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Bock F, Dong X, Li S, Viquez OM, Sha E, Tantengco M, Hennen EM, Plosa E, Ramezani A, Brown KL, Whang YM, Terker AS, Arroyo JP, Harrison DG, Fogo A, Brakebusch CH, Pozzi A, Zent R. Rac1 promotes kidney collecting duct repair by mechanically coupling cell morphology to mitotic entry. SCIENCE ADVANCES 2024; 10:eadi7840. [PMID: 38324689 PMCID: PMC10849615 DOI: 10.1126/sciadv.adi7840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 01/03/2024] [Indexed: 02/09/2024]
Abstract
Prolonged obstruction of the ureter, which leads to injury of the kidney collecting ducts, results in permanent structural damage, while early reversal allows for repair. Cell structure is defined by the actin cytoskeleton, which is dynamically organized by small Rho guanosine triphosphatases (GTPases). In this study, we identified the Rho GTPase, Rac1, as a driver of postobstructive kidney collecting duct repair. After the relief of ureteric obstruction, Rac1 promoted actin cytoskeletal reconstitution, which was required to maintain normal mitotic morphology allowing for successful cell division. Mechanistically, Rac1 restricted excessive actomyosin activity that stabilized the negative mitotic entry kinase Wee1. This mechanism ensured mechanical G2-M checkpoint stability and prevented premature mitotic entry. The repair defects following injury could be rescued by direct myosin inhibition. Thus, Rac1-dependent control of the actin cytoskeleton integrates with the cell cycle to mediate kidney tubular repair by preventing dysmorphic cells from entering cell division.
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Affiliation(s)
- Fabian Bock
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Veterans Affairs Hospital, Tennessee Valley Healthcare System, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Xinyu Dong
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Shensen Li
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Olga M. Viquez
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Eric Sha
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Matthew Tantengco
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Elizabeth M. Hennen
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Erin Plosa
- Division of Neonatology, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Alireza Ramezani
- Interdisciplinary Center for Quantitative Modeling in Biology, University of California, Riverside, CA, USA
- Department of Physics and Astronomy, University of California, Riverside, CA, USA
| | - Kyle L. Brown
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Young Mi Whang
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Andrew S. Terker
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Juan Pablo Arroyo
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Veterans Affairs Hospital, Tennessee Valley Healthcare System, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, TN, USA
| | - David G. Harrison
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Agnes Fogo
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Cord H. Brakebusch
- Biotech Research Center, University of Copenhagen, Copenhagen DK-2200, Denmark
| | - Ambra Pozzi
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Veterans Affairs Hospital, Tennessee Valley Healthcare System, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Physiology and Molecular Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Roy Zent
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Veterans Affairs Hospital, Tennessee Valley Healthcare System, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
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Integration of Transcriptomics and Non-Targeted Metabolomics Reveals the Underlying Mechanism of Skeletal Muscle Development in Duck during Embryonic Stage. Int J Mol Sci 2023; 24:ijms24065214. [PMID: 36982289 PMCID: PMC10049352 DOI: 10.3390/ijms24065214] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 03/02/2023] [Accepted: 03/03/2023] [Indexed: 03/11/2023] Open
Abstract
Skeletal muscle is an important economic trait in duck breeding; however, little is known about the molecular mechanisms of its embryonic development. Here, the transcriptomes and metabolomes of breast muscle of Pekin duck from 15 (E15_BM), 21 (E21_BM), and 27 (E27_BM) days of incubation were compared and analyzed. The metabolome results showed that the differentially accumulated metabolites (DAMs), including the up-regulated metabolites, l-glutamic acid, n-acetyl-1-aspartylglutamic acid, l-2-aminoadipic acid, 3-hydroxybutyric acid, bilirubin, and the significantly down-regulated metabolites, palmitic acid, 4-guanidinobutanoate, myristic acid, 3-dehydroxycarnitine, and s-adenosylmethioninamine, were mainly enriched in metabolic pathways, biosynthesis of secondary metabolites, biosynthesis of cofactors, protein digestion and absorption, and histidine metabolism, suggesting that these pathways may play important roles in the muscle development of duck during the embryonic stage. Moreover, a total of 2142 (1552 up-regulated and 590 down-regulated), 4873 (3810 up-regulated and 1063 down-regulated), and 2401 (1606 up-regulated and 795 down-regulated) DEGs were identified from E15_BM vs. E21_BM, E15_BM vs. E27_BM and E21_BM vs. E27_BM in the transcriptome, respectively. The significantly enriched GO terms from biological processes were positive regulation of cell proliferation, regulation of cell cycle, actin filament organization, and regulation of actin cytoskeleton organization, which were associated with muscle or cell growth and development. Seven significant pathways, highly enriched by FYN, PTK2, PXN, CRK, CRKL, PAK, RHOA, ROCK, INSR, PDPK1, and ARHGEF, were focal adhesion, regulation of actin cytoskeleton, wnt signaling pathway, insulin signaling pathway, extracellular matrix (ECM)-receptor interaction, cell cycle, and adherens junction, which participated in regulating the development of skeletal muscle in Pekin duck during the embryonic stage. KEGG pathway analysis of the integrated transcriptome and metabolome indicated that the pathways, including arginine and proline metabolism, protein digestion and absorption, and histidine metabolism, were involved in regulating skeletal muscle development in embryonic Pekin duck. These findings suggested that the candidate genes and metabolites involved in crucial biological pathways may regulate muscle development in the Pekin duck at the embryonic stage, and increased our understanding of the molecular mechanisms underlying the avian muscle development.
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Donker L, Houtekamer R, Vliem M, Sipieter F, Canever H, Gómez-González M, Bosch-Padrós M, Pannekoek WJ, Trepat X, Borghi N, Gloerich M. A mechanical G2 checkpoint controls epithelial cell division through E-cadherin-mediated regulation of Wee1-Cdk1. Cell Rep 2022; 41:111475. [DOI: 10.1016/j.celrep.2022.111475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 07/07/2022] [Accepted: 09/20/2022] [Indexed: 11/26/2022] Open
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4
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HREM, RNAseq and Cell Cycle Analyses Reveal the Role of the G2/M-Regulatory Protein, WEE1, on the Survivability of Chicken Embryos during Diapause. Biomedicines 2022; 10:biomedicines10040779. [PMID: 35453529 PMCID: PMC9033001 DOI: 10.3390/biomedicines10040779] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 03/15/2022] [Accepted: 03/22/2022] [Indexed: 02/04/2023] Open
Abstract
Avian blastoderm can enter into diapause when kept at low temperatures and successfully resume development (SRD) when re-incubated in body temperature. These abilities, which are largely affected by the temperature and duration of the diapause, are poorly understood at the cellular and molecular level. To determine how temperature affects embryonic morphology during diapause, high-resolution episcopic microscopy (HREM) analysis was utilized. While blastoderms diapausing at 12 °C for 28 days presented typical cytoarchitecture, similar to non-diapaused embryos, at 18 °C, much thicker blastoderms with higher cell number were observed. RNAseq was conducted to discover the genes underlying these phenotypes, revealing differentially expressed cell cycle regulatory genes. Among them, WEE1, a negative regulator of G2/M transition, was highly expressed at 12 °C compared to 18 °C. This finding suggested that cells at 12 °C are arrested at the G2/M phase, as supported by bromodeoxyuridine incorporation (BrdU) assay and phospho-histone H3 (pH 3) immunostaining. Inhibition of WEE1 during diapause at 12 °C resulted in cell cycle progression beyond the G2/M and augmented tissue volume, resembling the morphology of 18 °C-diapaused embryos. These findings suggest that diapause at low temperatures leads to WEE1 upregulation, which arrests the cell cycle at the G2/M phase, promoting the perseverance of embryonic cytoarchitecture and future SRD. In contrast, WEE1 is not upregulated during diapause at higher temperature, leading to continuous proliferation and maladaptive morphology associated with poor survivability. Combining HREM-based analysis with RNAseq and molecular manipulations, we present a novel mechanism that regulates the ability of diapaused avian embryos to maintain their cytoarchitecture via cell cycle arrest, which enables their SRD.
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Aiba Y, Kim J, Imamura A, Okumoto K, Nakajo N. Regulation of Myt1 kinase activity via its N-terminal region in Xenopus meiosis and mitosis. Cells Dev 2021; 169:203754. [PMID: 34695617 DOI: 10.1016/j.cdev.2021.203754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 10/13/2021] [Accepted: 10/15/2021] [Indexed: 11/28/2022]
Abstract
Immature animal oocytes are naturally arrested at the first meiotic prophase (Pro-I), which corresponds to the G2 phase of the cell cycle. In Xenopus oocytes, Myt1 kinase phosphorylates and inactivates cyclin-dependent kinase 1 (Cdk1) at Pro-I, thereby preventing oocytes from entering meiosis I (MI) prematurely. Previous studies have shown that, upon resuming MI, Cdk1 and p90rsk, which is a downstream kinase of the Mos-MAPK pathway, in turn phosphorylate the C-terminal region of Myt1, to suppress its activity, thereby ensuring high Cdk1 activity during M phase. However, the roles of the N-terminal region of Myt1 during meiosis and mitosis remain to be elucidated. In the present study, we show that the N-terminal region of Myt1 participates in the regulation of Myt1 activity in the Xenopus cell cycle. In particular, we found that a short, conserved sequence in the N-terminal region, termed here as the PAYF motif, is required for the normal activity of Myt1 in oocytes. Furthermore, multiple phosphorylations by Cdk1 at the Myt1 N-terminal region were found to be involved in the negative regulation of Myt1. In particular, phosphorylations at Thr11 and Thr16 of Myt1, which are adjacent to the PAYF motif, were found to be important for the inactivation of Myt1 in the M phase of the cell cycle. These results suggest that in addition to the regulation of Myt1 activity via the C-terminal region, the N-terminal region of Myt1 also plays an important role in the regulation of Myt1 activity.
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Affiliation(s)
- Yukito Aiba
- Graduate School of Systems Life Sciences, Kyushu University, Fukuoka, Japan.
| | - Jihoon Kim
- Graduate School of Systems Life Sciences, Kyushu University, Fukuoka, Japan.
| | - Arata Imamura
- Graduate School of Systems Life Sciences, Kyushu University, Fukuoka, Japan.
| | - Kanji Okumoto
- Graduate School of Systems Life Sciences, Kyushu University, Fukuoka, Japan; Department of Biology, Graduate School of Sciences, Kyushu University, Fukuoka, Japan.
| | - Nobushige Nakajo
- Graduate School of Systems Life Sciences, Kyushu University, Fukuoka, Japan; Department of Biology, Graduate School of Sciences, Kyushu University, Fukuoka, Japan.
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6
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Abstract
Understanding the mechanisms of embryonic cell cycles is a central goal of developmental biology, as the regulation of the cell cycle must be closely coordinated with other events during early embryogenesis. Quantitative imaging approaches have recently begun to reveal how the cell cycle oscillator is controlled in space and time, and how it is integrated with mechanical signals to drive morphogenesis. Here, we discuss how the Drosophila embryo has served as an excellent model for addressing the molecular and physical mechanisms of embryonic cell cycles, with comparisons to other model systems to highlight conserved and species-specific mechanisms. We describe how the rapid cleavage divisions characteristic of most metazoan embryos require chemical waves and cytoplasmic flows to coordinate morphogenesis across the large expanse of the embryo. We also outline how, in the late cleavage divisions, the cell cycle is inter-regulated with the activation of gene expression to ensure a reliable maternal-to-zygotic transition. Finally, we discuss how precise transcriptional regulation of the timing of mitosis ensures that tissue morphogenesis and cell proliferation are tightly controlled during gastrulation.
