of its mRNA to the centrosome via dynein. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.09.607365. [PMID: 39149256 PMCID: PMC11326273 DOI: 10.1101/2024.08.09.607365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
Centrosomes rely upon proteins within the pericentriolar material to nucleate and organize microtubules. Several mRNAs also reside at centrosomes, although less is known about how and why they accumulate there. We previously showed that local Centrocortin ( Cen ) mRNA supports centrosome separation, microtubule organization, and viability in Drosophila embryos. Here, using Cen mRNA as a model, we examine mechanisms of centrosomal mRNA localization. We find that while the Cen N'-terminus is sufficient for protein enrichment at centrosomes, multiple domains cooperate to concentrate Cen mRNA at this location. We further identify an N'-terminal motif within Cen that is conserved among dynein cargo adaptor proteins and test its contribution to RNA localization. Our results support a model whereby Cen protein enables the accumulation of its own mRNA to centrosomes through a mechanism requiring active translation, microtubules, and the dynein motor complex. Taken together, our data uncover the basis of translation-dependent localization of a centrosomal RNA required for mitotic integrity. Summary Enrichment of Centrocortin ( Cen ) mRNA at centrosomes is required for mitotic fidelity. This study describes a mechanism underlying co-translational Cen mRNA targeting involving microtubules, the dynein motor, and a highly conserved dynein binding motif within the Cen coding sequence.
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Schulte SJ, Fornace ME, Hall JK, Shin GJ, Pierce NA. HCR spectral imaging: 10-plex, quantitative, high-resolution RNA and protein imaging in highly autofluorescent samples. Development 2024; 151:dev202307. [PMID: 38415752 PMCID: PMC10941662 DOI: 10.1242/dev.202307] [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: 08/31/2023] [Accepted: 12/21/2023] [Indexed: 02/29/2024]
Abstract
Signal amplification based on the mechanism of hybridization chain reaction (HCR) provides a unified framework for multiplex, quantitative, high-resolution imaging of RNA and protein targets in highly autofluorescent samples. With conventional bandpass imaging, multiplexing is typically limited to four or five targets owing to the difficulty in separating signals generated by fluorophores with overlapping spectra. Spectral imaging has offered the conceptual promise of higher levels of multiplexing, but it has been challenging to realize this potential in highly autofluorescent samples, including whole-mount vertebrate embryos. Here, we demonstrate robust HCR spectral imaging with linear unmixing, enabling simultaneous imaging of ten RNA and/or protein targets in whole-mount zebrafish embryos and mouse brain sections. Further, we demonstrate that the amplified and unmixed signal in each of the ten channels is quantitative, enabling accurate and precise relative quantitation of RNA and/or protein targets with subcellular resolution, and RNA absolute quantitation with single-molecule resolution, in the anatomical context of highly autofluorescent samples.
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Affiliation(s)
- Samuel J. Schulte
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Mark E. Fornace
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - John K. Hall
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Grace J. Shin
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Niles A. Pierce
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Division of Engineering & Applied Science, California Institute of Technology, Pasadena, CA 91125, USA
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3
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Schulte SJ, Fornace ME, Hall JK, Pierce NA. HCR spectral imaging: 10-plex, quantitative, high-resolution RNA and protein imaging in highly autofluorescent samples. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.30.555626. [PMID: 37693627 PMCID: PMC10491186 DOI: 10.1101/2023.08.30.555626] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Signal amplification based on the mechanism of hybridization chain reaction (HCR) provides a unified framework for multiplex, quantitative, high-resolution imaging of RNA and protein targets in highly autofluorescent samples. With conventional bandpass imaging, multiplexing is typically limited to four or five targets due to the difficulty in separating signals generated by fluorophores with overlapping spectra. Spectral imaging has offered the conceptual promise of higher levels of multiplexing, but it has been challenging to realize this potential in highly autofluorescent samples including whole-mount vertebrate embryos. Here, we demonstrate robust HCR spectral imaging with linear unmixing, enabling simultaneous imaging of 10 RNA and/or protein targets in whole-mount zebrafish embryos and mouse brain sections. Further, we demonstrate that the amplified and unmixed signal in each of 10 channels is quantitative, enabling accurate and precise relative quantitation of RNA and/or protein targets with subcellular resolution, and RNA absolute quantitation with single-molecule resolution, in the anatomical context of highly autofluorescent samples. SUMMARY Spectral imaging with signal amplification based on the mechanism of hybridization chain reaction enables robust 10-plex, quantitative, high-resolution imaging of RNA and protein targets in whole-mount vertebrate embryos and brain sections.
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Dekker J, Alber F, Aufmkolk S, Beliveau BJ, Bruneau BG, Belmont AS, Bintu L, Boettiger A, Calandrelli R, Disteche CM, Gilbert DM, Gregor T, Hansen AS, Huang B, Huangfu D, Kalhor R, Leslie CS, Li W, Li Y, Ma J, Noble WS, Park PJ, Phillips-Cremins JE, Pollard KS, Rafelski SM, Ren B, Ruan Y, Shav-Tal Y, Shen Y, Shendure J, Shu X, Strambio-De-Castillia C, Vertii A, Zhang H, Zhong S. Spatial and temporal organization of the genome: Current state and future aims of the 4D nucleome project. Mol Cell 2023; 83:2624-2640. [PMID: 37419111 PMCID: PMC10528254 DOI: 10.1016/j.molcel.2023.06.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 06/10/2023] [Accepted: 06/12/2023] [Indexed: 07/09/2023]
Abstract
The four-dimensional nucleome (4DN) consortium studies the architecture of the genome and the nucleus in space and time. We summarize progress by the consortium and highlight the development of technologies for (1) mapping genome folding and identifying roles of nuclear components and bodies, proteins, and RNA, (2) characterizing nuclear organization with time or single-cell resolution, and (3) imaging of nuclear organization. With these tools, the consortium has provided over 2,000 public datasets. Integrative computational models based on these data are starting to reveal connections between genome structure and function. We then present a forward-looking perspective and outline current aims to (1) delineate dynamics of nuclear architecture at different timescales, from minutes to weeks as cells differentiate, in populations and in single cells, (2) characterize cis-determinants and trans-modulators of genome organization, (3) test functional consequences of changes in cis- and trans-regulators, and (4) develop predictive models of genome structure and function.
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Affiliation(s)
- Job Dekker
- University of Massachusetts Chan Medical School, Boston, MA, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA.
| | - Frank Alber
- University of California, Los Angeles, Los Angeles, CA, USA
| | | | | | - Benoit G Bruneau
- Gladstone Institutes, San Francisco, CA, USA; University of California, San Francisco, San Francisco, CA, USA
| | | | | | | | | | | | | | | | | | - Bo Huang
- University of California, San Francisco, San Francisco, CA, USA
| | - Danwei Huangfu
- Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Reza Kalhor
- Johns Hopkins University, Baltimore, MD, USA
| | | | - Wenbo Li
- University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Yun Li
- University of North Carolina, Gillings School of Global Public Health, Chapel Hill, NC, USA
| | - Jian Ma
- Carnegie Mellon University, Pittsburgh, PA, USA
| | | | | | | | - Katherine S Pollard
- Gladstone Institutes, San Francisco, CA, USA; University of California, San Francisco, San Francisco, CA, USA; Chan Zuckerberg Biohub, San Francisco, San Francisco, CA, USA
| | | | - Bing Ren
- University of California, San Diego, La Jolla, CA, USA
| | - Yijun Ruan
- Zhejiang University, Hangzhou, Zhejiang, China
| | | | - Yin Shen
- University of California, San Francisco, San Francisco, CA, USA
| | | | - Xiaokun Shu
- University of California, San Francisco, San Francisco, CA, USA
| | | | | | | | - Sheng Zhong
- University of California, San Diego, La Jolla, CA, USA.
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5
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Stark M, Levin M, Ulitsky I, Assaraf YG. Folylpolyglutamate synthetase mRNA G-quadruplexes regulate its cell protrusion localization and enhance a cancer cell invasive phenotype upon folate repletion. BMC Biol 2023; 21:13. [PMID: 36721160 PMCID: PMC9889130 DOI: 10.1186/s12915-023-01525-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Accepted: 01/23/2023] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Folates are crucial for the biosynthesis of nucleotides and amino acids, essential for cell proliferation and development. Folate deficiency induces DNA damage, developmental defects, and tumorigenicity. The obligatory enzyme folylpolyglutamate synthetase (FPGS) mediates intracellular folate retention via cytosolic and mitochondrial folate polyglutamylation. Our previous paper demonstrated the association of the cytosolic FPGS (cFPGS) with the cytoskeleton and various cell protrusion proteins. Based on these recent findings, the aim of the current study was to investigate the potential role of cFPGS at cell protrusions. RESULTS Here we uncovered a central role for two G-quadruplex (GQ) motifs in the 3'UTR of FPGS mediating the localization of cFPGS mRNA and protein at cell protrusions. Using the MBSV6-loop reporter system and fluorescence microscopy, we demonstrate that following folate deprivation, cFPGS mRNA is retained in the endoplasmic reticulum, whereas upon 15 min of folate repletion, this mRNA is rapidly translocated to cell protrusions in a 3'UTR- and actin-dependent manner. The actin dependency of this folate-induced mRNA translocation is shown by treatment with Latrunculin B and inhibitors of the Ras homolog family member A (RhoA) pathway. Upon folate repletion, the FPGS 3'UTR GQs induce an amoeboid/mesenchymal hybrid cell phenotype during migration and invasion through a collagen gel matrix. Targeted disruption of the 3'UTR GQ motifs by introducing point mutations or masking them by antisense oligonucleotides abrogated cell protrusion targeting of cFPGS mRNA. CONCLUSIONS Collectively, the GQ motifs within the 3'UTR of FPGS regulate its transcript and protein localization at cell protrusions in response to a folate cue, inducing cancer cell invasive phenotype. These novel findings suggest that the 3'UTR GQ motifs of FPGS constitute an attractive druggable target aimed at inhibition of cancer invasion and metastasis.
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Affiliation(s)
- Michal Stark
- grid.6451.60000000121102151The Fred Wyszkowski Cancer Research Laboratory, Department of Biology, Technion-Israel Institute of Technology, 3200003 Haifa, Israel
| | - May Levin
- grid.6451.60000000121102151The Fred Wyszkowski Cancer Research Laboratory, Department of Biology, Technion-Israel Institute of Technology, 3200003 Haifa, Israel ,grid.507132.2Present address: May Levin, MeMed Diagnostics Ltd, Tirat Carmel, Israel
| | - Igor Ulitsky
- grid.13992.300000 0004 0604 7563Department of Immunology and Regenerative Biology and Department of Molecular Neuroscience, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Yehuda G. Assaraf
- grid.6451.60000000121102151The Fred Wyszkowski Cancer Research Laboratory, Department of Biology, Technion-Israel Institute of Technology, 3200003 Haifa, Israel
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6
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Onda Y, Okino T. Thiol-disulfide oxidoreductase PDI1;1 regulates actin structures in Oryza sativa root cells. FEBS Lett 2022; 596:3015-3023. [PMID: 35781879 DOI: 10.1002/1873-3468.14445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 06/20/2022] [Accepted: 06/21/2022] [Indexed: 12/14/2022]
Abstract
The polarized and dynamic actin cytoskeleton is essential for root cell growth. Here, we report the key role of thiol-disulfide oxidoreductase PDI1;1 in actin structures. Microscopic analyses revealed that after Oryza sativa roots were exposed to H2 O2 , both actin and PDI1;1 were depolarized and arranged in a meshwork. In H2 O2 -exposed cells, actin formed intermolecularly disulfide-bonded high-molecular-weight structures, which were thiol-trapped by PDI1;1. Recombinant PDI1;1 exhibited the ability to recognize actin in an in vitro binding assay. During recovery from H2 O2 exposure, the amount of disulfide-bonded high-molecular-weight structures of actin decreased over time, but deficiency of PDI1;1 inhibited the decrease. These results suggest a PDI1;1-dependent pathway that reduces disulfide bonds in high-molecular-weight structures of actin, thus promoting their degradation.
