1
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Chen R, Pathirathna P, Balla RJ, Kim J, Amemiya S. Nanoscale Quantitative Imaging of Single Nuclear Pore Complexes by Scanning Electrochemical Microscopy. Anal Chem 2024; 96:10765-10771. [PMID: 38904303 PMCID: PMC11223102 DOI: 10.1021/acs.analchem.4c01890] [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: 04/10/2024] [Revised: 05/24/2024] [Accepted: 05/28/2024] [Indexed: 06/22/2024]
Abstract
The nuclear pore complex (NPC) is a proteinaceous nanopore that solely and selectively regulates the molecular transport between the cytoplasm and nucleus of a eukaryotic cell. The ∼50 nm-diameter pore of the NPC perforates the double-membrane nuclear envelope to mediate both passive and facilitated molecular transport, thereby playing paramount biological and biomedical roles. Herein, we visualize single NPCs by scanning electrochemical microscopy (SECM). The high spatial resolution is accomplished by employing ∼25 nm-diameter ion-selective nanopipets to monitor the passive transport of tetrabutylammonium at individual NPCs. SECM images are quantitatively analyzed by employing the finite element method to confirm that this work represents the highest-resolution nanoscale SECM imaging of biological samples. Significantly, we apply the powerful imaging technique to address the long-debated origin of the central plug of the NPC. Nanoscale SECM imaging demonstrates that unplugged NPCs are more permeable to the small probe ion than are plugged NPCs. This result supports the hypothesis that the central plug is not an intrinsic transporter, but is an impermeable macromolecule, e.g., a ribonucleoprotein, trapped in the nanopore. Moreover, this result also supports the transport mechanism where the NPC is divided into the central pathway for RNA export and the peripheral pathway for protein import to efficiently mediate the bidirectional traffic.
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Affiliation(s)
- Ran Chen
- Department
of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
- School
of Chemistry and Chemical Engineering, Southeast
University, Nanjing 211189, China
| | - Pavithra Pathirathna
- Department
of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
- Department
of Chemistry and Chemical Engineering, Florida
Institute of Technology, Melbourne, Florida 32901, United States
| | - Ryan J. Balla
- Department
of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Jiyeon Kim
- Department
of Chemistry, The University of Rhode Island, Kingston, Rhode Island 02881, United States
| | - Shigeru Amemiya
- Department
of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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2
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Yan J, Wu T, Zhang J, Gao Y, Wu JM, Wang S. Revolutionizing the female reproductive system research using microfluidic chip platform. J Nanobiotechnology 2023; 21:490. [PMID: 38111049 PMCID: PMC10729361 DOI: 10.1186/s12951-023-02258-7] [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: 08/19/2023] [Accepted: 12/07/2023] [Indexed: 12/20/2023] Open
Abstract
Comprehensively understanding the female reproductive system is crucial for safeguarding fertility and preventing diseases concerning women's health. With the capacity to simulate the intricate physio- and patho-conditions, and provide diagnostic platforms, microfluidic chips have fundamentally transformed the knowledge and management of female reproductive health, which will ultimately promote the development of more effective assisted reproductive technologies, treatments, and drug screening approaches. This review elucidates diverse microfluidic systems in mimicking the ovary, fallopian tube, uterus, placenta and cervix, and we delve into the culture of follicles and oocytes, gametes' manipulation, cryopreservation, and permeability especially. We investigate the role of microfluidics in endometriosis and hysteromyoma, and explore their applications in ovarian cancer, endometrial cancer and cervical cancer. At last, the current status of assisted reproductive technology and integrated microfluidic devices are introduced briefly. Through delineating the multifarious advantages and challenges of the microfluidic technology, we chart a definitive course for future research in the woman health field. As the microfluidic technology continues to evolve and advance, it holds great promise for revolutionizing the diagnosis and treatment of female reproductive health issues, thus propelling us into a future where we can ultimately optimize the overall wellbeing and health of women everywhere.
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Affiliation(s)
- Jinfeng Yan
- National Clinical Research Center for Obstetrical and Gynecological Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Key Laboratory of Cancer Invasion and Metastasis, Ministry of Education, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095, Jiefang Avenue, Wuhan, 430030, China
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
- Engineering Research Center of Ceramic Materials for Additive Manufacturing, Ministry of Education, Wuhan, 430074, China
| | - Tong Wu
- National Clinical Research Center for Obstetrical and Gynecological Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Key Laboratory of Cancer Invasion and Metastasis, Ministry of Education, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095, Jiefang Avenue, Wuhan, 430030, China
| | - Jinjin Zhang
- National Clinical Research Center for Obstetrical and Gynecological Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Key Laboratory of Cancer Invasion and Metastasis, Ministry of Education, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095, Jiefang Avenue, Wuhan, 430030, China
| | - Yueyue Gao
- National Clinical Research Center for Obstetrical and Gynecological Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Key Laboratory of Cancer Invasion and Metastasis, Ministry of Education, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095, Jiefang Avenue, Wuhan, 430030, China
| | - Jia-Min Wu
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China.
- Engineering Research Center of Ceramic Materials for Additive Manufacturing, Ministry of Education, Wuhan, 430074, China.
| | - Shixuan Wang
- National Clinical Research Center for Obstetrical and Gynecological Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
- Key Laboratory of Cancer Invasion and Metastasis, Ministry of Education, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095, Jiefang Avenue, Wuhan, 430030, China.
