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Brown W, Davidson LA, Deiters A. Expanding the Genetic Code of Xenopus laevis Embryos. ACS Chem Biol 2024; 19:516-525. [PMID: 38277773 PMCID: PMC10877573 DOI: 10.1021/acschembio.3c00686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 12/20/2023] [Accepted: 12/20/2023] [Indexed: 01/28/2024]
Abstract
The incorporation of unnatural amino acids into proteins through genetic code expansion has been successfully adapted to African claw-toed frog embryos. Six unique unnatural amino acids are incorporated site-specifically into proteins and demonstrate robust and reliable protein expression. Of these amino acids, several are caged analogues that can be used to establish conditional control over enzymatic activity. Using light or small molecule triggers, we exhibit activation and tunability of protein functions in live embryos. This approach was then applied to optical control over the activity of a RASopathy mutant of NRAS, taking advantage of generating explant cultures from Xenopus. Taken together, genetic code expansion is a robust approach in the Xenopus model to incorporate novel chemical functionalities into proteins of interest to study their function and role in a complex biological setting.
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Affiliation(s)
- Wes Brown
- Department
of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Lance A. Davidson
- Departments
of Bioengineering, Developmental Biology, and Computational and Systems
Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Alexander Deiters
- Department
of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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Eom S, Lee BB, Lee S, Park Y, Yeom HD, Kim TH, Nam SH, Lee JH. Antioxidative and Analgesic Effects of Naringin through Selective Inhibition of Transient Receptor Potential Vanilloid Member 1. Antioxidants (Basel) 2021; 11:64. [PMID: 35052566 PMCID: PMC8773328 DOI: 10.3390/antiox11010064] [Citation(s) in RCA: 9] [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: 12/04/2021] [Revised: 12/26/2021] [Accepted: 12/27/2021] [Indexed: 01/02/2023] Open
Abstract
Transient receptor potential vanilloid member 1 (TRPV1) is activated in response to capsaicin, protons, temperature, and free reactive oxygen species (ROS) released from inflammatory molecules after exposure to harmful stimuli. The expression level of TRPV1 is elevated in the dorsal root ganglion, and its activation through capsaicin and ROS mediates neuropathic pain in mice. Its expression is high in peripheral and central nervous systems. Although pain is a response evolved for survival, many studies have been conducted to develop analgesics, but no clear results have been reported. Here, we found that naringin selectively inhibited capsaicin-stimulated inward currents in Xenopus oocytes using a two-electrode voltage clamp. The results of this study showed that naringin has an IC50 value of 33.3 μM on TRPV1. The amino acid residues D471 and N628 of TRPV1 were involved in its binding to naringin. Our study bridged the gap between the pain suppression effect of TRPV1 and the preventive effect of naringin on neuropathic pain and oxidation. Naringin had the same characteristics as a model selective antagonist, which is claimed to be ideal for the development of analgesics targeting TRPV1. Thus, this study suggests the applicability of naringin as a novel analgesic candidate through antioxidative and analgesic effects of naringin.
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Affiliation(s)
- Sanung Eom
- Department of Biotechnology, Chonnam National University, Gwangju 61186, Korea; (S.E.); (S.L.); (Y.P.); (H.D.Y.)
| | - Bo-Bae Lee
- Fruit Research Institute of Jeollanamdo Agricultural Research and Extension Services, Haenam, Naju 59021, Korea;
| | - Shinhui Lee
- Department of Biotechnology, Chonnam National University, Gwangju 61186, Korea; (S.E.); (S.L.); (Y.P.); (H.D.Y.)
| | - Youngseo Park
- Department of Biotechnology, Chonnam National University, Gwangju 61186, Korea; (S.E.); (S.L.); (Y.P.); (H.D.Y.)
| | - Hye Duck Yeom
- Department of Biotechnology, Chonnam National University, Gwangju 61186, Korea; (S.E.); (S.L.); (Y.P.); (H.D.Y.)
| | - Tae-Hwan Kim
- Department of Animal Science, Chonnam National University, Gwangju 61186, Korea;
| | - Seung-Hee Nam
- Institute of Agricultural Science and Technology, Chonnam National University, Gwangju 61186, Korea
| | - Junho H. Lee
- Department of Biotechnology, Chonnam National University, Gwangju 61186, Korea; (S.E.); (S.L.); (Y.P.); (H.D.Y.)
