1
|
Junyent S, Meglicki M, Vetter R, Mandelbaum R, King C, Patel EM, Iwamoto-Stohl L, Reynell C, Chen DY, Rubino P, Arrach N, Paulson RJ, Iber D, Zernicka-Goetz M. The first two blastomeres contribute unequally to the human embryo. Cell 2024; 187:2838-2854.e17. [PMID: 38744282 DOI: 10.1016/j.cell.2024.04.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 12/06/2023] [Accepted: 04/22/2024] [Indexed: 05/16/2024]
Abstract
Retrospective lineage reconstruction of humans predicts that dramatic clonal imbalances in the body can be traced to the 2-cell stage embryo. However, whether and how such clonal asymmetries arise in the embryo is unclear. Here, we performed prospective lineage tracing of human embryos using live imaging, non-invasive cell labeling, and computational predictions to determine the contribution of each 2-cell stage blastomere to the epiblast (body), hypoblast (yolk sac), and trophectoderm (placenta). We show that the majority of epiblast cells originate from only one blastomere of the 2-cell stage embryo. We observe that only one to three cells become internalized at the 8-to-16-cell stage transition. Moreover, these internalized cells are more frequently derived from the first cell to divide at the 2-cell stage. We propose that cell division dynamics and a cell internalization bottleneck in the early embryo establish asymmetry in the clonal composition of the future human body.
Collapse
Affiliation(s)
- Sergi Junyent
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Maciej Meglicki
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
| | - Roman Vetter
- Department of Biosystems Science and Engineering (D-BSSE), ETH Zürich, Basel 4058, Switzerland; Swiss Institute of Bioinformatics (SIB), Mattenstrasse 26, 4058 Basel, Switzerland
| | - Rachel Mandelbaum
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of Southern California, Los Angeles, CA 90033, USA
| | - Catherine King
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
| | - Ekta M Patel
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Lisa Iwamoto-Stohl
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
| | - Clare Reynell
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Dong-Yuan Chen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Patrizia Rubino
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of Southern California, Los Angeles, CA 90033, USA
| | | | - Richard J Paulson
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of Southern California, Los Angeles, CA 90033, USA
| | - Dagmar Iber
- Department of Biosystems Science and Engineering (D-BSSE), ETH Zürich, Basel 4058, Switzerland; Swiss Institute of Bioinformatics (SIB), Mattenstrasse 26, 4058 Basel, Switzerland
| | - Magdalena Zernicka-Goetz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK.
| |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
Yamamoto T, Uehara R. Cell shape instability during cytokinesis in tetraploid HCT116 cells. Biochem Biophys Res Commun 2023; 678:39-44. [PMID: 37619310 DOI: 10.1016/j.bbrc.2023.08.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Accepted: 08/16/2023] [Indexed: 08/26/2023]
Abstract
Tetraploidy is a hallmark of broad cancer types, but it remains largely unknown which aspects of cellular processes are influenced by tetraploidization in human cells. Here, we found that tetraploid HCT116 cells manifested severe cell shape instability during cytokinesis, unlike their diploid counterparts. The cell shape instability accompanied the formation of protrusive deformation at the cell poles, indicating ectopic contractile activity of the cell cortex. While cytokinesis regulators such as RhoA and anillin correctly accumulated at the equatorial cortex, myosin II was over-accumulated at the cell poles, specifically in tetraploid cells. Suppression of myosin II activity by Y27632 treatment restored smooth cell shape in tetraploids during cytokinesis, indicating dysregulation of myosin II as a primary cause of the cell shape instability in the tetraploid state. Our results demonstrate a new aspect of the dynamic cellular process profoundly affected by tetraploidization in human cells, which provides a clue to molecular mechanisms of tetraploidy-driven pathogenic processes.
Collapse
Affiliation(s)
| | - Ryota Uehara
- Graduate School of Life Science, Hokkaido University, Japan; Faculty of Advanced Life Science, Hokkaido University, Japan.
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|