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3
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Tang HS, Gates CR, Schultz MC. Biochemical evidence that the whole compartment activity behavior of GAPDH differs between the cytoplasm and nucleus. PLoS One 2023; 18:e0290892. [PMID: 37651389 PMCID: PMC10470895 DOI: 10.1371/journal.pone.0290892] [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: 06/23/2023] [Accepted: 08/15/2023] [Indexed: 09/02/2023] Open
Abstract
Some metabolic enzymes normally occur in the nucleus and cytoplasm. These compartments differ in molecular composition. Since post-translational modification and interaction with allosteric effectors can tune enzyme activity, it follows that the behavior of an enzyme as a catalyst may differ between the cytoplasm and nucleus. We explored this possibility for the glycolytic enzyme glyceraldehyde 3-phosphate dehydrogenase (GAPDH). Homogenates of pristine nuclei and cytoplasms isolated from Xenopus laevis oocytes were used for whole compartment activity profiling in a near-physiological buffer. Titrations of NAD+ revealed similar whole compartment activity profiles for GAPDH in nuclear and cytoplasmic homogenates. Surprisingly however GAPDH in these compartments did not have the same behavior in assays of the dependence of initial velocity (v0) on G3P concentration. First, the peak v0 for nuclear GAPDH was up to 2.5-fold higher than the peak for cytoplasmic GAPDH. Second, while Michaelis Menten-like behavior was observed in all assays of cytoplasm, the v0 versus [G3P] plots for nuclear GAPDH typically exhibited a non-Michaelis Menten (sigmoidal) profile. Apparent Km and Vmax (G3P) values for nuclear GAPDH activity were highly variable, even between replicates of the same sample. Possible sources of this variability include in vitro processing of a metabolite that allosterically regulates GAPDH, turnover of a post-translational modification of the enzyme, and fluctuation of the state of interaction of GAPDH with other proteins. Collectively these findings are consistent with the hypothesis that the environment of the nucleus is distinct from the environment of the cytoplasm with regard to GAPDH activity and its modulation. This finding warrants further comparison of the regulation of nuclear and cytoplasmic GAPDH, as well as whole compartment activity profiling of other enzymes of metabolism with cytosolic and nuclear pools.
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Affiliation(s)
- Helen S. Tang
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Chelsea R. Gates
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Michael C. Schultz
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
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4
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Hwang H, Yun S, Arcanjo RB, Divyanshi, Chen S, Mei W, Nowak RA, Kwon T, Yang J. Regulation of RNA localization during oocyte maturation by dynamic RNA-ER association and remodeling of the ER. Cell Rep 2022; 41:111802. [PMID: 36516762 PMCID: PMC9811979 DOI: 10.1016/j.celrep.2022.111802] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 08/30/2022] [Accepted: 11/17/2022] [Indexed: 12/14/2022] Open
Abstract
Asymmetric localization of mRNAs is crucial for cell polarity and cell fate determination. By performing fractionation RNA-seq, we report here that a large number of maternal RNAs are associated with the ER in Xenopus oocytes but are released into the cytosol after oocyte maturation. We provide evidence that the majority of ER-associated RNA-binding proteins (RBPs) remain associated with the ER after oocyte maturation. However, all ER-associated RBPs analyzed exhibit reduced binding to some of their target RNAs after oocyte maturation. Our results further show that the ER is remodeled massively during oocyte maturation, leading to the formation of a widespread tubular ER network in the animal hemisphere that is required for the asymmetric localization of mRNAs in mature eggs. Thus, our findings demonstrate that dynamic regulation of RNA-ER association and remodeling of the ER are important for the asymmetric localization of RNAs during development.
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Affiliation(s)
- Hyojeong Hwang
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA
| | - Seongmin Yun
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Rachel Braz Arcanjo
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Divyanshi
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA
| | - Sijie Chen
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA
| | - Wenyan Mei
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA
| | - Romana A. Nowak
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Taejoon Kwon
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea,Correspondence: (T.K.), (J.Y.)
| | - Jing Yang
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA,Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA,Lead contact,Correspondence: (T.K.), (J.Y.)
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5
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Li R, Ren Y, Mo G, Swider Z, Mikoshiba K, Bement WM, Liu XJ. Inositol 1, 4, 5-trisphosphate receptor is required for spindle assembly in Xenopus oocytes. Mol Biol Cell 2022; 33:br27. [PMID: 36129775 PMCID: PMC9727787 DOI: 10.1091/mbc.e22-06-0218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The extent to which calcium signaling participates in specific events of animal cell meiosis or mitosis is a subject of enduring controversy. We have previously demonstrated that buffering intracellular calcium with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA, a fast calcium chelator), but not ethylenebis(oxyethylenenitrilo)tetraacetic acid (EGTA, a slow calcium chelator), rapidly depolymerizes spindle microtubules in Xenopus oocytes, suggesting that spindle assembly and/or stability requires calcium nanodomains-calcium transients at extremely restricted spatial-temporal scales. In this study, we have investigated the function of inositol-1,4,5-trisphosphate receptor (IP3R), an endoplasmic reticulum (ER) calcium channel, in spindle assembly using Trim21-mediated depletion of IP3R. Oocytes depleted of IP3R underwent germinal vesicle breakdown but failed to emit the first polar body and failed to assemble proper meiotic spindles. Further, we developed a cell-free spindle assembly assay in which cytoplasm was aspirated from single oocytes. Spindles assembled in this cell-free system were encased in ER membranes, with IP3R enriched at the poles, while disruption of either ER organization or calcium signaling resulted in rapid spindle disassembly. As in intact oocytes, formation of spindles in cell-free oocyte extracts also required IP3R. We conclude that intracellular calcium signaling involving IP3R-mediated calcium release is required for meiotic spindle assembly in Xenopus oocytes.
