1
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Zernicki-Glover S, Stanislawska N, Patel EM, Kavanagh YH, Meglicki M. Blastomere size in the human 2-cell embryo predicts the division order that leads to imbalanced lineage contribution to the future body. MICROPUBLICATION BIOLOGY 2024; 2024:10.17912/micropub.biology.001181. [PMID: 38841597 PMCID: PMC11151110 DOI: 10.17912/micropub.biology.001181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 04/09/2024] [Accepted: 04/19/2024] [Indexed: 06/07/2024]
Abstract
Retrospective tracing of somatic mutations predicted that most cells in the human body could be traced back to a single cell of the 2-cell stage embryo. Accordingly, a recent prospective study of the developmental trajectory of blastomeres in human embryos confirmed that progeny of the first 2-cell stage blastomere to divide generates more epiblast cells (future body). How the 2-cell blastomeres differ is unknown. Here, we show that 2-cell stage blastomeres in human embryos are asymmetric; they differ in size and the bigger blastomere divides first to 4-cell stage. We propose that this asymmetry might originate differences in cell fate.
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Affiliation(s)
| | | | - Ekta M. Patel
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, United States
| | - Yu Hua Kavanagh
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, England, United Kingdom
| | - Maciej Meglicki
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, England, United Kingdom
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2
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Woo S, Strasser L. Atypical RhoUV GTPases in development and disease. Biochem Soc Trans 2024; 52:89-97. [PMID: 38314621 PMCID: PMC10903452 DOI: 10.1042/bst20230212] [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: 10/24/2023] [Revised: 01/23/2024] [Accepted: 01/24/2024] [Indexed: 02/06/2024]
Abstract
RhoU and RhoV are members of the Rho family of small GTPases that comprise their own subfamily. RhoUV GTPases are classified as atypical due to the kinetics of their GTP/GDP binding cycles. They also possess unique N- and C-termini that regulate their subcellular localization and activity. RhoU and RhoV have been linked to cytoskeletal regulation, cell adhesion, and cell migration. They each exhibit distinct expression patterns during embryonic development and diseases such as cancer metastasis, suggesting they have specialized functions. In this review, we will discuss the known functions of RhoU and RhoV, with a focus on their roles in early development, organogenesis, and disease.
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Affiliation(s)
- Stephanie Woo
- Department of Molecular Cell Biology, University of California, Merced, CA, U.S.A
- Quantitative and Systems Biology Graduate Program, University of California, Merced, CA, U.S.A
| | - Leesa Strasser
- Department of Molecular Cell Biology, University of California, Merced, CA, U.S.A
- Quantitative and Systems Biology Graduate Program, University of California, Merced, CA, U.S.A
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3
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Bardhan S, Bhargava N, Dighe S, Vats N, Naganathan SR. Emergence of a left-right symmetric body plan in vertebrate embryos. Curr Top Dev Biol 2024; 159:310-342. [PMID: 38729680 DOI: 10.1016/bs.ctdb.2024.01.003] [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] [Indexed: 05/12/2024]
Abstract
External bilateral symmetry is a prevalent feature in vertebrates, which emerges during early embryonic development. To begin with, vertebrate embryos are largely radially symmetric before transitioning to bilaterally symmetry, after which, morphogenesis of various bilateral tissues (e.g somites, otic vesicle, limb bud), and structures (e.g palate, jaw) ensue. While a significant amount of work has probed the mechanisms behind symmetry breaking in the left-right axis leading to asymmetric positioning of internal organs, little is known about how bilateral tissues emerge at the same time with the same shape and size and at the same position on the two sides of the embryo. By discussing emergence of symmetry in many bilateral tissues and structures across vertebrate model systems, we highlight that understanding symmetry establishment is largely an open field, which will provide deep insights into fundamental problems in developmental biology for decades to come.
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Affiliation(s)
- Siddhartha Bardhan
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Nandini Bhargava
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Swarali Dighe
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Neha Vats
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Sundar Ram Naganathan
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India.