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Affiliation(s)
- Yayoi Onda
- Graduate School of Agriculture, Ehime University, Matsuyama, Japan
| | - Tomoya Okino
- Faculty of Agriculture, Ehime University, Matsuyama, Japan
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7
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Ivanov AI, Lechuga S, Marino‐Melendez A, Naydenov NG. Unique and redundant functions of cytoplasmic actins and nonmuscle myosin II isoforms at epithelial junctions. Ann N Y Acad Sci 2022; 1515:61-74. [PMID: 35673768 PMCID: PMC9489603 DOI: 10.1111/nyas.14808] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The integrity and functions of epithelial barriers depend on the formation of adherens junctions (AJs) and tight junctions (TJs). A characteristic feature of AJs and TJs is their association with the cortical cytoskeleton composed of actin filaments and nonmuscle myosin II (NM-II) motors. Mechanical forces generated by the actomyosin cytoskeleton are essential for junctional assembly, stability, and remodeling. Epithelial cells express two different actin proteins and three NM-II isoforms, all known to be associated with AJs and TJs. Despite their structural similarity, different actin and NM-II isoforms have distinct biochemical properties, cellular distribution, and functions. The diversity of epithelial actins and myosin motors could be essential for the regulation of different steps of junctional formation, maturation, and disassembly. This review focuses on the roles of actin and NM-II isoforms in controlling the integrity and barrier properties of various epithelia. We discuss the effects of the depletion of individual actin isoforms and NM-II motors on the assembly and barrier function of AJs and TJs in model epithelial monolayers in vitro. We also describe the functional consequences of either total or tissue-specific gene knockout of different actins and NM-II motors, with a focus on the development and integrity of different epithelia in vivo.
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Affiliation(s)
- Andrei I. Ivanov
- Department of Inflammation and Immunity, Lerner Research InstituteCleveland ClinicClevelandOhioUSA
| | - Susana Lechuga
- Department of Inflammation and Immunity, Lerner Research InstituteCleveland ClinicClevelandOhioUSA
| | - Armando Marino‐Melendez
- Department of Inflammation and Immunity, Lerner Research InstituteCleveland ClinicClevelandOhioUSA
| | - Nayden G. Naydenov
- Department of Inflammation and Immunity, Lerner Research InstituteCleveland ClinicClevelandOhioUSA
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8
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Bouilhol E, Savulescu AF, Lefevre E, Dartigues B, Brackin R, Nikolski M. DeepSpot: A deep neural network for RNA spot enhancement in single-molecule fluorescence in-situ hybridization microscopy images. BIOLOGICAL IMAGING 2022; 2:e4. [PMID: 38510431 PMCID: PMC10951802 DOI: 10.1017/s2633903x22000034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 02/25/2022] [Accepted: 03/31/2022] [Indexed: 03/22/2024]
Abstract
Detection of RNA spots in single-molecule fluorescence in-situ hybridization microscopy images remains a difficult task, especially when applied to large volumes of data. The variable intensity of RNA spots combined with the high noise level of the images often requires manual adjustment of the spot detection thresholds for each image. In this work, we introduce DeepSpot, a Deep Learning-based tool specifically designed for RNA spot enhancement that enables spot detection without the need to resort to image per image parameter tuning. We show how our method can enable downstream accurate spot detection. DeepSpot's architecture is inspired by small object detection approaches. It incorporates dilated convolutions into a module specifically designed for context aggregation for small object and uses Residual Convolutions to propagate this information along the network. This enables DeepSpot to enhance all RNA spots to the same intensity, and thus circumvents the need for parameter tuning. We evaluated how easily spots can be detected in images enhanced with our method by testing DeepSpot on 20 simulated and 3 experimental datasets, and showed that accuracy of more than 97% is achieved. Moreover, comparison with alternative deep learning approaches for mRNA spot detection (deepBlink) indicated that DeepSpot provides more precise mRNA detection. In addition, we generated single-molecule fluorescence in-situ hybridization images of mouse fibroblasts in a wound healing assay to evaluate whether DeepSpot enhancement can enable seamless mRNA spot detection and thus streamline studies of localized mRNA expression in cells.
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Affiliation(s)
- Emmanuel Bouilhol
- CNRS, IBGC, UMR 5095, Université de Bordeaux, Bordeaux, France
- Bordeaux Bioinformatics Center, Université de Bordeaux, Bordeaux, France
| | - Anca F. Savulescu
- IDM, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Edgar Lefevre
- Bordeaux Bioinformatics Center, Université de Bordeaux, Bordeaux, France
| | - Benjamin Dartigues
- Bordeaux Bioinformatics Center, Université de Bordeaux, Bordeaux, France
| | - Robyn Brackin
- Advanced Medical Bioimaging CF, Charité—Universitätsmedizin, Berlin, Germany
| | - Macha Nikolski
- CNRS, IBGC, UMR 5095, Université de Bordeaux, Bordeaux, France
- Bordeaux Bioinformatics Center, Université de Bordeaux, Bordeaux, France
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9
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Pichon X, Moissoglu K, Coleno E, Wang T, Imbert A, Robert MC, Peter M, Chouaib R, Walter T, Mueller F, Zibara K, Bertrand E, Mili S. The kinesin KIF1C transports APC-dependent mRNAs to cell protrusions. RNA (NEW YORK, N.Y.) 2021; 27:1528-1544. [PMID: 34493599 PMCID: PMC8594469 DOI: 10.1261/rna.078576.120] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 09/01/2021] [Indexed: 05/25/2023]
Abstract
RNA localization and local translation are important for numerous cellular functions. In mammals, a class of mRNAs localize to cytoplasmic protrusions in an APC-dependent manner, with roles during cell migration. Here, we investigated this localization mechanism. We found that the KIF1C motor interacts with APC-dependent mRNAs and is required for their localization. Live cell imaging revealed rapid, active transport of single mRNAs over long distances that requires both microtubules and KIF1C. Two-color imaging directly revealed single mRNAs transported by single KIF1C motors, with the 3'UTR being sufficient to trigger KIF1C-dependent RNA transport and localization. Moreover, KIF1C remained associated with peripheral, multimeric RNA clusters and was required for their formation. These results reveal a widespread RNA transport pathway in mammalian cells, in which the KIF1C motor has a dual role in transporting RNAs and clustering them within cytoplasmic protrusions. Interestingly, KIF1C also transports its own mRNA, suggesting a possible feedback loop acting at the level of mRNA transport.
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Affiliation(s)
- Xavier Pichon
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, 34293 Montpellier, France
- Equipe labélisée Ligue Nationale Contre le Cancer, University of Montpellier, CNRS, 34000 Montpellier, France
| | - Konstadinos Moissoglu
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland 20814, USA
| | - Emeline Coleno
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, 34293 Montpellier, France
- Equipe labélisée Ligue Nationale Contre le Cancer, University of Montpellier, CNRS, 34000 Montpellier, France
- Institut de Génétique Humaine, University of Montpellier, CNRS, 34396 Montpellier, France
| | - Tianhong Wang
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland 20814, USA
| | - Arthur Imbert
- MINES ParisTech, PSL-Research University, CBIO-Centre for Computational Biology, 77300 Fontainebleau, France
- Institut Curie, 75248 Paris Cedex, France
- INSERM, U900, 75248 Paris Cedex, France
| | - Marie-Cécile Robert
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, 34293 Montpellier, France
- Equipe labélisée Ligue Nationale Contre le Cancer, University of Montpellier, CNRS, 34000 Montpellier, France
- Institut de Génétique Humaine, University of Montpellier, CNRS, 34396 Montpellier, France
| | - Marion Peter
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, 34293 Montpellier, France
- Equipe labélisée Ligue Nationale Contre le Cancer, University of Montpellier, CNRS, 34000 Montpellier, France
| | - Racha Chouaib
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, 34293 Montpellier, France
- Equipe labélisée Ligue Nationale Contre le Cancer, University of Montpellier, CNRS, 34000 Montpellier, France
- Biology Department, Faculty of Sciences-I, Lebanese University, Beirut, Lebanon
| | - Thomas Walter
- MINES ParisTech, PSL-Research University, CBIO-Centre for Computational Biology, 77300 Fontainebleau, France
- Institut Curie, 75248 Paris Cedex, France
- INSERM, U900, 75248 Paris Cedex, France
| | - Florian Mueller
- Unité Imagerie et Modélisation, Institut Pasteur and CNRS UMR 3691, 75015 Paris, France
- C3BI, USR 3756 IP CNRS - Paris, France
| | - Kazem Zibara
- Biology Department, Faculty of Sciences-I, Lebanese University, Beirut, Lebanon
- ER045, PRASE, DSST, Lebanese University, Beirut, Lebanon
| | - Edouard Bertrand
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, 34293 Montpellier, France
- Equipe labélisée Ligue Nationale Contre le Cancer, University of Montpellier, CNRS, 34000 Montpellier, France
- Institut de Génétique Humaine, University of Montpellier, CNRS, 34396 Montpellier, France
| | - Stavroula Mili
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland 20814, USA
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10
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Schwarzkopf M, Liu MC, Schulte SJ, Ives R, Husain N, Choi HMT, Pierce NA. Hybridization chain reaction enables a unified approach to multiplexed, quantitative, high-resolution immunohistochemistry and in situ hybridization. Development 2021; 148:dev199847. [PMID: 35020875 PMCID: PMC8645210 DOI: 10.1242/dev.199847] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 10/12/2021] [Indexed: 12/20/2022]
Abstract
RNA in situ hybridization based on the mechanism of the hybridization chain reaction (HCR) enables multiplexed, quantitative, high-resolution RNA imaging in highly autofluorescent samples, including whole-mount vertebrate embryos, thick brain slices and formalin-fixed paraffin-embedded tissue sections. Here, we extend the benefits of one-step, multiplexed, quantitative, isothermal, enzyme-free HCR signal amplification to immunohistochemistry, enabling accurate and precise protein relative quantitation with subcellular resolution in an anatomical context. Moreover, we provide a unified framework for simultaneous quantitative protein and RNA imaging with one-step HCR signal amplification performed for all target proteins and RNAs simultaneously.