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Affiliation(s)
- Ruizhen Li
- Ottawa Hospital Research Institute, The Ottawa Hospital—General Campus, Ottawa, ON K1H 8L6, Canada
| | - Yanping Ren
- Ottawa Hospital Research Institute, The Ottawa Hospital—General Campus, Ottawa, ON K1H 8L6, Canada,Department of Histology and Embryology, Zunyi Medical University, Zunyi, Guizhou 563003, China
| | - Guolong Mo
- Ottawa Hospital Research Institute, The Ottawa Hospital—General Campus, Ottawa, ON K1H 8L6, Canada,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Zackary Swider
- Graduate Program in Cellular and Molecular Biology, University of Wisconsin—Madison, Madison, WI 53706,Center for Quantitative Cell Imaging, University of Wisconsin—Madison, Madison, WI 53706
| | - Katsuhiko Mikoshiba
- SIAIS ShanghaiTech University, Middle Huaxia Road, Shanghai 201210, China,Faculty of Science, Toho University Miyama, Funabashi, Chiba, 247-8510 Japan
| | - William M. Bement
- Graduate Program in Cellular and Molecular Biology, University of Wisconsin—Madison, Madison, WI 53706,Center for Quantitative Cell Imaging, University of Wisconsin—Madison, Madison, WI 53706
| | - X. Johné Liu
- Ottawa Hospital Research Institute, The Ottawa Hospital—General Campus, Ottawa, ON K1H 8L6, Canada,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada,Department of Obstetrics and Gynaecology, University of Ottawa, Ottawa, ON K1H 8M5, Canada,*Address correspondence to: Johné Liu ()
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6
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Gill GS, Schultz MC. Multienzyme activity profiling for evaluation of cell‐to‐cell variability of metabolic state. FASEB Bioadv 2022; 4:709-723. [PMID: 36349298 PMCID: PMC9635011 DOI: 10.1096/fba.2022-00073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/25/2022] [Accepted: 08/29/2022] [Indexed: 11/29/2022] Open
Abstract
In solid organs, cells of the same “type” can vary in their molecular phenotype. The basis of this state variation is being revealed by characterizing cell features including the expression pattern of mRNAs and the internal distribution of proteins. Here, the variability of metabolic state between cells is probed by enzyme activity profiling. We study individual cells of types that can be identified during the post‐mitotic phase of oogenesis in Xenopus laevis. Whole‐cell homogenates of isolated oocytes are used for kinetic analysis of enzymes, with a focus on the initial reaction rate. For each oocyte type studied, the activity signatures of glyceraldehyde 3‐phosphate dehydrogenase (GAPDH) and malate dehydrogenase 1 (MDH1) vary more between the homogenates of single oocytes than between repeat samplings of control homogenates. Unexpectedly, the activity signatures of GAPDH and MDH1 strongly co‐vary between oocytes of each type and change in strength of correlation during oogenesis. Therefore, variability of the kinetic behavior of these housekeeping enzymes between “identical” cells is physiologically programmed. Based on these findings, we propose that single‐cell profiling of enzyme kinetics will improve understanding of how metabolic state heterogeneity is related to heterogeneity revealed by omics methods including proteomics, epigenomics, and metabolomics.
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Affiliation(s)
- Govind S. Gill
- Department of Biochemistry University of Alberta Edmonton Alberta Canada
- Department of Pediatrics & Group on the Molecular and Cell Biology of Lipids University of Alberta Edmonton Alberta Canada
| | - Michael C. Schultz
- Department of Biochemistry University of Alberta Edmonton Alberta Canada
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7
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Mo G, Li R, Swider Z, Leblanc J, Bement WM, Liu XJ. A localized calcium transient and polar body abscission. Cell Cycle 2022; 21:2239-2254. [PMID: 35775922 DOI: 10.1080/15384101.2022.2092815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Polar body emission is a special form of cytokinesis in oocyte meiosis that ensures the correct number of chromosomes in reproduction-competent eggs. The molecular mechanism of the last step, polar body abscission, is poorly understood. While it has been proposed that Ca2+ signaling plays important roles in embryonic cytokinesis, to date transient increases in intracellular free Ca2+ have been difficult to document in oocyte meiosis except for the global Ca2+ wave induced by sperm at fertilization. Here, we find that microinjection of the calcium chelator dibromo-BAPTA inhibits polar body abscission in Xenopus laevis oocytes. Using a novel, microtubule-targeted ratio-metric calcium sensor, we detected a calcium transient that is focused at the contractile ring-associated plasma membrane and which occurred after anaphase and constriction of the contractile ring but prior to abscission. This calcium transient was confirmed by mobile calcium probes. Further, the Ca2+-sensitive protein kinase Cβ C2 domain transiently translocated to the contractile ring-associated membrane simultaneously with the calcium transient. Collectively, these results demonstrate that a calcium transient, apparently originating at the contractile ring-associated plasma membrane, promotes polar body abscission.
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Affiliation(s)
- Guolong Mo
- Ottawa Hospital Research Institute, Ottawa Hospital General Campus, Ottawa, Ontario, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Ruizhen Li
- Ottawa Hospital Research Institute, Ottawa Hospital General Campus, Ottawa, Ontario, Canada
| | - Zachary Swider
- Graduate Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, WI, USA.,Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Madison, WI, USA
| | - Julie Leblanc
- Ottawa Hospital Research Institute, Ottawa Hospital General Campus, Ottawa, Ontario, Canada
| | - William M Bement
- Graduate Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, WI, USA.,Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Madison, WI, USA.,Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI, USA
| | - X Johné Liu
- Ottawa Hospital Research Institute, Ottawa Hospital General Campus, Ottawa, Ontario, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada.,Department of Obstetrics and Gynaecology, University of Ottawa, Ottawa, Ontario, Canada
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8
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Alfieri JM, Wang G, Jonika MM, Gill CA, Blackmon H, Athrey GN. A Primer for Single-Cell Sequencing in Non-Model Organisms. Genes (Basel) 2022; 13:380. [PMID: 35205423 PMCID: PMC8872538 DOI: 10.3390/genes13020380] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 02/12/2022] [Accepted: 02/17/2022] [Indexed: 02/05/2023] Open
Abstract
Single-cell sequencing technologies have led to a revolution in our knowledge of the diversity of cell types, connections between biological levels of organization, and relationships between genotype and phenotype. These advances have mainly come from using model organisms; however, using single-cell sequencing in non-model organisms could enable investigations of questions inaccessible with typical model organisms. This primer describes a general workflow for single-cell sequencing studies and considerations for using non-model organisms (limited to multicellular animals). Importantly, single-cell sequencing, when further applied in non-model organisms, will allow for a deeper understanding of the mechanisms between genotype and phenotype and the basis for biological variation.
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Affiliation(s)
- James M. Alfieri
- Department of Biology, Texas A&M University, College Station, TX 77843, USA; (M.M.J.); (H.B.)