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4
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Machacova S, Kozmik Z, Kozmikova I. Identification of Nodal-dependent enhancer of amphioxus Chordin sufficient to drive gene expression into the chordate dorsal organizer. Dev Genes Evol 2022; 232:137-145. [PMID: 36372862 DOI: 10.1007/s00427-022-00698-z] [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: 09/06/2022] [Accepted: 10/12/2022] [Indexed: 11/15/2022]
Abstract
The core molecular mechanisms of dorsal organizer formation during gastrulation are highly conserved within the chordate lineage. One of the key characteristics is that Nodal signaling is required for the organizer-specific gene expression. This feature appears to be ancestral, as evidenced by the presence in the most basally divergent chordate amphioxus. To provide a better understanding of the evolution of organizer-specific gene regulation in chordates, we analyzed the cis-regulatory sequence of amphioxus Chordin in the context of the vertebrate embryo. First, we generated stable zebrafish transgenic lines, and by using light-sheet fluorescent microscopy, characterized in detail the expression pattern of GFP driven by the cis-regulatory sequences of amphioxus Chordin. Next, we performed a 5'deletion analysis and identified an enhancer sufficient to drive the expression of the reporter gene into a chordate dorsal organizer. Finally, we found that the identified enhancer element strongly depends on Nodal signaling, which is consistent with the well-established role of this pathway in the regulation of the expression of dorsal organizer-specific genes across chordates. The enhancer identified in our study may represent a suitable simple system to study the interplay of the evolutionarily conserved regulatory mechanisms operating during early chordate development.
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Affiliation(s)
- Simona Machacova
- Laboratory of Transcriptional Regulation, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague 4, Videnska, 1083, Czech Republic
| | - Zbynek Kozmik
- Laboratory of Transcriptional Regulation, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague 4, Videnska, 1083, Czech Republic
| | - Iryna Kozmikova
- Laboratory of Transcriptional Regulation, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague 4, Videnska, 1083, Czech Republic.
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5
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Houston DW, Elliott KL, Coppenrath K, Wlizla M, Horb ME. Maternal Wnt11b regulates cortical rotation during Xenopus axis formation: analysis of maternal-effect wnt11b mutants. Development 2022; 149:dev200552. [PMID: 35946588 PMCID: PMC9515810 DOI: 10.1242/dev.200552] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 08/01/2022] [Indexed: 12/13/2022]
Abstract
Asymmetric signalling centres in the early embryo are essential for axis formation in vertebrates. These regions (e.g. amphibian dorsal morula, mammalian anterior visceral endoderm) require stabilised nuclear β-catenin, but the role of localised Wnt ligand signalling activity in their establishment remains unclear. In Xenopus, dorsal β-catenin is initiated by vegetal microtubule-mediated symmetry breaking in the fertilised egg, known as 'cortical rotation'. Localised wnt11b mRNA and ligand-independent activators of β-catenin have been implicated in dorsal β-catenin activation, but the extent to which each contributes to axis formation in this paradigm remains unclear. Here, we describe a CRISPR-mediated maternal-effect mutation in Xenopus laevis wnt11b.L. We find that wnt11b is maternally required for robust dorsal axis formation and for timely gastrulation, and zygotically for left-right asymmetry. Importantly, we show that vegetal microtubule assembly and cortical rotation are reduced in wnt11b mutant eggs. In addition, we show that activated Wnt coreceptor Lrp6 and Dishevelled lack behaviour consistent with roles in early β-catenin stabilisation, and that neither is regulated by Wnt11b. This work thus implicates Wnt11b in the distribution of putative dorsal determinants rather than in comprising the determinants themselves. This article has an associated 'The people behind the papers' interview.