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Affiliation(s)
- Maayan Schwarzkopf
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Mike C. Liu
- Molecular Instruments, Los Angeles, CA 90041, USA
| | - Samuel J. Schulte
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Rachel Ives
- Molecular Instruments, Los Angeles, CA 90041, USA
| | - Naeem Husain
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | | | - Niles A. Pierce
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Division of Engineering & Applied Science, California Institute of Technology, Pasadena, CA 91125, USA
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11
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Vedula P, Kurosaka S, MacTaggart B, Ni Q, Papoian G, Jiang Y, Dong DW, Kashina A. Different translation dynamics of β- and γ-actin regulates cell migration. eLife 2021; 10:68712. [PMID: 34165080 PMCID: PMC8328520 DOI: 10.7554/elife.68712] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 06/19/2021] [Indexed: 12/13/2022] Open
Abstract
β- and γ-cytoplasmic actins are ubiquitously expressed in every cell type and are nearly identical at the amino acid level but play vastly different roles in vivo. Their essential roles in embryogenesis and mesenchymal cell migration critically depend on the nucleotide sequences of their genes, rather than their amino acid sequences; however, it is unclear which gene elements underlie this effect. Here we address the specific role of the coding sequence in β- and γ-cytoplasmic actins’ intracellular functions, using stable polyclonal populations of immortalized mouse embryonic fibroblasts with exogenously expressed actin isoforms and their ‘codon-switched’ variants. When targeted to the cell periphery using β-actin 3′UTR; β-actin and γ-actin have differential effects on cell migration. These effects directly depend on the coding sequence. Single-molecule measurements of actin isoform translation, combined with fluorescence recovery after photobleaching, demonstrate a pronounced difference in β- and γ-actins’ translation elongation rates in cells, leading to changes in their dynamics at focal adhesions, impairments in actin bundle formation, and reduced cell anchoring to the substrate during migration. Our results demonstrate that coding sequence-mediated differences in actin translation play a key role in cell migration. Most mammalian cells make both β- and γ-actin, two proteins which shape the cell’s internal skeleton and its ability to migrate. The molecules share over 99% of their sequence, yet they play distinct roles. In fact, deleting the β-actin gene in mice causes death in the womb, while the animals can survive with comparatively milder issues without their γ-actin gene. How two similar proteins can have such different biological roles is a long-standing mystery. A closer look could hold some clues: β- and γ-actin may contain the same blocks (or amino acids), but the genetic sequences that encode these proteins differ by about 13%. This is because different units of genetic information – known as synonymous codons – can encode the same amino acid. These ‘silent substitutions’ have no effect on the sequence of the proteins, yet a cell reads synonymous codons (and therefore produces proteins) at different speeds. To find out the impact of silent substitutions, Vedula et al. swapped the codons for the two proteins, forcing mouse cells to produce β-actin using γ-actin codons, and vice versa. Cells with non-manipulated γ-actin and those with β-actin made using γ-actin codons could move much faster than cells with β-actin. This suggested that silent substitutions were indeed affecting the role of the protein. Vedula et al. found that cells read γ-codons – and therefore made γ-actin – much more slowly than β-codons: this also affected how quickly the protein could be dispatched where it was needed in the cell. Slower production meant that bundles of γ-actin were shorter, which allowed cells to move faster by providing a weaker anchoring system. Overall, this work provides new links between silent substitutions and protein behavior, a relatively new research area which is likely to shed light on other protein families.
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Affiliation(s)
- Pavan Vedula
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, United States
| | - Satoshi Kurosaka
- Institute of Advanced Technology, Kindai University, Kainan, Wakayama, Japan
| | - Brittany MacTaggart
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, United States
| | - Qin Ni
- Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, United States
| | - Garegin Papoian
- Department of Chemistry, University of Maryland, College Park, United States
| | - Yi Jiang
- Department of Mathematics and Statistics, Georgia State University, Atlanta, United States
| | - Dawei W Dong
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, United States.,Institute for Biomedical Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Anna Kashina
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, United States
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12
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Young AP, Jackson DJ, Wyeth RC. A technical review and guide to RNA fluorescence in situ hybridization. PeerJ 2020; 8:e8806. [PMID: 32219032 PMCID: PMC7085896 DOI: 10.7717/peerj.8806] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 02/25/2020] [Indexed: 12/20/2022] Open
Abstract
RNA-fluorescence in situ hybridization (FISH) is a powerful tool to visualize target messenger RNA transcripts in cultured cells, tissue sections or whole-mount preparations. As the technique has been developed over time, an ever-increasing number of divergent protocols have been published. There is now a broad selection of options available to facilitate proper tissue preparation, hybridization, and post-hybridization background removal to achieve optimal results. Here we review the technical aspects of RNA-FISH, examining the most common methods associated with different sample types including cytological preparations and whole-mounts. We discuss the application of commonly used reagents for tissue preparation, hybridization, and post-hybridization washing and provide explanations of the functional roles for each reagent. We also discuss the available probe types and necessary controls to accurately visualize gene expression. Finally, we review the most recent advances in FISH technology that facilitate both highly multiplexed experiments and signal amplification for individual targets. Taken together, this information will guide the methods development process for investigators that seek to perform FISH in organisms that lack documented or optimized protocols.
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Affiliation(s)
- Alexander P Young
- Department of Biology, St. Francis Xavier University, Antigonish, NS, Canada
| | - Daniel J Jackson
- Department of Geobiology, Georg-August Universität Göttingen, Göttingen, Germany
| | - Russell C Wyeth
- Department of Biology, St. Francis Xavier University, Antigonish, NS, Canada
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13
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Abstract
RNA localization is a key biological strategy for organizing the cytoplasm and generating both cellular and developmental polarity. During RNA localization, RNAs are targeted asymmetrically to specific subcellular destinations, resulting in spatially and temporally restricted gene expression through local protein synthesis. First discovered in oocytes and embryos, RNA localization is now recognized as a significant regulatory strategy for diverse RNAs, both coding and non-coding, in a wide range of cell types. Yet, the highly polarized cytoplasm of the oocyte remains a leading model to understand not only the principles and mechanisms underlying RNA localization, but also links to the formation of biomolecular condensates through phase separation. Here, we discuss both RNA localization and biomolecular condensates in oocytes with a particular focus on the oocyte of the frog, Xenopus laevis.
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Affiliation(s)
- Sarah E Cabral
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, United States
| | - Kimberly L Mowry
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, United States.
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14
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Dugina VB, Shagieva GS, Kopnin PB. Biological Role of Actin Isoforms in Mammalian Cells. BIOCHEMISTRY (MOSCOW) 2019; 84:583-592. [DOI: 10.1134/s0006297919060014] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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15
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Nir G, Farabella I, Pérez Estrada C, Ebeling CG, Beliveau BJ, Sasaki HM, Lee SD, Nguyen SC, McCole RB, Chattoraj S, Erceg J, AlHaj Abed J, Martins NMC, Nguyen HQ, Hannan MA, Russell S, Durand NC, Rao SSP, Kishi JY, Soler-Vila P, Di Pierro M, Onuchic JN, Callahan SP, Schreiner JM, Stuckey JA, Yin P, Aiden EL, Marti-Renom MA, Wu CT. Walking along chromosomes with super-resolution imaging, contact maps, and integrative modeling. PLoS Genet 2018; 14:e1007872. [PMID: 30586358 PMCID: PMC6324821 DOI: 10.1371/journal.pgen.1007872] [Citation(s) in RCA: 164] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 01/08/2019] [Accepted: 12/04/2018] [Indexed: 12/13/2022] Open
Abstract
Chromosome organization is crucial for genome function. Here, we present a method for visualizing chromosomal DNA at super-resolution and then integrating Hi-C data to produce three-dimensional models of chromosome organization. Using the super-resolution microscopy methods of OligoSTORM and OligoDNA-PAINT, we trace 8 megabases of human chromosome 19, visualizing structures ranging in size from a few kilobases to over a megabase. Focusing on chromosomal regions that contribute to compartments, we discover distinct structures that, in spite of considerable variability, can predict whether such regions correspond to active (A-type) or inactive (B-type) compartments. Imaging through the depths of entire nuclei, we capture pairs of homologous regions in diploid cells, obtaining evidence that maternal and paternal homologous regions can be differentially organized. Finally, using restraint-based modeling to integrate imaging and Hi-C data, we implement a method-integrative modeling of genomic regions (IMGR)-to increase the genomic resolution of our traces to 10 kb.
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MESH Headings
- Cells, Cultured
- Chromosome Painting/methods
- Chromosome Structures/chemistry
- Chromosome Structures/genetics
- Chromosome Structures/ultrastructure
- Chromosome Walking/methods
- Chromosomes, Human, Pair 19/chemistry
- Chromosomes, Human, Pair 19/genetics
- Chromosomes, Human, Pair 19/ultrastructure
- Female
- Fluorescent Dyes
- Humans
- Imaging, Three-Dimensional
- In Situ Hybridization, Fluorescence/methods
- Male
- Models, Genetic
- Oligonucleotide Probes
- Pedigree
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Affiliation(s)
- Guy Nir
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Irene Farabella
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Cynthia Pérez Estrada
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
- Center for Genome Architecture, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Center for Theoretical Biological Physics, Rice University, Houston, Texas, United States of America
| | - Carl G. Ebeling
- Bruker Nano Inc., Salt Lake City, Utah, United States of America
| | - Brian J. Beliveau
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts, United States of America
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Hiroshi M. Sasaki
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts, United States of America
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - S. Dean Lee
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Son C. Nguyen
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Ruth B. McCole
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Shyamtanu Chattoraj
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jelena Erceg
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jumana AlHaj Abed
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Nuno M. C. Martins
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Huy Q. Nguyen
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Mohammed A. Hannan
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sheikh Russell
- Center for Genome Architecture, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Neva C. Durand
- Center for Genome Architecture, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Broad Institute of the Massachusetts Institute of Technology and Harvard University, Cambridge, Massachusetts, United States of America
| | - Suhas S. P. Rao
- Center for Genome Architecture, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Center for Theoretical Biological Physics, Rice University, Houston, Texas, United States of America
- Department of Structural Biology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Jocelyn Y. Kishi
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts, United States of America
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Paula Soler-Vila
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Michele Di Pierro
- Center for Theoretical Biological Physics, Rice University, Houston, Texas, United States of America
| | - José N. Onuchic
- Center for Theoretical Biological Physics, Rice University, Houston, Texas, United States of America
| | | | | | - Jeff A. Stuckey
- Bruker Nano Inc., Middleton, Wisconsin, United States of America
| | - Peng Yin
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts, United States of America
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Erez Lieberman Aiden
- Center for Genome Architecture, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Center for Theoretical Biological Physics, Rice University, Houston, Texas, United States of America
- Broad Institute of the Massachusetts Institute of Technology and Harvard University, Cambridge, Massachusetts, United States of America
- Departments of Computer Science and Computational and Applied Mathematics, Rice University, Houston, Texas, United States of America
| | - Marc A. Marti-Renom
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
- Gene Regulation, Stem Cells and Cancer Program, Centre for Genomic Regulation (CRG), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- ICREA, Barcelona, Spain
| | - C.-ting Wu
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts, United States of America
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16
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Ouwenga R, Lake AM, Aryal S, Lagunas T, Dougherty JD. The Differences in Local Translatome across Distinct Neuron Types Is Mediated by Both Baseline Cellular Differences and Post-transcriptional Mechanisms. eNeuro 2018; 5:ENEURO.0320-18.2018. [PMID: 30723792 PMCID: PMC6361723 DOI: 10.1523/eneuro.0320-18.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 12/05/2018] [Accepted: 12/12/2018] [Indexed: 12/13/2022] Open
Abstract
Local translation in neurites is a phenomenon that enhances the spatial segregation of proteins and their functions away from the cell body, yet it is unclear how local translation varies across neuronal cell types. Further, it is unclear whether differences in local translation across cell types simply reflect differences in transcription or whether there is also a cell type-specific post-transcriptional regulation of the location and translation of specific mRNAs. Most of the mRNAs discovered as being locally translated have been identified from hippocampal neurons because their laminar organization facilitates neurite-specific dissection and microscopy methods. Given the diversity of neurons across the brain, studies have not yet analyzed how locally translated mRNAs differ across cell types. Here, we used the SynapTRAP method to harvest two broad cell types in the mouse forebrain: GABAergic neurons and layer 5 projection neurons. While some transcripts overlap, the majority of the local translatome is not shared across these cell types. In addition to differences driven by baseline expression levels, some transcripts also exhibit cell type-specific post-transcriptional regulation. Finally, we provide evidence that GABAergic neurons specifically localize mRNAs for peptide neurotransmitters, including somatostatin and cortistatin, suggesting localized production of these key signaling molecules in the neurites of GABAergic neurons. Overall, this work suggests that differences in local translation in neurites across neuronal cell types are poised to contribute substantially to the heterogeneity in neuronal phenotypes.