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3
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Abstract
The Xenopus oocyte is a unique model system, allowing both the study of complex biological processes within a cellular context through expression of exogenous mRNAs and proteins, and the study of the cell, molecular, and developmental biology of the oocyte itself. During oogenesis, Xenopus oocytes grow dramatically in size, with a mature oocyte having a diameter of ∼1.3 mm, and become highly polarized, localizing many mRNAs and proteins. Thus, the mature oocyte is a repository of maternal mRNAs and proteins that will direct early embryogenesis prior to zygotic genome transcription. Importantly, the Xenopus oocyte also has the capacity to translate exogenous microinjected RNAs, which has enabled breakthroughs in a wide range of areas including cell biology, developmental biology, molecular biology, and physiology. This introduction outlines how Xenopus oocytes can be used to study a variety of important biological questions.
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Affiliation(s)
- Kimberly L Mowry
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Box G-L268, Providence, Rhode Island 02912
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4
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Zeng SL, Sudlow LC, Berezin MY. Using Xenopus oocytes in neurological disease drug discovery. Expert Opin Drug Discov 2019; 15:39-52. [PMID: 31674217 DOI: 10.1080/17460441.2020.1682993] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Introduction: Neurological diseases present a difficult challenge in drug discovery. Many of the current treatments have limited efficiency or result in a variety of debilitating side effects. The search of new therapies is of a paramount importance, since the number of patients that require a better treatment is growing rapidly. As an in vitro model, Xenopus oocytes provide the drug developer with many distinct advantages, including size, durability, and efficiency in exogenous protein expression. However, there is an increasing need to refine the recent breakthroughs.Areas covered: This review covers the usage and recent advancements of Xenopus oocytes for drug discovery in neurological diseases from expression and functional measurement techniques to current applications in Alzheimer's disease, painful neuropathies, and amyotrophic lateral sclerosis (ALS). The existing limitations of Xenopus oocytes in drug discovery are also discussed.Expert opinion: With the rise of aging population and neurological disorders, Xenopus oocytes, will continue to play an important role in understanding the mechanism of the disease, identification and validation of novel molecular targets, and drug screening, providing high-quality data despite the technical limitations. With further advances in oocytes-related techniques toward an accurate modeling of the disease, the diagnostics and treatment of neuropathologies will be becoming increasing personalized.
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Affiliation(s)
- Steven L Zeng
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Leland C Sudlow
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Mikhail Y Berezin
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
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Aguero T, Jin Z, Owens D, Malhotra A, Newman K, Yang J, King ML. Combined functions of two RRMs in Dead-end1 mimic helicase activity to promote nanos1 translation in the germline. Mol Reprod Dev 2018; 85:896-908. [PMID: 30230100 DOI: 10.1002/mrd.23062] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 09/14/2018] [Indexed: 12/31/2022]
Abstract
Dead-end1 (Dnd1) expression is restricted to the vertebrate germline where it is believed to activate translation of messenger RNAs (mRNAs) required to protect and promote that unique lineage. Nanos1 is one such germline mRNA whose translation is blocked by a secondary mRNA structure within the open reading frame (ORF). Dnd1 contains a canonical RNA recognition motif (RRM1) in its N-terminus but also contains a less conserved RRM2. Here we provide a mechanistic picture of the nanos1 mRNA-Dnd1 interaction in the Xenopus germline. We show that RRM1, but not RRM2, is required for binding nanos1. Similar to the zebrafish homolog, Xenopus Dnd1 possesses ATPase activity. Surprisingly, this activity appears to be within the RRM2, different from the C-terminal region where it is found in zebrafish. More importantly, we show that RRM2 is required for nanos1 translation and germline survival. Further, Dnd1 functions as a homodimer and binds nanos1 mRNA just downstream of the secondary structure required for nanos1 repression. We propose a model in which the RRM1 is required to bind nanos1 mRNA while the RRM2 is required to promote translation through the action of ATPase. Dnd1 appears to use RRMs to mimic the function of helicases.