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Affiliation(s)
- Douglas W. Houston
- Department of Biology, The University of Iowa, 257 BB, Iowa City, IA 52242-1324, USA
| | - Karen L. Elliott
- Department of Biology, The University of Iowa, 257 BB, Iowa City, IA 52242-1324, USA
| | - Kelsey Coppenrath
- National Xenopus Resource and Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Marcin Wlizla
- National Xenopus Resource and Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Marko E. Horb
- National Xenopus Resource and Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA 02543, USA
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6
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Evolutionary conservation of maternal RNA localization in fishes and amphibians revealed by TOMO-Seq. Dev Biol 2022; 489:146-160. [PMID: 35752299 DOI: 10.1016/j.ydbio.2022.06.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Revised: 05/18/2022] [Accepted: 06/19/2022] [Indexed: 11/24/2022]
Abstract
Asymmetrical localization of biomolecules inside the egg, results in uneven cell division and establishment of many biological processes, cell types and the body plan. However, our knowledge about evolutionary conservation of localized transcripts is still limited to a few models. Our goal was to compare localization profiles along the animal-vegetal axis of mature eggs from four vertebrate models, two amphibians (Xenopus laevis, Ambystoma mexicanum) and two fishes (Acipenser ruthenus, Danio rerio) using the spatial expression method called TOMO-Seq. We revealed that RNAs of many known important transcripts such as germ layer determinants, germ plasm factors and members of key signalling pathways, are localized in completely different profiles among the models. It was also observed that there was a poor correlation between the vegetally localized transcripts but a relatively good correlation between the animally localized transcripts. These findings indicate that the regulation of embryonic development within the animal kingdom is highly diverse and cannot be deduced based on a single model.
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7
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Della Gaspera B, Weill L, Chanoine C. Evolution of Somite Compartmentalization: A View From Xenopus. Front Cell Dev Biol 2022; 9:790847. [PMID: 35111756 PMCID: PMC8802780 DOI: 10.3389/fcell.2021.790847] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 11/26/2021] [Indexed: 11/13/2022] Open
Abstract
Somites are transitory metameric structures at the basis of the axial organization of vertebrate musculoskeletal system. During evolution, somites appear in the chordate phylum and compartmentalize mainly into the dermomyotome, the myotome, and the sclerotome in vertebrates. In this review, we summarized the existing literature about somite compartmentalization in Xenopus and compared it with other anamniote and amniote vertebrates. We also present and discuss a model that describes the evolutionary history of somite compartmentalization from ancestral chordates to amniote vertebrates. We propose that the ancestral organization of chordate somite, subdivided into a lateral compartment of multipotent somitic cells (MSCs) and a medial primitive myotome, evolves through two major transitions. From ancestral chordates to vertebrates, the cell potency of MSCs may have evolved and gave rise to all new vertebrate compartments, i.e., the dermomyome, its hypaxial region, and the sclerotome. From anamniote to amniote vertebrates, the lateral MSC territory may expand to the whole somite at the expense of primitive myotome and may probably facilitate sclerotome formation. We propose that successive modifications of the cell potency of some type of embryonic progenitors could be one of major processes of the vertebrate evolution.
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8
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Manicka S, Levin M. Minimal Developmental Computation: A Causal Network Approach to Understand Morphogenetic Pattern Formation. ENTROPY (BASEL, SWITZERLAND) 2022; 24:107. [PMID: 35052133 PMCID: PMC8774453 DOI: 10.3390/e24010107] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 01/05/2022] [Accepted: 01/07/2022] [Indexed: 12/22/2022]
Abstract
What information-processing strategies and general principles are sufficient to enable self-organized morphogenesis in embryogenesis and regeneration? We designed and analyzed a minimal model of self-scaling axial patterning consisting of a cellular network that develops activity patterns within implicitly set bounds. The properties of the cells are determined by internal 'genetic' networks with an architecture shared across all cells. We used machine-learning to identify models that enable this virtual mini-embryo to pattern a typical axial gradient while simultaneously sensing the set boundaries within which to develop it from homogeneous conditions-a setting that captures the essence of early embryogenesis. Interestingly, the model revealed several features (such as planar polarity and regenerative re-scaling capacity) for which it was not directly selected, showing how these common biological design principles can emerge as a consequence of simple patterning modes. A novel "causal network" analysis of the best model furthermore revealed that the originally symmetric model dynamically integrates into intercellular causal networks characterized by broken-symmetry, long-range influence and modularity, offering an interpretable macroscale-circuit-based explanation for phenotypic patterning. This work shows how computation could occur in biological development and how machine learning approaches can generate hypotheses and deepen our understanding of how featureless tissues might develop sophisticated patterns-an essential step towards predictive control of morphogenesis in regenerative medicine or synthetic bioengineering contexts. The tools developed here also have the potential to benefit machine learning via new forms of backpropagation and by leveraging the novel distributed self-representation mechanisms to improve robustness and generalization.