- Interdisciplinary Program in Ecology and Evolutionary Biology, Texas A&M University, College Station, TX 77843, USA;
- Department of Poultry Science, Texas A&M University, College Station, TX 77843, USA
| | - Guosong Wang
- Department of Animal Science, Texas A&M University, College Station, TX 77843, USA; (G.W.); (C.A.G.)
| | - Michelle M. Jonika
- Department of Biology, Texas A&M University, College Station, TX 77843, USA; (M.M.J.); (H.B.)
- Interdisciplinary Program in Genetics and Genomics, Texas A&M University, College Station, TX 77843, USA
| | - Clare A. Gill
- Department of Animal Science, Texas A&M University, College Station, TX 77843, USA; (G.W.); (C.A.G.)
- Interdisciplinary Program in Genetics and Genomics, Texas A&M University, College Station, TX 77843, USA
| | - Heath Blackmon
- Department of Biology, Texas A&M University, College Station, TX 77843, USA; (M.M.J.); (H.B.)
- Interdisciplinary Program in Ecology and Evolutionary Biology, Texas A&M University, College Station, TX 77843, USA;
- Interdisciplinary Program in Genetics and Genomics, Texas A&M University, College Station, TX 77843, USA
| | - Giridhar N. Athrey
- Interdisciplinary Program in Ecology and Evolutionary Biology, Texas A&M University, College Station, TX 77843, USA;
- Department of Poultry Science, Texas A&M University, College Station, TX 77843, USA
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9
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Luchinat E, Cremonini M, Banci L. Radio Signals from Live Cells: The Coming of Age of In-Cell Solution NMR. Chem Rev 2022; 122:9267-9306. [PMID: 35061391 PMCID: PMC9136931 DOI: 10.1021/acs.chemrev.1c00790] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
![]()
A detailed knowledge
of the complex processes that make cells and
organisms alive is fundamental in order to understand diseases and
to develop novel drugs and therapeutic treatments. To this aim, biological
macromolecules should ideally be characterized at atomic resolution
directly within the cellular environment. Among the existing structural
techniques, solution NMR stands out as the only one able to investigate
at high resolution the structure and dynamic behavior of macromolecules
directly in living cells. With the advent of more sensitive NMR hardware
and new biotechnological tools, modern in-cell NMR approaches have
been established since the early 2000s. At the coming of age of in-cell
NMR, we provide a detailed overview of its developments and applications
in the 20 years that followed its inception. We review the existing
approaches for cell sample preparation and isotopic labeling, the
application of in-cell NMR to important biological questions, and
the development of NMR bioreactor devices, which greatly increase
the lifetime of the cells allowing real-time monitoring of intracellular
metabolites and proteins. Finally, we share our thoughts on the future
perspectives of the in-cell NMR methodology.
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Affiliation(s)
- Enrico Luchinat
- Dipartimento di Scienze e Tecnologie Agro-Alimentari, Alma Mater Studiorum−Università di Bologna, Piazza Goidanich 60, 47521 Cesena, Italy
- Magnetic Resonance Center, Università degli Studi di Firenze, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
| | - Matteo Cremonini
- Magnetic Resonance Center, Università degli Studi di Firenze, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
| | - Lucia Banci
- Magnetic Resonance Center, Università degli Studi di Firenze, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
- Consorzio Interuniversitario Risonanze Magnetiche di Metallo Proteine, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
- Dipartimento di Chimica, Università degli Studi di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
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10
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Pathirathna P, Balla RJ, Jantz DT, Kurapati N, Gramm ER, Leonard KC, Amemiya S. Probing High Permeability of Nuclear Pore Complexes by Scanning Electrochemical Microscopy: Ca 2+ Effects on Transport Barriers. Anal Chem 2019; 91:5446-5454. [PMID: 30907572 PMCID: PMC6535230 DOI: 10.1021/acs.analchem.9b00796] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The nuclear pore complex (NPC) solely mediates molecular transport between the nucleus and cytoplasm of a eukaryotic cell to play important biological and biomedical roles. However, it is not well-understood chemically how this biological nanopore selectively and efficiently transports various substances, including small molecules, proteins, and RNAs by using transport barriers that are rich in highly disordered repeats of hydrophobic phenylalanine and glycine intermingled with charged amino acids. Herein, we employ scanning electrochemical microscopy to image and measure the high permeability of NPCs to small redox molecules. The effective medium theory demonstrates that the measured permeability is controlled by diffusional translocation of probe molecules through water-filled nanopores without steric or electrostatic hindrance from hydrophobic or charged regions of transport barriers, respectively. However, the permeability of NPCs is reduced by a low millimolar concentration of Ca2+, which can interact with anionic regions of transport barriers to alter their spatial distributions within the nanopore. We employ atomic force microscopy to confirm that transport barriers of NPCs are dominantly recessed (∼80%) or entangled (∼20%) at the high Ca2+ level in contrast to authentic populations of entangled (∼50%), recessed (∼25%), and "plugged" (∼25%) conformations at a physiological Ca2+ level of submicromolar. We propose a model for synchronized Ca2+ effects on the conformation and permeability of NPCs, where transport barriers are viscosified to lower permeability. Significantly, this result supports a hypothesis that the functional structure of transport barriers is maintained not only by their hydrophobic regions, but also by charged regions.
