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Husser MC, Pham NP, Law C, Araujo FRB, Martin VJJ, Piekny A. Endogenous tagging using split mNeonGreen in human iPSCs for live imaging studies. eLife 2024; 12:RP92819. [PMID: 38652106 PMCID: PMC11037917 DOI: 10.7554/elife.92819] [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] [Indexed: 04/25/2024] Open
Abstract
Endogenous tags have become invaluable tools to visualize and study native proteins in live cells. However, generating human cell lines carrying endogenous tags is difficult due to the low efficiency of homology-directed repair. Recently, an engineered split mNeonGreen protein was used to generate a large-scale endogenous tag library in HEK293 cells. Using split mNeonGreen for large-scale endogenous tagging in human iPSCs would open the door to studying protein function in healthy cells and across differentiated cell types. We engineered an iPS cell line to express the large fragment of the split mNeonGreen protein (mNG21-10) and showed that it enables fast and efficient endogenous tagging of proteins with the short fragment (mNG211). We also demonstrate that neural network-based image restoration enables live imaging studies of highly dynamic cellular processes such as cytokinesis in iPSCs. This work represents the first step towards a genome-wide endogenous tag library in human stem cells.
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Affiliation(s)
| | - Nhat P Pham
- Biology Department, Concordia University, Montreal, Canada
| | - Chris Law
- Biology Department, Concordia University, Montreal, Canada
- Center for Microscopy and Cellular Imaging, Concordia University, Montreal, Canada
| | - Flavia R B Araujo
- Center for Applied Synthetic Biology, Concordia University, Montreal, Canada
| | - Vincent J J Martin
- Biology Department, Concordia University, Montreal, Canada
- Center for Applied Synthetic Biology, Concordia University, Montreal, Canada
| | - Alisa Piekny
- Biology Department, Concordia University, Montreal, Canada
- Center for Microscopy and Cellular Imaging, Concordia University, Montreal, Canada
- Center for Applied Synthetic Biology, Concordia University, Montreal, Canada
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Hsu CR, Sangha G, Fan W, Zheng J, Sugioka K. Contractile ring mechanosensation and its anillin-dependent tuning during early embryogenesis. Nat Commun 2023; 14:8138. [PMID: 38065974 PMCID: PMC10709429 DOI: 10.1038/s41467-023-43996-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023] Open
Abstract
Cytokinesis plays crucial roles in morphogenesis. Previous studies have examined how tissue mechanics influences the position and closure direction of the contractile ring. However, the mechanisms by which the ring senses tissue mechanics remain largely elusive. Here, we show the mechanism of contractile ring mechanosensation and its tuning during asymmetric ring closure of Caenorhabditis elegans embryos. Integrative analysis of ring closure and cell cortex dynamics revealed that mechanical suppression of the ring-directed cortical flow is associated with asymmetric ring closure. Consistently, artificial obstruction of ring-directed cortical flow induces asymmetric ring closure in otherwise symmetrically dividing cells. Anillin is vital for mechanosensation. Our genetic analysis suggests that the positive feedback loop among ring-directed cortical flow, myosin enrichment, and ring constriction constitutes a mechanosensitive pathway driving asymmetric ring closure. These findings and developed tools should advance the 4D mechanobiology of cytokinesis in more complex tissues.
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Affiliation(s)
- Christina Rou Hsu
- Life Sciences Institute, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T1Z3, Canada
- Department of Zoology, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T1Z3, Canada
| | - Gaganpreet Sangha
- Life Sciences Institute, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T1Z3, Canada
- Department of Zoology, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T1Z3, Canada
| | - Wayne Fan
- Life Sciences Institute, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T1Z3, Canada
- Department of Zoology, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T1Z3, Canada
| | - Joey Zheng
- Life Sciences Institute, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T1Z3, Canada
- Department of Zoology, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T1Z3, Canada
| | - Kenji Sugioka
- Life Sciences Institute, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T1Z3, Canada.
- Department of Zoology, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T1Z3, Canada.
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Werner ME, Ray DD, Breen C, Staddon MF, Jug F, Banerjee S, Maddox AS. Mechanical positive feedback and biochemical negative feedback combine to generate complex contractile oscillations in cytokinesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.01.569672. [PMID: 38076901 PMCID: PMC10705528 DOI: 10.1101/2023.12.01.569672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/23/2024]
Abstract
Contractile force generation by the cortical actomyosin cytoskeleton is essential for a multitude of biological processes. The actomyosin cortex behaves as an active material that drives local and large-scale shape changes via cytoskeletal remodeling in response to biochemical cues and feedback loops. Cytokinesis is the essential cell division event during which a cortical actomyosin ring generates contractile force to change cell shape and separate two daughter cells. Our recent work with active gel theory predicts that actomyosin systems under the control of a biochemical oscillator and experiencing mechanical strain will exhibit complex spatiotemporal behavior, but cytokinetic contractility was thought to be kinetically simple. To test whether active materials in vivo exhibit spatiotemporally complex kinetics, we used 4-dimensional imaging with unprecedented temporal resolution and discovered sections of the cytokinetic cortex undergo periodic phases of acceleration and deceleration. Quantification of ingression speed oscillations revealed wide ranges of oscillation period and amplitude. In the cytokinetic ring, activity of the master regulator RhoA pulsed with a timescale of approximately 20 seconds, shorter than that reported for any other biological context. Contractility oscillated with 20-second periodicity and with much longer periods. A combination of in vivo and in silico approaches to modify mechanical feedback revealed that the period of contractile oscillation is prolonged as a function of the intensity of mechanical feedback. Effective local ring ingression is characterized by slower speed oscillations, likely due to increased local stresses and therefore mechanical feedback. Fast ingression also occurs where material turnover is high, in vivo and in silico . We propose that downstream of initiation by pulsed RhoA activity, mechanical positive feedback, including but not limited to material advection, extends the timescale of contractility beyond that of biochemical input and therefore makes it robust to fluctuations in activation. Circumferential propagation of contractility likely allows sustained contractility despite cytoskeletal remodeling necessary to recover from compaction. Our work demonstrates that while biochemical feedback loops afford systems responsiveness and robustness, mechanical feedback must also be considered to describe and understand the behaviors of active materials in vivo .