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Affiliation(s)
| | - Michael Levin
- Allen Discovery Center, Tufts University, Medford, MA 02155, USA;
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9
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Novel Pickering High Internal Phase Emulsion Stabilized by Food Waste-Hen Egg Chalaza. Foods 2021; 10:foods10030599. [PMID: 33809138 PMCID: PMC7998105 DOI: 10.3390/foods10030599] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 03/01/2021] [Accepted: 03/10/2021] [Indexed: 12/29/2022] Open
Abstract
A massive amount of chalaza with nearly 400 metric tons is produced annually as waste in the liquid-egg industry. The present study aimed to look for ways to utilize chalaza as a natural emulsifier for high internal phase emulsions (HIPEs) at the optimal production conditions to expand the utilization of such abundant material. To the author’s knowledge, for the first time, we report the usage of hen egg chalaza particles as particulate emulsifiers for Pickering (HIPEs) development. The chalaza particles with partial wettability were fabricated at different pH or ionic strengths by freeze-drying. The surface electricity of the chalaza particles was neutralized when the pH was adjusted to 4, where the chalaza contained a particle size around 1500 nm and held the best capability to stabilize the emulsions. Similarly, the chalaza reaches proper electrical charging (−6 mv) and size (700 nm) after the ionic strength was modified to 0.6 M. Following the characterization of chalaza particles, we successfully generated stable Pickering HIPEs with up to 86% internal phase at proper particle concentrations (0.5–2%). The emulsion contained significant stability against coalescence and flocculation during long term storage due to the electrical hindrance raised by the chalaza particles which absorbed on the oil–water interfaces. Different rheological models were tested on the formed HIPEs, indicating the outstanding stability of such emulsions. Concomitantly, a percolating 3D-network was formed in the Pickering HIPES stabilized by chalaza which provided the emulsions with viscoelastic and self-standing features. Moreover, the current study provides an attractive strategy to convert liquid oils to viscoelastic soft solids without artificial trans fats.
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10
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Exner CRT, Willsey HR. Xenopus leads the way: Frogs as a pioneering model to understand the human brain. Genesis 2021; 59:e23405. [PMID: 33369095 PMCID: PMC8130472 DOI: 10.1002/dvg.23405] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 12/12/2020] [Accepted: 12/14/2020] [Indexed: 12/20/2022]
Abstract
From its long history in the field of embryology to its recent advances in genetics, Xenopus has been an indispensable model for understanding the human brain. Foundational studies that gave us our first insights into major embryonic patterning events serve as a crucial backdrop for newer avenues of investigation into organogenesis and organ function. The vast array of tools available in Xenopus laevis and Xenopus tropicalis allows interrogation of developmental phenomena at all levels, from the molecular to the behavioral, and the application of CRISPR technology has enabled the investigation of human disorder risk genes in a higher-throughput manner. As the only major tetrapod model in which all developmental stages are easily manipulated and observed, frogs provide the unique opportunity to study organ development from the earliest stages. All of these features make Xenopus a premier model for studying the development of the brain, a notoriously complex process that demands an understanding of all stages from fertilization to organogenesis and beyond. Importantly, core processes of brain development are conserved between Xenopus and human, underlining the advantages of this model. This review begins by summarizing discoveries made in amphibians that form the cornerstones of vertebrate neurodevelopmental biology and goes on to discuss recent advances that have catapulted our understanding of brain development in Xenopus and in relation to human development and disease. As we engage in a new era of patient-driven gene discovery, Xenopus offers exceptional potential to uncover conserved biology underlying human brain disorders and move towards rational drug design.