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Affiliation(s)
- Pavithra Pathirathna
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260, United States
| | - Ryan J. Balla
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260, United States
| | - Dylan T. Jantz
- Center for Environmentally Beneficial Catalysis, Department of Chemical and Petroleum Engineering, University of Kansas, 1501 Wakarusa Drive, Lawrence, Kansas 66047, United States
| | - Niraja Kurapati
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260, United States
| | - Erin R. Gramm
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260, United States
| | - Kevin C. Leonard
- Center for Environmentally Beneficial Catalysis, Department of Chemical and Petroleum Engineering, University of Kansas, 1501 Wakarusa Drive, Lawrence, Kansas 66047, United States
| | - Shigeru Amemiya
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260, United States
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11
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Zhan C, Liu W, Hegazy AM, Zhang T, Kawan A, Zhang X. Explorations of the optimal method for isolating oocytes from zebrafish (
Danio rerio
) ovary. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2019; 330:417-426. [DOI: 10.1002/jez.b.22841] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 11/29/2018] [Accepted: 12/23/2019] [Indexed: 11/10/2022]
Affiliation(s)
- Chunhua Zhan
- College of Fisheries, Huazhong Agricultural University, Hubei Provincial Engineering Laboratory for Pond AquacultureWuhan China
| | - Wanjing Liu
- College of Fisheries, Huazhong Agricultural University, Hubei Provincial Engineering Laboratory for Pond AquacultureWuhan China
| | - Abeer M. Hegazy
- College of Fisheries, Huazhong Agricultural University, Hubei Provincial Engineering Laboratory for Pond AquacultureWuhan China
- Central Laboratory for Environmental Quality Monitoring “CLEQM,” National Water Research Center “NWRC”Cairo Egypt
| | - Tongzhou Zhang
- College of Fisheries, Huazhong Agricultural University, Hubei Provincial Engineering Laboratory for Pond AquacultureWuhan China
| | - Atufa Kawan
- College of Fisheries, Huazhong Agricultural University, Hubei Provincial Engineering Laboratory for Pond AquacultureWuhan China
| | - Xuezhen Zhang
- College of Fisheries, Huazhong Agricultural University, Hubei Provincial Engineering Laboratory for Pond AquacultureWuhan China
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12
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Li R, Leblanc J, He K, Liu XJ. Spindle function in Xenopus oocytes involves possible nanodomain calcium signaling. Mol Biol Cell 2016; 27:3273-3283. [PMID: 27582389 PMCID: PMC5170860 DOI: 10.1091/mbc.e16-05-0338] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 08/25/2016] [Indexed: 11/11/2022] Open
Abstract
Injection of dibromo-BAPTA caused immediate collapse of meiotic spindles in frog oocytes. In contrast, EGTA had no effect on the spindle or polar body emission. The disruption of spindle integrity by the fast but not slow calcium chelators suggests that meiotic spindle function in the oocytes involves nanodomain calcium signaling. Intracellular calcium transients are a universal phenomenon at fertilization and are required for egg activation, but the exact role of Ca2+ in second-polar-body emission remains unknown. On the other hand, similar calcium transients have not been demonstrated during oocyte maturation, and yet, manipulating intracellular calcium levels interferes with first-polar-body emission in mice and frogs. To determine the precise role of calcium signaling in polar body formation, we used live-cell imaging coupled with temporally precise intracellular calcium buffering. We found that BAPTA-based calcium chelators cause immediate depolymerization of spindle microtubules in meiosis I and meiosis II. Surprisingly, EGTA at similar or higher intracellular concentrations had no effect on spindle function or polar body emission. Using two calcium probes containing permutated GFP and the calcium sensor calmodulin (Lck-GCaMP3 and GCaMP3), we demonstrated enrichment of the probes at the spindle but failed to detect calcium increase during oocyte maturation at the spindle or elsewhere. Finally, endogenous calmodulin was found to colocalize with spindle microtubules throughout all stages of meiosis. Our results—most important, the different sensitivities of the spindle to BAPTA and EGTA—suggest that meiotic spindle function in frog oocytes requires highly localized, or nanodomain, calcium signaling.
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Affiliation(s)
- Ruizhen Li
- Ottawa Hospital Research Institute, Ottawa Hospital-General Campus, Ottawa, ON K1H 8L6, Canada
| | - Julie Leblanc
- Ottawa Hospital Research Institute, Ottawa Hospital-General Campus, Ottawa, ON K1H 8L6, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Kevin He
- Ottawa Hospital Research Institute, Ottawa Hospital-General Campus, Ottawa, ON K1H 8L6, Canada
| | - X Johné Liu
- Ottawa Hospital Research Institute, Ottawa Hospital-General Campus, Ottawa, ON K1H 8L6, Canada .,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada.,Department of Obstetrics and Gynaecology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
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13
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Jørgensen ME, Nour-Eldin HH, Halkier BA. A Western Blot Protocol for Detection of Proteins Heterologously Expressed in Xenopus laevis Oocytes. Methods Mol Biol 2016; 1405:99-107. [PMID: 26843169 DOI: 10.1007/978-1-4939-3393-8_10] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Oocytes of the African clawed frog, Xenopus laevis, are often used for expression and biochemical characterization of transporter proteins as the oocytes are particularly suitable for uptake assays and electrophysiological recordings. Assessment of the expression level of expressed transporters at the individual oocyte level is often desirable when comparing properties of wild type and mutant transporters. However, a large content of yolk platelets in the oocyte cytoplasm makes this a challenging task. Here we report a method for fast and easy, semiquantitative Western blot analysis of proteins heterologously expressed in Xenopus oocytes.
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Affiliation(s)
- Morten Egevang Jørgensen
- DynaMo Center, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, 1871, Frederiksberg C, Denmark
| | - Hussam Hassan Nour-Eldin
- DynaMo Center, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, 1871, Frederiksberg C, Denmark
| | - Barbara Ann Halkier
- DynaMo Center, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, 1871, Frederiksberg C, Denmark.
