1
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Sun H, Wang X, Pratt RE, Dzau VJ, Hodgkinson CP. C166 EVs potentiate miR cardiac reprogramming via miR-148a-3p. J Mol Cell Cardiol 2024; 190:48-61. [PMID: 38582260 DOI: 10.1016/j.yjmcc.2024.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 03/28/2024] [Accepted: 04/03/2024] [Indexed: 04/08/2024]
Abstract
We have demonstrated that directly reprogramming cardiac fibroblasts into new cardiomyocytes via miR combo improves cardiac function in the infarcted heart. However, major challenges exist with delivery and efficacy. During a screening based approach to improve delivery, we discovered that C166-derived EVs were effective delivery agents for miR combo both in vitro and in vivo. In the latter, EV mediated delivery of miR combo induced significant conversion of cardiac fibroblasts into cardiomyocytes (∼20%), reduced fibrosis and improved cardiac function in a myocardial infarction injury model. When compared to lipid-based transfection, C166 EV mediated delivery of miR combo enhanced reprogramming efficacy. Improved reprogramming efficacy was found to result from a miRNA within the exosome: miR-148a-3p. The target of miR-148a-3p was identified as Mdfic. Over-expression and targeted knockdown studies demonstrated that Mdfic was a repressor of cardiomyocyte specific gene expression. In conclusion, we have demonstrated that C166-derived EVs are an effective method for delivering reprogramming factors to cardiac fibroblasts and we have identified a novel miRNA contained within C166-derived EVs which enhances reprogramming efficacy.
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Affiliation(s)
- Hualing Sun
- Mandel Center for Heart and Vascular Research, and the Duke Cardiovascular Research Center, Duke University Medical Center, Durham, NC 27710, United States of America; Department of Periodontology, School and Hospital of Stomatology, Wuhan University, Hubei Province, China
| | - Xinghua Wang
- Mandel Center for Heart and Vascular Research, and the Duke Cardiovascular Research Center, Duke University Medical Center, Durham, NC 27710, United States of America
| | - Richard E Pratt
- Mandel Center for Heart and Vascular Research, and the Duke Cardiovascular Research Center, Duke University Medical Center, Durham, NC 27710, United States of America
| | - Victor J Dzau
- Mandel Center for Heart and Vascular Research, and the Duke Cardiovascular Research Center, Duke University Medical Center, Durham, NC 27710, United States of America.
| | - Conrad P Hodgkinson
- Mandel Center for Heart and Vascular Research, and the Duke Cardiovascular Research Center, Duke University Medical Center, Durham, NC 27710, United States of America.
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2
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Lei Q, Yu Q, Yang N, Xiao Z, Song C, Zhang R, Yang S, Liu Z, Deng H. Therapeutic potential of targeting polo-like kinase 4. Eur J Med Chem 2024; 265:116115. [PMID: 38199166 DOI: 10.1016/j.ejmech.2023.116115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 12/21/2023] [Accepted: 12/30/2023] [Indexed: 01/12/2024]
Abstract
Polo-like kinase 4 (PLK4), a highly conserved serine/threonine kinase, masterfully regulates centriole duplication in a spatiotemporal manner to ensure the fidelity of centrosome duplication and proper mitosis. Abnormal expression of PLK4 contributes to genomic instability and associates with a poor prognosis in cancer. Inhibition of PLK4 is demonstrated to exhibit significant efficacy against various types of human cancers, further highlighting its potential as a promising therapeutic target for cancer treatment. As such, numerous small-molecule inhibitors with distinct chemical scaffolds targeting PLK4 have been extensively investigated for the treatment of different human cancers, with several undergoing clinical evaluation (e.g., CFI-400945). Here, we review the structure, distribution, and biological functions of PLK4, encapsulate its intricate regulatory mechanisms of expression, and highlighting its multifaceted roles in cancer development and metastasis. Moreover, the recent advancements of PLK4 inhibitors in patent or literature are summarized, and their therapeutic potential as monotherapies or combination therapies with other anticancer agents are also discussed.
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Affiliation(s)
- Qian Lei
- Department of Respiratory and Critical Care Medicine, West China Hospital and Targeted Tracer Research and Development Laboratory, Precision Medicine Key Laboratory of Sichuan Province & Precision Medicine Center, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China
| | - Quanwei Yu
- Department of Respiratory and Critical Care Medicine, West China Hospital and Targeted Tracer Research and Development Laboratory, Precision Medicine Key Laboratory of Sichuan Province & Precision Medicine Center, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China
| | - Na Yang
- Laboratory of Clinical Pharmacy and Adverse Drug Reaction, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China
| | - Zhaolin Xiao
- Department of Respiratory and Critical Care Medicine, West China Hospital and Targeted Tracer Research and Development Laboratory, Precision Medicine Key Laboratory of Sichuan Province & Precision Medicine Center, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China
| | - Chao Song
- Department of Respiratory and Critical Care Medicine, West China Hospital and Targeted Tracer Research and Development Laboratory, Precision Medicine Key Laboratory of Sichuan Province & Precision Medicine Center, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China
| | - Rui Zhang
- Department of Pharmacy, Guizhou Provincial People's Hospital, Guizhou, Guiyang, 550002, China
| | - Shuxin Yang
- Key Laboratory of Quantitative Synthetic Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Zhihao Liu
- Department of Emergency Medicine and Laboratory of Emergency Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China.
| | - Hui Deng
- Department of Respiratory and Critical Care Medicine, West China Hospital and Targeted Tracer Research and Development Laboratory, Precision Medicine Key Laboratory of Sichuan Province & Precision Medicine Center, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China.
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3
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Yu Y, Mu C, Xu Y, Li Y, Ren S, Kong S, Deng W, Wang Y, Wang H, Lu J. Adgrg1 is a new transcriptional target of Hand1 during trophoblast giant cell differentiation. J Reprod Immunol 2022; 154:103753. [PMID: 36228547 DOI: 10.1016/j.jri.2022.103753] [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: 02/27/2022] [Revised: 08/14/2022] [Accepted: 09/26/2022] [Indexed: 12/14/2022]
Abstract
The placenta, forming the maternal-fetal interface, is essential for the survival and development of the fetus. It has been shown that the basic helix-loop-helix (bHLH) transcription factor Hand1 plays an important role in trophoblast giant cells (TGCs) differentiation during placental development in mice. However, the underlying molecular mechanism remains elusive. We hereby report that Adgrg1 (GPR56), a G protein coupled receptor, was a new transcriptional target of Hand1. Hand1 activated the expression of Adgrg1 by binding to its promoter region during TGCs differentiation. Double in situ hybridization revealed co-expression of Hand1 and Adgrg1 in Prl2c2+ TGCs located in the junctional zone of the placenta. Knockdown of Adgrg1 not only led to increased Prl2c2 expression, but also the improvement of cell migration and invasion during TGC differentiation. Moreover, the ligand of Adgrg1, Tgm2, was expressed in Prl2c2+ TGCs located in the placental junctional zone and Tgm2 Knockdown increased cell migration and invasion, suggesting Tgm2 is a potential ligand involved in the functions of Adgrg1 during TGC differentiation in the manners of autocrine. Collectively, these results demonstrate that Adgrg1 is a new transcriptional target of Hand1, affecting Prl2c2 expression as well as cell migration and invasion during TGCs differentiation. As a transmembrane receptor, Adgrg1 perhaps could act as a potential therapeutic target for placental-associated diseases caused by abnormal trophoblast migration and invasion, providing new insights for the preventions and therapies of placenta-related diseases.