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Affiliation(s)
- Cameron R T Exner
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California, 94143, USA
| | - Helen Rankin Willsey
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California, 94143, USA
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11
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Oh JN, Lee M, Choe GC, Lee DK, Choi KH, Kim SH, Jeong J, Lee CK. Identification of the Lineage Markers and Inhibition of DAB2 in In Vitro Fertilized Porcine Embryos. Int J Mol Sci 2020; 21:ijms21197275. [PMID: 33019677 PMCID: PMC7582820 DOI: 10.3390/ijms21197275] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/28/2020] [Accepted: 09/29/2020] [Indexed: 12/18/2022] Open
Abstract
Specification of embryonic lineages is an important question in the field of early development. Numerous studies analyzed the expression patterns of the candidate transcripts and proteins in humans and mice and clearly determined the markers of each lineage. To overcome the limitations of human and mouse embryos, the expression of the marker transcripts in each cell has been investigated using in vivo embryos in pigs. In vitro produced embryos are more accessible, can be rapidly processed with low cost. Therefore, we analyzed the characteristics of lineage markers and the effects of the DAB2 gene (trophectoderm marker) in in vitro fertilized porcine embryos. We investigated the expression levels of the marker genes during embryonic stages and distribution of the marker proteins was assayed in day 7 blastocysts. Then, the shRNA vectors were injected into the fertilized embryos and the differences in the marker transcripts were analyzed. Marker transcripts showed diverse patterns of expression, and each embryonic lineage could be identified with localization of marker proteins. In DAB2-shRNA vectors injected embryos, HNF4A and PDGFRA were upregulated. DAB2 protein level was lower in shRNA-injected embryos without significant differences. Our results will contribute to understanding of the mechanisms of embryonic lineage specification in pigs.
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Affiliation(s)
- Jong-Nam Oh
- Department of Agricultural Biotechnology, Animal Biotechnology Major and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea; (J.-N.O.); (M.L.); (G.C.C.); (D.-K.L.); (K.-H.C.); (S.-H.K.); (J.J.)
| | - Mingyun Lee
- Department of Agricultural Biotechnology, Animal Biotechnology Major and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea; (J.-N.O.); (M.L.); (G.C.C.); (D.-K.L.); (K.-H.C.); (S.-H.K.); (J.J.)
| | - Gyung Cheol Choe
- Department of Agricultural Biotechnology, Animal Biotechnology Major and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea; (J.-N.O.); (M.L.); (G.C.C.); (D.-K.L.); (K.-H.C.); (S.-H.K.); (J.J.)
| | - Dong-Kyung Lee
- Department of Agricultural Biotechnology, Animal Biotechnology Major and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea; (J.-N.O.); (M.L.); (G.C.C.); (D.-K.L.); (K.-H.C.); (S.-H.K.); (J.J.)
| | - Kwang-Hwan Choi
- Department of Agricultural Biotechnology, Animal Biotechnology Major and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea; (J.-N.O.); (M.L.); (G.C.C.); (D.-K.L.); (K.-H.C.); (S.-H.K.); (J.J.)
| | - Seung-Hun Kim
- Department of Agricultural Biotechnology, Animal Biotechnology Major and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea; (J.-N.O.); (M.L.); (G.C.C.); (D.-K.L.); (K.-H.C.); (S.-H.K.); (J.J.)
| | - Jinsol Jeong
- Department of Agricultural Biotechnology, Animal Biotechnology Major and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea; (J.-N.O.); (M.L.); (G.C.C.); (D.-K.L.); (K.-H.C.); (S.-H.K.); (J.J.)
| | - Chang-Kyu Lee
- Department of Agricultural Biotechnology, Animal Biotechnology Major and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea; (J.-N.O.); (M.L.); (G.C.C.); (D.-K.L.); (K.-H.C.); (S.-H.K.); (J.J.)