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14
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Kırlı K, Karaca S, Dehne HJ, Samwer M, Pan KT, Lenz C, Urlaub H, Görlich D. A deep proteomics perspective on CRM1-mediated nuclear export and nucleocytoplasmic partitioning. eLife 2015; 4:e11466. [PMID: 26673895 PMCID: PMC4764573 DOI: 10.7554/elife.11466] [Citation(s) in RCA: 157] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 12/13/2015] [Indexed: 12/23/2022] Open
Abstract
CRM1 is a highly conserved, RanGTPase-driven exportin that carries proteins and RNPs from the nucleus to the cytoplasm. We now explored the cargo-spectrum of CRM1 in depth and identified surprisingly large numbers, namely >700 export substrates from the yeast S. cerevisiae, ≈1000 from Xenopus oocytes and >1050 from human cells. In addition, we quantified the partitioning of ≈5000 unique proteins between nucleus and cytoplasm of Xenopus oocytes. The data suggest new CRM1 functions in spatial control of vesicle coat-assembly, centrosomes, autophagy, peroxisome biogenesis, cytoskeleton, ribosome maturation, translation, mRNA degradation, and more generally in precluding a potentially detrimental action of cytoplasmic pathways within the nuclear interior. There are also numerous new instances where CRM1 appears to act in regulatory circuits. Altogether, our dataset allows unprecedented insights into the nucleocytoplasmic organisation of eukaryotic cells, into the contributions of an exceedingly promiscuous exportin and it provides a new basis for NES prediction.
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Affiliation(s)
- Koray Kırlı
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Samir Karaca
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Heinz Jürgen Dehne
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Matthias Samwer
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Kuan Ting Pan
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Christof Lenz
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
- Bioanalytics, Institute for Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
- Bioanalytics, Institute for Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Dirk Görlich
- Department of Cellular Logistics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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15
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Liu D, Shao H, Wang H, Liu XJ. Meiosis I in Xenopus oocytes is not error-prone despite lacking spindle assembly checkpoint. Cell Cycle 2014; 13:1602-6. [PMID: 24646611 DOI: 10.4161/cc.28562] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The spindle assembly checkpoint, SAC, is a surveillance mechanism to control the onset of anaphase during cell division. SAC prevents anaphase initiation until all chromosome pairs have achieved bipolar attachment and aligned at the metaphase plate of the spindle. In doing so, SAC is thought to be the key mechanism to prevent chromosome nondisjunction in mitosis and meiosis. We have recently demonstrated that Xenopus oocyte meiosis lacks SAC control. This prompted the question of whether Xenopus oocyte meiosis is particularly error-prone. In this study, we have karyotyped a total of 313 Xenopus eggs following in vitro oocyte maturation. We found no hyperploid egg, out of 204 metaphase II eggs with countable chromosome spreads. Therefore, chromosome nondisjunction is very rare during Xenopus oocyte meiosis I, despite the lack of SAC.
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Affiliation(s)
- Dandan Liu
- State Key Laboratory of Reproductive Biology; Institute of Zoology; Chinese Academy of Sciences; Beijing, China; University of Chinese Academy of Sciences; Beijing, China; Ottawa Hospital Research Institute; The Ottawa Hospital - General Campus; Ottawa, Ontario, Canada
| | - Hua Shao
- Ottawa Hospital Research Institute; The Ottawa Hospital - General Campus; Ottawa, Ontario, Canada
| | - Hongmei Wang
- State Key Laboratory of Reproductive Biology; Institute of Zoology; Chinese Academy of Sciences; Beijing, China
| | - X Johné Liu
- Ottawa Hospital Research Institute; The Ottawa Hospital - General Campus; Ottawa, Ontario, Canada; Department of Biochemistry, Microbiology, and Immunology and Department of Obstetrics and Gynecology; University of Ottawa; Ottawa, Ontario, Canada
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16
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The nuclear F-actin interactome of Xenopus oocytes reveals an actin-bundling kinesin that is essential for meiotic cytokinesis. EMBO J 2013; 32:1886-902. [PMID: 23727888 PMCID: PMC3981176 DOI: 10.1038/emboj.2013.108] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2013] [Accepted: 04/23/2013] [Indexed: 11/09/2022] Open
Abstract
Nuclei of Xenopus laevis oocytes grow 100 000-fold larger in volume than a typical somatic nucleus and require an unusual intranuclear F-actin scaffold for mechanical stability. We now developed a method for mapping F-actin interactomes and identified a comprehensive set of F-actin binders from the oocyte nuclei. Unexpectedly, the most prominent interactor was a novel kinesin termed NabKin (Nuclear and meiotic actin-bundling Kinesin). NabKin not only binds microtubules but also F-actin structures, such as the intranuclear actin bundles in prophase and the contractile actomyosin ring during cytokinesis. The interaction between NabKin and F-actin is negatively regulated by Importin-β and is responsive to spatial information provided by RanGTP. Disconnecting NabKin from F-actin during meiosis caused cytokinesis failure and egg polyploidy. We also found actin-bundling activity in Nabkin's somatic paralogue KIF14, which was previously shown to be essential for somatic cell division. Our data are consistent with the notion that NabKin/KIF14 directly link microtubules with F-actin and that such link is essential for cytokinesis. The presence and role of actin filaments in cell nuclei remains incompletely understood. A proteomics approach now reveals a highly distinct set of F-actin-binding proteins in the nucleus, including a novel kinesin family member.
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17
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Shao H, Li R, Ma C, Chen E, Liu XJ. Xenopus oocyte meiosis lacks spindle assembly checkpoint control. ACTA ACUST UNITED AC 2013; 201:191-200. [PMID: 23569212 PMCID: PMC3628510 DOI: 10.1083/jcb.201211041] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In contrast to the situation in mammalian oocytes, the metaphase-to-anaphase transition in frog oocytes is not regulated by a spindle assembly checkpoint. The spindle assembly checkpoint (SAC) functions as a surveillance mechanism to detect chromosome misalignment and to delay anaphase until the errors are corrected. The SAC is thought to control mitosis and meiosis, including meiosis in mammalian eggs. However, it remains unknown if meiosis in the eggs of nonmammalian vertebrate species is also regulated by SAC. Using a novel karyotyping technique, we demonstrate that complete disruption of spindle microtubules in Xenopus laevis oocytes did not affect the bivalent-to-dyad transition at the time oocytes are undergoing anaphase I. These oocytes also acquired the ability to respond to parthenogenetic activation, which indicates proper metaphase II arrest. Similarly, oocytes exhibiting monopolar spindles, via inhibition of aurora B or Eg5 kinesin, underwent monopolar anaphase on time and without additional intervention. Therefore, the metaphase-to-anaphase transition in frog oocytes is not regulated by SAC.