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Affiliation(s)
| | - Stefano Di Talia
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27705, USA
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7
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Adikes RC, Kohrman AQ, Martinez MAQ, Palmisano NJ, Smith JJ, Medwig-Kinney TN, Min M, Sallee MD, Ahmed OB, Kim N, Liu S, Morabito RD, Weeks N, Zhao Q, Zhang W, Feldman JL, Barkoulas M, Pani AM, Spencer SL, Martin BL, Matus DQ. Visualizing the metazoan proliferation-quiescence decision in vivo. eLife 2020; 9:e63265. [PMID: 33350383 PMCID: PMC7880687 DOI: 10.7554/elife.63265] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 12/21/2020] [Indexed: 12/15/2022] Open
Abstract
Cell proliferation and quiescence are intimately coordinated during metazoan development. Here, we adapt a cyclin-dependent kinase (CDK) sensor to uncouple these key events of the cell cycle in Caenorhabditis elegans and zebrafish through live-cell imaging. The CDK sensor consists of a fluorescently tagged CDK substrate that steadily translocates from the nucleus to the cytoplasm in response to increasing CDK activity and consequent sensor phosphorylation. We show that the CDK sensor can distinguish cycling cells in G1 from quiescent cells in G0, revealing a possible commitment point and a cryptic stochasticity in an otherwise invariant C. elegans cell lineage. Finally, we derive a predictive model of future proliferation behavior in C. elegans based on a snapshot of CDK activity in newly born cells. Thus, we introduce a live-cell imaging tool to facilitate in vivo studies of cell-cycle control in a wide-range of developmental contexts.
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Affiliation(s)
- Rebecca C Adikes
- Department of Biochemistry and Cell Biology, Stony Brook UniversityStony BrookUnited States
| | - Abraham Q Kohrman
- Department of Biochemistry and Cell Biology, Stony Brook UniversityStony BrookUnited States
| | - Michael A Q Martinez
- Department of Biochemistry and Cell Biology, Stony Brook UniversityStony BrookUnited States
| | - Nicholas J Palmisano
- Department of Biochemistry and Cell Biology, Stony Brook UniversityStony BrookUnited States
| | - Jayson J Smith
- Department of Biochemistry and Cell Biology, Stony Brook UniversityStony BrookUnited States
| | - Taylor N Medwig-Kinney
- Department of Biochemistry and Cell Biology, Stony Brook UniversityStony BrookUnited States
| | - Mingwei Min
- Department of Biochemistry and BioFrontiers Institute, University of Colorado BoulderBoulderUnited States
| | - Maria D Sallee
- Department of Biology, Stanford UniversityStanfordUnited States
| | - Ononnah B Ahmed
- Department of Biochemistry and Cell Biology, Stony Brook UniversityStony BrookUnited States
| | - Nuri Kim
- Department of Biochemistry and Cell Biology, Stony Brook UniversityStony BrookUnited States
| | - Simeiyun Liu
- Department of Biochemistry and Cell Biology, Stony Brook UniversityStony BrookUnited States
| | - Robert D Morabito
- Department of Biochemistry and Cell Biology, Stony Brook UniversityStony BrookUnited States
| | - Nicholas Weeks
- Department of Biochemistry and Cell Biology, Stony Brook UniversityStony BrookUnited States
| | - Qinyun Zhao
- Department of Biochemistry and Cell Biology, Stony Brook UniversityStony BrookUnited States
| | - Wan Zhang
- Department of Biochemistry and Cell Biology, Stony Brook UniversityStony BrookUnited States
| | | | | | - Ariel M Pani
- Department of Biology, University of VirginiaCharlottesvilleUnited States
| | - Sabrina L Spencer
- Department of Biochemistry and BioFrontiers Institute, University of Colorado BoulderBoulderUnited States
| | - Benjamin L Martin
- Department of Biochemistry and Cell Biology, Stony Brook UniversityStony BrookUnited States
| | - David Q Matus
- Department of Biochemistry and Cell Biology, Stony Brook UniversityStony BrookUnited States
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8
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Fiuza UM, Negishi T, Rouan A, Yasuo H, Lemaire P. A Nodal/Eph signalling relay drives the transition from apical constriction to apico-basal shortening in ascidian endoderm invagination. Development 2020; 147:dev.186965. [DOI: 10.1242/dev.186965] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 07/02/2020] [Indexed: 01/13/2023]
Abstract
Gastrulation is the first major morphogenetic event during animal embryogenesis. Ascidian gastrulation starts with the invagination of 10 endodermal precursor cells between the 64- and late 112-cell stages. This process occurs in the absence of endodermal cell division and in two steps, driven by myosin-dependent contractions of the acto-myosin network. First, endoderm precursors constrict their apex. Second, they shorten apico-basally, while retaining small apical surfaces, thereby causing invagination. The mechanisms that prevent endoderm cell division, trigger the transition between step 1 and step 2, and drive apico-basal shortening have remained elusive. Here, we demonstrate a conserved role for Nodal and Eph signalling during invagination in two distantly related ascidian species, Phallusia mammillata and Ciona intestinalis. Specifically, we show that the transition to step 2 is triggered by Nodal relayed by Eph signalling. Additionally, our results indicate that Eph signalling lengthens the endodermal cell cycle, independently of Nodal. Finally, we find that both Nodal and Eph signals are dispensable for endoderm fate specification. These results illustrate commonalities as well as differences in the action of Nodal during ascidian and vertebrate gastrulation.
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Affiliation(s)
- Ulla-Maj Fiuza
- CRBM, University of Montpellier, CNRS, Montpellier, France
| | - Takefumi Negishi
- Laboratoire de Biologie du Développement de Villefranche-sur-Mer, CNRS, Sorbonne Universités, 06230 Villefranche-sur-Mer, France
| | - Alice Rouan
- Laboratoire de Biologie du Développement de Villefranche-sur-Mer, CNRS, Sorbonne Universités, 06230 Villefranche-sur-Mer, France
| | - Hitoyoshi Yasuo
- Laboratoire de Biologie du Développement de Villefranche-sur-Mer, CNRS, Sorbonne Universités, 06230 Villefranche-sur-Mer, France
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9
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Epithelial-Mesenchymal Plasticity in Circulating Tumor Cells, the Precursors of Metastasis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1220:11-34. [PMID: 32304077 DOI: 10.1007/978-3-030-35805-1_2] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Circulating tumor cells offer an unprecedented window into the metastatic cascade, and to some extent can be considered as intermediates in the process of metastasis. They exhibit dynamic oscillations in epithelial to mesenchymal plasticity and provide important opportunities for prognosis, therapy response monitoring, and targeting of metastatic disease. In this manuscript, we review the involvement of epithelial-mesenchymal plasticity in the early steps of metastasis and what we have learned about its contribution to genomic instability and genetic diversity, tumor progression and therapeutic responses using cell culture, mouse models and circulating tumor cells enriched from patients.
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10
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Chen P, Tomschik M, Nelson KM, Oakey J, Gatlin JC, Levy DL. Nucleoplasmin is a limiting component in the scaling of nuclear size with cytoplasmic volume. J Cell Biol 2019; 218:4063-4078. [PMID: 31636119 PMCID: PMC6891103 DOI: 10.1083/jcb.201902124] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 07/08/2019] [Accepted: 09/06/2019] [Indexed: 12/27/2022] Open
Abstract
How is nuclear size regulated relative to cell size? Using microfluidic encapsulation of Xenopuslaevis embryo extracts, biochemical fractionation, and in vivo experiments, Chen et al. demonstrate that reductions in cytoplasmic volume and limiting components, including the histone chaperone nucleoplasmin, contribute to developmental nuclear size scaling. How nuclear size is regulated relative to cell size is a fundamental cell biological question. Reductions in both cell and nuclear sizes during Xenopus laevis embryogenesis provide a robust scaling system to study mechanisms of nuclear size regulation. To test if the volume of embryonic cytoplasm is limiting for nuclear growth, we encapsulated gastrula-stage embryonic cytoplasm and nuclei in droplets of defined volume using microfluidics. Nuclei grew and reached new steady-state sizes as a function of cytoplasmic volume, supporting a limiting component mechanism of nuclear size control. Through biochemical fractionation, we identified the histone chaperone nucleoplasmin (Npm2) as a putative nuclear size effector. Cellular amounts of Npm2 decrease over development, and nuclear size was sensitive to Npm2 levels both in vitro and in vivo, affecting nuclear histone levels and chromatin organization. We propose that reductions in cell volume and the amounts of limiting components, such as Npm2, contribute to developmental nuclear size scaling.
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Affiliation(s)
- Pan Chen
- Department of Molecular Biology, University of Wyoming, Laramie, WY
| | | | - Katherine M Nelson
- Department of Molecular Biology, University of Wyoming, Laramie, WY.,Department of Chemical Engineering, University of Wyoming, Laramie, WY
| | - John Oakey
- Department of Chemical Engineering, University of Wyoming, Laramie, WY
| | - Jesse C Gatlin
- Department of Molecular Biology, University of Wyoming, Laramie, WY
| | - Daniel L Levy
- Department of Molecular Biology, University of Wyoming, Laramie, WY
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11
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Yoshitome S, Aiba Y, Yuge M, Furuno N, Watanabe M, Nakajo N. Involvement of Myt1 kinase in the G2 phase of the first cell cycle in Xenopus laevis. Biochem Biophys Res Commun 2019; 515:139-144. [PMID: 31128913 DOI: 10.1016/j.bbrc.2019.05.104] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 05/14/2019] [Indexed: 10/26/2022]
Abstract
During cleavage of Xenopus laevis, the first mitotic cell cycle immediately following fertilization is approximately 90 min and consists of S, G2, and M phases. In contrast, the subsequent eleven cell cycles are approximately 30 min and consist mostly of S and M phases. The balance between Cdc25 and Wee1A/Myt1 is thought to be crucial for Xenopus first cell cycle progression; however, the role of Myt1 in this period has not been fully investigated. In this study, we examined the roles of Myt1, Wee1A, and Cdc25A in the first cell cycle of Xenopus laevis. Inhibition of Cdc25A with antisense morpholino oligonucleotides lengthened the duration of the first cell cycle to some extent, whereas it was slightly shortened by ectopic Cdc25A expression, suggesting that the low concentration of Cdc25A during the first cell cycle does not fully account for the long duration of this cycle. Using the Wee1A antisense morpholino oligonucleotide and neutralizing antibody against Myt1, we found that Myt1 phosphorylates and inhibits Cdk1 much more effectively than Wee1A during the first cell cycle in Xenopus. Taken together, these results suggest that the activity of Myt1 is predominantly responsible for the duration of the long G2 phase in the first mitotic cell cycle in Xenopus.