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Affiliation(s)
- Rebecca Ouwenga
- Division of Biology and Biomedical Sciences, Washington University School of Medicine, St. Louis, Missouri 63110
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Allison M. Lake
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Shivani Aryal
- Division of Biology and Biomedical Sciences, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Tomas Lagunas
- Division of Biology and Biomedical Sciences, Washington University School of Medicine, St. Louis, Missouri 63110
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Joseph D. Dougherty
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri 63110
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri 63110
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17
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Fluorescence in situ hybridization (FISH): History, limitations and what to expect from micro-scale FISH? MICRO AND NANO ENGINEERING 2018. [DOI: 10.1016/j.mne.2018.10.006] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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18
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Leung KM, Lu B, Wong HHW, Lin JQ, Turner-Bridger B, Holt CE. Cue-Polarized Transport of β-actin mRNA Depends on 3'UTR and Microtubules in Live Growth Cones. Front Cell Neurosci 2018; 12:300. [PMID: 30250426 PMCID: PMC6139529 DOI: 10.3389/fncel.2018.00300] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 08/17/2018] [Indexed: 11/13/2022] Open
Abstract
Guidance cues trigger fast responses in axonal growth cones such as directional turning and collapse that require local protein synthesis. An attractive cue-gradient, such as Netrin-1, triggers de novo synthesis of β-actin localized to the near-side compartment of the growth cone that promotes F-actin assembly and attractive steering. How this precise spatial asymmetry in mRNA translation arises across the small expanse of the growth cone is poorly understood. Pre-localized mRNAs in the vicinity of activated receptors could be selectively translated and/or new mRNAs could be trafficked into the area. Here we have performed live imaging of fluorescent-tagged β-actin mRNA to investigate mRNA trafficking dynamics in Xenopus retinal ganglion cell (RGC) axons and growth cones in response to Netrin-1. A Netrin-1 gradient was found to elicit the transport of β-actin mRNA granules to the near-side of growth cones within a 4-7 min window. This polarized mRNA trafficking depended on the 3' untranslated region (UTR) since mRNA-Δ3'UTR mutant failed to exhibit cue-induced localization. Global application of Netrin-1 significantly increased the anterograde movement of β-actin mRNA along axons and also promoted microtubule-dependent mRNA excursions from the central domain of the growth cone into the periphery (filopodia and lamellipodia). Dual channel imaging revealed β-actin mRNA riding behind the microtubule plus-end tracking protein, EB1, in movements along dynamic microtubules into filopodia. The mRNA-EB1 movements were unchanged by a Netrin-1 gradient indicating the dynamic microtubules themselves do not underlie the cue-induced polarity of RNA movement. Finally, fast-moving elongated "worm-like" trains of Cy3-RNA, distinct from mitochondria, were seen transporting RNA along axons in vitro and in vivo suggesting the existence of a novel transport organelle. Overall, the results provide evidence that the axonal trafficking of β-actin mRNA can be regulated by the guidance cue Netrin-1 to transduce the polarity of an extracellular stimulus and that the 3'UTR is essential for this cue-induced regulation.
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Affiliation(s)
| | | | | | | | | | - Christine E. Holt
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
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19
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Balajee AS, Hande MP. History and evolution of cytogenetic techniques: Current and future applications in basic and clinical research. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2018; 836:3-12. [PMID: 30389159 DOI: 10.1016/j.mrgentox.2018.08.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 08/23/2018] [Accepted: 08/23/2018] [Indexed: 12/13/2022]
Abstract
Chromosomes are the vehicles of genes, which are the functional units of a cell's nucleus. In humans, there are more than 20,000 genes that are distributed among 46 chromosomes in somatic cells. The study of chromosome structure and function is known as cytogenetics which is historically a field of hybrid science encompassing cytology and genetics. The field of cytogenetics has undergone rapid developments over the last several decades from classical Giemsa staining of chromosomes to 3-dimensional spatial organization of chromosomes with a high resolution mapping of gene structure at the nucleotide level. Improved molecular cytogenetic techniques have opened up exciting possibilities for understanding the chromosomal/molecular basis of various human diseases including cancer and tissue degeneration. This review summaries the history and evolution of various cytogenetic techniques and their current and future applications in diverse areas of basic research and medical diagnostics.
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Affiliation(s)
- Adayabalam S Balajee
- Cytogenetics Biodosimetry Laboratory, Radiation Emergency Assistance Center and Training Site, Oak Ridge Institute for Science and Education, Oak Ridge Associated Universities, 1299, Bethel Valley Road, Oak Ridge, TN 37830, USA.
| | - M Prakash Hande
- Department of Physiology, Yong Loo Lin School of Medicine and Tembusu College, National University of Singapore, 117593, Singapore.
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20
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Turkgenc B, Sanlidag B, Eker A, Giray A, Kutuk O, Yakicier C, Tolun A, Temel SG. STUB1 polyadenylation signal variant AACAAA does not affect polyadenylation but decreases STUB1 translation causing SCAR16. Hum Mutat 2018; 39:1344-1348. [PMID: 30058754 DOI: 10.1002/humu.23601] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Revised: 05/30/2018] [Accepted: 07/04/2018] [Indexed: 11/09/2022]
Abstract
We present three siblings afflicted with a disease characterized by cerebellar ataxia, cerebellar atrophy, pyramidal tract damage with increased lower limb tendon reflexes, and onset of 31 to 57 years, which is not typical for a known disease. In a region of shared homozygosity in patients, exome sequencing revealed novel homozygous c.*240T > C variant in the 3'UTR of STUB1, the gene responsible for autosomal recessive spinocerebellar ataxia 16 (SCAR16). In other genes, such an alteration of the evolutionarily highly conserved polyadenylation signal from AATAAA to AACAAA is known to highly impair polyadenylation. In contrast, RNA sequencing and quantification revealed that neither polyadenylation nor stability of STUB1 mRNA is affected. In silico analysis predicted that the secondary structure of the mRNA is altered. We propose that this change underlies the extremely low amounts of the encoded protein in patient leukocytes.
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Affiliation(s)
| | - Burcin Sanlidag
- Department of Pediatric Neurology, Near East University Faculty of Medicine, Nicosia, Cyprus
| | - Amber Eker
- Department of Neurology, Near East University Faculty of Medicine, Nicosia, Cyprus
| | - Aslı Giray
- Faculty of Engineering, Department of Genetics and Bioengineering, Alaaddin Keykubat University, Antalya, Turkey
| | - Ozgur Kutuk
- Department of Medical Genetics, Adana Dr. Turgut Noyan Medical and Research Center, Baskent University School of Medicine, Adana, Turkey
| | - Cengiz Yakicier
- Department of Molecular Biology and Genetics, Acıbadem University, Istanbul, Turkey
| | - Aslıhan Tolun
- Department of Molecular Biology and Genetics, Boğaziçi University, Istanbul, Turkey
| | - Sehime G Temel
- Department of Medical Genetics, Uludağ University, Bursa, Turkey.,Department of Histology and Embryology, Uludağ University, Bursa, Turkey.,Department of Histology and Embryology, Near East University, Nicosia, Cyprus
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21
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Vedula P, Kashina A. The makings of the 'actin code': regulation of actin's biological function at the amino acid and nucleotide level. J Cell Sci 2018; 131:131/9/jcs215509. [PMID: 29739859 DOI: 10.1242/jcs.215509] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The actin cytoskeleton plays key roles in every eukaryotic cell and is essential for cell adhesion, migration, mechanosensing, and contractility in muscle and non-muscle tissues. In higher vertebrates, from birds through to mammals, actin is represented by a family of six conserved genes. Although these genes have evolved independently for more than 100 million years, they encode proteins with ≥94% sequence identity, which are differentially expressed in different tissues, and tightly regulated throughout embryogenesis and adulthood. It has been previously suggested that the existence of such similar actin genes is a fail-safe mechanism to preserve the essential function of actin through redundancy. However, knockout studies in mice and other organisms demonstrate that the different actins have distinct biological roles. The mechanisms maintaining this distinction have been debated in the literature for decades. This Review summarizes data on the functional regulation of different actin isoforms, and the mechanisms that lead to their different biological roles in vivo We focus here on recent studies demonstrating that at least some actin functions are regulated beyond the amino acid level at the level of the actin nucleotide sequence.
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Affiliation(s)
- Pavan Vedula
- Department of Biomedical Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Anna Kashina
- Department of Biomedical Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
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22
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Trivedi V, Choi HMT, Fraser SE, Pierce NA. Multidimensional quantitative analysis of mRNA expression within intact vertebrate embryos. Development 2018; 145:dev156869. [PMID: 29311262 PMCID: PMC5825878 DOI: 10.1242/dev.156869] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 11/23/2017] [Indexed: 12/29/2022]
Abstract
For decades, in situ hybridization methods have been essential tools for studies of vertebrate development and disease, as they enable qualitative analyses of mRNA expression in an anatomical context. Quantitative mRNA analyses typically sacrifice the anatomy, relying on embryo microdissection, dissociation, cell sorting and/or homogenization. Here, we eliminate the trade-off between quantitation and anatomical context, using quantitative in situ hybridization chain reaction (qHCR) to perform accurate and precise relative quantitation of mRNA expression with subcellular resolution within whole-mount vertebrate embryos. Gene expression can be queried in two directions: read-out from anatomical space to expression space reveals co-expression relationships in selected regions of the specimen; conversely, read-in from multidimensional expression space to anatomical space reveals those anatomical locations in which selected gene co-expression relationships occur. As we demonstrate by examining gene circuits underlying somitogenesis, quantitative read-out and read-in analyses provide the strengths of flow cytometry expression analyses, but by preserving subcellular anatomical context, they enable bi-directional queries that open a new era for in situ hybridization.