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Affiliation(s)
- Hua Shao
- Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, Ontario K1H BL6, Canada
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18
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Kim J, Izadyar A, Nioradze N, Amemiya S. Nanoscale mechanism of molecular transport through the nuclear pore complex as studied by scanning electrochemical microscopy. J Am Chem Soc 2013; 135:2321-9. [PMID: 23320434 PMCID: PMC3572272 DOI: 10.1021/ja311080j] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The nuclear pore complex (NPC) is the proteinaceous nanopore that solely mediates molecular transport across the nuclear envelope between the nucleus and cytoplasm of a eukaryotic cell. Small molecules (<40 kDa) diffuse through the large pore of this multiprotein complex. A passively impermeable macromolecule tagged with a signal peptide is chaperoned through the nanopore by nuclear transport receptors (e.g., importins) owing to their interactions with barrier-forming proteins. Presently, this bimodal transport mechanism is not well understood and is described by controversial models. Herein, we report on a dynamic and spatially resolved mechanism for NPC-mediated molecular transport through nanoscale central and peripheral routes with distinct permeabilities. Specifically, we develop a nanogap-based approach of scanning electrochemical microscopy to precisely measure the extremely high permeability of the nuclear envelope to a small probe molecule, (ferrocenylmethyl)trimethylammonium. Effective medium theories indicate that the passive permeability of 5.9 × 10(-2) cm/s corresponds to the free diffusion of the probe molecule through ~22 nanopores with a radius of 24 nm and a length of 35 nm. Peripheral routes are blocked by wheat germ agglutinin to yield 2-fold lower permeability for 17 nm-radius central routes. This lectin is also used in fluorescence assays to find that importins facilitate the transport of signal-tagged albumin mainly through the 7 nm-thick peripheral route rather than through the sufficiently large central route. We propose that this spatial selectivity is regulated by the conformational changes in barrier-forming proteins that transiently and locally expand the impermeably thin peripheral route while blocking the central route.
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Affiliation(s)
- Jiyeon Kim
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260
| | | | - Nikoloz Nioradze
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260
| | - Shigeru Amemiya
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania, 15260
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19
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Semenov A, Möykkynen T, Coleman SK, Korpi ER, Keinänen K. Autoinactivation of the stargazin-AMPA receptor complex: subunit-dependency and independence from physical dissociation. PLoS One 2012; 7:e49282. [PMID: 23166629 PMCID: PMC3498123 DOI: 10.1371/journal.pone.0049282] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 10/08/2012] [Indexed: 11/18/2022] Open
Abstract
Agonist responses and channel kinetics of native α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors are modulated by transmembrane accessory proteins. Stargazin, the prototypical accessory protein, decreases desensitization and increases agonist potency at AMPA receptors. Furthermore, in the presence of stargazin, the steady-state responses of AMPA receptors show a gradual decline at higher glutamate concentrations. This "autoinactivation" has been assigned to physical dissociation of the stargazin-AMPA receptor complex and suggested to serve as a protective mechanism against overactivation. Here, we analyzed autoinactivation of GluA1-A4 AMPA receptors (all flip isoform) expressed in the presence of stargazin. Homomeric GluA1, GluA3, and GluA4 channels showed pronounced autoinactivation indicated by the bell-shaped steady-state dose response curves for glutamate. In contrast, homomeric GluA2i channels did not show significant autoinactivation. The resistance of GluA2 to autoinactivation showed striking dependence on the splice form as GluA2-flop receptors displayed clear autoinactivation. Interestingly, the resistance of GluA2-flip containing receptors to autoinactivation was transferred onto heteromeric receptors in a dominant fashion. To examine the relationship of autoinactivation to physical separation of stargazin from the AMPA receptor, we analyzed a GluA4-stargazin fusion protein. Notably, the covalently linked complex and separately expressed proteins expressed a similar level of autoinactivation. We conclude that autoinactivation is a subunit and splice form dependent property of AMPA receptor-stargazin complexes, which involves structural rearrangements within the complex rather than any physical dissociation.
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Affiliation(s)
- Artur Semenov
- Department of Biosciences, Division of Biochemistry and Biotechnology, University of Helsinki, Helsinki, Finland
| | - Tommi Möykkynen
- Department of Biosciences, Division of Biochemistry and Biotechnology, University of Helsinki, Helsinki, Finland
- Institute of Biomedicine, Pharmacology, University of Helsinki, Helsinki, Finland
| | - Sarah K. Coleman
- Department of Biosciences, Division of Biochemistry and Biotechnology, University of Helsinki, Helsinki, Finland
| | - Esa R. Korpi
- Institute of Biomedicine, Pharmacology, University of Helsinki, Helsinki, Finland
| | - Kari Keinänen
- Department of Biosciences, Division of Biochemistry and Biotechnology, University of Helsinki, Helsinki, Finland
- * E-mail:
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20
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Leblond GG, Sarazin H, Li R, Suzuki M, Ueno N, Liu XJ. Translation of incenp during oocyte maturation is required for embryonic development in Xenopus laevis. Biol Reprod 2012; 86:161, 1-8. [PMID: 22378760 DOI: 10.1095/biolreprod.111.097972] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The chromosome passenger complex (CPC) consists of Aurora-B kinase and several other subunits. One of these, incenp, binds Aurora-B and regulates its kinase activity. During Xenopus oocyte maturation, incenp accumulates through translation, contributing to aurora-b activation. A previous study has demonstrated that inhibition of incenp translation during oocyte maturation diminishes aurora-b activation but does not interfere with oocyte maturation, characterized by normal maturation-specific cyclin-b phosphorylation, degradation, and resynthesis. Here we have extended these findings, showing that inhibition of incenp translation during oocyte maturation did not interfere with meiosis I or II, as indicated by the normal emission of the first polar body and metaphase II arrest, followed by the successful emission of the second polar body upon parthenogenetic egg activation. Most importantly, however, when transferred to host frogs and subsequently ovulated, the incenp-deficient eggs were fertilized but failed to undergo mitotic cleavage. Thus, translation of incenp during oocyte maturation appears to be part of oocyte cytoplasmic maturation, preparing the egg for the rapid mitosis following fertilization.