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Affiliation(s)
- Satoshi Yoshitome
- Department of Biology, Graduate School of Sciences, Kyushu University, Motooka 744, Nishi-ku, Fukuoka, 819-0395, Japan; Department of Enviromental Science, International College of Arts and Sciences, Fukuoka Women's University, Kasumigaoka 1-1-1, Higashi-Ku, Fukuoka, 813-8529, Japan.
| | - Yukito Aiba
- Department of Biology, Graduate School of Sciences, Kyushu University, Motooka 744, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Masahiro Yuge
- Department of Enviromental Science, International College of Arts and Sciences, Fukuoka Women's University, Kasumigaoka 1-1-1, Higashi-Ku, Fukuoka, 813-8529, Japan
| | - Nobuaki Furuno
- Amphibian Research Center, Hiroshima University, Kagamiyama 1-3-1, Higashihiroshima, 739-8526, Japan
| | - Minoru Watanabe
- Institute of Liberal Arts and Sciences, Tokushima University, Minamijosanjima-cho 1-1, Tokushima, 770-8502, Japan
| | - Nobushige Nakajo
- Department of Biology, Graduate School of Sciences, Kyushu University, Motooka 744, Nishi-ku, Fukuoka, 819-0395, Japan
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12
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Micalizzi DS, Haber DA, Maheswaran S. Cancer metastasis through the prism of epithelial-to-mesenchymal transition in circulating tumor cells. Mol Oncol 2017; 11:770-780. [PMID: 28544498 PMCID: PMC5496489 DOI: 10.1002/1878-0261.12081] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 05/15/2017] [Accepted: 05/18/2017] [Indexed: 12/23/2022] Open
Abstract
Metastasis of epithelial cancer cells to distant sites is a particularly critical stage of cancer progression that typically marks the incurability of the disease. It is governed by a complex series of events including invasion and intravasation of tumor cells into the stroma and blood, respectively. Epithelial-to-mesenchymal transition (EMT), a phenotypic change marked by the loss of epithelial characteristics and the acquisition of invasive mesenchymal properties, is implicated in the dissemination of tumor cells. Circulating tumor cells (CTCs), the precursors of metastasis, can be used to interrogate the contribution of EMT in metastasis and therapeutic responses. The analysis of these CTCs and in particular the presence of inter- and intrapatient heterogeneity for markers of EMT has provided new insights into the metastatic process. This review will focus on epithelial-mesenchymal plasticity in CTCs and its potential clinical implications.
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Affiliation(s)
- Douglas S. Micalizzi
- Massachusetts General Hospital Cancer CenterHarvard Medical SchoolCharlestownMAUSA
- Department of MedicineHarvard Medical SchoolCharlestownMAUSA
| | - Daniel A. Haber
- Massachusetts General Hospital Cancer CenterHarvard Medical SchoolCharlestownMAUSA
- Department of MedicineHarvard Medical SchoolCharlestownMAUSA
- Howard Hughes Medical InstituteChevy ChaseMDUSA
| | - Shyamala Maheswaran
- Massachusetts General Hospital Cancer CenterHarvard Medical SchoolCharlestownMAUSA
- Department of SurgeryHarvard Medical SchoolCharlestownMAUSA
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13
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Dumollard R, Minc N, Salez G, Aicha SB, Bekkouche F, Hebras C, Besnardeau L, McDougall A. The invariant cleavage pattern displayed by ascidian embryos depends on spindle positioning along the cell's longest axis in the apical plane and relies on asynchronous cell divisions. eLife 2017; 6. [PMID: 28121291 PMCID: PMC5319837 DOI: 10.7554/elife.19290] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 01/24/2017] [Indexed: 12/24/2022] Open
Abstract
The ascidian embryo is an ideal system to investigate how cell position is determined during embryogenesis. Using 3D timelapse imaging and computational methods we analyzed the planar cell divisions in ascidian early embryos and found that spindles in every cell tend to align at metaphase in the long length of the apical surface except in cells undergoing unequal cleavage. Furthermore, the invariant and conserved cleavage pattern of ascidian embryos was found to consist in alternate planar cell divisions between ectoderm and endomesoderm. In order to test the importance of alternate cell divisions we manipulated zygotic transcription induced by β-catenin or downregulated wee1 activity, both of which abolish this cell cycle asynchrony. Crucially, abolishing cell cycle asynchrony consistently disrupted the spindle orienting mechanism underpinning the invariant cleavage pattern. Our results demonstrate how an evolutionary conserved cell cycle asynchrony maintains the invariant cleavage pattern driving morphogenesis of the ascidian blastula. DOI:http://dx.doi.org/10.7554/eLife.19290.001 The position of cells within an embryo early in development determines what type of cells they will become in the fully formed embryo. The embryos of ascidians, commonly known as sea squirts, are ideal for studying what influences cell positioning. These embryos consist of a small number of cells that divide according to an “invariant cleavage pattern”, which means that the positioning and timing of the cell divisions is identical between different individuals of the same species. The pattern of cell division is also largely the same across different ascidian species, which raises questions about how it is controlled. When a cell divides, a structure called the spindle forms inside it to distribute copies of the cell’s genetic material between the new cells. The orientation of the spindle determines the direction in which the cell will divide. Now, by combining 3D imaging of living ascidian embryos with computational modeling, Dumollard et al. show that the spindles in every equally dividing cell tend to all align in the long length of the cell’s “apical” surface. Such alignment allows the cells to be on the outside of the embryo and implements the ascidian invariant cleavage pattern. The cells in the embryo do not all divide at the same time. Indeed, the shape of the cells (and especially their apical surface) depends on two layers of cells in the embryo not dividing at the same time; instead, periods of cell division alternate between the layers. A network of genes in the embryo regulates the timing of these cell divisions and makes it possible for the cells to divide according to an invariant cleavage pattern. However, this network of genes is not the only control mechanism that shapes the early embryo. A structure found in egg cells (and hence produced by the embryo’s mother) causes cells at the rear of the embryo to divide unequally, and this influences the shape of all the cells in the embryo. Thus it appears that maternal mechanisms work alongside the embryo’s gene network to shape the early embryo. The next step will be to determine how physical forces – for example, from the cells pressing against each other – influence the position of the embryo’s cells. How do gene networks relay the biomechanical properties of the embryo to help it take shape? DOI:http://dx.doi.org/10.7554/eLife.19290.002
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Affiliation(s)
- Rémi Dumollard
- Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) UMR7009, Sorbonne Universités, Université Pierre-et-Marie-Curie, CNRS, Villefranche sur mer, France
| | - Nicolas Minc
- Institut Jacques Monod, UMR7592 CNRS, Paris, France
| | - Gregory Salez
- Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) UMR7009, Sorbonne Universités, Université Pierre-et-Marie-Curie, CNRS, Villefranche sur mer, France
| | - Sameh Ben Aicha
- Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) UMR7009, Sorbonne Universités, Université Pierre-et-Marie-Curie, CNRS, Villefranche sur mer, France
| | - Faisal Bekkouche
- Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) UMR7009, Sorbonne Universités, Université Pierre-et-Marie-Curie, CNRS, Villefranche sur mer, France
| | - Céline Hebras
- Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) UMR7009, Sorbonne Universités, Université Pierre-et-Marie-Curie, CNRS, Villefranche sur mer, France
| | - Lydia Besnardeau
- Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) UMR7009, Sorbonne Universités, Université Pierre-et-Marie-Curie, CNRS, Villefranche sur mer, France
| | - Alex McDougall
- Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) UMR7009, Sorbonne Universités, Université Pierre-et-Marie-Curie, CNRS, Villefranche sur mer, France
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Cooperation Between T-Box Factors Regulates the Continuous Segregation of Germ Layers During Vertebrate Embryogenesis. Curr Top Dev Biol 2017; 122:117-159. [DOI: 10.1016/bs.ctdb.2016.07.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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15
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Zhang M, Skirkanich J, Lampson MA, Klein PS. Cell Cycle Remodeling and Zygotic Gene Activation at the Midblastula Transition. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 953:441-487. [DOI: 10.1007/978-3-319-46095-6_9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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16
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Comaills V, Kabeche L, Morris R, Buisson R, Yu M, Madden MW, LiCausi JA, Boukhali M, Tajima K, Pan S, Aceto N, Sil S, Zheng Y, Sundaresan T, Yae T, Jordan NV, Miyamoto DT, Ting DT, Ramaswamy S, Haas W, Zou L, Haber DA, Maheswaran S. Genomic Instability Is Induced by Persistent Proliferation of Cells Undergoing Epithelial-to-Mesenchymal Transition. Cell Rep 2016; 17:2632-2647. [PMID: 27926867 PMCID: PMC5320932 DOI: 10.1016/j.celrep.2016.11.022] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 09/16/2016] [Accepted: 11/03/2016] [Indexed: 12/13/2022] Open
Abstract
TGF-β secreted by tumor stroma induces epithelial-to-mesenchymal transition (EMT) in cancer cells, a reversible phenotype linked to cancer progression and drug resistance. However, exposure to stromal signals may also lead to heritable changes in cancer cells, which are poorly understood. We show that epithelial cells failing to undergo proliferation arrest during TGF-β-induced EMT sustain mitotic abnormalities due to failed cytokinesis, resulting in aneuploidy. This genomic instability is associated with the suppression of multiple nuclear envelope proteins implicated in mitotic regulation and is phenocopied by modulating the expression of LaminB1. While TGF-β-induced mitotic defects in proliferating cells are reversible upon its withdrawal, the acquired genomic abnormalities persist, leading to increased tumorigenic phenotypes. In metastatic breast cancer patients, increased mesenchymal marker expression within single circulating tumor cells is correlated with genomic instability. These observations identify a mechanism whereby microenvironment-derived signals trigger heritable genetic changes within cancer cells, contributing to tumor evolution.
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Affiliation(s)
- Valentine Comaills
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA; Department of Surgery, Harvard Medical School, Charlestown, MA 02129, USA
| | - Lilian Kabeche
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Robert Morris
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Rémi Buisson
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Min Yu
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Marissa Wells Madden
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Joseph A LiCausi
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Myriam Boukhali
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Ken Tajima
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA; Department of Surgery, Harvard Medical School, Charlestown, MA 02129, USA
| | - Shiwei Pan
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Nicola Aceto
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Srinjoy Sil
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Yu Zheng
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Tilak Sundaresan
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA; Department of Medicine, Harvard Medical School, Charlestown, MA 02129, USA
| | - Toshifumi Yae
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA; Department of Surgery, Harvard Medical School, Charlestown, MA 02129, USA
| | - Nicole Vincent Jordan
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - David T Miyamoto
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA; Department of Medicine, Harvard Medical School, Charlestown, MA 02129, USA
| | - David T Ting
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA; Department of Medicine, Harvard Medical School, Charlestown, MA 02129, USA
| | - Sridhar Ramaswamy
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA; Department of Medicine, Harvard Medical School, Charlestown, MA 02129, USA
| | - Wilhelm Haas
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Lee Zou
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA; Department of Pathology, Harvard Medical School, Charlestown, MA 02129, USA
| | - Daniel A Haber
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA; Department of Medicine, Harvard Medical School, Charlestown, MA 02129, USA
| | - Shyamala Maheswaran
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA; Department of Surgery, Harvard Medical School, Charlestown, MA 02129, USA.
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17
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Ogura Y, Sasakura Y. Switching the rate and pattern of cell division for neural tube closure. NEUROGENESIS 2016; 3:e1235938. [PMID: 27928549 PMCID: PMC5120683 DOI: 10.1080/23262133.2016.1235938] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 09/04/2016] [Accepted: 09/07/2016] [Indexed: 01/04/2023]
Abstract
The morphogenetic movement associated with neural tube closure (NTC) requires both positive and negative regulations of cell proliferation. The dual requirement of cell division control during NTC underscores the importance of the developmental control of cell division. In the chordate ascidian, midline fusions of the neural ectoderm and surface ectoderm (SE) proceed in the posterior-to-anterior direction, followed by a single wave of asynchronous and patterned cell division in SE. Before NTC, SE exhibits synchronous mitoses; disruption of the synchrony causes a failure of NTC. Therefore, NTC is the crucial turning point at which SE switches from synchronous to patterned mitosis. Our recent work discovered that the first sign of patterned cell division in SE appears was an asynchronous S-phase length along the anterior-posterior axis before NTC: the asynchrony of S-phase is offset by the compensatory G2-phase length, thus maintaining the apparent synchrony of cell division. By the loss of compensatory G2 phase, the synchronized cell division harmoniously switches to a patterned cell division at the onset of NTC. Here we review the developmental regulation of rate and pattern of cell division during NTC with emphasis on the switching mechanism identified in our study.