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Affiliation(s)
- Yongqin Yu
- Fujian Provincial Key Laboratory of Reproductive Health Research, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Change Mu
- Fujian Provincial Key Laboratory of Reproductive Health Research, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Yingchun Xu
- Fujian Provincial Key Laboratory of Reproductive Health Research, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Yuanyuan Li
- Fujian Provincial Key Laboratory of Reproductive Health Research, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Shengnan Ren
- Fujian Provincial Key Laboratory of Reproductive Health Research, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Shuangbo Kong
- Fujian Provincial Key Laboratory of Reproductive Health Research, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Wenbo Deng
- Fujian Provincial Key Laboratory of Reproductive Health Research, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Yinan Wang
- Fujian Provincial Key Laboratory of Reproductive Health Research, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Haibin Wang
- Fujian Provincial Key Laboratory of Reproductive Health Research, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China.
| | - Jinhua Lu
- Fujian Provincial Key Laboratory of Reproductive Health Research, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian, China.
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4
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Buss G, Stratton MB, Milenkovic L, Stearns T. Postmitotic centriole disengagement and maturation leads to centrosome amplification in polyploid trophoblast giant cells. Mol Biol Cell 2022; 33:ar118. [PMID: 36001376 PMCID: PMC9634975 DOI: 10.1091/mbc.e22-05-0182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
DNA replication is normally coupled with centriole duplication in the cell cycle. Trophoblast giant cells (TGCs) of the placenta undergo endocycles resulting in polyploidy but their centriole state is not known. We used a cell culture model for TGC differentiation to examine centriole and centrosome number and properties. Before differentiation, trophoblast stem cells (TSCs) have either two centrioles before duplication or four centrioles after. We find that the average nuclear area increases approximately eight-fold over differentiation, but most TGCs do not have more than four centrioles. However, these centrioles become disengaged, acquire centrosome proteins, and can nucleate microtubules. In addition, some TGCs undergo further duplication and disengagement of centrioles, resulting in substantially higher numbers. Live imaging revealed that disengagement and separation are centriole autonomous and can occur asynchronously. Centriole amplification, when present, occurs by the standard mechanism of one centriole generating one procentriole. PLK4 inhibition blocks centriole formation in differentiating TGCs but does not affect endocycle progression. In summary, centrioles in TGC endocycles undergo disengagement and conversion to centrosomes. This increases centrosome number but to a limited extent compared with DNA reduplication.
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Affiliation(s)
- Garrison Buss
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305
| | | | | | - Tim Stearns
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305,Department of Biology, Stanford University, Stanford, CA 94305,*Address correspondence to: Tim Stearns ()
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5
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Byrne AB, Brouillard P, Sutton DL, Kazenwadel J, Montazaribarforoushi S, Secker GA, Oszmiana A, Babic M, Betterman KL, Brautigan PJ, White M, Piltz SG, Thomas PQ, Hahn CN, Rath M, Felbor U, Korenke GC, Smith CL, Wood KH, Sheppard SE, Adams DM, Kariminejad A, Helaers R, Boon LM, Revencu N, Moore L, Barnett C, Haan E, Arts P, Vikkula M, Scott HS, Harvey NL. Pathogenic variants in MDFIC cause recessive central conducting lymphatic anomaly with lymphedema. Sci Transl Med 2022; 14:eabm4869. [PMID: 35235341 DOI: 10.1126/scitranslmed.abm4869] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Central conducting lymphatic anomaly (CCLA), characterized by the dysfunction of core collecting lymphatic vessels including the thoracic duct and cisterna chyli, and presenting as chylothorax, pleural effusions, chylous ascites, and lymphedema, is a severe disorder often resulting in fetal or perinatal demise. Although pathogenic variants in RAS/mitogen activated protein kinase (MAPK) signaling pathway components have been documented in some patients with CCLA, the genetic etiology of the disorder remains uncharacterized in most cases. Here, we identified biallelic pathogenic variants in MDFIC, encoding the MyoD family inhibitor domain containing protein, in seven individuals with CCLA from six independent families. Clinical manifestations of affected fetuses and children included nonimmune hydrops fetalis (NIHF), pleural and pericardial effusions, and lymphedema. Generation of a mouse model of human MDFIC truncation variants revealed that homozygous mutant mice died perinatally exhibiting chylothorax. The lymphatic vasculature of homozygous Mdfic mutant mice was profoundly mispatterned and exhibited major defects in lymphatic vessel valve development. Mechanistically, we determined that MDFIC controls collective cell migration, an important early event during the formation of lymphatic vessel valves, by regulating integrin β1 activation and the interaction between lymphatic endothelial cells and their surrounding extracellular matrix. Our work identifies MDFIC variants underlying human lymphatic disease and reveals a crucial, previously unrecognized role for MDFIC in the lymphatic vasculature. Ultimately, understanding the genetic and mechanistic basis of CCLA will facilitate the development and implementation of new therapeutic approaches to effectively treat this complex disease.
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Affiliation(s)
- Alicia B Byrne
- Centre for Cancer Biology, University of South Australia and SA Pathology, 5001 Adelaide, Australia.,Clinical and Health Sciences, University of South Australia, 5001 Adelaide, Australia
| | - Pascal Brouillard
- Human Molecular Genetics, de Duve Institute, University of Louvain, 1200 Brussels, Belgium
| | - Drew L Sutton
- Centre for Cancer Biology, University of South Australia and SA Pathology, 5001 Adelaide, Australia
| | - Jan Kazenwadel
- Centre for Cancer Biology, University of South Australia and SA Pathology, 5001 Adelaide, Australia
| | | | - Genevieve A Secker
- Centre for Cancer Biology, University of South Australia and SA Pathology, 5001 Adelaide, Australia
| | - Anna Oszmiana
- Centre for Cancer Biology, University of South Australia and SA Pathology, 5001 Adelaide, Australia
| | - Milena Babic
- Centre for Cancer Biology, University of South Australia and SA Pathology, 5001 Adelaide, Australia.,Department of Genetics and Molecular Pathology, SA Pathology, 5000 Adelaide, Australia
| | - Kelly L Betterman
- Centre for Cancer Biology, University of South Australia and SA Pathology, 5001 Adelaide, Australia
| | - Peter J Brautigan
- Centre for Cancer Biology, University of South Australia and SA Pathology, 5001 Adelaide, Australia.,Department of Genetics and Molecular Pathology, SA Pathology, 5000 Adelaide, Australia
| | - Melissa White
- Adelaide Medical School, University of Adelaide, 5005 Adelaide, Australia.,Genome Editing Program, South Australian Health and Medical Research Institute, 5000 Adelaide, Australia.,South Australian Genome Editing Facility, University of Adelaide, 5005 Adelaide, Australia
| | - Sandra G Piltz