- Institute of Green Bio Science and Technology, Seoul National University, Pyeongchang 25354, Korea
- Correspondence:
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12
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Shin JM, Yuan L, Ohme-Takagi M, Kawashima T. Cellular dynamics of double fertilization and early embryogenesis in flowering plants. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2020; 336:642-651. [PMID: 32638525 DOI: 10.1002/jez.b.22981] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 06/12/2020] [Accepted: 06/18/2020] [Indexed: 12/12/2022]
Abstract
Flowering plants (angiosperms) perform a unique double fertilization in which two sperm cells fuse with two female gamete cells in the embryo sac to develop a seed. Furthermore, during land plant evolution, the mode of sexual reproduction has been modified dramatically from motile sperm in the early-diverging land plants, such as mosses and ferns as well as some gymnosperms (Ginkgo and cycads) to nonmotile sperm that are delivered to female gametes by the pollen tube in flowering plants. Recent studies have revealed the cellular dynamics and molecular mechanisms for the complex series of double fertilization processes and elucidated differences and similarities between animals and plants. Here, together with a brief comparison with animals, we review the current understanding of flowering plant zygote dynamics, covering from gamete nuclear migration, karyogamy, and polyspermy block, to zygotic genome activation as well as asymmetrical division of the zygote. Further analyses of the detailed molecular and cellular mechanisms of flowering plant fertilization should shed light on the evolution of the unique sexual reproduction of flowering plants.
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Affiliation(s)
- Ji Min Shin
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky.,Kentucky Tobacco Research and Development Center, University of Kentucky, Lexington, Kentucky.,Graduate School of Science and Engineering, Saitama University, Saitama, Saitama, Japan
| | - Ling Yuan
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky.,Kentucky Tobacco Research and Development Center, University of Kentucky, Lexington, Kentucky
| | - Masaru Ohme-Takagi
- Graduate School of Science and Engineering, Saitama University, Saitama, Saitama, Japan.,Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan
| | - Tomokazu Kawashima
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky
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13
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Abstract
Gastrulation is a critical early morphogenetic process of animal development, during which the three germ layers; mesoderm, endoderm and ectoderm, are rearranged by internalization movements. Concurrent epiboly movements spread and thin the germ layers while convergence and extension movements shape them into an anteroposteriorly elongated body with head, trunk, tail and organ rudiments. In zebrafish, gastrulation follows the proliferative and inductive events that establish the embryonic and extraembryonic tissues and the embryonic axis. Specification of these tissues and embryonic axes are controlled by the maternal gene products deposited in the egg. These early maternally controlled processes need to generate sufficient cell numbers and establish the embryonic polarity to ensure normal gastrulation. Subsequently, after activation of the zygotic genome, the zygotic gene products govern mesoderm and endoderm induction and germ layer patterning. Gastrulation is initiated during the maternal-to-zygotic transition, a process that entails both activation of the zygotic genome and downregulation of the maternal transcripts. Genomic studies indicate that gastrulation is largely controlled by the zygotic genome. Nonetheless, genetic studies that investigate the relative contributions of maternal and zygotic gene function by comparing zygotic, maternal and maternal zygotic mutant phenotypes, reveal significant contribution of maternal gene products, transcripts and/or proteins, that persist through gastrulation, to the control of gastrulation movements. Therefore, in zebrafish, the maternally expressed gene products not only set the stage for, but they also actively participate in gastrulation morphogenesis.
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Affiliation(s)
- Lilianna Solnica-Krezel
- Department of Developmental Biology and Center of Regenerative Medicine, Washington University School of Medicine, St. Louis, MO, United States.