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Affiliation(s)
- Yosuke Ogura
- Shimoda Marine Research Center, University of Tsukuba , Shimoda, Shizuoka, Japan
| | - Yasunori Sasakura
- Shimoda Marine Research Center, University of Tsukuba , Shimoda, Shizuoka, Japan
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18
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Vargas A, Del Pino EM. Analysis of Cell Size in the Gastrula of Ten Frog Species Reveals a Correlation of Egg with Cell Sizes, and a Conserved Pattern of Small Cells in the Marginal Zone. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2016; 328:88-96. [DOI: 10.1002/jez.b.22685] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 05/06/2016] [Accepted: 06/10/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Alexandra Vargas
- Escuela de Ciencias Biológicas; Pontificia Universidad Católica del Ecuador; Quito Ecuador
| | - Eugenia M. Del Pino
- Escuela de Ciencias Biológicas; Pontificia Universidad Católica del Ecuador; Quito Ecuador
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19
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Bouldin CM, Kimelman D. Cdc25 and the importance of G2 control: insights from developmental biology. Cell Cycle 2014; 13:2165-71. [PMID: 24914680 DOI: 10.4161/cc.29537] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
While cell proliferation is an essential part of embryonic development, cells within an embryo cannot proliferate freely. Instead, they must balance proliferation and other cellular events such as differentiation and morphogenesis throughout embryonic growth. Although the G1 phase has been a major focus of study in cell cycle control, it is becoming increasingly clear that G2 regulation also plays an essential role during embryonic development. Here we discuss the role of Cdc25, a key regulator of mitotic entry, with a focus on several recent examples that show how the precise control of Cdc25 activity and the G2/M transition are critical for different aspects of embryogenesis. We finish by discussing a promising technology that allows easy visualization of embryonic and adult cells potentially regulated at mitotic entry, permitting the rapid identification of other instances where the exit from G2 plays an essential role in development and tissue homeostasis.
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Affiliation(s)
- Cortney M Bouldin
- Department of Biochemistry; University of Washington; Seattle, WA USA
| | - David Kimelman
- Department of Biochemistry; University of Washington; Seattle, WA USA
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20
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Bouldin CM, Snelson CD, Farr GH, Kimelman D. Restricted expression of cdc25a in the tailbud is essential for formation of the zebrafish posterior body. Genes Dev 2014; 28:384-95. [PMID: 24478331 PMCID: PMC3937516 DOI: 10.1101/gad.233577.113] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The vertebrate body forms from a multipotent stem cell-like progenitor population that contributes newly differentiated cells to the posterior end of the embryo. Here, in vivo analyses show that proliferation is compartmentalized at the posterior end of the zebrafish embryo via regulated expression of mitotic factor Cdc25a. Furthermore, compartmentalization of proliferation during embryogenesis is critical to both body extension and muscle cell fate. This study reveals an unexpected link between precise regulation of the cell cycle and differentiation from multipotency in the vertebrate embryo. The vertebrate body forms from a multipotent stem cell-like progenitor population that progressively contributes newly differentiated cells to the most posterior end of the embryo. How the progenitor population balances proliferation and other cellular functions is unknown due to the difficulty of analyzing cell division in vivo. Here, we show that proliferation is compartmentalized at the posterior end of the embryo during early zebrafish development by the regulated expression of cdc25a, a key controller of mitotic entry. Through the use of a transgenic line that misexpresses cdc25a, we show that this compartmentalization is critical for the formation of the posterior body. Upon misexpression of cdc25a, several essential T-box transcription factors are abnormally expressed, including Spadetail/Tbx16, which specifically prevents the normal onset of myoD transcription, leading to aberrant muscle formation. Our results demonstrate that compartmentalization of proliferation during early embryogenesis is critical for both extension of the vertebrate body and differentiation of the multipotent posterior progenitor cells to the muscle cell fate.
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Affiliation(s)
- Cortney M Bouldin
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA
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21
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Dumollard R, Hebras C, Besnardeau L, McDougall A. Beta-catenin patterns the cell cycle during maternal-to-zygotic transition in urochordate embryos. Dev Biol 2013; 384:331-42. [PMID: 24140189 DOI: 10.1016/j.ydbio.2013.10.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 09/18/2013] [Accepted: 10/03/2013] [Indexed: 11/18/2022]
Abstract
During the transition from maternal to zygotic control of development, cell cycle length varies in different lineages, and this is important for their fates and functions. The maternal to zygotic transition (MZT) in metazoan embryos involves a profound remodeling of the cell cycle: S phase length increases then G2 is introduced. Although β-catenin is the master regulator of endomesoderm patterning at MZT in all metazoans, the influence of maternal β-catenin on the cell cycle at MZT remains poorly understood. By studying urochordate embryogenesis we found that cell cycle remodeling during MZT begins with the formation of 3 mitotic domains at the 16-cell stage arising from differential S phase lengthening, when endomesoderm is specified. Then, at the 64-cell stage, a G2 phase is introduced in the endoderm lineage during its specification. Strikingly, these two phases of cell cycle remodeling are patterned by β-catenin-dependent transcription. Functional analysis revealed that, at the 16-cell stage, β-catenin speeds up S phase in the endomesoderm. In contrast, two cell cycles later at gastrulation, nuclear β-catenin induces endoderm fate and delays cell division. Such interphase lengthening in invaginating cells is known to be a requisite for gastrulation movements. Therefore, in basal chordates β-catenin has a dual role to specify germ layers and remodel the cell cycle.
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Affiliation(s)
- Rémi Dumollard
- UMR 7009, UPMC University, Paris 06, France; Centre National de la Recherche (CNRS), Observatoire Océanologique, 06230 Villefranche-sur-Mer, France.
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22
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Zar1 represses translation in Xenopus oocytes and binds to the TCS in maternal mRNAs with different characteristics than Zar2. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1829:1034-46. [PMID: 23827238 DOI: 10.1016/j.bbagrm.2013.06.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 06/20/2013] [Accepted: 06/24/2013] [Indexed: 12/23/2022]
Abstract
Maternal mRNAs are translationally regulated during early development. Zar1 and its closely related homolog, Zar2, are both crucial in early development. Xenopus laevis Zygote arrest 2 (Zar2) binds to the Translational Control Sequence (TCS) in maternal mRNAs and regulates translation. The molecular mechanism of Zar1 has not been described. Here we report similarities and differences between Xenopus Zar1 and Zar2. Analysis of Zar sequences in vertebrates revealed two Zar family members with conserved, characteristic amino acid differences in the C-terminal domain. The presence of only two vertebrate Zar proteins was supported by analyzing Zar1 synteny. We propose that the criteria for naming Zar sequences are based on the characteristic amino acids and the chromosomal context. We also propose reclassification of some Zar sequences. We found that Zar1 is expressed throughout oogenesis and is stable during oocyte maturation. The N-terminal domain of Zar1 repressed translation of a reporter construct in immature oocytes. Both Zar1 and Zar2 bound to the TCS in the Wee1 and Mos 3' UTRs using a zinc finger in the C-terminal domain. However, Zar1 had much higher affinity for RNA than Zar2. To show the functional significance of the conserved amino acid substitutions, these residues in Zar2 were mutated to those found in Zar1. We show that these residues contributed to the different RNA binding characteristics of Zar1 compared to Zar2. Our study shows that Zar proteins have generally similar molecular functions in the translational regulation of maternal mRNAs, but they may have different roles in early development.
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23
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Rengaraj D, Lee BR, Choi JW, Lee SI, Seo HW, Kim TH, Choi HJ, Song G, Han JY. Gene pathways and cell cycle-related genes in cultured avian primordial germ cells. Poult Sci 2013; 91:3167-77. [PMID: 23155027 DOI: 10.3382/ps.2012-02279] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Primordial germ cells (PGC) from early embryos are applicable to various kinds of research, including the production of transgenic animals. Primordial germ cells eventually migrate and differentiate into germ cells in the gonads, where they settle and rapidly proliferate. However, the proliferation rate of PGC is low in early embryos, and there are many significant pathways that mediate PGC activity. Therefore, in vitro culture of PGC from early embryos with efficient growth factors has been necessary. Recently, we cultured chicken PGC from embryonic d 2.5 with basic fibroblast growth factor and characterized the PGC through analysis of cell morphology, survival, proliferation, and apoptosis. However, large-scale analyses of genes expressed in cultured PGC and the genes involved in associated pathways are limited. The objective of the present investigation was to identify the signaling and metabolic pathways of expressed genes by microarray comparison between PGC and their somatic counterpart, chicken embryonic fibroblasts (CEF). We identified 795 genes that were expressed more predominantly in PGC and 824 genes that were expressed more predominantly in CEF. Among the predominant genes in PGC, 201 were differentially identified in 106 pathways. Among the predominant genes in CEF, 242 were differentially identified in 99 pathways. To further validate the genes involved in at least one candidate pathway, those involved in the cell cycle (12 predominant genes in PGC and 8 predominant genes in CEF) were examined by real-time PCR. To the best of our knowledge, this study is the first to investigate signaling and metabolic pathways in cultured PGC.
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Affiliation(s)
- D Rengaraj
- Department of Agricultural Biotechnology and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea
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24
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Calder A, Roth-Albin I, Bhatia S, Pilquil C, Lee JH, Bhatia M, Levadoux-Martin M, McNicol J, Russell J, Collins T, Draper JS. Lengthened G1 phase indicates differentiation status in human embryonic stem cells. Stem Cells Dev 2012; 22:279-95. [PMID: 22827698 DOI: 10.1089/scd.2012.0168] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The cell cycle in pluripotent stem cells is notable for the brevity of the G1 phase, permitting rapid proliferation and reducing the duration of differentiation signal sensitivity associated with the G1 phase. Changes in the length of G1 phase are understood to accompany the differentiation of human embryonic stem cells (hESCs), but the timing and extent of such changes are poorly defined. Understanding the early steps governing the differentiation of hESCs will facilitate better control over differentiation for regenerative medicine and drug discovery applications. Here we report the first use of real-time cell cycle reporters in hESCs. We coexpressed the chromatin-decorating H2B-GFP fusion protein and the fluorescence ubiquitination cell cycle indicator (FUCCI)-G1 fusion protein, a G1 phase-specific reporter, in hESCs to measure the cell cycle status in live cells. We found that FUCCI-G1 expression is weakly detected in undifferentiated hESCs, but rapidly increases upon differentiation. hESCs in the G1 phase display a reduction in undifferentiated colony-initiating cell function, underscoring the relationship between G1 phase residence and differentiation. Importantly, we demonstrate inter- and intracolony variation in response to chemicals that induce differentiation, implying extensive cell-cell variation in the threshold necessary to alter the G1 phase length. Finally, gain of differentiation markers appears to be coincident with G1 phase lengthening, with distinct G1 phase profiles associated with different markers of early hESC differentiation. Our data demonstrate the tight coupling of cell cycle changes to hESC differentiation, and highlight the cell cycle reporter system and assays we have implemented as a novel avenue for investigating pluripotency and differentiation.