- Adelaide Medical School, University of Adelaide, 5005 Adelaide, Australia.,Genome Editing Program, South Australian Health and Medical Research Institute, 5000 Adelaide, Australia.,South Australian Genome Editing Facility, University of Adelaide, 5005 Adelaide, Australia
| | - Paul Q Thomas
- Adelaide Medical School, University of Adelaide, 5005 Adelaide, Australia.,Genome Editing Program, South Australian Health and Medical Research Institute, 5000 Adelaide, Australia.,South Australian Genome Editing Facility, University of Adelaide, 5005 Adelaide, Australia
| | - Christopher N Hahn
- Centre for Cancer Biology, University of South Australia and SA Pathology, 5001 Adelaide, Australia.,Adelaide Medical School, University of Adelaide, 5005 Adelaide, Australia.,Department of Genetics and Molecular Pathology, SA Pathology, 5000 Adelaide, Australia.,ACRF Cancer Genomics Facility, Centre for Cancer Biology, University of South Australia and SA Pathology, 5001 Adelaide, Australia
| | - Matthias Rath
- Department of Human Genetics, University Medicine Greifswald and Interfaculty Institute of Genetics and Functional Genomics, University of Greifswald, 17489 Greifswald, Germany
| | - Ute Felbor
- Department of Human Genetics, University Medicine Greifswald and Interfaculty Institute of Genetics and Functional Genomics, University of Greifswald, 17489 Greifswald, Germany
| | - G Christoph Korenke
- Department of Neuropediatrics, University Children's Hospital, Klinikum Oldenburg, 26133 Oldenburg, Germany
| | - Christopher L Smith
- Jill and Mark Fishman Center for Lymphatic Disorders, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.,Division of Cardiology, Children's Hospital of Philadelphia and Department of Pediatrics Perelman School of Medicine at The University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kathleen H Wood
- Division of Genomic Diagnostics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Sarah E Sheppard
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Denise M Adams
- Vascular Anomalies Centre, Division of Haematology/Oncology, Cancer and Blood Disorders Centre, Boston Children's Hospital, Boston, PA 02115, USA
| | | | - Raphael Helaers
- Human Molecular Genetics, de Duve Institute, University of Louvain, 1200 Brussels, Belgium
| | - Laurence M Boon
- Human Molecular Genetics, de Duve Institute, University of Louvain, 1200 Brussels, Belgium.,Center for Vascular Anomalies, Division of Plastic Surgery, VASCERN VASCA European Reference Centre, Cliniques Universitaires Saint-Luc and University of Louvain, 1200 Brussels, Belgium
| | - Nicole Revencu
- Center for Vascular Anomalies, Division of Plastic Surgery, VASCERN VASCA European Reference Centre, Cliniques Universitaires Saint-Luc and University of Louvain, 1200 Brussels, Belgium.,Centre for Human Genetics, Cliniques Universitaires Saint-Luc and University of Louvain, 1200 Brussels, Belgium
| | - Lynette Moore
- Adelaide Medical School, University of Adelaide, 5005 Adelaide, Australia.,Anatomical Pathology, SA Pathology, 5000 Adelaide, Australia
| | - Christopher Barnett
- Paediatric and Reproductive Genetics Unit, South Australian Clinical Genetics Service, Women's and Children's Hospital, 5006 Adelaide, South Australia, Australia
| | - Eric Haan
- Adelaide Medical School, University of Adelaide, 5005 Adelaide, Australia
| | - Peer Arts
- Centre for Cancer Biology, University of South Australia and SA Pathology, 5001 Adelaide, Australia
| | - Miikka Vikkula
- Human Molecular Genetics, de Duve Institute, University of Louvain, 1200 Brussels, Belgium.,Center for Vascular Anomalies, Division of Plastic Surgery, VASCERN VASCA European Reference Centre, Cliniques Universitaires Saint-Luc and University of Louvain, 1200 Brussels, Belgium.,Centre for Human Genetics, Cliniques Universitaires Saint-Luc and University of Louvain, 1200 Brussels, Belgium.,Walloon Excellence in Life Sciences and Biotechnology, University of Louvain, 1200 Brussels, Belgium
| | - Hamish S Scott
- Centre for Cancer Biology, University of South Australia and SA Pathology, 5001 Adelaide, Australia.,Adelaide Medical School, University of Adelaide, 5005 Adelaide, Australia.,Department of Genetics and Molecular Pathology, SA Pathology, 5000 Adelaide, Australia.,ACRF Cancer Genomics Facility, Centre for Cancer Biology, University of South Australia and SA Pathology, 5001 Adelaide, Australia
| | - Natasha L Harvey
- Centre for Cancer Biology, University of South Australia and SA Pathology, 5001 Adelaide, Australia.,Adelaide Medical School, University of Adelaide, 5005 Adelaide, Australia
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6
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TEC kinase stabilizes PLK4 to promote liver cancer metastasis. Cancer Lett 2022; 524:70-81. [PMID: 34637843 DOI: 10.1016/j.canlet.2021.08.038] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 08/12/2021] [Accepted: 08/27/2021] [Indexed: 01/09/2023]
Abstract
Aberrated PLK4 expression has been reported in different malignancies and causes centrosome amplification, aneuploidy, and genomic instability. However, the mechanism by which PLK4 is regulated in carcinogenesis remains not fully characterised. Here, we showed that PLK4 was overexpressed in human HCC and overexpression of PLK4 predicted poorer patient prognosis. Unexpectedly, we found that induced expression of PLK4 promotes, but knockdown of PLK4 inhibits, HCC cell migration and invasion. Mechanistically, we found that TEC tyrosine kinase, which also promotes HCC cell migration, stabilizes PLK4 by phosphorylation. TEC directly phosphorylates PLK4 at tyrosine 86 residue, which not only stabilizes the protein but also enhances PLK4-mediated HCC cell invasion. Further investigation by transcriptome sequencing indicated that PLK4 promotes the phosphorylation of focal adhesion kinase to regulate the focal adhesion pathway in HCC cell migration. Taken together, our results demonstrated that PLK4 plays an important role in HCC metastasis and revealed for the first time the mechanism by which PLK4 promotes HCC metastasis via TEC phosphorylation.
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7
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Human HAND1 Inhibits the Conversion of Cholesterol to Steroids in Trophoblasts. J Genet Genomics 2021; 49:350-363. [PMID: 34391879 DOI: 10.1016/j.jgg.2021.07.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 07/11/2021] [Accepted: 07/17/2021] [Indexed: 11/24/2022]
Abstract
Steroidogenesis from cholesterol in placental trophoblasts is fundamentally involved in the establishment and maintenance of pregnancy. The transcription factor gene Heart And Neural crest Derivatives expressed 1 (Hand1) promotes differentiation of mouse trophoblast giant cells. However, the role of HAND1 in human trophoblasts remains unknown. Here, we report that HAND1 inhibits human trophoblastic progesterone (P4) and estradiol (E2) from cholesterol through down-regulation of the expression of steroidogenic enzymes including aromatase, P450 cholesterol side-chain cleavage enzyme (P450scc) and 3β-hydroxysteroid dehydrogenase type 1 (3β-HSD1). Mechanically, while HAND1 inhibits transcription of aromatase by directly binding to aromatase gene promoter, it restrains transcription of P450scc by up-regulation of the methylation status of P450scc gene promoter through its binding to ALKBH1, a demethylase. Unlike aromatase and P450scc, HAND1 decreases 3β-HSD1 mRNA levels by reduction of its RNA stability through binding to and subsequent destabilization of protein HuR. Finally, HAND1 suppresses circulating P4 and E2 levels derived from JEG-3 xenograft, and attenuates uterine response to P4 and E2. Thus, our results uncover a hitherto uncharacterized role of HAND1 in regulation of cholesterol metabolism in human trophoblasts, which may help pinpoint the underlying mechanisms involved in supporting the development and physiological function of the human placenta.