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14
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Kozmikova I, Kozmik Z. Wnt/β-catenin signaling is an evolutionarily conserved determinant of chordate dorsal organizer. eLife 2020; 9:56817. [PMID: 32452768 PMCID: PMC7292647 DOI: 10.7554/elife.56817] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 05/25/2020] [Indexed: 12/11/2022] Open
Abstract
Deciphering the mechanisms of axis formation in amphioxus is a key step to understanding the evolution of chordate body plan. The current view is that Nodal signaling is the only factor promoting the dorsal axis specification in the amphioxus, whereas Wnt/β-catenin signaling plays no role in this process. Here, we re-examined the role of Wnt/βcatenin signaling in the dorsal/ventral patterning of amphioxus embryo. We demonstrated that the spatial activity of Wnt/β-catenin signaling is located in presumptive dorsal cells from cleavage to gastrula stage, and provided functional evidence that Wnt/β-catenin signaling is necessary for the specification of dorsal cell fate in a stage-dependent manner. Microinjection of Wnt8 and Wnt11 mRNA induced ectopic dorsal axis in neurulae and larvae. Finally, we demonstrated that Nodal and Wnt/β-catenin signaling cooperate to promote the dorsal-specific gene expression in amphioxus gastrula. Our study reveals high evolutionary conservation of dorsal organizer formation in the chordate lineage.
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Affiliation(s)
- Iryna Kozmikova
- Laboratory of Transcriptional Regulation, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Zbynek Kozmik
- Laboratory of Transcriptional Regulation, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
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15
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Zhang Z, Ursin R, Mahapatra S, Gallicano GI. CRISPR/CAS9 ablation of individual miRNAs from a miRNA family reveals their individual efficacies for regulating cardiac differentiation. Mech Dev 2018; 150:10-20. [PMID: 29427756 DOI: 10.1016/j.mod.2018.02.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Revised: 02/01/2018] [Accepted: 02/05/2018] [Indexed: 12/12/2022]
Abstract
Although it is well understood that genetic mutations, chromosomal abnormalities, and epigenetic miscues can cause congenital birth defects, many defects are still labeled idiopathic, meaning their origin is not yet understood. microRNAs are quickly entering the causal fray of developmental defects. miRNAs use a 7-8 base-pair seed sequence to target a corresponding sequence on one or multiple mRNAs resulting in rapid down-regulation of translation. miRNAs can also control protein 'amounts' in cells. As a result if miRNAs are over or under expressed during development protein homeostasis can be compromised resulting in defects in the development of organ systems. Here, we show that during differentiation of embryonic stem cells, individual miRNAs that reside in the miRNA17 family (composed of 14 miRNAs) do not share the same function even though they have the same seed sequence. The advent of CRISPR/CAS9 technology has not only yielded a true observation of individual miRNA function, it has also reconnected advanced molecular biology approaches to classical cell biology approaches such as gene rescue. We show that miRNA106a and to a lesser extent miR17 and 93 target the cardiac suppressor gene Fog2, which specifically suppress Gata-4 and Coup-TF2. However, when each miRNA is knocked out, we find that their targeting efficacies for Fog2 differ resulting in varying degrees of cardiac differentiation.
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Affiliation(s)
- Ziyao Zhang
- Department of Biochemistry and Molecular Biology, Georgetown University Medical Center, 3900 Reservoir Rd, Washington, DC 20057-145, United States
| | - Rebecca Ursin
- Department of Biochemistry and Molecular Biology, Georgetown University Medical Center, 3900 Reservoir Rd, Washington, DC 20057-145, United States
| | - Samiksha Mahapatra
- Department of Biochemistry and Molecular Biology, Georgetown University Medical Center, 3900 Reservoir Rd, Washington, DC 20057-145, United States
| | - G Ian Gallicano
- Department of Biochemistry and Molecular Biology, Georgetown University Medical Center, 3900 Reservoir Rd, Washington, DC 20057-145, United States.