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Affiliation(s)
- Ashley Calder
- McMaster Stem Cell and Cancer Research Institute, Michael G. DeGroote School of Medicine, McMaster University , Hamilton, Ontario, Canada
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25
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Dobens LL, Bouyain S. Developmental roles of tribbles protein family members. Dev Dyn 2012; 241:1239-48. [PMID: 22711497 DOI: 10.1002/dvdy.23822] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/11/2012] [Indexed: 12/15/2022] Open
Abstract
The gene tribbles (trbl), identified 12 years ago in genetic screens for mutations that control both cell division and cell migration during embryonic Drosophila development, is the founding member of the Tribbles (Trib) family of kinase-like proteins that have diverse roles in cell signaling, tissue homeostasis, and cancer. Trib proteins share three motifs: (1) a divergent kinase region (Trib domain) with undetermined catalytic activity, (2) a COP1 site used to direct key target proteins to the proteosome for degradation, and (3) a MEK1 site that binds and modulates MAPKK kinase activity. The notion that Tribs act as scaffolding proteins to balance signaling levels in multiple pathways retains an attractive simplicity, but given recent data showing that divergent kinases act by means of novel catalytic mechanisms, the enzymatic activity of Tribs remains untested. Here, we focus on the role of Tribs during development. Developmental analysis of Drosophila trbl phenotypes reveals tissue-specific, sometimes contradictory roles. In mammals, multiple Trib isoforms exhibit overlapping and tissue-specific functions. Recent data indicate the mechanism of Trib activity is conserved and requires the Trib domain. Finally, we discuss the connections between Tribs in disease and cancer that have implications for their normal roles during organogenesis.
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Affiliation(s)
- Leonard L Dobens
- Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, Missouri, USA.
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26
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Xenopus laevis zygote arrest 2 (zar2) encodes a zinc finger RNA-binding protein that binds to the translational control sequence in the maternal Wee1 mRNA and regulates translation. Dev Biol 2012; 369:177-90. [PMID: 22732570 DOI: 10.1016/j.ydbio.2012.06.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 06/12/2012] [Accepted: 06/17/2012] [Indexed: 11/22/2022]
Abstract
Zygote arrest (Zar) proteins are crucial for early embryonic development, but their molecular mechanism of action is unknown. The Translational Control Sequence (TCS) in the 3' untranslated region (UTR) of the maternal mRNA, Wee1, mediates translational repression in immature Xenopus oocytes and translational activation in mature oocytes, but the protein that binds to the TCS and mediates translational control is not known. Here we show that Xenopus laevis Zar2 (encoded by zar2) binds to the TCS in maternal Wee1 mRNA and represses translation in immature oocytes. Using yeast 3 hybrid assays and electrophoretic mobility shift assays, Zar2 was shown to bind specifically to the TCS in the Wee1 3'UTR. RNA binding required the presence of Zn(2+) and conserved cysteines in the C-terminal domain, suggesting that Zar2 contains a zinc finger. Consistent with regulating maternal mRNAs, Zar2 was present throughout oogenesis, and endogenous Zar2 co-immunoprecipitated endogenous Wee1 mRNA from immature oocytes, demonstrating the physiological significance of the protein-RNA interaction. Interestingly, Zar2 levels decreased during oocyte maturation. Dual luciferase reporter tethered assays showed that Zar2 repressed translation in immature oocytes. Translational repression was relieved during oocyte maturation and this coincided with degradation of Zar2 during maturation. This is the first report of a molecular function of zygote arrest proteins. These data show that Zar2 contains a zinc finger and is a trans-acting factor for the TCS in maternal mRNAs in immature Xenopus oocytes.
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Ogura Y, Sakaue-Sawano A, Nakagawa M, Satoh N, Miyawaki A, Sasakura Y. Coordination of mitosis and morphogenesis: role of a prolonged G2 phase during chordate neurulation. Development 2011; 138:577-87. [DOI: 10.1242/dev.053132] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Chordates undergo a characteristic morphogenetic process during neurulation to form a dorsal hollow neural tube. Neurulation begins with the formation of the neural plate and ends when the left epidermis and right epidermis overlying the neural tube fuse to close the neural fold. During these processes, mitosis and the various morphogenetic movements need to be coordinated. In this study, we investigated the epidermal cell cycle in Ciona intestinalis embryos in vivo using a fluorescent ubiquitination-based cell cycle indicator (Fucci). Epidermal cells of Ciona undergo 11 divisions as the embryos progress from fertilization to the tadpole larval stage. We detected a long G2 phase between the tenth and eleventh cell divisions, during which fusion of the left and right epidermis occurred. Characteristic cell shape change and actin filament regulation were observed during the G2 phase. CDC25 is probably a key regulator of the cell cycle progression of epidermal cells. Artificially shortening this G2 phase by overexpressing CDC25 caused precocious cell division before or during neural tube closure, thereby disrupting the characteristic morphogenetic movement. Delaying the precocious cell division by prolonging the S phase with aphidicolin ameliorated the effects of CDC25. These results suggest that the long interphase during the eleventh epidermal cell cycle is required for neurulation.
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Affiliation(s)
- Yosuke Ogura
- Shimoda Marine Research Center, University of Tsukuba, Shimoda, Shizuoka 415-0025, Japan
| | - Asako Sakaue-Sawano
- Laboratory for Cell Function and Dynamics, Advanced Technology Development Group, Brain Science Institute, RIKEN, 2-1 Hirosawa, Wako-city, Saitama 351-0198, Japan
- Life Function and Dynamics, ERATO, JST, 2-1 Hirosawa, Wako-city, Saitama 351-0198, Japan
| | - Masashi Nakagawa
- Department of Life Science, Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Ako-gun, Hyogo 678-1297, Japan
| | - Nori Satoh
- Marine Genomics Unit, Okinawa Institute of Science and Technology Promotion Corporation, Uruma, Okinawa 904-2234, Japan
| | - Atsushi Miyawaki
- Laboratory for Cell Function and Dynamics, Advanced Technology Development Group, Brain Science Institute, RIKEN, 2-1 Hirosawa, Wako-city, Saitama 351-0198, Japan
- Life Function and Dynamics, ERATO, JST, 2-1 Hirosawa, Wako-city, Saitama 351-0198, Japan
| | - Yasunori Sasakura
- Shimoda Marine Research Center, University of Tsukuba, Shimoda, Shizuoka 415-0025, Japan
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Owens L, Simanski S, Squire C, Smith A, Cartzendafner J, Cavett V, Caldwell Busby J, Sato T, Ayad NG. Activation domain-dependent degradation of somatic Wee1 kinase. J Biol Chem 2009; 285:6761-9. [PMID: 20038582 DOI: 10.1074/jbc.m109.093237] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cell cycle progression is dependent upon coordinate regulation of kinase and proteolytic pathways. Inhibitors of cell cycle transitions are degraded to allow progression into the subsequent cell cycle phase. For example, the tyrosine kinase and Cdk1 inhibitor Wee1 is degraded during G(2) and mitosis to allow mitotic progression. Previous studies suggested that the N terminus of Wee1 directs Wee1 destruction. Using a chemical mutagenesis strategy, we report that multiple regions of Wee1 control its destruction. Most notably, we find that the activation domain of the Wee1 kinase is also required for its degradation. Mutations in this domain inhibit Wee1 degradation in somatic cell extracts and in cells without affecting the overall Wee1 structure or kinase activity. More broadly, these findings suggest that kinase activation domains may be previously unappreciated sites of recognition by the ubiquitin proteasome pathway.
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Affiliation(s)
- Laura Owens
- Department of Cancer Biology, Scripps Research Institute, Scripps Florida, Jupiter, Florida 33458, USA
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29
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Tyrosines in the kinesin-5 head domain are necessary for phosphorylation by Wee1 and for mitotic spindle integrity. Curr Biol 2009; 19:1670-6. [PMID: 19800237 DOI: 10.1016/j.cub.2009.08.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Revised: 08/05/2009] [Accepted: 08/07/2009] [Indexed: 11/23/2022]
Abstract
Mitotic spindle assembly and maintenance relies on kinesin-5 motors that act as bipolar homotetramers to crosslink microtubules. Kinesin-5 motors have been the subject of extensive structure-function analysis, but the regulation of their activity in the context of mitotic progression remains less well understood. We report here that Drosophila kinesin-5 (KLP61F) is regulated by Drosophila Wee1 (dWee1). Wee1 tyrosine kinases are known to regulate mitotic entry via inhibitory phosphorylation of Cdk1. Recently, we showed that dWee1 also plays a role in mitotic spindle positioning through gamma-tubulin and spindle fidelity through an unknown mechanism. Here, we investigated whether a KLP61F-dWee1 interaction could explain the latter role of dWee1. We found that dWee1 phosphorylates KLP61F in vitro on three tyrosines within the head domain, the catalytic region that mediates movement along microtubules. In vivo, KLP61F with tyrosine-->phenylalanine mutations fails to complement a klp61f mutant and dominantly induces spindle defects similar to ones seen in dwee1 mutants. We propose that phosphorylation of the KLP61F catalytic domain by dWee1 is important for the motor's function. This study identifies a second substrate for a Wee1 kinase and provides evidence for phosphoregulation of a kinesin in the head domain.
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Drosophila myt1 is the major cdk1 inhibitory kinase for wing imaginal disc development. Genetics 2008; 180:2123-33. [PMID: 18940789 DOI: 10.1534/genetics.108.093195] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Mitosis is triggered by activation of Cdk1, a cyclin-dependent kinase. Conserved checkpoint mechanisms normally inhibit Cdk1 by inhibitory phosphorylation during interphase, ensuring that DNA replication and repair is completed before cells begin mitosis. In metazoans, this regulatory mechanism is also used to coordinate cell division with critical developmental processes, such as cell invagination. Two types of Cdk1 inhibitory kinases have been found in metazoans. They differ in subcellular localization and Cdk1 target-site specificity: one (Wee1) being nuclear and the other (Myt1), membrane-associated and cytoplasmic. Drosophila has one representative of each: dMyt1 and dWee1. Although dWee1 and dMyt1 are not essential for zygotic viability, loss of both resulted in synthetic lethality, indicating that they are partially functionally redundant. Bristle defects in myt1 mutant adult flies prompted a phenotypic analysis that revealed cell-cycle defects, ectopic apoptosis, and abnormal responses to ionizing radiation in the myt1 mutant imaginal wing discs that give rise to these mechanosensory organs. Cdk1 inhibitory phosphorylation was also aberrant in these myt1 mutant imaginal wing discs, indicating that dMyt1 serves Cdk1 regulatory functions that are important both for normal cell-cycle progression and for coordinating mitosis with critical developmental processes.
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31
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Yao S, Xie L, Qian M, Yang H, Zhou L, Zhou Q, Yan F, Gou L, Wei Y, Zhao X, Mo X. Pnas4 is a novel regulator for convergence and extension during vertebrate gastrulation. FEBS Lett 2008; 582:2325-32. [PMID: 18538138 DOI: 10.1016/j.febslet.2008.05.036] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 05/25/2008] [Accepted: 05/26/2008] [Indexed: 02/05/2023]
Abstract
Recent studies show that human Pnas4 might be tumor associated, while its function remains unknown. Here, we investigate the developmental function of Pnas4 using zebrafish as a model system. Knocking down Pnas4 causes gastrulation defects with a shorter and broader axis, as well as a posteriorly mis-positioned prechordal plate, due to the defective convergence and extension movement. Conversely, over-expression of Pnas4 mRNA leads to an elongated body axis. We further demonstrate that Pnas4 is required cell-autonomously for dorsal convergence but not for anterior migration. In addition, genetic interaction assays indicate that Pnas4 might act in parallel with non-canonical Wnt signal in the regulation of cell movement. Our data suggest that Pnas4 is a key regulator of cell movement during gastrulation.