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8
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Sui Y, Li X, Oh S, Zhang B, Freeman WM, Shin S, Janknecht R. Opposite Roles of the JMJD1A Interaction Partners MDFI and MDFIC in Colorectal Cancer. Sci Rep 2020; 10:8710. [PMID: 32457453 PMCID: PMC7250871 DOI: 10.1038/s41598-020-65536-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 05/06/2020] [Indexed: 12/12/2022] Open
Abstract
MyoD family inhibitor (MDFI) and MDFI domain-containing (MDFIC) are homologous proteins known to regulate myogenic transcription factors. Hitherto, their role in cancer is unknown. We discovered that MDFI is up- and MDFIC downregulated in colorectal tumors. Mirroring these different expression patterns, MDFI stimulated and MDFIC inhibited growth of HCT116 colorectal cancer cells. Further, MDFI and MDFIC interacted with Jumonji C domain-containing (JMJD) 1 A, a histone demethylase and epigenetic regulator involved in colorectal cancer. JMJD1A influenced transcription of several genes that were also regulated by MDFI or MDFIC. Notably, the HIC1 tumor suppressor gene was stimulated by JMJD1A and MDFIC, but not by MDFI, and HIC1 overexpression phenocopied the growth suppressive effects of MDFIC in HCT116 cells. Similar to colorectal cancer, MDFI was up- and MDFIC downregulated in breast, ovarian and prostate cancer, but both were overexpressed in brain, gastric and pancreatic tumors that implies MDFIC to also promote tumorigenesis in certain tissues. Altogether, our data suggest a tumor modulating function for MDFI and MDFIC in colorectal and other cancers that may involve their interaction with JMJD1A and a MDFIC→HIC1 axis.
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Affiliation(s)
- Yuan Sui
- Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Xiaomeng Li
- China-Japan Union Hospital of Jilin University, Changchun, Jilin, 130033, China.,Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Sangphil Oh
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.,Stephenson Cancer Center, Oklahoma City, OK, 73104, USA
| | - Bin Zhang
- China-Japan Union Hospital of Jilin University, Changchun, Jilin, 130033, China
| | - Willard M Freeman
- Stephenson Cancer Center, Oklahoma City, OK, 73104, USA.,Genes and Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA
| | - Sook Shin
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.,Stephenson Cancer Center, Oklahoma City, OK, 73104, USA
| | - Ralf Janknecht
- Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA. .,Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA. .,Stephenson Cancer Center, Oklahoma City, OK, 73104, USA.
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9
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Denu RA, Sass MM, Johnson JM, Potts GK, Choudhary A, Coon JJ, Burkard ME. Polo-like kinase 4 maintains centriolar satellite integrity by phosphorylation of centrosomal protein 131 (CEP131). J Biol Chem 2019; 294:6531-6549. [PMID: 30804208 PMCID: PMC6484138 DOI: 10.1074/jbc.ra118.004867] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 02/07/2019] [Indexed: 11/06/2022] Open
Abstract
The centrosome, consisting of two centrioles surrounded by a dense network of proteins, is the microtubule-organizing center of animal cells. Polo-like kinase 4 (PLK4) is a Ser/Thr protein kinase and the master regulator of centriole duplication, but it may play additional roles in centrosome function. To identify additional proteins regulated by PLK4, we generated an RPE-1 human cell line with a genetically engineered "analog-sensitive" PLK4AS, which genetically encodes chemical sensitivity to competitive inhibition via a bulky ATP analog. We used this transgenic line in an unbiased multiplex phosphoproteomic screen. Several hits were identified and validated as direct PLK4 substrates by in vitro kinase assays. Among them, we confirmed Ser-78 in centrosomal protein 131 (CEP131, also known as AZI1) as a direct substrate of PLK4. Using immunofluorescence microscopy, we observed that although PLK4-mediated phosphorylation of Ser-78 is dispensable for CEP131 localization, ciliogenesis, and centriole duplication, it is essential for maintaining the integrity of centriolar satellites. We also found that PLK4 inhibition or use of a nonphosphorylatable CEP131 variant results in dispersed centriolar satellites. Moreover, replacement of endogenous WT CEP131 with an S78D phosphomimetic variant promoted aggregation of centriolar satellites. We conclude that PLK4 phosphorylates CEP131 at Ser-78 to maintain centriolar satellite integrity.
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Affiliation(s)
- Ryan A Denu
- From the Medical Scientist Training Program
- the Division of Hematology/Oncology, Department of Medicine
- the University of Wisconsin Carbone Cancer Center, University of Wisconsin, Madison, Wisconsin 53705
| | - Madilyn M Sass
- the Division of Hematology/Oncology, Department of Medicine
- the University of Wisconsin Carbone Cancer Center, University of Wisconsin, Madison, Wisconsin 53705
| | - James M Johnson
- the Division of Hematology/Oncology, Department of Medicine
- the University of Wisconsin Carbone Cancer Center, University of Wisconsin, Madison, Wisconsin 53705
| | - Gregory K Potts
- the Department of Chemistry
- the Department of Biomolecular Chemistry
- the Genome Center, and
| | - Alka Choudhary
- the Division of Hematology/Oncology, Department of Medicine
- the University of Wisconsin Carbone Cancer Center, University of Wisconsin, Madison, Wisconsin 53705
| | - Joshua J Coon
- the Department of Chemistry
- the Department of Biomolecular Chemistry
- the Genome Center, and
| | - Mark E Burkard
- the Division of Hematology/Oncology, Department of Medicine,
- the University of Wisconsin Carbone Cancer Center, University of Wisconsin, Madison, Wisconsin 53705
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10
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Das DR, Horváth B, Kundu A, Kaló P, DasGupta M. Functional conservation of CYCLOPS in crack entry legume Arachis hypogaea. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 281:232-241. [PMID: 30824056 DOI: 10.1016/j.plantsci.2018.12.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 12/05/2018] [Accepted: 12/07/2018] [Indexed: 06/09/2023]
Abstract
Root nodule symbiosis in legumes is established following interaction of compatible rhizobia that activates an array of genes, commonly known as symbiotic-pathway, resulting in nodule development. In model legumes, bacterial entry mainly occurs through infection thread involving the expression of transcription factor CYCLOPS/IPD3. Here we show the functional analysis of AhCYCLOPS in Arachis hypogaea where bacteria invade roots through epidermal cracks. Exploiting significant cross-species domain conservation, trans-complementation experiments involving ectopic expression of AhCYCLOPS in transgenic hairy-roots of Medicago truncatula ipd3 mutants resulted in functional complementation of Medicago nodules. Moreover, native promoter of AhCYCLOPS was sufficient for this cross-species complementation irrespective of the different modes of infection of roots by rhizobia and nodule ontology. To unravel the role of AhCYCLOPS during 'crack-entry' nodulation in A. hypogaea, RNAi of AhCYCLOPS was performed which resulted in delayed nodule inception followed by drastic reduction in nodule number on transgenic hairy-roots. The infection zone of a significant number of RNAi nodules showed presence of infected cells with enlarged nucleus and rod shaped undifferentiated bacteria. Expression analysis showed downregulation of several nodulation responsible effectors endorsing the compromised condition of RNAi roots. Together, the results indicated that AhCYCLOPS plays an important role in A. hypogaea nodule development.
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Affiliation(s)
- Debapriya Rajlakshmi Das
- Department of Biochemistry, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, West Bengal, India
| | - Beatrix Horváth
- Agricultural Biotechnology Institute, NARIC, Szent-Györgyi Albert u. 4, Gödöllő, Hungary
| | - Anindya Kundu
- Department of Biochemistry, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, West Bengal, India
| | - Péter Kaló
- Agricultural Biotechnology Institute, NARIC, Szent-Györgyi Albert u. 4, Gödöllő, Hungary
| | - Maitrayee DasGupta
- Department of Biochemistry, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, West Bengal, India.