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21
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Azarkh M, Okle O, Singh V, Seemann IT, Hartig JS, Dietrich DR, Drescher M. Long-range distance determination in a DNA model system inside Xenopus laevis oocytes by in-cell spin-label EPR. Chembiochem 2011; 12:1992-5. [PMID: 21726034 DOI: 10.1002/cbic.201100281] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Indexed: 12/13/2022]
Affiliation(s)
- Mykhailo Azarkh
- Department of Chemistry, Konstanz Research School Chemical Biology, Zukunftskolleg, University of Konstanz, 78457 Konstanz, Germany
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22
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Anas MKI, Lee MB, Zhou C, Hammer MA, Slow S, Karmouch J, Liu XJ, Bröer S, Lever M, Baltz JM. SIT1 is a betaine/proline transporter that is activated in mouse eggs after fertilization and functions until the 2-cell stage. Development 2009; 135:4123-30. [PMID: 19029042 DOI: 10.1242/dev.026575] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Betaine (N,N,N-trimethylglycine) added to culture media is known to substantially improve the development of preimplantation mouse embryos in vitro, and to be imported into 1-cell embryos by a transporter that also accepts proline. Here, we found that the betaine/proline transporter is active in preimplantation mouse embryos only for a short period of development, between the 1- and 2-cell stages. Betaine/proline transport was activated after fertilization, beginning approximately 4 hours post-egg activation and reaching a maximum by approximately 10 hours. One- and 2-cell embryos contained endogenous betaine, indicating that a likely function for the transporter in vivo is the accumulation or retention of intracellular betaine. The appearance of transport activity after egg activation was independent of protein synthesis, but was reversibly blocked by disruption of the Golgi with brefeldin A. We assessed two candidates for the betaine/proline transporter: SIT1 (IMINO; encoded by Slc6a20a) and PROT (Slc6a7). mRNA from both genes was present in eggs and 1-cell embryos. However, when exogenously expressed in Xenopus oocytes, mouse PROT did not transport betaine and had an inhibition profile different from that of the embryonic transporter. By contrast, exogenously expressed mouse SIT1 transported both betaine and proline and closely resembled the embryonic transporter. A morpholino oligonucleotide designed to block translation of SIT1, when present from the germinal vesicle stage, blocked the appearance of betaine transport activity in parthenogenotes. Thus, SIT1 is likely to be a developmentally restricted betaine transporter in mouse preimplantation embryos that is activated by fertilization.
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23
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Abstract
Ornithine decarboxylase (ODC), the rate-limiting enzyme in polyamine biosynthesis, is a nonredundant and essential gene in all eukaryotes. During the mitotic cell cycle, ODC exhibits two activity peaks: one at the G(1)/S transition and one during the G(2)/M transition. The physiological role of this cell cycle-dependent ODC activity dynamic is not clear. Previous studies have reported a significant elevation of ODC activity during Xenopus oocyte maturation, which resembles mitotic G(2)/M transition. In order to study the roles of ODC activity in the oocytes, we utilized antisense morpholino (xODC mo) oligonucleotides to inhibit ODC translation. We report here that xODC mo abolished ODC activity increase during oocyte maturation. xODC mo-injected oocytes underwent germinal vesicle breakdown, emitted the first polar body, and reached metaphase II, thus completing nuclear maturation. However, the metaphase II oocytes exhibited high levels of reactive oxygen species and became apoptotic. When transferred to host frogs and subsequently ovulated, these eggs were fertilized but exhibited embryo fragmentation. Translation of ODC is therefore integral to cytoplasmic maturation, protecting metaphase II oocytes from reactive oxygen species-induced apoptosis.
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24
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Guan M, Rawson D, Zhang T. Development of a new method for isolating zebrafish oocytes (Danio rerio) from ovary tissue masses. Theriogenology 2008; 69:269-75. [DOI: 10.1016/j.theriogenology.2007.09.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Revised: 09/19/2007] [Accepted: 09/19/2007] [Indexed: 11/29/2022]
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25
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Selenko P, Serber Z, Gadea B, Ruderman J, Wagner G. Quantitative NMR analysis of the protein G B1 domain in Xenopus laevis egg extracts and intact oocytes. Proc Natl Acad Sci U S A 2006; 103:11904-9. [PMID: 16873549 PMCID: PMC1523310 DOI: 10.1073/pnas.0604667103] [Citation(s) in RCA: 181] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We introduce a eukaryotic cellular system, the Xenopus laevis oocyte, for in-cell NMR analyses of biomolecules at high resolution and delineate the experimental reference conditions for successful implementations of in vivo NMR measurements in this cell type. This approach enables quantitative NMR experiments at defined intracellular concentrations of exogenous proteins, which is exemplified by the description of in-cell NMR properties of the protein G B1 domain (GB1). Additional experiments in Xenopus egg extracts and artificially crowded in vitro solutions suggest that for this biologically inert protein domain, intracellular viscosity and macromolecular crowding dictate its in vivo behavior. These contributions appear particularly pronounced for protein regions with high degrees of internal mobility in the pure state. We also evaluate the experimental limitations of this method and discuss potential applications toward the in situ structural characterization of eukaryotic cellular activities.
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Affiliation(s)
- Philipp Selenko
- Departments of *Biological Chemistry and Molecular Pharmacology and
- To whom correspondence may be addressed. E-mail:
, , or
| | - Zach Serber
- Department of Molecular Pharmacology, Stanford University Medical School, 269 West Campus Drive, Stanford, CA 94305
| | - Bedrick Gadea
- Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115; and
| | - Joan Ruderman
- Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115; and
- To whom correspondence may be addressed. E-mail:
, , or
| | - Gerhard Wagner
- Departments of *Biological Chemistry and Molecular Pharmacology and
- To whom correspondence may be addressed. E-mail:
, , or
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