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Affiliation(s)
- Shaohua Yao
- State Key Laboratory of Biotherapy, West China Hospital and Life Science College, Sichuan University, Chengdu, China
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32
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Budirahardja Y, Gönczy P. PLK-1 asymmetry contributes to asynchronous cell division of C. elegans embryos. Development 2008; 135:1303-13. [PMID: 18305005 DOI: 10.1242/dev.019075] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Acquisition of lineage-specific cell cycle duration is an important feature of metazoan development. In Caenorhabditis elegans, differences in cell cycle duration are already apparent in two-cell stage embryos, when the larger anterior blastomere AB divides before the smaller posterior blastomere P1. This time difference is under the control of anterior-posterior (A-P) polarity cues set by the PAR proteins. The mechanisms by which these cues regulate the cell cycle machinery differentially in AB and P1 are incompletely understood. Previous work established that retardation of P1 cell division is due in part to preferential activation of an ATL-1/CHK-1 dependent checkpoint in P1, but how the remaining time difference is controlled is not known. Here, we establish that differential timing relies also on a mechanism that promotes mitosis onset preferentially in AB. The polo-like kinase PLK-1, a positive regulator of mitotic entry, is distributed in an asymmetric manner in two-cell stage embryos, with more protein present in AB than in P1. We find that PLK-1 asymmetry is regulated by A-P polarity cues through preferential protein retention in the embryo anterior. Importantly, mild inactivation of plk-1 by RNAi delays entry into mitosis in P1, but not in AB, in a manner that is independent of ATL-1/CHK-1. Together, our findings support a model in which differential timing of mitotic entry in C. elegans embryos relies on two complementary mechanisms: ATL-1/CHK-1-dependent preferential retardation in P1 and PLK-1-dependent preferential promotion in AB, which together couple polarity cues and cell cycle progression during early development.
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Affiliation(s)
- Yemima Budirahardja
- Swiss Institute for Experimental Cancer Research (ISREC Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland
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Nogare DED, Arguello A, Sazer S, Lane ME. Zebrafish cdc25a is expressed during early development and limiting for post-blastoderm cell cycle progression. Dev Dyn 2008; 236:3427-35. [PMID: 17969147 DOI: 10.1002/dvdy.21363] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Cdc25 phosphatases are required for eukaryotic cell cycle progression. To investigate mechanisms governing spatiotemporal dynamics of cell cycle progression during vertebrate development, we isolated two cdc25 genes from the zebrafish, Danio rerio, cdc25a, and cdc25d. We propose that Zebrafish cdc25a is the zebrafish orthologue of the tetrapod Cdc25A genes, while cdc25d is of indeterminate origin. We show that both genes have proliferation promoting activity, but that only cdc25d can complement a Schizosaccharomyces pombe loss of function cdc25 mutation. We present expression data demonstrating that cdc25d expression is very limited during early development, while cdc25a is widely expressed and consistent with the mitotic activity in previously identified mitotic domains of the post-blastoderm zebrafish embryo. Finally, we show that cdc25a can accelerate the entry of post-blastoderm cells into mitosis, suggesting that levels of cdc25a are rate limiting for cell cycle progression during gastrulation.
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Affiliation(s)
- Damian E Dalle Nogare
- Department of Biochemistry and Cell Biology, Rice University, Houston, Texas 77005, USA
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34
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Discovering implicit protein-protein interactions in the cell cycle using bioinformatics approaches. J Biomed Sci 2008; 15:317-31. [PMID: 18204916 DOI: 10.1007/s11373-007-9231-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2007] [Accepted: 12/27/2007] [Indexed: 10/22/2022] Open
Abstract
The cell division control protein (Cdc2) kinase is a catalytic subunit of a protein kinase complex, called the M phase promoting factor, which induces entry into mitosis and is universal among eukaryotes. This protein is believed to play a major role in cell division and control. The lives of biological cells are controlled by proteins interacting in metabolic and signaling pathways, in complexes that replicate genes and regulate gene activity, and in the assembly of the cytoskeletal infrastructure. Our knowledge of protein-protein (P-P) interactions has been accumulated from biochemical and genetic experiments, including the widely used yeast two-hybrid test. In this paper we examine if P-P interactions in regenerating tissues and cells of the anuran Xenopus laevis can be discovered from biomedical literature using computational and literature mining techniques. Using literature mining techniques, we have identified a set of implicitly interacting proteins in regenerating tissues and cells of Xenopus laevis that may interact with Cdc2 to control cell division. Genome sequence based bioinformatics tools were then applied to validate a set of proteins that appear to interact with the Cdc2 protein. Pathway analysis of these proteins suggests that Myc proteins function as the regulator of M phase initiation by controlling expression of the Akt1 molecule that ultimately inhibits the Cdc2-cyclin B complex in cells. P-P interactions that are implicitly appearing in literature can be effectively discovered using literature mining techniques. By applying evolutionary principles on the P-P interacting pairs, it is possible to quantitatively analyze the significance of the associations with biological relevance. The developed BioMap system allows discovering implicit P-P interactions from large quantity of biomedical literature data. The unique similarities and differences observed within the interacting proteins can lead to the development of the new hypotheses that can be used to design further laboratory experiments.
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35
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Hashiguchi A, Hitachi K, Inui M, Okabayashi K, Asashima M. TSC-box is essential for the nuclear localization and antiproliferative effect of XTSC-22. Dev Growth Differ 2007; 49:197-204. [PMID: 17394598 DOI: 10.1111/j.1440-169x.2007.00908.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Transforming growth factor-beta1-stimulated clone 22 (TSC-22) encodes a leucine zipper-containing protein that is highly conserved among various species. Mammalian TSC-22 is a potential tumor suppressor gene. It translocates into nuclei and suppresses cell division upon antiproliferative stimuli. In human colon carcinoma cells, TSC-22 inhibits cell growth by upregulating expression of the p21 gene, a cyclin-dependent kinase (Cdk) inhibitor. We previously showed that the Xenopus laevis homologue of the TSC-22 gene (XTSC-22) is required for cell movement during gastrulation through cell cycle regulation. In this report, we investigated the molecular mechanism of the antiproliferative effect of XTSC-22. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis suggested that XTSC-22 did not affect the expression levels of the p21 family of Cdk inhibitors or other cell cycle regulators. Analysis of deletion mutants of XTSC-22 revealed that nuclear localization of the N-terminal TSC-box is necessary for cell cycle inhibition by XTSC-22. Further experiments suggested that p27Xic1, a key Cdk inhibitor in Xenopus, interacts with XTSC-22. Because p27Xic1 is a cell cycle inhibitor with a nuclear localization signal, it is possible that XTSC-22 suppresses cell division by translocating into the nucleus with p27Xic1, where it may potentiate the intranuclear action of p27Xic1.
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Affiliation(s)
- Akiko Hashiguchi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan
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36
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Traverso EE, Cho MS, Wu CF, Sater AK, Larabell CA, Kloc M, Etkin LD. Disruption of the dynamic sub-cellular localization of the Xenopus tumorhead protein causes embryonic lethality at the early gastrula transition. Differentiation 2007; 75:947-56. [PMID: 17459085 DOI: 10.1111/j.1432-0436.2007.00179.x] [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] [Indexed: 11/30/2022]
Abstract
The Xenopus laevis tumorhead (TH) protein, a positive regulator of cell proliferation during embryogenesis, shuttles from the cell periphery into the nucleus during embryogenesis. In these studies, we performed a detailed analysis of TH's subcellular localization pattern to characterize its dynamic behavior. We found that TH exhibits distinct patterns of localization in different germ layers. At the blastula stage, TH is present in the apical cell periphery of prospective mesodermal and ectodermal cells. At the gastrula stage, TH is distributed throughout the entire cytoplasm of prospective mesodermal and ectodermal cells, whereas it shows nuclear localization in presumptive endodermal cells. TH moves into the nucleus of mesodermal and ectodermal cells during the neurula and early tailbud stages. To understand if TH is regulated by changes in its subcellular localization, we used a TH mutant containing signals for farnesylation and palmitoylation to tether the protein to the plasma membrane. Ubiquitous overexpression of this mutant causes embryonic lethality at the early gastrula transition. Further examination using TUNEL assays indicated that wild-type TH overexpression induces apoptosis during gastrulation, and that this effect is exacerbated by the overexpression of the membrane-bound TH mutant. Taken together, our results suggest that changes in the sub-cellular localization of the TH protein are important for its function because blocking the nuclear translocation of overexpressed TH increases apoptosis and causes embryos to die. Our data also suggest that TH plays a role outside the nucleus when it is present at the cell periphery.
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Affiliation(s)
- Edwin E Traverso
- Department of Molecular Genetics, The University of Texas, M. D. Anderson Cancer Center, Houston, TX 77030, USA
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37
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Ramis JM, Collart C, Smith JC. Xnrs and activin regulate distinct genes during Xenopus development: activin regulates cell division. PLoS One 2007; 2:e213. [PMID: 17299593 PMCID: PMC1790703 DOI: 10.1371/journal.pone.0000213] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Accepted: 01/19/2007] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The mesoderm of the amphibian embryo is formed through an inductive interaction in which vegetal cells of the blastula-staged embryo act on overlying equatorial cells. Candidate mesoderm-inducing factors include members of the transforming growth factor type beta family such as Vg1, activin B, the nodal-related proteins and derrière. METHODOLOGY AND PRINCIPLE FINDINGS Microarray analysis reveals different functions for activin B and the nodal-related proteins during early Xenopus development. Inhibition of nodal-related protein function causes the down-regulation of regionally expressed genes such as chordin, dickkopf and XSox17alpha/beta, while genes that are mis-regulated in the absence of activin B tend to be more widely expressed and, interestingly, include several that are involved in cell cycle regulation. Consistent with the latter observation, cells of the involuting dorsal axial mesoderm, which normally undergo cell cycle arrest, continue to proliferate when the function of activin B is inhibited. CONCLUSIONS/SIGNIFICANCE These observations reveal distinct functions for these two classes of the TGF-beta family during early Xenopus development, and in doing so identify a new role for activin B during gastrulation.
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Affiliation(s)
- Joana M. Ramis
- Wellcome Trust/Cancer Research UK Gurdon Institute and Department of Zoology, University of Cambridge, Cambridge, United Kindgom
| | - Clara Collart
- Wellcome Trust/Cancer Research UK Gurdon Institute and Department of Zoology, University of Cambridge, Cambridge, United Kindgom
| | - James C. Smith
- Wellcome Trust/Cancer Research UK Gurdon Institute and Department of Zoology, University of Cambridge, Cambridge, United Kindgom
- * To whom correspondence should be addressed. E-mail:
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Arai S, Miyake K, Voit R, Nemoto S, Wakeland EK, Grummt I, Miyazaki T. Death-effector domain-containing protein DEDD is an inhibitor of mitotic Cdk1/cyclin B1. Proc Natl Acad Sci U S A 2007; 104:2289-94. [PMID: 17283331 PMCID: PMC1793902 DOI: 10.1073/pnas.0611167104] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Accumulating evidence has shown that many molecules, including some cyclin-dependent kinases (Cdks) and cyclins, as well as the death-effector domain (DED)-containing FADD, function for both apoptosis and cell cycle. Here we identified that DEDD, which also possesses the DED domain, acts as a novel inhibitor of the mitotic Cdk1/cyclin B1 complex. DEDD associates with mitotic Cdk1/cyclin B1 complexes via direct binding to cyclin B1 and reduces their function. In agreement, kinase activity of nuclear Cdk1/cyclin B1 in DEDD-null (DEDD-/-) embryonic fibroblasts is increased compared with that in DEDD+/+ cells, which results in accelerated mitotic progression, thus exhibiting a shortened G2/M stage. Interestingly, DEDD-/- cells also demonstrated decreased G1 duration, which perhaps enhanced the overall reduction in rRNA amounts and cell volume, primarily caused by the rapid termination of rRNA synthesis before cell division. Likewise, DEDD-/- mice show decreased body and organ weights relative to DEDD+/+ mice. Thus, DEDD is an impeder of cell mitosis, and its absence critically influences cell and body size via modulation of rRNA synthesis.