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11
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Wang M, Bokros M, Theodoridis PR, Lee S. Nucleolar Sequestration: Remodeling Nucleoli Into Amyloid Bodies. Front Genet 2019; 10:1179. [PMID: 31824572 PMCID: PMC6881480 DOI: 10.3389/fgene.2019.01179] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Accepted: 10/24/2019] [Indexed: 01/14/2023] Open
Abstract
This year marks the 20th anniversary of the discovery that the nucleolus can temporarily immobilize proteins, a process known as nucleolar sequestration. This review reflects on the progress made to understand the physiological roles of nucleolar sequestration and the mechanisms involved in the immobilization of proteins. We discuss how protein immobilization can occur through a highly choreographed amyloidogenic program that converts the nucleolus into a large fibrous organelle with amyloid-like characteristics called the amyloid body (A-body). We propose a working model of A-body biogenesis that includes a role for low-complexity ribosomal intergenic spacer RNA (rIGSRNA) and a discrete peptide sequence, the amyloid-converting motif (ACM), found in many proteins that undergo immobilization. Amyloid bodies provide a unique model to study the multistep assembly of a membraneless compartment and may provide alternative insights into the pathological amyloidogenesis involved in neurological disorders.
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Affiliation(s)
- Miling Wang
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, United States
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Michael Bokros
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, United States
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Phaedra Rebecca Theodoridis
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, United States
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Stephen Lee
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, United States
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, United States
- Department of Urology, Miller School of Medicine, University of Miami, FL, United States
- *Correspondence: Stephen Lee,
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12
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Firulli BA, Milliar H, Toolan KP, Harkin J, Fuchs RK, Robling AG, Firulli AB. Defective Hand1 phosphoregulation uncovers essential roles for Hand1 in limb morphogenesis. Development 2017; 144:2480-2489. [PMID: 28576769 PMCID: PMC5536869 DOI: 10.1242/dev.149963] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 05/18/2017] [Indexed: 11/20/2022]
Abstract
The morphogenesis of the vertebrate limbs is a complex process in which cell signaling and transcriptional regulation coordinate diverse structural adaptations in diverse species. In this study, we examine the consequences of altering Hand1 dimer choice regulation within developing vertebrate limbs. Although Hand1 deletion via the limb-specific Prrx1-Cre reveals a non-essential role for Hand1 in mouse limb morphogenesis, altering Hand1 phosphoregulation, and consequently Hand1 dimerization affinities, results in a severe truncation of proximal-anterior limb elements. Molecular analysis reveals a non-cell-autonomous mechanism that causes widespread cell death within the embryonic limb bud. In addition, we observe changes in proximal-anterior gene regulation, including a reduction in the expression of Irx3, Irx5, Gli3 and Alx4, all of which are upregulated in Hand2 limb conditional knockouts. A reduction of Hand2 and Shh gene dosage improves the integrity of anterior limb structures, validating the importance of the Twist-family bHLH dimer pool in limb morphogenesis. Summary: Altering Hand1 phosphoregulation, and consequently Hand1 dimerization affinities, results in a severe truncation of anterior-proximal limb elements in mice.
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Affiliation(s)
- Beth A Firulli
- Riley Heart Research Center, Herman B Wells Center for Pediatric Research, Departments of Anatomy and Cell Biology, Biochemistry, Medical and Molecular Genetics, Indiana University School of Medicine
| | - Hannah Milliar
- Riley Heart Research Center, Herman B Wells Center for Pediatric Research, Departments of Anatomy and Cell Biology, Biochemistry, Medical and Molecular Genetics, Indiana University School of Medicine
| | - Kevin P Toolan
- Riley Heart Research Center, Herman B Wells Center for Pediatric Research, Departments of Anatomy and Cell Biology, Biochemistry, Medical and Molecular Genetics, Indiana University School of Medicine
| | - Jade Harkin
- Riley Heart Research Center, Herman B Wells Center for Pediatric Research, Departments of Anatomy and Cell Biology, Biochemistry, Medical and Molecular Genetics, Indiana University School of Medicine
| | - Robyn K Fuchs
- Department of Physical Therapy and the Center for Translational Musculoskeletal Research, School of Health and Rehabilitation Science, Indiana University, Indianapolis, IN 46202, USA
| | - Alex G Robling
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202-5225, USA
| | - Anthony B Firulli
- Riley Heart Research Center, Herman B Wells Center for Pediatric Research, Departments of Anatomy and Cell Biology, Biochemistry, Medical and Molecular Genetics, Indiana University School of Medicine
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13
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Levine MS, Bakker B, Boeckx B, Moyett J, Lu J, Vitre B, Spierings DC, Lansdorp PM, Cleveland DW, Lambrechts D, Foijer F, Holland AJ. Centrosome Amplification Is Sufficient to Promote Spontaneous Tumorigenesis in Mammals. Dev Cell 2017; 40:313-322.e5. [PMID: 28132847 DOI: 10.1016/j.devcel.2016.12.022] [Citation(s) in RCA: 252] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 11/14/2016] [Accepted: 12/23/2016] [Indexed: 12/14/2022]
Abstract
Centrosome amplification is a common feature of human tumors, but whether this is a cause or a consequence of cancer remains unclear. Here, we test the consequence of centrosome amplification by creating mice in which centrosome number can be chronically increased in the absence of additional genetic defects. We show that increasing centrosome number elevated tumor initiation in a mouse model of intestinal neoplasia. Most importantly, we demonstrate that supernumerary centrosomes are sufficient to drive aneuploidy and the development of spontaneous tumors in multiple tissues. Tumors arising from centrosome amplification exhibit frequent mitotic errors and possess complex karyotypes, recapitulating a common feature of human cancer. Together, our data support a direct causal relationship among centrosome amplification, genomic instability, and tumor development.
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Affiliation(s)
- Michelle S Levine
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Bjorn Bakker
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen 9713 AV, the Netherlands
| | - Bram Boeckx
- Laboratory of Translational Genetics, Vesalius Research Center, VIB, 3000 Leuven, Belgium; Laboratory of Translational Genetics, Department of Oncology, KU Leuven, 3000 Leuven, Belgium
| | - Julia Moyett
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - James Lu
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Benjamin Vitre
- CNRS UMR-5237, Centre de Recherche en Biochimie Macromoleculaire, University of Montpellier, Montpellier 34093, France
| | - Diana C Spierings
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen 9713 AV, the Netherlands
| | - Peter M Lansdorp
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen 9713 AV, the Netherlands
| | - Don W Cleveland
- San Diego Branch, Ludwig Institute for Cancer Research, La Jolla, CA 92093, USA; Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Diether Lambrechts
- Laboratory of Translational Genetics, Vesalius Research Center, VIB, 3000 Leuven, Belgium; Laboratory of Translational Genetics, Department of Oncology, KU Leuven, 3000 Leuven, Belgium
| | - Floris Foijer
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen 9713 AV, the Netherlands
| | - Andrew J Holland
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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Matheson TD, Kaufman PD. Grabbing the genome by the NADs. Chromosoma 2016; 125:361-71. [PMID: 26174338 PMCID: PMC4714962 DOI: 10.1007/s00412-015-0527-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 06/19/2015] [Accepted: 06/25/2015] [Indexed: 12/31/2022]
Abstract
The regions of the genome that interact frequently with the nucleolus have been termed nucleolar-associated domains (NADs). Deep sequencing and DNA-fluorescence in situ hybridization (FISH) experiments have revealed that these domains are enriched for repetitive elements, regions of the inactive X chromosome (Xi), and several RNA polymerase III-transcribed genes. NADs are often marked by chromatin modifications characteristic of heterochromatin, including H3K27me3, H3K9me3, and H4K20me3, and artificial targeting of genes to this area is correlated with reduced expression. It has therefore been hypothesized that NAD localization to the nucleolar periphery contributes to the establishment and/or maintenance of heterochromatic silencing. Recently published studies from several multicellular eukaryotes have begun to reveal the trans-acting factors involved in NAD localization, including the insulator protein CCCTC-binding factor (CTCF), chromatin assembly factor (CAF)-1 subunit p150, several nucleolar proteins, and two long non-coding RNAs (lncRNAs). The mechanisms by which these factors coordinate with one another in regulating NAD localization and/or silencing are still unknown. This review will summarize recently published studies, discuss where additional research is required, and speculate about the mechanistic and functional implications of genome organization around the nucleolus.