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Ozugergin I, Piekny A. Diversity is the spice of life: An overview of how cytokinesis regulation varies with cell type. Front Cell Dev Biol 2022; 10:1007614. [PMID: 36420142 PMCID: PMC9676254 DOI: 10.3389/fcell.2022.1007614] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 10/24/2022] [Indexed: 09/01/2023] Open
Abstract
Cytokinesis is required to physically cleave a cell into two daughters at the end of mitosis. Decades of research have led to a comprehensive understanding of the core cytokinesis machinery and how it is regulated in animal cells, however this knowledge was generated using single cells cultured in vitro, or in early embryos before tissues develop. This raises the question of how cytokinesis is regulated in diverse animal cell types and developmental contexts. Recent studies of distinct cell types in the same organism or in similar cell types from different organisms have revealed striking differences in how cytokinesis is regulated, which includes different threshold requirements for the structural components and the mechanisms that regulate them. In this review, we highlight these differences with an emphasis on pathways that are independent of the mitotic spindle, and operate through signals associated with the cortex, kinetochores, or chromatin.
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Affiliation(s)
- Imge Ozugergin
- Department of Biology, McGill University, Montreal, QC, Canada
- Department of Biology, Concordia University, Montreal, QC, Canada
| | - Alisa Piekny
- Department of Biology, Concordia University, Montreal, QC, Canada
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Husser MC, Ozugergin I, Resta T, Martin VJJ, Piekny AJ. Cytokinetic diversity in mammalian cells is revealed by the characterization of endogenous anillin, Ect2 and RhoA. Open Biol 2022; 12:220247. [PMID: 36416720 PMCID: PMC9683116 DOI: 10.1098/rsob.220247] [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] [Indexed: 11/24/2022] Open
Abstract
Cytokinesis is required to physically separate the daughter cells at the end of mitosis. This crucial process requires the assembly and ingression of an actomyosin ring, which must occur with high fidelity to avoid aneuploidy and cell fate changes. Most of our knowledge of mammalian cytokinesis was generated using over-expressed transgenes in HeLa cells. Over-expression can introduce artefacts, while HeLa are cancerous human cells that have lost their epithelial identity, and the mechanisms controlling cytokinesis in these cells could be vastly different from other cell types. Here, we tagged endogenous anillin, Ect2 and RhoA with mNeonGreen and characterized their localization during cytokinesis for the first time in live human cells. Comparing anillin localization in multiple cell types revealed cytokinetic diversity with differences in the duration and symmetry of ring closure, and the timing of cortical recruitment. Our findings show that the breadth of anillin correlates with the rate of ring closure, and support models where cell size or ploidy affects the cortical organization, and intrinsic mechanisms control the symmetry of ring closure. This work highlights the need to study cytokinesis in more diverse cell types, which will be facilitated by the reagents generated for this study.
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Affiliation(s)
| | - Imge Ozugergin
- Biology Department, Concordia University, Montreal, Quebec, Canada
| | - Tiziana Resta
- Biology Department, Concordia University, Montreal, Quebec, Canada
| | - Vincent J. J. Martin
- Biology Department, Concordia University, Montreal, Quebec, Canada,Center for Applied Synthetic Biology, Concordia University, Montreal, Quebec, Canada
| | - Alisa J. Piekny
- Biology Department, Concordia University, Montreal, Quebec, Canada,Center for Applied Synthetic Biology, Concordia University, Montreal, Quebec, Canada,Center for Microscopy and Cellular Imaging, Concordia University, Montreal, Quebec, Canada
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First person – Imge Ozugergin. J Cell Sci 2022. [DOI: 10.1242/jcs.259794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
ABSTRACT
First Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping early-career researchers promote themselves alongside their papers. Imge Ozugergin is first author on ‘Diverse mechanisms regulate contractile ring assembly for cytokinesis in the two-cell Caenorhabditis elegans embryo’, published in JCS. Imge is a PhD student in the lab of Alisa Piekny at Concordia University, Montreal, Canada, investigating the mechanisms regulating cytokinesis, as well as how and why this process varies between different cell types.
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