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Affiliation(s)
- Satoko Arai
- *Division of Molecular Biomedicine for Pathogenesis, Center for Disease Biology and Integrative Medicine, Faculty of Medicine, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Center for Immunology, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, NA7200, Dallas, TX 75390-9093; and
| | - Katsuhisa Miyake
- Center for Immunology, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, NA7200, Dallas, TX 75390-9093; and
| | - Renate Voit
- Department of Molecular Biology of the Cell II, German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany
| | - Shino Nemoto
- *Division of Molecular Biomedicine for Pathogenesis, Center for Disease Biology and Integrative Medicine, Faculty of Medicine, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Edward K. Wakeland
- Center for Immunology, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, NA7200, Dallas, TX 75390-9093; and
| | - Ingrid Grummt
- Department of Molecular Biology of the Cell II, German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany
| | - Toru Miyazaki
- *Division of Molecular Biomedicine for Pathogenesis, Center for Disease Biology and Integrative Medicine, Faculty of Medicine, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Center for Immunology, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, NA7200, Dallas, TX 75390-9093; and
- To whom correspondence should be addressed. E-mail:
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Sugimoto K, Okabayashi K, Sedohara A, Hayata T, Asashima M. The role of XBtg2 in Xenopus neural development. Dev Neurosci 2006; 29:468-79. [PMID: 17119321 DOI: 10.1159/000097320] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2006] [Accepted: 08/17/2006] [Indexed: 11/19/2022] Open
Abstract
In early neural development, active cell proliferation and apoptosis take place concurrent with cell differentiation, but how these processes are coordinated remains unclear. In this study, we characterized the role of XBtg2 in Xenopus neural development. XBtg2 transcripts were detected at the edge of the anterolateral neural plate and the neural crest region at the midneurula stage, and in eyes and in part of the neural tube at the tailbud stage. Translational inhibition of XBtg2 affected anterior neural development and impaired eye formation. XBtg2 depletion altered the expression patterns of the early neural genes, Zic3 and SoxD, at the midneurula stage, but not at the early neurula stage. At the midneurula stage, XBtg2-depleted embryos exhibited a marked decrease in the expression of anterior neural genes, En2, Otx2, and Rx1, without any changes in neural crest genes, Slug and Snail, or an epidermal gene, XK81. These results suggest that XBtg2 is required for the differentiation of the anterior neural plate from the midneurula stage, but not for the specification of the fate and patterning of the neural plate. XBtg2-depleted embryos also exhibited an increase in both proliferation and apoptosis in the anterior neural plate; however, the altered expression patterns of neural markers were not reversed by inhibition of either the cell cycle or apoptosis. Based on these data, we propose that XBtg2 plays an essential role in the anterior neural development, by regulating neural cell differentiation, and, independently, cell proliferation and survival.
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Affiliation(s)
- Kaoru Sugimoto
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
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40
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Ueno S, Kono R, Iwao Y. PTEN is required for the normal progression of gastrulation by repressing cell proliferation after MBT in Xenopus embryos. Dev Biol 2006; 297:274-83. [PMID: 16919259 DOI: 10.1016/j.ydbio.2006.06.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2006] [Revised: 05/30/2006] [Accepted: 06/01/2006] [Indexed: 11/16/2022]
Abstract
PTEN phosphatase mediates several developmental cues involving cell proliferation, growth, death, and migration. We investigated the function of the PTEN gene at the transition from the cell proliferation state to morphogenesis around the midblastula transition (MBT) and gastrulation in Xenopus embryos. An immunoblotting analysis indicated that PTEN expresses constantly through embryogenesis. By up- or down-regulating PTEN activity using overexpression of the active form or C terminus of PTEN before MBT, we induced elongation of the cell cycle time just before MBT or maintained its speed even after MBT, respectively. The disruption of the cell cycle time by changing the activity of PTEN delayed gastrulation after MBT. In addition, PTEN began to localize to the plasma membranes and nuclei at MBT. Overexpression of a membrane-localizing mutant of PTEN caused dephosphorylation of Akt, whereas overexpression of the C terminus of PTEN caused phosphorylation of Akt and inhibited the localization of EGFP-PTEN to the plasma membranes and nuclei. These results indicate that an appropriate PTEN activity, probably regulated by its differential localization, is necessary for coordinating cell proliferation and early morphogenesis.
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Affiliation(s)
- Shuichi Ueno
- Department of Biological Science, Faculty of Science, Yamaguchi University, 753-8512 Yamaguchi, Japan.
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41
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Abstract
Developmental biology teachers use the example of the frog embryo to introduce young scientists to the wonders of vertebrate development, and to pose the crucial question, 'How does a ball of cells become an exquisitely patterned embryo?'. Classical embryologists also recognized the power of the amphibian model and used extirpation and explant studies to explore early embryo polarity and to define signaling centers in blastula and gastrula stage embryos. This review revisits these early stages of Xenopus development and summarizes the recent explosion of information on the intrinsic and extrinsic factors that are responsible for the first phases of embryonic patterning.
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Affiliation(s)
- Janet Heasman
- Division of Developmental Biology, Cincinnati Children's Hospital Research Foundation, 3333 Burnet Avenue, OH 45229-3039, USA.
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42
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Chesnel F, Vignaux F, Richard-Parpaillon L, Huguet A, Kubiak JZ. Differences in regulation of the first two M-phases in Xenopus laevis embryo cell-free extracts. Dev Biol 2006; 285:358-75. [PMID: 16087172 DOI: 10.1016/j.ydbio.2005.06.028] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2004] [Revised: 06/21/2005] [Accepted: 06/23/2005] [Indexed: 11/28/2022]
Abstract
The first embryonic M-phase is special, being the time when paternal and maternal chromosomes mix together for the first time. Reports from a variety of species suggest that the regulation of first M-phase has many particularities; however, no systematic comparative study of the biochemical aspects of first and the following M-phases has been previously undertaken. Here, we ask whether the regulation of the first embryonic M-phase is modified, using Xenopus cell-free extracts. We developed new types of extract specific for the first and the second M-phase obtained either from parthenogenetic or from in vitro fertilized embryos. Analyses of these extracts confirmed that the amplitude of histone H1 kinase activity reflecting CDK1/cyclin B (or MPF for M-phase Promoting Factor) activity is higher and persists longer than during the second M-phase, and that levels of cyclins B1 and B2 are correspondingly higher during the first than the second embryonic M-phase. Inhibition of protein synthesis shortly before M-phase entry reduced mitotic histone H1 kinase amplitude, shortened the period of mitotic phosphorylation of chosen marker proteins, and reduced cyclin B1 and B2 levels, suggesting a role of B-type cyclins in regulating the duration of mitotic events. Moreover, addition of exogenous cyclin B to the extract prior the second mitosis brought forward the activation of mitotic histone H1 kinase but prolonged the duration of this activity. We also confirmed that the inhibitory phosphorylation of CDK1 on tyrosine 15 oscillates between the first two embryonic M-phases, but is clearly more pronounced before the first than the second mitosis, while the MAP kinase ERK2 tended to show greater activation during the first embryonic M-phase but with a similar duration of activation. We conclude that discrete differences exist between the first two M-phases in Xenopus embryo and that higher CDK1/cyclin B activity and B-type cyclin levels could account for the different characteristics of these M-phases.
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Affiliation(s)
- Franck Chesnel
- UMR 6061 CNRS, Biology and Genetics of Development, Mitosis and Meiosis Group, IFR140 GFAS, University of Rennes 1, Faculty of Medicine, 2 Ave. Prof. Léon Bernard, CS 34317, 35043 Rennes cedex, France
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43
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Abstract
ErbB signaling has long been implicated in cancer formation and progression and is shown to regulate cell division, migration, and death during tumorigenesis. The functions of the ErbB pathway during early vertebrate embryogenesis, however, are not well understood. Here we report characterization of ErbB activities during early frog development. Gain-of-function analyses show that EGFR, ErbB2, and ErbB4 induce ectopic tumor-like cell mass that contains increased numbers of mitotic cells. Both the muscle and the neural markers are expressed in these ectopic protrusions. ErbBs also induce mesodermal markers in ectodermal explants. Loss-of-function studies using carboxyl terminal-truncated dominant-negative ErbB receptors demonstrate that blocking ErbB signals leads to defective gastrulation movements and malformation of the embryonic axis with a reduction in the head structures in early frog embryos. These data, together with the observation that ErbBs are expressed early during frog embryogenesis, suggest that ErbBs regulate cell proliferation, movements, and embryonic patterning during early Xenopus development.
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MESH Headings
- Amino Acid Sequence
- Animals
- Biomarkers
- Cell Proliferation
- Embryo, Nonmammalian/abnormalities
- Embryo, Nonmammalian/cytology
- Embryo, Nonmammalian/embryology
- Embryo, Nonmammalian/metabolism
- ErbB Receptors/chemistry
- ErbB Receptors/genetics
- ErbB Receptors/metabolism
- Gene Expression Regulation, Developmental/genetics
- Head/abnormalities
- Head/embryology
- Humans
- Molecular Sequence Data
- Phylogeny
- Receptor, ErbB-2/chemistry
- Receptor, ErbB-2/genetics
- Receptor, ErbB-2/metabolism
- Receptor, ErbB-3/chemistry
- Receptor, ErbB-3/genetics
- Receptor, ErbB-3/metabolism
- Receptor, ErbB-4
- Sequence Alignment
- Sequence Homology, Amino Acid
- Signal Transduction
- Time Factors
- Xenopus laevis/abnormalities
- Xenopus laevis/embryology
- Xenopus laevis/metabolism
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Affiliation(s)
| | - Chenbei Chang
- Corresponding author. ; Phone: 205-975-7229; Fax: 205-975-5648
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44
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Abstract
The Cdk1 inhibitor Wee1 is inactivated during mitotic entry by proteolysis, translational regulation, and transcriptional regulation. Wee1 is also regulated by posttranslational modifications, and here we have identified five phosphorylation sites in the N-terminal domain of embryonic Xenopus Wee1A through a combination of mutagenesis studies and matrix-assisted laser desorption ionization-time of flight mass spectrometry. All five sites conform to the Ser-Pro/Thr-Pro consensus for proline-directed kinases like Cdks. Three of the sites (Ser 38, Thr 53, and Ser 62) are required for the mitotic gel shift, and at least two of these sites (Ser 38 and Thr 53) regulate the proteolysis of Wee1A during interphase. The other two sites (Thr 104 and Thr 150) are primarily responsible for the mitotic inactivation of Wee1A. Alanine mutants of Thr 150 or Thr 104 had an increased capacity to inhibit mitotic entry in cyclin B-treated interphase extracts, and Thr 150 was found to be transiently phosphorylated just prior to nuclear envelope breakdown in cycling egg extracts. These findings establish the phosphorylation-dependent direct inactivation of Wee1A as a critical mechanism for the promotion of M-phase entry. These results also show that multisite phosphorylation cooperatively inactivates Wee1A and cooperatively promotes Wee1A proteolysis.