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Affiliation(s)
- Timothy D Matheson
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Paul D Kaufman
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA, 01605, USA.
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15
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Coelho PA, Bury L, Shahbazi MN, Liakath-Ali K, Tate PH, Wormald S, Hindley CJ, Huch M, Archer J, Skarnes WC, Zernicka-Goetz M, Glover DM. Over-expression of Plk4 induces centrosome amplification, loss of primary cilia and associated tissue hyperplasia in the mouse. Open Biol 2015; 5:150209. [PMID: 26701933 PMCID: PMC4703062 DOI: 10.1098/rsob.150209] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 12/02/2015] [Indexed: 12/28/2022] Open
Abstract
To address the long-known relationship between supernumerary centrosomes and cancer, we have generated a transgenic mouse that permits inducible expression of the master regulator of centriole duplication, Polo-like-kinase-4 (Plk4). Over-expression of Plk4 from this transgene advances the onset of tumour formation that occurs in the absence of the tumour suppressor p53. Plk4 over-expression also leads to hyperproliferation of cells in the pancreas and skin that is enhanced in a p53 null background. Pancreatic islets become enlarged following Plk4 over-expression as a result of equal expansion of α- and β-cells, which exhibit centrosome amplification. Mice overexpressing Plk4 develop grey hair due to a loss of differentiated melanocytes and bald patches of skin associated with a thickening of the epidermis. This reflects an increase in proliferating cells expressing keratin 5 in the basal epidermal layer and the expansion of these cells into suprabasal layers. Such cells also express keratin 6, a marker for hyperplasia. This is paralleled by a decreased expression of later differentiation markers, involucrin, filaggrin and loricrin. Proliferating cells showed an increase in centrosome number and a loss of primary cilia, events that were mirrored in primary cultures of keratinocytes established from these animals. We discuss how repeated duplication of centrioles appears to prevent the formation of basal bodies leading to loss of primary cilia, disruption of signalling and thereby aberrant differentiation of cells within the epidermis. The absence of p53 permits cells with increased centrosomes to continue dividing, thus setting up a neoplastic state of error prone mitoses, a prerequisite for cancer development.
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Affiliation(s)
- Paula A Coelho
- Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, UK
| | - Leah Bury
- Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, UK
| | - Marta N Shahbazi
- Department of Physiology, Development and Neuroscience, Physiological Laboratory, University of Cambridge, Downing Street, Cambridge CB2 3EG, UK
| | - Kifayathullah Liakath-Ali
- Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, UK Centre for Stem Cells and Regenerative Medicine, King's College London, Floor 28, Tower Wing, Guy's Hospital, Great Maze Pond, London SE1 9RT, UK
| | - Peri H Tate
- Wellcome Trust Genome Campus, the Wellcome Trust Sanger Institute, Cambridge, Hinxton CB10 1SA, UK
| | - Sam Wormald
- Wellcome Trust Genome Campus, the Wellcome Trust Sanger Institute, Cambridge, Hinxton CB10 1SA, UK
| | - Christopher J Hindley
- Henry Wellcome Building of Cancer and Developmental Biology, the Wellcome Trust/Cancer Research UK Gurdon Institute, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Meritxell Huch
- Henry Wellcome Building of Cancer and Developmental Biology, the Wellcome Trust/Cancer Research UK Gurdon Institute, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Joy Archer
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
| | - William C Skarnes
- Wellcome Trust Genome Campus, the Wellcome Trust Sanger Institute, Cambridge, Hinxton CB10 1SA, UK
| | - Magdalena Zernicka-Goetz
- Department of Physiology, Development and Neuroscience, Physiological Laboratory, University of Cambridge, Downing Street, Cambridge CB2 3EG, UK
| | - David M Glover
- Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, UK
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16
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Rapchak CE, Patel N, Hudson J, Crawford M. Developmental role of plk4 in Xenopus laevis and Danio rerio: implications for Seckel Syndrome. Biochem Cell Biol 2015; 93:396-404. [PMID: 26150138 DOI: 10.1139/bcb-2015-0003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The polo-like kinases are a family of conserved serine/threonine kinases that play multiple roles in regulation of the cell cycle. Unlike its four other family members, the role of Plk4 in embryonic development has not been well characterized. In mice, Plk4(-)(/)(-) embryos arrest at E7.5, just prior to the initiation of somitogenesis. This has led to the hypothesis that Plk4 expression may be essential to somitogenesis. Recently characterized human mutations lead to Seckel Syndrome. Riboprobe in situ hybridization revealed that plk4 is ubiquitously expressed during early stages of development of Xenopus and Danio; in later stages, expression in frogs restricts to somites as well as eye, otic vesicle, and branchial arch, and brain. Expression patterns in fish remain ubiquitous. Both somite and eye development require planar cell polarity, and disruption of plk4 function in frog by means of morpholino-mediated translational knockdown yields orientational disorganization of both these structures. These results provide the first steps in defining a new role for plk4 in organogenesis and implies a role in planar cell polarity, segmentation, and in recently described PLK4 mutations in human.