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Affiliation(s)
- Vikas Trivedi
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Translational Imaging Center, University of Southern California, Los Angeles, CA 90089, USA
- Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
| | - Harry M T Choi
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Scott E Fraser
- Translational Imaging Center, University of Southern California, Los Angeles, CA 90089, USA
- Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Niles A Pierce
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Division of Engineering & Applied Science, California Institute of Technology, Pasadena, CA 91125, USA
- Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
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23
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Kar AN, Lee SJ, Twiss JL. Expanding Axonal Transcriptome Brings New Functions for Axonally Synthesized Proteins in Health and Disease. Neuroscientist 2017; 24:111-129. [PMID: 28593814 DOI: 10.1177/1073858417712668] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Intra-axonal protein synthesis has been shown to play critical roles in both development and repair of axons. Axons provide long-range connectivity in the nervous system, and disruption of their function and/or structure is seen in several neurological diseases and disorders. Axonally synthesized proteins or losses in axonally synthesized proteins contribute to neurodegenerative diseases, neuropathic pain, viral transport, and survival of axons. Increasing sensitivity of RNA detection and quantitation coupled with methods to isolate axons to purity has shown that a surprisingly complex transcriptome exists in axons. This extends across different species, neuronal populations, and physiological conditions. These studies have helped define the repertoire of neuronal mRNAs that can localize into axons and imply previously unrecognized functions for local translation in neurons. Here, we review the current state of transcriptomics studies of isolated axons, contrast axonal mRNA profiles between different neuronal types and growth states, and discuss how mRNA transport into and translation within axons contribute to neurological disorders.
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Affiliation(s)
- Amar N Kar
- 1 Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Seung Joon Lee
- 1 Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Jeffery L Twiss
- 1 Department of Biological Sciences, University of South Carolina, Columbia, SC, USA.,2 Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, USA
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24
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Astrocytes locally translate transcripts in their peripheral processes. Proc Natl Acad Sci U S A 2017; 114:E3830-E3838. [PMID: 28439016 DOI: 10.1073/pnas.1617782114] [Citation(s) in RCA: 114] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Local translation in neuronal processes is key to the alteration of synaptic strength necessary for long-term potentiation, learning, and memory. Here, we present evidence that regulated de novo protein synthesis occurs within distal, perisynaptic astrocyte processes. Astrocyte ribosomal proteins are found adjacent to synapses in vivo, and immunofluorescent detection of peptide elongation in acute slices demonstrates robust translation in distal processes. We have also developed a biochemical approach to define candidate transcripts that are locally translated in astrocyte processes. Computational analyses indicate that astrocyte-localized translation is both sequence-dependent and enriched for particular biological functions, such as fatty acid synthesis, and for pathways consistent with known roles for astrocyte processes, such as GABA and glutamate metabolism. These transcripts also include glial regulators of synaptic refinement, such as Sparc Finally, the transcripts contain a disproportionate amount of a binding motif for the quaking RNA binding protein, a sequence we show can significantly regulate mRNA localization and translation in the astrocytes. Overall, our observations raise the possibility that local production of astrocyte proteins may support microscale alterations of adjacent synapses.
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25
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Moradi M, Sivadasan R, Saal L, Lüningschrör P, Dombert B, Rathod RJ, Dieterich DC, Blum R, Sendtner M. Differential roles of α-, β-, and γ-actin in axon growth and collateral branch formation in motoneurons. J Cell Biol 2017; 216:793-814. [PMID: 28246119 PMCID: PMC5346967 DOI: 10.1083/jcb.201604117] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 11/11/2016] [Accepted: 01/17/2017] [Indexed: 12/17/2022] Open
Abstract
α-, β-, and γ-actin differentially regulate cytoskeletal dynamics and stability in axons of motoneurons. Locally translated α-actin contributes to stable actin filaments in axonal branches, whereas β- and γ-actin give rise to highly dynamic filaments that modulate growth cone dynamics. Axonal branching and terminal arborization are fundamental events during the establishment of synaptic connectivity. They are triggered by assembly of actin filaments along axon shafts giving rise to filopodia. The specific contribution of the three actin isoforms, Actα, Actβ, and Actγ, to filopodia stability and dynamics during this process is not well understood. Here, we report that Actα, Actβ, and Actγ isoforms are expressed in primary mouse motoneurons and their transcripts are translocated into axons. shRNA-mediated depletion of Actα reduces axonal filopodia dynamics and disturbs collateral branch formation. Knockdown of Actβ reduces dynamic movements of growth cone filopodia and impairs presynaptic differentiation. Ablation of Actβ or Actγ leads to compensatory up-regulation of the two other isoforms, which allows maintenance of total actin levels and preserves F-actin polymerization. Collectively, our data provide evidence for specific roles of different actin isoforms in spatial regulation of actin dynamics and stability in axons of developing motoneurons.
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Affiliation(s)
- Mehri Moradi
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, University of Wuerzburg, 97078 Wuerzburg, Germany
| | - Rajeeve Sivadasan
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, University of Wuerzburg, 97078 Wuerzburg, Germany
| | - Lena Saal
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, University of Wuerzburg, 97078 Wuerzburg, Germany
| | - Patrick Lüningschrör
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, University of Wuerzburg, 97078 Wuerzburg, Germany
| | - Benjamin Dombert
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, University of Wuerzburg, 97078 Wuerzburg, Germany
| | - Reena Jagdish Rathod
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, University of Wuerzburg, 97078 Wuerzburg, Germany
| | - Daniela C Dieterich
- Institute for Pharmacology and Toxicology, Medical Faculty, University of Magdeburg, 39120 Magdeburg, Germany.,Center for Behavioral Brain Sciences, Medical Faculty, University of Magdeburg, 39120 Magdeburg, Germany
| | - Robert Blum
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, University of Wuerzburg, 97078 Wuerzburg, Germany
| | - Michael Sendtner
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, University of Wuerzburg, 97078 Wuerzburg, Germany
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Patrinostro X, O'Rourke AR, Chamberlain CM, Moriarity BS, Perrin BJ, Ervasti JM. Relative importance of β cyto- and γ cyto-actin in primary mouse embryonic fibroblasts. Mol Biol Cell 2017; 28:771-782. [PMID: 28077619 PMCID: PMC5349784 DOI: 10.1091/mbc.e16-07-0503] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 11/29/2016] [Accepted: 01/05/2017] [Indexed: 12/14/2022] Open
Abstract
The highly homologous β (βcyto) and γ (γcyto) cytoplasmic actins are hypothesized to carry out both redundant and unique essential functions, but studies using targeted gene knockout and siRNA-mediated transcript knockdown to examine βcyto- and γcyto-isoform--specific functions in various cell types have yielded conflicting data. Here we quantitatively characterized actin transcript and protein levels, as well as cellular phenotypes, in both gene- and transcript-targeted primary mouse embryonic fibroblasts. We found that the smooth muscle αsm-actin isoform was the dominantly expressed actin isoform in WT primary fibroblasts and was also the most dramatically up-regulated in primary βcyto- or β/γcyto-actin double-knockout fibroblasts. Gene targeting of βcyto-actin, but not γcyto-actin, led to greatly decreased cell proliferation, decreased levels of cellular ATP, and increased serum response factor signaling in primary fibroblasts, whereas immortalization induced by SV40 large T antigen supported fibroblast proliferation in the absence of βcyto-actin. Consistent with in vivo gene-targeting studies in mice, both gene- and transcript-targeting approaches demonstrate that the loss of βcyto-actin protein is more disruptive to primary fibroblast function than is the loss of γcyto-actin.
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Affiliation(s)
- Xiaobai Patrinostro
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455
| | - Allison R O'Rourke
- Program in Molecular, Cellular, Developmental Biology, and Genetics, University of Minnesota, Minneapolis, MN 55455
| | - Christopher M Chamberlain
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455
| | | | - Benjamin J Perrin
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46022
| | - James M Ervasti
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455 .,Program in Molecular, Cellular, Developmental Biology, and Genetics, University of Minnesota, Minneapolis, MN 55455
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Faus-Garriga J, Novoa I, Ozaita A. mTOR signaling in proteostasis and its relevance to autism spectrum disorders. AIMS BIOPHYSICS 2017. [DOI: 10.3934/biophy.2017.1.63] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Choi HMT, Calvert CR, Husain N, Huss D, Barsi JC, Deverman BE, Hunter RC, Kato M, Lee SM, Abelin ACT, Rosenthal AZ, Akbari OS, Li Y, Hay BA, Sternberg PW, Patterson PH, Davidson EH, Mazmanian SK, Prober DA, van de Rijn M, Leadbetter JR, Newman DK, Readhead C, Bronner ME, Wold B, Lansford R, Sauka-Spengler T, Fraser SE, Pierce NA. Mapping a multiplexed zoo of mRNA expression. Development 2016; 143:3632-3637. [PMID: 27702788 PMCID: PMC5087610 DOI: 10.1242/dev.140137] [Citation(s) in RCA: 128] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 08/01/2016] [Indexed: 12/11/2022]
Abstract
In situ hybridization methods are used across the biological sciences to map mRNA expression within intact specimens. Multiplexed experiments, in which multiple target mRNAs are mapped in a single sample, are essential for studying regulatory interactions, but remain cumbersome in most model organisms. Programmable in situ amplifiers based on the mechanism of hybridization chain reaction (HCR) overcome this longstanding challenge by operating independently within a sample, enabling multiplexed experiments to be performed with an experimental timeline independent of the number of target mRNAs. To assist biologists working across a broad spectrum of organisms, we demonstrate multiplexed in situ HCR in diverse imaging settings: bacteria, whole-mount nematode larvae, whole-mount fruit fly embryos, whole-mount sea urchin embryos, whole-mount zebrafish larvae, whole-mount chicken embryos, whole-mount mouse embryos and formalin-fixed paraffin-embedded human tissue sections. In addition to straightforward multiplexing, in situ HCR enables deep sample penetration, high contrast and subcellular resolution, providing an incisive tool for the study of interlaced and overlapping expression patterns, with implications for research communities across the biological sciences.
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Affiliation(s)
- Harry M T Choi
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Colby R Calvert
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Naeem Husain
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - David Huss
- Department of Radiology, Children's Hospital Los Angeles, CA 90027, USA Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Julius C Barsi
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Benjamin E Deverman
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Ryan C Hunter
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Mihoko Kato
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - S Melanie Lee
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Anna C T Abelin
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Adam Z Rosenthal
- Division of Engineering & Applied Science, California Institute of Technology, Pasadena, CA 91125, USA
| | - Omar S Akbari
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Yuwei Li
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Bruce A Hay
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Paul W Sternberg
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Paul H Patterson
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Eric H Davidson
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Sarkis K Mazmanian
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - David A Prober
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Matt van de Rijn
- Department of Pathology, Stanford University Medical School, Stanford, CA 94305, USA
| | - Jared R Leadbetter
- Division of Engineering & Applied Science, California Institute of Technology, Pasadena, CA 91125, USA
| | - Dianne K Newman
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Carol Readhead
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Marianne E Bronner
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Barbara Wold
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Rusty Lansford
- Department of Radiology, Children's Hospital Los Angeles, CA 90027, USA Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Tatjana Sauka-Spengler
- Radcliffe Department of Medicine, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Scott E Fraser
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Niles A Pierce
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA Division of Engineering & Applied Science, California Institute of Technology, Pasadena, CA 91125, USA
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Abstract
The localization of mRNAs to specific subcellular sites is widespread, allowing cells to spatially restrict and regulate protein production, and playing important roles in development and cellular physiology. This process has been studied in mechanistic detail for several RNAs. However, the generality or specificity of RNA localization systems and mechanisms that impact the many thousands of localized mRNAs has been difficult to assess. In this review, we discuss the current state of the field in determining which RNAs localize, which RNA sequences mediate localization, the protein factors involved, and the biological implications of localization. For each question, we examine prominent systems and techniques that are used to study individual messages, highlight recent genome-wide studies of RNA localization, and discuss the potential for adapting other high-throughput approaches to the study of localization.