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16
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Waddington JL, Katina S, O'Tuathaigh CMP, Bowman AW. Translational Genetic Modelling of 3D Craniofacial Dysmorphology: Elaborating the Facial Phenotype of Neurodevelopmental Disorders Through the "Prism" of Schizophrenia. Curr Behav Neurosci Rep 2017; 4:322-330. [PMID: 29201594 PMCID: PMC5694503 DOI: 10.1007/s40473-017-0136-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Purpose of Review In the context of human developmental conditions, we review the conceptualisation of schizophrenia as a neurodevelopmental disorder, the status of craniofacial dysmorphology as a clinically accessible index of brain dysmorphogenesis, the ability of genetically modified mouse models of craniofacial dysmorphology to inform on the underlying dysmorphogenic process and how geometric morphometric techniques in mutant mice can extend quantitative analysis. Recent Findings Mutant mice with disruption of neuregulin-1, a gene associated meta-analytically with risk for schizophrenia, constitute proof-of-concept studies of murine facial dysmorphology in a manner analogous to clinical studies in schizophrenia. Geometric morphometric techniques informed on the topography of facial dysmorphology and identified asymmetry therein. Summary Targeted disruption in mice of genes involved in individual components of developmental processes and analysis of resultant facial dysmorphology using geometric morphometrics can inform on mechanisms of dysmorphogenesis at levels of incisiveness not possible in human subjects.
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Affiliation(s)
- John L Waddington
- Molecular & Cellular Therapeutics, Royal College of Surgeons in Ireland, St. Stephen's Green, Dublin 2, Ireland.,Jiangsu Key Laboratory of Translational Research & Therapy for Neuro-Psychiatric-Disorders and Department of Pharmacology, College of Pharmaceutical Sciences, Soochow University, Suzhou, 215123 China
| | - Stanislav Katina
- School of Mathematics and Statistics, University of Glasgow, Glasgow, G12 8QQ UK.,Institute of Mathematics and Statistics, Masaryk University, Brno, Czech Republic.,Institute of Normal and Pathological Physiology, Slovak Academy of Sciences, Bratislava, Slovakia
| | | | - Adrian W Bowman
- School of Mathematics and Statistics, University of Glasgow, Glasgow, G12 8QQ UK
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17
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Oh D, Houston DW. Role of maternal Xenopus syntabulin in germ plasm aggregation and primordial germ cell specification. Dev Biol 2017; 432:237-247. [PMID: 29037933 DOI: 10.1016/j.ydbio.2017.10.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 09/20/2017] [Accepted: 10/11/2017] [Indexed: 01/04/2023]
Abstract
The localization and organization of mitochondria- and ribonucleoprotein granule-rich germ plasm is essential for many aspects of germ cell development. In Xenopus, germ plasm is maternally inherited and is required for the specification of primordial germ cells (PGCs). Germ plasm is aggregated into larger patches during egg activation and cleavage and is ultimately translocated perinuclearly during gastrulation. Although microtubule dynamics and a kinesin (Kif4a) have been implicated in Xenopus germ plasm localization, little is known about how germ plasm distribution is regulated. Here, we identify a role for maternal Xenopus Syntabulin in the aggregation of germ plasm following fertilization. We show that depletion of sybu mRNA using antisense oligonucleotides injected into oocytes results in defects in the aggregation and perinuclear transport of germ plasm and subsequently in reduced PGC numbers. Using live imaging analysis, we also characterize a novel role for Sybu in the collection of germ plasm in vegetal cleavage furrows by surface contraction waves. Additionally, we show that a localized kinesin-like protein, Kif3b, is also required for germ plasm aggregation and that Sybu functionally interacts with Kif3b and Kif4a in germ plasm aggregation. Overall, these data suggest multiple coordinate roles for kinesins and adaptor proteins in controlling the localization and distribution of a cytoplasmic determinant in early development.
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Affiliation(s)
- Denise Oh
- The University of Iowa, Department of Biology, 257 BB, Iowa City, IA 52242-1324, USA
| | - Douglas W Houston
- The University of Iowa, Department of Biology, 257 BB, Iowa City, IA 52242-1324, USA.
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