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Affiliation(s)
- Sun Young Kim
- Department of Molecular Pharmacology, Stanford University School of Medicine, Stanford, CA 94305-5174, USA
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45
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Lee HS, Bong YS, Moore KB, Soria K, Moody SA, Daar IO. Dishevelled mediates ephrinB1 signalling in the eye field through the planar cell polarity pathway. Nat Cell Biol 2005; 8:55-63. [PMID: 16362052 DOI: 10.1038/ncb1344] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2005] [Accepted: 11/25/2005] [Indexed: 02/01/2023]
Abstract
An important step in retinal development is the positioning of progenitors within the eye field where they receive the local environmental signals that will direct their ultimate fate. Recent evidence indicates that ephrinB1 functions in retinal progenitor movement, but the signalling pathway is unclear. We present evidence that ephrinB1 signals through its intracellular domain to control retinal progenitor movement into the eye field by interacting with Xenopus Dishevelled (Xdsh), and by using the planar cell polarity (PCP) pathway. Blocking Xdsh translation prevents retinal progeny from entering the eye field, similarly to the morpholino-mediated loss of ephrinB1 (ref. 2). Overexpression of Xdsh can rescue the phenotype induced by loss of ephrinB1, and this rescue (as well as a physical association between Xdsh and ephrinB1) is completely dependent on the DEP (Dishevelled, Egl-10, Pleckstrin) domain of Xdsh. Similar gain- and loss-of-function experiments suggest that Xdsh associates with ephrinB1 and mediates ephrinB1 signalling through downstream members of the PCP pathway during eye field formation.
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Affiliation(s)
- Hyun-Shik Lee
- Laboratory of Protein Dynamics and Signaling, National Cancer Institute-Frederick, Frederick, MD 21702, USA
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46
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Kurth T. A cell cycle arrest is necessary for bottle cell formation in the early Xenopus gastrula: Integrating cell shape change, local mitotic control and mesodermal patterning. Mech Dev 2005; 122:1251-65. [PMID: 16275039 DOI: 10.1016/j.mod.2005.09.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2005] [Revised: 09/09/2005] [Accepted: 09/12/2005] [Indexed: 01/23/2023]
Abstract
During development cell proliferation and morphogenetic movements are tightly intermingled. Both processes depend on the same cytoskeletal elements. Therefore, precise regulation of local mitotic activity seems to be basic for proper embryogenesis. Here, I report on bottle cells as an early non-mitotic cell population in the Xenopus gastrula. Endogenous and activin/BVg1-induced ectopic bottle cells do not proliferate. Overexpression of the mitosis-promoting phosphatase cdc25C increases the proliferation rate and interferes with bottle cell formation whereas the phosphatase-dead mutant cdc25C(C457A) does not. Cdc25C also affects other gastrulation processes such as epiboly, vegetal rotation or tissue separation as inferred from histological inspection of early gastrulae. Double stainings of gsc/Xbra transcripts and mitotic nuclei in ectopic and endogenous lips demonstrated that non-mitotic cells occur in the bottle cell region and, to a lesser extent, in the gsc domain which both are indicative of high TGF-beta signalling. In contrast, the Xbra-region and the remainder of the animal cap appear to be permissive for higher rates of cell proliferation. These data suggest inhibition of cell proliferation by high levels of activin-type signals and a close link of mesodermal and mitotic patterning. Finally, coexpression of eFGF together with activin/BVg1 interferes with TGF-beta-induced bottle cell formation. This inhibitory effect correlates with increased cell proliferation as compared to embryos injected with activin/BVg1 alone. Taken together, these data suggest that TGF-beta and FGF signals play antagonistic roles in bottle cell formation and the spatial control of the cell cycle in early Xenopus gastrulae.
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Affiliation(s)
- Thomas Kurth
- Fachrichtung Biologie, Studiengang Molekulare Biotechnologie, Fakultät für Mathematik und Naturwissenschaften, Technische Universität Dresden, D-01062 Dresden, Germany.
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47
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Jin Z, Homola EM, Goldbach P, Choi Y, Brill JA, Campbell SD. Drosophila Myt1 is a Cdk1 inhibitory kinase that regulates multiple aspects of cell cycle behavior during gametogenesis. Development 2005; 132:4075-85. [PMID: 16107480 DOI: 10.1242/dev.01965] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The metazoan Wee1-like kinases Wee1 and Myt1 regulate the essential mitotic regulator Cdk1 by inhibitory phosphorylation. This regulatory mechanism, which prevents Cdk1 from triggering premature mitotic events, is also induced during the DNA damage response and used to coordinate cell proliferation with crucial developmental events. Despite the previously demonstrated role for Myt1 regulation of Cdk1 during meiosis, relatively little is known of how Myt1 functions at other developmental stages. To address this issue, we have undertaken a functional analysis of Drosophila Myt1 that has revealed novel developmental roles for this conserved cell cycle regulator during gametogenesis. Notably, more proliferating cells were observed in myt1 mutant testes and ovaries than controls. This can partly be attributed to ectopic division of germline-associated somatic cells in myt1 mutants, suggesting that Myt1 serves a role in regulating exit from the cell cycle. Moreover, mitotic index measurements suggested that germline stem cells proliferate more rapidly, in myt1 mutant females. In addition, male myt1 germline cells occasionally undergo an extra mitotic division, resulting in meiotic cysts with twice the normal numbers of cells. Based on these observations, we propose that Myt1 serves unique Cdk1 regulatory functions required for efficient coupling of cell differentiation with cell cycle progression.
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Affiliation(s)
- Zhigang Jin
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
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48
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Hashiguchi A, Okabayashi K, Asashima M. Role of TSC-22 during early embryogenesis in Xenopus laevis. Dev Growth Differ 2005; 46:535-44. [PMID: 15610143 DOI: 10.1111/j.1440-169x.2004.00770.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Transforming growth factor-beta1-stimulated clone 22 (TSC-22) encodes a leucine zipper-containing protein that is highly conserved. During mouse embryogenesis, TSC-22 is expressed at the site of epithelial-mesenchymal interaction. Here, we isolated Xenopus laevis TSC-22 (XTSC-22) and analyzed its function in early development. XTSC-22 mRNA was first detected in the ectoderm of late blastulae. Translational knockdown using XTSC-22 antisense morpholino oligonucleotides (XTSC-22-MO) caused a severe delay in blastopore closure in gastrulating embryos. This was not due to mesoderm induction or convergent-extension, as confirmed by whole-mount in situ hybridization and animal cap assay. Cell lineage tracing revealed that migration of ectoderm cells toward blastopore was disrupted in XTSC-22-depleted embryos, and these embryos had a marked increase in the number of dividing cells. In contrast, cell division was suppressed in XTSC-22 mRNA-injected embryos. Co-injection of XTSC-22-MO and mRNA encoding p27Xic1, which inhibits cell cycle promotion by binding cyclin/Cdk complexes, reversed aberrant cell division. This was accompanied by rescue of the delay in blastopore closure and cell migration. These results indicate that XTSC-22 is required for cell movement during gastrulation though cell cycle regulation.
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Affiliation(s)
- Akiko Hashiguchi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
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49
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Etard C, Gradl D, Kunz M, Eilers M, Wedlich D. Pontin and Reptin regulate cell proliferation in early Xenopus embryos in collaboration with c-Myc and Miz-1. Mech Dev 2005; 122:545-56. [PMID: 15804567 DOI: 10.1016/j.mod.2004.11.010] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2004] [Revised: 11/17/2004] [Accepted: 11/17/2004] [Indexed: 01/28/2023]
Abstract
Pontin (Tip49) and Reptin (Tip48) are highly conserved components of multimeric protein complexes important for chromatin remodelling and transcription. They interact with many different proteins including TATA box binding protein (TBP), beta-catenin and c-Myc and thus, potentially modulate different pathways. As antagonistic regulators of Wnt-signalling, they control wing development in Drosophila and heart growth in zebrafish. Here we show that the Xenopus xPontin and xReptin in conjunction with c-Myc regulate cell proliferation in early development. Overexpression of xPontin or xReptin results in increased mitoses and bending of embryos, which is mimicked by c-Myc overexpression. Furthermore, the knockdown of either xPontin or xReptin resulted in embryonic lethality at late gastrula stage, which is abrogated by the injection of c-Myc-RNA. The N-termini of xPontin and xReptin, which mediate the mitogenic effect were mapped to contain c-Myc interaction domains. c-Myc protein promotes cell cycle progression either by transcriptional activation through the c-Myc/Max complex or by repression of cyclin dependent kinase inhibitors (p21, p15) through c-Myc/Miz-1 interaction. Importantly, xPontin and xReptin exert their mitogenic effect through the c-Myc/Miz-1 pathway as dominant negative Miz-1 and wild-type c-Myc but not a c-Myc mutant deficient in Miz-1 binding could rescue embryonic lethality. Finally, promoter reporter studies revealed that xPontin and xReptin but not the N-terminal deletion mutants enhance p21 repression by c-Myc. We conclude that xPontin and xReptin are essential genes regulating cell proliferation in early Xenopus embryogenesis through interaction with c-Myc. We propose a novel function of xPontin and xReptin as co-repressors in the c-Myc/Miz-1 pathway.
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Affiliation(s)
- Christelle Etard
- Zoologisches Institut II, Universität Karlsruhe (TH), Kaiserstrasse 12, 76131 Karlsruhe, Germany
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50
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Stumpff J, Duncan T, Homola E, Campbell SD, Su TT. Drosophila Wee1 kinase regulates Cdk1 and mitotic entry during embryogenesis. Curr Biol 2005; 14:2143-8. [PMID: 15589158 PMCID: PMC3242732 DOI: 10.1016/j.cub.2004.11.050] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2004] [Revised: 10/18/2004] [Accepted: 10/20/2004] [Indexed: 12/12/2022]
Abstract
Cyclin-dependent kinases (Cdks) are the central regulators of the cell division cycle. Inhibitors of Cdks ensure proper coordination of cell cycle events and help regulate cell proliferation in the context of tissues and organs. Wee1 homologs phosphorylate a conserved tyrosine to inhibit the mitotic cyclin-dependent kinase Cdk1. Loss of Wee1 function in fission or budding yeast causes premature entry into mitosis. The importance of metazoan Wee1 homologs for timing mitosis, however, has been demonstrated only in Xenopus egg extracts and via ectopic Cdk1 activation . Here, we report that Drosophila Wee1 (dWee1) regulates Cdk1 via phosphorylation of tyrosine 15 and times mitotic entry during the cortical nuclear cycles of syncytial blastoderm embryos, which lack gap phases. Loss of maternal dwee1 leads to premature entry into mitosis, mitotic spindle defects, chromosome condensation problems, and a Chk2-dependent block of subsequent development, and then embryonic lethality. These findings modify previous models about cell cycle regulation in syncytial embryos and demonstrate that Wee1 kinases can regulate mitotic entry in vivo during metazoan development even in cycles that lack a G2 phase.
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Affiliation(s)
- Jason Stumpff
- Department of Molecular, Cellular, and Developmental Biology University of Colorado Boulder, Colorado 80309-0347
| | - Tod Duncan
- Department of Molecular, Cellular, and Developmental Biology University of Colorado Boulder, Colorado 80309-0347
| | - Ellen Homola
- Department of Biological Sciences University of Alberta Edmonton, Alberta T6G 2E9 Canada
| | - Shelagh D. Campbell
- Department of Biological Sciences University of Alberta Edmonton, Alberta T6G 2E9 Canada
| | - Tin Tin Su
- Department of Molecular, Cellular, and Developmental Biology University of Colorado Boulder, Colorado 80309-0347
- Correspondence:
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