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Affiliation(s)
- J Matthew Taliaferro
- a Department of Biology; Massachusetts Institute of Technology ; Cambridge , MA USA
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Kim HH, Lee SJ, Gardiner AS, Perrone-Bizzozero NI, Yoo S. Different motif requirements for the localization zipcode element of β-actin mRNA binding by HuD and ZBP1. Nucleic Acids Res 2015; 43:7432-46. [PMID: 26152301 PMCID: PMC4551932 DOI: 10.1093/nar/gkv699] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 06/29/2015] [Indexed: 11/13/2022] Open
Abstract
Interactions of RNA-binding proteins (RBPs) with their target transcripts are essential for regulating gene expression at the posttranscriptional level including mRNA export/localization, stability, and translation. ZBP1 and HuD are RBPs that play pivotal roles in mRNA transport and local translational control in neuronal processes. While HuD possesses three RNA recognition motifs (RRMs), ZBP1 contains two RRMs and four K homology (KH) domains that either increase target specificity or provide a multi-target binding capability. Here we used isolated cis-element sequences of the target mRNA to examine directly protein-RNA interactions in cell-free systems. We found that both ZBP1 and HuD bind the zipcode element in rat β-actin mRNA's 3' UTR. Differences between HuD and ZBP1 were observed in their binding preference to the element. HuD showed a binding preference for U-rich sequence. In contrast, ZBP1 binding to the zipcode RNA depended more on the structural level, as it required the proper spatial organization of a stem-loop that is mainly determined by the U-rich element juxtaposed to the 3' end of a 5'-ACACCC-3' motif. On the basis of this work, we propose that ZBP1 and HuD bind to overlapping sites in the β-actin zipcode, but they recognize different features of this target sequence.
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Affiliation(s)
- Hak Hee Kim
- Nemours Biomedical Research, Alfred I. duPont Hosp. for Children, Wilmington, DE 19803, USA
| | - Seung Joon Lee
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Amy S Gardiner
- Department of Neuroscience, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA
| | - Nora I Perrone-Bizzozero
- Department of Neuroscience, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA
| | - Soonmoon Yoo
- Nemours Biomedical Research, Alfred I. duPont Hosp. for Children, Wilmington, DE 19803, USA
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31
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In the right place at the right time: visualizing and understanding mRNA localization. Nat Rev Mol Cell Biol 2014; 16:95-109. [PMID: 25549890 DOI: 10.1038/nrm3918] [Citation(s) in RCA: 388] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The spatial regulation of protein translation is an efficient way to create functional and structural asymmetries in cells. Recent research has furthered our understanding of how individual cells spatially organize protein synthesis, by applying innovative technology to characterize the relationship between mRNAs and their regulatory proteins, single-mRNA trafficking dynamics, physiological effects of abrogating mRNA localization in vivo and for endogenous mRNA labelling. The implementation of new imaging technologies has yielded valuable information on mRNA localization, for example, by observing single molecules in tissues. The emerging movements and localization patterns of mRNAs in morphologically distinct unicellular organisms and in neurons have illuminated shared and specialized mechanisms of mRNA localization, and this information is complemented by transgenic and biochemical techniques that reveal the biological consequences of mRNA mislocalization.
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32
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Chen J, Grunwald D, Sardo L, Galli A, Plisov S, Nikolaitchik OA, Chen D, Lockett S, Larson DR, Pathak VK, Hu WS. Cytoplasmic HIV-1 RNA is mainly transported by diffusion in the presence or absence of Gag protein. Proc Natl Acad Sci U S A 2014; 111:E5205-13. [PMID: 25404326 PMCID: PMC4260538 DOI: 10.1073/pnas.1413169111] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Full-length HIV-1 RNA plays a central role in viral replication by serving as the mRNA for essential viral proteins and as the genome packaged into infectious virions. Proper RNA trafficking is required for the functions of RNA and its encoded proteins; however, the mechanism by which HIV-1 RNA is transported within the cytoplasm remains undefined. Full-length HIV-1 RNA transport is further complicated when group-specific antigen (Gag) protein is expressed, because a significant portion of HIV-1 RNA may be transported as Gag-RNA complexes, whose properties could differ greatly from Gag-free RNA. In this report, we visualized HIV-1 RNA and monitored its movement in the cytoplasm by using single-molecule tracking. We observed that most of the HIV-1 RNA molecules move in a nondirectional, random-walk manner, which does not require an intact cytoskeletal structure, and that the mean-squared distance traveled by the RNA increases linearly with time, indicative of diffusive movement. We also observed that a single HIV-1 RNA molecule can move at various speeds when traveling through the cytoplasm, indicating that its movement is strongly affected by the immediate environment. To examine the effect of Gag protein on HIV-1 RNA transport, we analyzed the cytoplasmic HIV-1 RNA movement in the presence of sufficient Gag for virion assembly and found that HIV-1 RNA is still transported by diffusion with mobility similar to the mobility of RNAs unable to express functional Gag. These studies define a major mechanism of HIV-1 gene expression and resolve the long-standing question of how the RNA genome is transported to the assembly site.
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Affiliation(s)
| | - David Grunwald
- RNA Therapeutics Institute and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605
| | | | | | | | | | - De Chen
- Optical Microscopy and Analysis Laboratory, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702; and
| | - Stephen Lockett
- Optical Microscopy and Analysis Laboratory, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702; and
| | - Daniel R Larson
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, Bethesda, MD 20892
| | - Vinay K Pathak
- Viral Mutation Section, HIV Drug Resistance Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702
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Bartels H, Luban J. Gammaretroviral pol sequences act in cis to direct polysome loading and NXF1/NXT-dependent protein production by gag-encoded RNA. Retrovirology 2014; 11:73. [PMID: 25212909 PMCID: PMC4174252 DOI: 10.1186/s12977-014-0073-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 08/11/2014] [Indexed: 11/21/2022] Open
Abstract
Background All retroviruses synthesize essential proteins via alternatively spliced mRNAs. Retrovirus genera, though, exploit different mechanisms to coordinate the synthesis of proteins from alternatively spliced mRNAs. The best studied of these retroviral, post-transcriptional effectors are the trans-acting Rev protein of lentiviruses and the cis-acting constitutive transport element (CTE) of the betaretrovirus Mason-Pfizer monkey virus (MPMV). How members of the gammaretrovirus genus translate protein from unspliced RNA has not been elucidated. Results The mechanism by which two gammaretroviruses, XMRV and MLV, synthesize the Gag polyprotein (Pr65Gag) from full-length, unspliced mRNA was investigated here. The yield of Pr65Gag from a gag–only expression plasmid was found to be at least 30-fold less than that from an otherwise isogenic gag-pol expression plasmid. A frameshift mutation disrupting the pol open reading frame within the gag-pol expression plasmid did not decrease Pr65Gag production and 398 silent nucleotide changes engineered into gag rendered Pr65Gag synthesis pol-independent. These results are consistent with pol-encoded RNA acting in cis to promote Pr65Gag translation. Two independently-acting pol fragments were identified by screening 17 pol deletion mutations. To determine the mechanism by which pol promoted Pr65Gag synthesis, gag RNA in total and cytoplasmic fractions was quantitated by northern blot and by RT-PCR. The pol sequences caused, maximally, three-fold increase in total or cytoplasmic gag mRNA. Instead, pol sequences increased gag mRNA association with polyribosomes ~100-fold, a magnitude sufficient to explain the increase in Pr65Gag translation efficiency. The MPMV CTE, an NXF1-binding element, substituted for pol in promoting Pr65Gag synthesis. A pol RNA stem-loop resembling the CTE promoted Pr65Gag synthesis. Over-expression of NXF1 and NXT, host factors that bind to the MPMV CTE, synergized with pol to promote gammaretroviral gag RNA loading onto polysomes and to increase Pr65Gag synthesis. Conversely, Gag polyprotein synthesis was decreased by NXF1 knockdown. Finally, overexpression of SRp20, a shuttling protein that binds to NXF1 and promotes NXF1 binding to RNA, also increased gag RNA loading onto polysomes and increased Pr65Gag synthesis. Conclusion These experiments demonstrate that gammaretroviral pol sequences act in cis to recruit NXF1 and SRp20 to promote polysome loading of gag RNA and, thereby license the synthesis of Pr65Gag from unspliced mRNA.
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Affiliation(s)
| | - Jeremy Luban
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva 1205, Switzerland.
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Barakat TS, Gribnau J. Combined DNA-RNA fluorescent in situ hybridization (FISH) to study X chromosome inactivation in differentiated female mouse embryonic stem cells. J Vis Exp 2014. [PMID: 24961515 DOI: 10.3791/51628] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Fluorescent in situ hybridization (FISH) is a molecular technique which enables the detection of nucleic acids in cells. DNA FISH is often used in cytogenetics and cancer diagnostics, and can detect aberrations of the genome, which often has important clinical implications. RNA FISH can be used to detect RNA molecules in cells and has provided important insights in regulation of gene expression. Combining DNA and RNA FISH within the same cell is technically challenging, as conditions suitable for DNA FISH might be too harsh for fragile, single stranded RNA molecules. We here present an easily applicable protocol which enables the combined, simultaneous detection of Xist RNA and DNA encoded by the X chromosomes. This combined DNA-RNA FISH protocol can likely be applied to other systems where both RNA and DNA need to be detected.
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Affiliation(s)
| | - Joost Gribnau
- Department of Reproduction and Development, Erasmus MC - University Medical Center
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35
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Choi HMT, Beck VA, Pierce NA. Next-generation in situ hybridization chain reaction: higher gain, lower cost, greater durability. ACS NANO 2014; 8:4284-94. [PMID: 24712299 PMCID: PMC4046802 DOI: 10.1021/nn405717p] [Citation(s) in RCA: 396] [Impact Index Per Article: 39.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 03/31/2014] [Indexed: 05/17/2023]
Abstract
Hybridization chain reaction (HCR) provides multiplexed, isothermal, enzyme-free, molecular signal amplification in diverse settings. Within intact vertebrate embryos, where signal-to-background is at a premium, HCR in situ amplification enables simultaneous mapping of multiple target mRNAs, addressing a longstanding challenge in the biological sciences. With this approach, RNA probes complementary to mRNA targets trigger chain reactions in which metastable fluorophore-labeled RNA hairpins self-assemble into tethered fluorescent amplification polymers. The properties of HCR lead to straightforward multiplexing, deep sample penetration, high signal-to-background, and sharp subcellular signal localization within fixed whole-mount zebrafish embryos, a standard model system for the study of vertebrate development. However, RNA reagents are expensive and vulnerable to enzymatic degradation. Moreover, the stringent hybridization conditions used to destabilize nonspecific hairpin binding also reduce the energetic driving force for HCR polymerization, creating a trade-off between minimization of background and maximization of signal. Here, we eliminate this trade-off by demonstrating that low background levels can be achieved using permissive in situ amplification conditions (0% formamide, room temperature) and engineer next-generation DNA HCR amplifiers that maximize the free energy benefit per polymerization step while preserving the kinetic trapping property that underlies conditional polymerization, dramatically increasing signal gain, reducing reagent cost, and improving reagent durability.