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Affiliation(s)
- Candace Elaine Rapchak
- a Dept. Biological Sciences, University of Windsor, 401 Sunset Ave, Windsor Ontario N9B 3P4, Canada
| | - Neeraj Patel
- b Western Centre for Public Health and Family Medicine, The University of Western Ontario, London, ON N6A 2B7, Canada
| | - John Hudson
- a Dept. Biological Sciences, University of Windsor, 401 Sunset Ave, Windsor Ontario N9B 3P4, Canada
| | - Michael Crawford
- a Dept. Biological Sciences, University of Windsor, 401 Sunset Ave, Windsor Ontario N9B 3P4, Canada
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17
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Pappas A, Chaiworapongsa T, Romero R, Korzeniewski SJ, Cortez JC, Bhatti G, Gomez-Lopez N, Hassan SS, Shankaran S, Tarca AL. Transcriptomics of maternal and fetal membranes can discriminate between gestational-age matched preterm neonates with and without cognitive impairment diagnosed at 18-24 months. PLoS One 2015; 10:e0118573. [PMID: 25822971 PMCID: PMC4379164 DOI: 10.1371/journal.pone.0118573] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 01/20/2015] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Neurocognitive impairment among children born preterm may arise from complex interactions between genes and the intra-uterine environment. OBJECTIVES (1) To characterize the transcriptomic profiles of chorioamniotic membranes in preterm neonates with and without neurocognitive impairment via microarrays and (2) to determine if neonates with neurocognitive impairment can be identified at birth. MATERIALS/METHODS A retrospective case-control study was conducted to examine the chorioamniotic transcriptome of gestational-age matched very preterm neonates with and without neurocognitive impairment at 18-24 months' corrected-age defined by a Bayley-III Cognitive Composite Score <80 (n = 14 each). Pathway analysis with down-weighting of overlapping genes (PADOG) was performed to identify KEGG pathways relevant to the phenotype. Select differentially expressed genes were profiled using qRT-PCR and a multi-gene disease prediction model was developed using linear discriminant analysis. The model's predictive performance was tested on a new set of cases and controls (n = 19 each). RESULTS 1) 117 genes were differentially expressed among neonates with and without subsequent neurocognitive impairment (p<0.05 and fold change >1.5); 2) Gene ontology analysis indicated enrichment of 19 biological processes and 3 molecular functions; 3)PADOG identified 4 significantly perturbed KEGG pathways: oxidative phosphorylation, Parkinson's disease, Alzheimer's disease and Huntington's disease (q-value <0.1); 4) 48 of 90 selected differentially expressed genes were confirmed by qRT-PCR, including genes implicated in energy metabolism, neuronal signaling, vascular permeability and response to injury (e.g., up-regulation of SEPP1, APOE, DAB2, CD163, CXCL12, VWF; down-regulation of HAND1, OSR1)(p<0.05); and 5) a multi-gene model predicted 18-24 month neurocognitive impairment (using the ratios of OSR1/VWF and HAND1/VWF at birth) in a larger, independent set (sensitivity = 74%, at specificity = 83%). CONCLUSIONS Gene expression patterns in the chorioamniotic membranes link neurocognitive impairment in preterm infants to neurodegenerative disease pathways and might be used to predict neurocognitive impairment. Further prospective studies are needed.
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Affiliation(s)
- Athina Pappas
- Perinatology Research Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development / NIH / DHHS, Bethesda, MD and Detroit, MI, United States of America
- Department of Pediatrics, Division of Neonatal and Perinatal Medicine, Wayne State University, Detroit, MI, United States of America
- * E-mail: (AP); (AT)
| | - Tinnakorn Chaiworapongsa
- Perinatology Research Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development / NIH / DHHS, Bethesda, MD and Detroit, MI, United States of America
- Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI, United States of America
| | - Roberto Romero
- Perinatology Research Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development / NIH / DHHS, Bethesda, MD and Detroit, MI, United States of America
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI, United States of America
- Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, MI, United States of America
| | - Steven J. Korzeniewski
- Perinatology Research Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development / NIH / DHHS, Bethesda, MD and Detroit, MI, United States of America
- Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI, United States of America
- Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, MI, United States of America
| | - Josef C. Cortez
- Perinatology Research Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development / NIH / DHHS, Bethesda, MD and Detroit, MI, United States of America
- Department of Pediatrics, Division of Neonatal and Perinatal Medicine, Wayne State University, Detroit, MI, United States of America
| | - Gaurav Bhatti
- Perinatology Research Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development / NIH / DHHS, Bethesda, MD and Detroit, MI, United States of America
| | - Nardhy Gomez-Lopez
- Perinatology Research Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development / NIH / DHHS, Bethesda, MD and Detroit, MI, United States of America
- Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI, United States of America
- Department of Immunology and Microbiology, Wayne State University, Detroit, MI, United States of America
| | - Sonia S. Hassan
- Perinatology Research Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development / NIH / DHHS, Bethesda, MD and Detroit, MI, United States of America
- Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI, United States of America
| | - Seetha Shankaran
- Perinatology Research Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development / NIH / DHHS, Bethesda, MD and Detroit, MI, United States of America
- Department of Pediatrics, Division of Neonatal and Perinatal Medicine, Wayne State University, Detroit, MI, United States of America
| | - Adi L. Tarca
- Perinatology Research Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development / NIH / DHHS, Bethesda, MD and Detroit, MI, United States of America
- Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI, United States of America
- * E-mail: (AP); (AT)
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Puscheck EE, Awonuga AO, Yang Y, Jiang Z, Rappolee DA. Molecular biology of the stress response in the early embryo and its stem cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 843:77-128. [PMID: 25956296 DOI: 10.1007/978-1-4939-2480-6_4] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Stress is normal during early embryogenesis and transient, elevated stress is commonplace. Stress in the milieu of the peri-implantation embryo is a summation of maternal hormones, and other elements of the maternal milieu, that signal preparedness for development and implantation. Examples discussed here are leptin, adrenaline, cortisol, and progesterone. These hormones signal maternal nutritional status and provide energy, but also signal stress that diverts maternal and embryonic energy from an optimal embryonic developmental trajectory. These hormones communicate endocrine maternal effects and local embryonic effects although signaling mechanisms are not well understood. Other in vivo stresses affect the embryo such as local infection and inflammation, hypoxia, environmental toxins such as benzopyrene, dioxin, or metals, heat shock, and hyperosmotic stress due to dehydration or diabetes. In vitro, stresses include shear during handling, improper culture media and oxygen levels, cryopreservation, and manipulations of the embryo to introduce sperm or mitochondria. We define stress as any stimulus that slows stem cell accumulation or diminishes the ability of cells to produce normal and sufficient parenchymal products upon differentiation. Thus stress deflects downwards the normal trajectories of development, growth and differentiation. Typically stress is inversely proportional to embryonic developmental and proliferative rates, but can be proportional to induction of differentiation of stem cells in the peri-implantation embryo. When modeling stress it is most interesting to produce a 'runting model' where stress exposures slow accumulation but do not create excessive apoptosis or morbidity. Windows of stress sensitivity may occur when major new embryonic developmental programs require large amounts of energy and are exacerbated if nutritional flow decreases and removes energy from the normal developmental programs and stress responses. These windows correspond to zygotic genome activation, the large mRNA program initiated at compaction, ion pumping required for cavitation, the differentiation of the first lineages, integration with the uterine environment at implantation, rapid proliferation of stem cells, and production of certain lineages which require the highest energy and are most sensitive to mitochondrial inhibition. Stress response mechanisms insure that stem cells for the early embryo and placenta survive at lower stress exposures, and that the organism survives through compensatory and prioritized stem cell differentiation, at higher stress exposures. These servomechanisms include a small set of stress enzymes from the 500 protein kinases in the kinome; the part of the genome coding for protein kinases that hierarchically regulate the activity of other proteins and enzymes. Important protein kinases that mediate the stress response of embryos and their stem cells are SAPK, p38MAPK, AMPK, PI3K, Akt, MEK1/2, MEKK4, PKA, IRE1 and PERK. These stress enzymes have cytosolic function in cell survival at low stress exposures and nuclear function in modifying transcription factor activity at higher stress exposures. Some of the transcription factors (TFs) that are most important in the stress response are JunC, JunB, MAPKAPs, ATF4, XBP1, Oct1, Oct4, HIFs, Nrf2/KEAP, NFKB, MT1, Nfat5, HSF1/2 and potency-maintaining factors Id2, Cdx2, Eomes, Sox2, Nanog, Rex1, and Oct4. Clearly the stress enzymes have a large number of cytosolic and nuclear substrates and the TFs regulate large numbers of genes. The interaction of stress enzymes and TFs in the early embryo and its stem cells are a continuing central focus of research. In vitro regulation of TFs by stress enzymes leads to reprogramming of the stem cell when stress diminishes stem cell accumulation. Since more differentiated product is produced by fewer cells, the process compensates for fewer cells. Coupled with stress-induced compensatory differentiation of stem cells is a tendency to prioritize differentiation by increasing the first essential lineage and decreasing later lineages. These mechanisms include stress enzymes that regulate TFs and provide stress-specific, shared homeostatic cellular and organismal responses of prioritized differentiation.