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Affiliation(s)
- Tristan Aguero
- Department of Cell Biology University of Miami, Miller School of Medicine, Miami, Florida
| | - Zhigang Jin
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Dawn Owens
- Department of Cell Biology University of Miami, Miller School of Medicine, Miami, Florida
| | - Arun Malhotra
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida
| | - Karen Newman
- Department of Cell Biology University of Miami, Miller School of Medicine, Miami, Florida
| | - Jing Yang
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Mary Lou King
- Department of Cell Biology University of Miami, Miller School of Medicine, Miami, Florida
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Jeschonek SP, Mowry KL. Whole-Mount Immunofluorescence for Visualizing Endogenous Protein and Injected RNA in Xenopus Oocytes. Cold Spring Harb Protoc 2018; 2018:pdb.prot097022. [PMID: 29321279 DOI: 10.1101/pdb.prot097022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Asymmetric distribution of mRNA and protein is a hallmark of cell polarity in many systems. The Xenopus laevis oocyte provides many technical advantages to studying such polarity. Thousands of oocytes at different stages of maturity can be harvested from a single ovary and, owing to their relatively large size, even the youngest oocytes can be manually microinjected. Microinjection of fluorescently labeled RNA combined with immunofluorescence of endogenous proteins can provide insight into the cytoplasmic interactions contributing to polarity. Here, we present an updated method to image endogenous protein and microinjected RNA in X. laevis oocytes.
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Affiliation(s)
- Samantha P Jeschonek
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University, Providence, Rhode Island 02912
| | - Kimberly L Mowry
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University, Providence, Rhode Island 02912
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7
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Abstract
The Xenopus oocyte is a specialized single cell of colossal size (>1 mm diameter) that is highly amenable for microinjection and a stalwart model for heterologous expression. Oocytes are easily obtainable, robust in vitro, and faithfully express injected constructs. Their large size translational capacity provides a huge canvas for observing and recording integrated cellular responses-from studies of single molecules within single cells to medium-throughput drug-screening applications. Most eukaryotic promoters suffice for Xenopus expression, and the oocyte can functionally express proteins from many diverse organisms. This protocol provides a basic introduction for scientists keen to perform nuclear microinjections of cDNA constructs. These are easy methods to master, do not require elaborate equipment, and make accessible a wonderful model cell system for studying signaling, transport, cell architecture, and protein function.
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Zhang G, Cui J. Patch-Clamp and Perfusion Techniques to Study Ion Channels Expressed in Xenopus Oocytes. Cold Spring Harb Protoc 2018; 2018:pdb.prot099051. [PMID: 29382809 DOI: 10.1101/pdb.prot099051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The Xenopus oocyte expression system is ideal for electrophysiological characterization of voltage-dependent and ligand-dependent ion channels because of its relatively low background of endogenous channels and the large size of the cell. Here, we present a protocol to study voltage- and ligand-dependent activation of ion channels expressed in Xenopus oocytes using patch-clamp techniques designed to control both the membrane voltage and the intracellular solution. In this protocol, the large conductance voltage- and Ca2+-activated K+ (BK) channel is studied as an example. After injection of BK channel mRNA, oocytes are incubated for 2-7 d at 18°C. Inside-out membrane patches containing single or multiple BK channels are excised with perfusion of different solutions during recording. The protocol can be used to study structure-function relations for ion channels and neurotransmitter receptors.
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Affiliation(s)
- Guohui Zhang
- Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University, St. Louis, Missouri 63130
| | - Jianmin Cui
- Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Disorders, Cardiac Bioelectricity and Arrhythmia Center, Washington University, St. Louis, Missouri 63130
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Bauermeister D, Pieler T. Whole-Mount In Situ Hybridization of Xenopus Oocytes. Cold Spring Harb Protoc 2018; 2018:2018/3/pdb.prot097014. [PMID: 29496817 DOI: 10.1101/pdb.prot097014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Whole-mount in situ hybridization (WMISH) is a common approach that is used to visualize spatial and temporal gene expression in embryos. In this process, digoxygenin-labeled antisense RNA is hybridized to the complementary transcript of interest and RNA hybrids are immunohistochemically detected using an alkaline phosphatase-conjugated antibody against digoxigenin. During Xenopus laevis oogenesis, certain RNAs localize to the animal or vegetal pole laying the foundation for germ cell development and germ layer formation of the future embryo. Here we present a WMISH protocol for Xenopus laevis oocytes allowing for the efficient detection of localized RNAs in a large number of oocytes during different stages of oogenesis. The application of this approach might be combined with microinjection of tagged reporter RNAs and/or a gain- or loss-of-function background, allowing for the functional analysis of single protein factors involved in RNA localization.
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Affiliation(s)
- Diana Bauermeister
- Department of Developmental Biochemistry, Göttingen Center for Molecular Biosciences (GZMB), University of Göttingen, 37077 Göttingen, Germany
| | - Tomas Pieler
- Department of Developmental Biochemistry, Göttingen Center for Molecular Biosciences (GZMB), University of Göttingen, 37077 Göttingen, Germany
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