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Affiliation(s)
- Harry M. T. Choi
- Division of Biology & Biological Engineering and Division of Engineering & Applied Science, California Institute of Technology, Pasadena, California 91125, United States
| | - Victor A. Beck
- Division of Biology & Biological Engineering and Division of Engineering & Applied Science, California Institute of Technology, Pasadena, California 91125, United States
| | - Niles A. Pierce
- Division of Biology & Biological Engineering and Division of Engineering & Applied Science, California Institute of Technology, Pasadena, California 91125, United States
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36
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Artman L, Dormoy-Raclet V, von Roretz C, Gallouzi IE. Planning your every move: the role of β-actin and its post-transcriptional regulation in cell motility. Semin Cell Dev Biol 2014; 34:33-43. [PMID: 24878350 DOI: 10.1016/j.semcdb.2014.05.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 05/21/2014] [Indexed: 01/23/2023]
Abstract
Cell motility is a tightly regulated process that involves the polymerization of actin subunits. The formation of actin filaments is controlled through a variety of protein factors that accelerate or perturb the polymerization process. As is the case for most biological events, cell movement is also controlled at the level of gene expression. Growing research explains how the β-actin isoform of actin is particularly regulated through post-transcriptional events. This includes the discovery of multiple sites in the 3' untranslated region of β-actin mRNA to which RNA-binding proteins can associate. The control such proteins have on β-actin expression, and as a result, cell migration, continues to develop, and presents a thorough process that involves guiding an mRNA out of the nucleus, to a specific cytosolic destination, and then controlling the translation and decay of this message. In this review we will provide an overview on the recent progress regarding the mechanisms by which actin polymerization modulates cell movement and invasion and we will discuss the importance of post-transcriptional regulatory events in β-actin mediated effects on these processes.
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Affiliation(s)
- Lise Artman
- McGill University, Biochemistry Department and Rosalind and Morris Goodman Cancer Center, Montreal, Canada
| | | | | | - Imed-Eddine Gallouzi
- McGill University, Biochemistry Department and Rosalind and Morris Goodman Cancer Center, Montreal, Canada.
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Joseph R, Srivastava O, Pfister R. Downregulation of β-actin and its regulatory gene HuR affect cell migration of human corneal fibroblasts. Mol Vis 2014; 20:593-605. [PMID: 24826067 PMCID: PMC4016806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 04/30/2014] [Indexed: 11/16/2022] Open
Abstract
PURPOSE In an earlier study, we showed that human antigen R (HuR) and β-actin expression levels were downregulated in fibroblasts isolated from human keratoconus stroma compared to normal corneal stroma. To further extend the finding, we determined whether HuR expression affects β-actin gene expression and in turn affects corneal fibroblast migration and wound healing. METHODS Stromal keratocytes from normal human corneas were cultured in the presence of serum. Cells were transfected with siRNA specific for β-actin or HuR. SiRNAs specific for GAPDH or a scrambled sequence were used as positive and negative controls (siCTR) for transfection, respectively. The effects of gene silencing were analyzed at the transcriptional and translational levels. Specific proteins were immunohistochemically localized using confocal imaging. The effects of gene silencing on cell migration and cell proliferation were analyzed using a modified Boyden chamber and with a wound healing assay, respectively. RESULTS Reverse-transcription PCR (RT-PCR) and western blot analyses showed that when the HuR gene was silenced, β-actin expression was significantly downregulated. This was further confirmed at the translational level with immunohistochemical-confocal analysis. However, when the β-actin gene was silenced, its expression was significantly decreased but showed no effect on HuR gene expression. When the β-actin or HuR gene was individually silenced, the motility and proliferation of corneal fibroblasts were significantly reduced. CONCLUSIONS The results show that downregulation of the HuR gene results in decreased β-actin gene expression, which in turn results in decreased motility and proliferation of corneal fibroblasts. We conclude that decreased β-actin expression in normal corneal stroma clearly disrupts the cytoskeletal structure and functions, including keratocyte motility and wound healing.
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Affiliation(s)
- R. Joseph
- Department of Vision Sciences, University of Alabama at Birmingham, Birmingham, AL
| | - O.P. Srivastava
- Department of Vision Sciences, University of Alabama at Birmingham, Birmingham, AL
| | - R.R. Pfister
- Eye Research Laboratory, Eye Research Foundation, Birmingham, AL
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Carrascoso I, Sánchez-Jiménez C, Izquierdo JM. Long-term reduction of T-cell intracellular antigens leads to increased beta-actin expression. Mol Cancer 2014; 13:90. [PMID: 24766723 PMCID: PMC4113145 DOI: 10.1186/1476-4598-13-90] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 04/17/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The permanent down-regulated expression of T-cell intracellular antigen (TIA) proteins in HeLa cells improves cytoskeleton-mediated functions such as cell proliferation and tumor growth. METHODS Making use of human and mouse cells with knocked down/out expression of T-cell intracellular antigen 1 (TIA1) and/or TIA1 related/like (TIAR/TIAL1) proteins and classical RNA (e.g. reverse transcription-quantitative polymerase chain reaction, polysomal profiling analysis using sucrose gradients, immunoblotting, immunoprecipitation, electrophoretic mobility shift assays, ultraviolet light crosslinking and poly (A+) test analysis) and cellular (e.g. immunofluorescence microscopy and quimeric mRNA transfections) biology methods, we have analyzed the regulatory role of TIA proteins in the post-transcriptional modulation of beta-actin (ACTB) mRNA. RESULTS Our observations show that the acquisition of above cellular capacities is concomitant with increased expression levels of the actin beta subunit (ACTB) protein. Regulating TIA abundance does not modify ACTB mRNA levels, however, an increase of ACTB mRNA translation is observed. This regulatory capacity of TIA proteins is linked to the ACTB mRNA 3'-untranslated region (3'-UTR), where these proteins could function as RNA binding proteins. The expression of GFP from a chimeric reporter containing human ΑCΤΒ 3'-UTR recapitulates the translational control found by the endogenous ACTB mRNA in the absence of TIA proteins. Additionally, murine embryonic fibroblasts (MEF) knocked out for TIA1 rise mouse ACTB protein expression compared to the controls. Once again steady-state levels of mouse ACTB mRNA remained unchanged. CONCLUSIONS Collectively, these results suggest that TIA proteins can function as long-term regulators of the ACTB mRNA metabolism in mouse and human cells.
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Affiliation(s)
| | | | - José M Izquierdo
- Centro de Biología Molecular 'Severo Ochoa', Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid (CSIC/UAM), C/Nicolás Cabrera 1, Cantoblanco, DP 28049 Madrid, Spain.
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Kannaiah S, Amster-Choder O. Protein targeting via mRNA in bacteria. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1843:1457-65. [PMID: 24263243 DOI: 10.1016/j.bbamcr.2013.11.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Revised: 11/09/2013] [Accepted: 11/11/2013] [Indexed: 01/10/2023]
Abstract
Proteins of all living organisms must reach their subcellular destination to sustain the cell structure and function. The proteins are transported to one of the cellular compartments, inserted into the membrane, or secreted across the membrane to the extracellular milieu. Cells have developed various mechanisms to transport proteins across membranes, among them localized translation. Evidence for targeting of Messenger RNA for the sake of translation of their respective protein products at specific subcellular sites in many eukaryotic model organisms have been accumulating in recent years. Cis-acting RNA localizing elements, termed RNA zip-codes, which are embedded within the mRNA sequence, are recognized by RNA-binding proteins, which in turn interact with motor proteins, thus coordinating the intracellular transport of the mRNA transcripts. Despite the rareness of conventional organelles, first and foremost a nucleus, pieces of evidence for mRNA localization to specific subcellular domains, where their protein products function, have also been obtained for prokaryotes. Although the underlying mechanisms for transcript localization in bacteria are yet to be unraveled, it is now obvious that intracellular localization of mRNA is a common mechanism to spatially localize proteins in both eukaryotes and prokaryotes. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey.
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Affiliation(s)
- Shanmugapriya Kannaiah
- Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University - Faculty of Medicine, P.O.Box 12272, Jerusalem 91120, Israel
| | - Orna Amster-Choder
- Department of Microbiology and Molecular Genetics, IMRIC, The Hebrew University - Faculty of Medicine, P.O.Box 12272, Jerusalem 91120, Israel.
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Minis A, Dahary D, Manor O, Leshkowitz D, Pilpel Y, Yaron A. Subcellular transcriptomics-Dissection of the mRNA composition in the axonal compartment of sensory neurons. Dev Neurobiol 2013; 74:365-81. [DOI: 10.1002/dneu.22140] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Revised: 09/06/2013] [Accepted: 10/03/2013] [Indexed: 12/19/2022]
Affiliation(s)
- Adi Minis
- Department of Biological Chemistry; Weizmann Institute of Science; Rehovot 76100 Israel
| | - Dvir Dahary
- Department of Molecular Genetics; Weizmann Institute of Science; Rehovot 76100 Israel
| | - Ohad Manor
- Department of Computer Science and Applied Mathematics; Weizmann Institute of Science; Rehovot 76100 Israel
| | - Dena Leshkowitz
- Biological Services Department; Bioinformatics Unit, Weizmann Institute of Science; Rehovot 76100 Israel
| | - Yitzhak Pilpel
- Department of Molecular Genetics; Weizmann Institute of Science; Rehovot 76100 Israel
| | - Avraham Yaron
- Department of Biological Chemistry; Weizmann Institute of Science; Rehovot 76100 Israel
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41
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Rockey DC, Weymouth N, Shi Z. Smooth muscle α actin (Acta2) and myofibroblast function during hepatic wound healing. PLoS One 2013; 8:e77166. [PMID: 24204762 PMCID: PMC3812165 DOI: 10.1371/journal.pone.0077166] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 08/30/2013] [Indexed: 01/18/2023] Open
Abstract
Smooth muscle α actin (Acta2) expression is largely restricted to smooth muscle cells, pericytes and specialized fibroblasts, known as myofibroblasts. Liver injury, associated with cirrhosis, induces transformation of resident hepatic stellate cells into liver specific myofibroblasts, also known as activated cells. Here, we have used in vitro and in vivo wound healing models to explore the functional role of Acta2 in this transformation. Acta2 was abundant in activated cells isolated from injured livers but was undetectable in quiescent cells isolated from normal livers. Both cellular motility and contraction were dramatically increased in injured liver cells, paralleled by an increase in Acta2 expression, when compared with quiescent cells. Inhibition of Acta2 using several different techniques had no effect on cytoplasmic actin isoform expression, but led to reduced cellular motility and contraction. Additionally, Acta2 knockdown was associated with a significant reduction in Erk1/2 phosphorylation compared to control cells. The data indicate that Acta2 is important specifically in myofibroblast cell motility and contraction and raise the possibility that the Acta2 cytoskeleton, beyond its structural importance in the cell, could be important in regulating signaling processes during wound healing in vivo.
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Affiliation(s)
- Don C. Rockey
- Department of Internal Medicine, Medical University of South Carolina, Charleston, South Carolina, United States of America
- * E-mail:
| | - Nate Weymouth
- Division of Digestive and Liver Diseases, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Zengdun Shi
- Department of Internal Medicine, Medical University of South Carolina, Charleston, South Carolina, United States of America
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42
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Optimized RNA ISH, RNA FISH and protein-RNA double labeling (IF/FISH) in Drosophila ovaries. Nat Protoc 2013; 8:2158-79. [PMID: 24113787 DOI: 10.1038/nprot.2013.136] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In situ hybridization (ISH) is a powerful technique for detecting nucleic acids in cells and tissues. Here we describe three ISH procedures that are optimized for Drosophila ovaries: whole-mount, digoxigenin-labeled RNA ISH; RNA fluorescent ISH (FISH); and protein immunofluorescence (IF)-RNA FISH double labeling (IF/FISH). Each procedure balances conflicting requirements for permeabilization, fixation and preservation of antigenicity to detect RNA and protein expression with high resolution and sensitivity. The ISH protocol uses alkaline phosphatase-conjugated digoxigenin antibodies followed by a color reaction, whereas FISH detection involves tyramide signal amplification (TSA). To simultaneously preserve antigens for protein detection and enable RNA probe penetration for IF/FISH, we perform IF before FISH and use xylenes and detergents to permeabilize the tissue rather than proteinase K, which can damage the antigens. ISH and FISH take 3 d to perform, whereas IF/FISH takes 5 d. Probe generation takes 1 or 2 d to perform.
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43
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Foeger NC, Wang W, Mellor RL, Nerbonne JM. Stabilization of Kv4 protein by the accessory K(+) channel interacting protein 2 (KChIP2) subunit is required for the generation of native myocardial fast transient outward K(+) currents. J Physiol 2013; 591:4149-66. [PMID: 23713033 DOI: 10.1113/jphysiol.2013.255836] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The fast transient outward K(+) current (Ito,f) underlies the early phase of myocardial action potential repolarization, contributing importantly to the coordinated propagation of activity in the heart and to the generation of normal cardiac rhythms. Native Ito,f channels reflect the tetrameric assembly of Kv4 pore-forming (α) subunits, and previous studies suggest roles for accessory and regulatory proteins in controlling the cell surface expression and the biophysical properties of Kv4-encoded Ito,f channels. Here, we demonstrate that the targeted deletion of the cytosolic accessory subunit, K(+) channel interacting protein 2 (KChIP2), results in the complete loss of the Kv4.2 protein, the α subunit critical for the generation of mouse ventricular Ito,f. Expression of the Kcnd2 (Kv4.2) transcript in KChIP2(-/-) ventricles, however, is unaffected. The loss of the Kv4.2 protein results in the elimination of Ito,f in KChIP2(-/-) ventricular myocytes. In parallel with the elimination of Ito,f, the slow transient outward K(+) current (Ito,s) is upregulated and voltage-gated Ca(2+) currents (ICa,L) are decreased. In addition, surface electrocardiograms and ventricular action potential waveforms in KChIP2(-/-) and wild-type mice are not significantly different, suggesting that the upregulation of Ito,s and the reduction in ICa,L compensate for the loss of Ito,f. Additional experiments revealed that Ito,f is not 'rescued' by adenovirus-mediated expression of KChIP2 in KChIP2(-/-) myocytes, although ICa,L densities are increased. Taken together, these results demonstrate that association with KChIP2 early in the biosynthetic pathway and KChIP2-mediated stabilization of Kv4 protein are critical determinants of native cardiac Ito,f channel expression.
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Affiliation(s)
- Nicholas C Foeger
- J. M. Nerbonne: Department of Developmental Biology, Washington University School of Medicine, Campus Box 8103, 660 South Euclid Avenue, St. Louis, MO 63110, USA.
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Dong H, Lei J, Ding L, Wen Y, Ju H, Zhang X. MicroRNA: Function, Detection, and Bioanalysis. Chem Rev 2013; 113:6207-33. [PMID: 23697835 DOI: 10.1021/cr300362f] [Citation(s) in RCA: 836] [Impact Index Per Article: 76.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Haifeng Dong
- Research Center for Bioengineering and Sensing Technology, University of Science & Technology Beijing, Beijing 100083, P. R. China
| | - Jianping Lei
- State Key Laboratory of Analytical
Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China
| | - Lin Ding
- State Key Laboratory of Analytical
Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China
| | - Yongqiang Wen
- Research Center for Bioengineering and Sensing Technology, University of Science & Technology Beijing, Beijing 100083, P. R. China
| | - Huangxian Ju
- State Key Laboratory of Analytical
Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China
| | - Xueji Zhang
- Research Center for Bioengineering and Sensing Technology, University of Science & Technology Beijing, Beijing 100083, P. R. China
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Actin isoforms in neuronal development and function. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 301:157-213. [PMID: 23317819 DOI: 10.1016/b978-0-12-407704-1.00004-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The actin cytoskeleton contributes directly or indirectly to nearly every aspect of neuronal development and function. This diversity of functions is often attributed to actin regulatory proteins, although how the composition of the actin cytoskeleton itself may influence its function is often overlooked. In neurons, the actin cytoskeleton is composed of two distinct isoforms, β- and γ-actin. Functions for β-actin have been investigated in axon guidance, synaptogenesis, and disease. Insight from loss-of-function in vivo studies has also revealed novel roles for β-actin in select brain structures and behaviors. Conversely, very little is known regarding functions of γ-actin in neurons. The dysregulation or mutation of both β- and γ-actin has been implicated in multiple human neurological disorders, however, demonstrating the critical importance of these still poorly understood proteins. This chapter highlights what is currently known regarding potential distinct functions for β- and γ-actin in neurons as well as the significant areas that remain unexplored.
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Inducible control of subcellular RNA localization using a synthetic protein-RNA aptamer interaction. PLoS One 2012; 7:e46868. [PMID: 23056498 PMCID: PMC3466194 DOI: 10.1371/journal.pone.0046868] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2012] [Accepted: 09/05/2012] [Indexed: 12/18/2022] Open
Abstract
Evidence is accumulating in support of the functional importance of subcellular RNA localization in diverse biological contexts. In different cell types, distinct RNA localization patterns are frequently observed, and the available data indicate that this is achieved through a series of highly coordinated events. Classically, cis–elements within the RNA to be localized are recognized by RNA-binding proteins (RBPs), which then direct specific localization of a target RNA. Until now, the precise control of the spatiotemporal parameters inherent to regulating RNA localization has not been experimentally possible. Here, we demonstrate the development and use of a chemically–inducible RNA–protein interaction to regulate subcellular RNA localization. Our system is composed primarily of two parts: (i) the Tet Repressor protein (TetR) genetically fused to proteins natively involved in localizing endogenous transcripts; and (ii) a target transcript containing genetically encoded TetR–binding RNA aptamers. TetR–fusion protein binding to the target RNA and subsequent localization of the latter are directly regulated by doxycycline. Using this platform, we demonstrate that enhanced and controlled subcellular localization of engineered transcripts are achievable. We also analyze rules for forward engineering this RNA localization system in an effort to facilitate its straightforward application to studying RNA localization more generally.
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47
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Govindarajan S, Nevo-Dinur K, Amster-Choder O. Compartmentalization and spatiotemporal organization of macromolecules in bacteria. FEMS Microbiol Rev 2012; 36:1005-22. [DOI: 10.1111/j.1574-6976.2012.00348.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 06/27/2012] [Accepted: 06/28/2012] [Indexed: 12/18/2022] Open
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Gonsalvez GB, Long RM. Spatial regulation of translation through RNA localization. F1000 BIOLOGY REPORTS 2012; 4:16. [PMID: 22912650 PMCID: PMC3412389 DOI: 10.3410/b4-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
RNA localization is a mechanism to post-transcriptionally regulate gene
expression. Eukaryotic organisms ranging from fungi to mammals localize mRNAs to
spatially restrict synthesis of specific proteins to distinct regions of the
cytoplasm. In this review, we provide a general summary of RNA localization
pathways in Saccharomyces cerevisiae, Xenopus,
Drosophila and mammalian neurons.
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Affiliation(s)
- Graydon B. Gonsalvez
- Department of Cellular Biology and
Anatomy, Georgia Health Sciences UniversityC2915D,
1459 Laney Walker Blvd., Augusta, GA
30912USA
| | - Roy M. Long
- Department of Microbiology, Immunology
& Molecular Genetics, Medical College of
Wisconsin8701 Watertown Plank Rd., Milwaukee, WI
53226USA
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49
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Han TW, Kato M, Xie S, Wu LC, Mirzaei H, Pei J, Chen M, Xie Y, Allen J, Xiao G, McKnight SL. Cell-free formation of RNA granules: bound RNAs identify features and components of cellular assemblies. Cell 2012; 149:768-79. [PMID: 22579282 DOI: 10.1016/j.cell.2012.04.016] [Citation(s) in RCA: 604] [Impact Index Per Article: 50.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Revised: 03/22/2012] [Accepted: 04/24/2012] [Indexed: 12/30/2022]
Abstract
Cellular granules lacking boundary membranes harbor RNAs and their associated proteins and play diverse roles controlling the timing and location of protein synthesis. Formation of such granules was emulated by treatment of mouse brain extracts and human cell lysates with a biotinylated isoxazole (b-isox) chemical. Deep sequencing of the associated RNAs revealed an enrichment for mRNAs known to be recruited to neuronal granules used for dendritic transport and localized translation at synapses. Precipitated mRNAs contain extended 3' UTR sequences and an enrichment in binding sites for known granule-associated proteins. Hydrogels composed of the low complexity (LC) sequence domain of FUS recruited and retained the same mRNAs as were selectively precipitated by the b-isox chemical. Phosphorylation of the LC domain of FUS prevented hydrogel retention, offering a conceptual means of dynamic, signal-dependent control of RNA granule assembly.
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Affiliation(s)
- Tina W Han
- Department of Biochemistry, UT Southwestern Medical Center, Dallas, TX 75390-9152, USA
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Joseph R, Srivastava OP, Pfister RR. Downregulation of β-actin gene and human antigen R in human keratoconus. Invest Ophthalmol Vis Sci 2012; 53:4032-41. [PMID: 22562506 DOI: 10.1167/iovs.11-9062] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The purpose of this study was to determine the expression levels and regulation of β-actin in the stroma of keratoconus (KC) and normal corneas. METHODS A total of 15 different human corneas from both KC and normal individuals were used for this study. Additionally, 3 Fuch's dystrophic corneas were also used. The β-actin gene expression was analyzed at the transcriptional and translational levels in the epithelium and stroma of the KC and normal corneas. The human antigen R (HuR) gene expression was analyzed by real-time PCR in the stroma of five KC and five normal corneas. The keratocytes from three normal and three KC corneas were cultured in the presence of serum, and the expression levels of β-actin and human antigen R (HuR) were analyzed by using confocal imaging in both normal and KC fibroblasts. RESULTS The expression of the β-actin gene was downregulated in the stroma of the six KC corneas but not in the stroma of six normal and Fuchs' dystrophic corneas. Immunofluorescence detection of β-actin showed that it was absent in the KC fibroblast. The real-time PCR analysis of the HuR gene showed a relative 4.7-fold lower expression in KC corneas relative to the normal corneas, which was further confirmed by the immunofluorescence detection of HuR in fibroblasts of KC corneas. CONCLUSIONS Although ubiquitous β-actins are essential for cell survival during early embryogenesis, the effects on various stages of development are not well understood. Our results show that β-actin is downregulated in the corneal stroma of patients with KC, which may be related to reduced levels of a stabilizing factor (HuR) for β-actin mRNA. We propose that loss of β-actin in the corneal stroma might be a triggering factor in the development of KC.
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Affiliation(s)
- Roy Joseph
- Department of Vision Sciences, University of Alabama at Birmingham, Birmingham, Alabama 35294-4390, USA
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