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Affiliation(s)
- Elizabeth E Puscheck
- Department of Ob/Gyn, REI Division, Wayne State University School of Medicine, Detroit, MI, USA
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19
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Rosario CO, Kazazian K, Zih FSW, Brashavitskaya O, Haffani Y, Xu RSZ, George A, Dennis JW, Swallow CJ. A novel role for Plk4 in regulating cell spreading and motility. Oncogene 2014; 34:3441-51. [PMID: 25174401 DOI: 10.1038/onc.2014.275] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Revised: 07/01/2014] [Accepted: 07/19/2014] [Indexed: 12/18/2022]
Abstract
Polo family kinase 4 (Plk4) is required for mitotic progression, and is haploinsufficient for tumor suppression and timely hepatocyte polarization in regenerating liver. At the same time, recent evidence suggests that Plk4 expression may have a role in clinical cancer progression, although the mechanisms are not clear. Here we identify a gene expression pattern predictive of reduced motility in Plk4(+/-) murine embryonic fibroblasts (MEFs) and validate this prediction with functional assays of cell spreading, migration and invasion. Increased Plk4 expression enhances cell spreading in Plk4(+/-) MEFs and migration in human embryonic kidney 293T cells, and increases invasion by DLD-1 colon cancer cells. Plk4 depletion impairs invasion of wild-type MEFs and suppresses invasion by MDA-MB231 breast cancer cells. Cytoskeletal reorganization and development of polarity are impaired in Plk4-deficient cells that have been stimulated to migrate. Endogenous Plk4 phosphorylated at the autophosphorylation site S305 localizes to the protrusions of motile cells, coincident with the RhoA GEF Ect2, GTP-bound RhoA and the RhoA effector mDia. Taken together, our findings reveal an unexpected activity of Plk4 that promotes cell migration and may underlie an association between increased Plk4 expression, cancer progression and death from metastasis in solid tumor patients.
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Affiliation(s)
- C O Rosario
- 1] Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada [2] Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - K Kazazian
- 1] Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada [2] Department of Surgery, University of Toronto, Toronto, ON, Canada [3] Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - F S W Zih
- 1] Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada [2] Department of Surgery, University of Toronto, Toronto, ON, Canada [3] Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - O Brashavitskaya
- 1] Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada [2] Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Y Haffani
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - R S Z Xu
- 1] Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada [2] Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - A George
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - J W Dennis
- 1] Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada [2] Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada [3] Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - C J Swallow
- 1] Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada [2] Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada [3] Department of Surgery, University of Toronto, Toronto, ON, Canada [4] Institute of Medical Science, University of Toronto, Toronto, ON, Canada
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Integrative epigenome analysis identifies a Polycomb-targeted differentiation program as a tumor-suppressor event epigenetically inactivated in colorectal cancer. Cell Death Dis 2014; 5:e1324. [PMID: 25032847 PMCID: PMC4123077 DOI: 10.1038/cddis.2014.283] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 05/26/2014] [Accepted: 05/27/2014] [Indexed: 12/14/2022]
Abstract
Aberrant DNA hypermethylation in human cancer has been associated with Polycomb target genes in embryonic stem (ES) cells, but a functional link of the Polycomb-targeted differentiation program to tumorigenesis remains to be established. Here, through epigenome analysis correlating DNA hypermethylation in colon cancer with ES cell pluripotency and differentiation, we identified a set of DNA hypermethylated genes in cancer cells that are Polycomb targets strongly associated with ES cell differentiation, including HAND1, a developmental regulator. Intriguingly, HAND1 is silenced in over 90% of human primary colorectal tumors, and re-expression of HAND1 in colon cancer cells induces terminal differentiation, inhibits proliferation and prevents xenograft tumor formation. Moreover, hypermethylated HAND1 has a minimum enrichment of EZH2-H3K27me3 in cancer cells, but becomes EZH2 bound and bivalent upon the loss of DNA methylation, suggesting a sequential gene silencing event during oncogenesis. These findings established a functional role of Polycomb-targeted differentiation program as a tumor-suppressor event epigenetically inactivated in human cancer.
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21
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RAS/ERK signaling controls proneural genetic programs in cortical development and gliomagenesis. J Neurosci 2014; 34:2169-90. [PMID: 24501358 DOI: 10.1523/jneurosci.4077-13.2014] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Neural cell fate specification is well understood in the embryonic cerebral cortex, where the proneural genes Neurog2 and Ascl1 are key cell fate determinants. What is less well understood is how cellular diversity is generated in brain tumors. Gliomas and glioneuronal tumors, which are often localized in the cerebrum, are both characterized by a neoplastic glial component, but glioneuronal tumors also have an intermixed neuronal component. A core abnormality in both tumor groups is overactive RAS/ERK signaling, a pro-proliferative signal whose contributions to cell differentiation in oncogenesis are largely unexplored. We found that RAS/ERK activation levels differ in two distinct human tumors associated with constitutively active BRAF. Pilocytic astrocytomas, which contain abnormal glial cells, have higher ERK activation levels than gangliogliomas, which contain abnormal neuronal and glial cells. Using in vivo gain of function and loss of function in the mouse embryonic neocortex, we found that RAS/ERK signals control a proneural genetic switch, inhibiting Neurog2 expression while inducing Ascl1, a competing lineage determinant. Furthermore, we found that RAS/ERK levels control Ascl1's fate specification properties in murine cortical progenitors--at higher RAS/ERK levels, Ascl1(+) progenitors are biased toward proliferative glial programs, initiating astrocytomas, while at moderate RAS/ERK levels, Ascl1 promotes GABAergic neuronal and less glial differentiation, generating glioneuronal tumors. Mechanistically, Ascl1 is phosphorylated by ERK, and ERK phosphoacceptor sites are necessary for Ascl1's GABAergic neuronal and gliogenic potential. RAS/ERK signaling thus acts as a rheostat to influence neural cell fate selection in both normal cortical development and gliomagenesis, controlling Neurog2-Ascl1 expression and Ascl1 function.
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22
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Asuthkar S, Gogineni VR, Rao JS, Velpula KK. Nuclear Translocation of Hand-1 Acts as a Molecular Switch to Regulate Vascular Radiosensitivity in Medulloblastoma Tumors: The Protein uPAR Is a Cytoplasmic Sequestration Factor for Hand-1. Mol Cancer Ther 2014; 13:1309-22. [DOI: 10.1158/1535-7163.mct-13-0892] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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23
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Tan T, Lu B, Zhang J, Niu Y, Si W, Wei Q, Ji W. Notch1 signaling antagonizes transforming growth factor-β pathway and induces apoptosis in rabbit trophoblast stem cells. Stem Cells Dev 2014; 23:813-22. [PMID: 24251382 DOI: 10.1089/scd.2013.0280] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
During mammalian development, placental growth needs to be tightly controlled by apoptosis. However, despite the potentially significant problems, the strategies used to balance growth and apoptosis have remained elusive. Here we report that activation of the Notch1 signal pathway inhibits transduction of transforming growth factor (TGF)-β signaling, which leads to cell cycle arrest and apoptosis in rabbit trophoblast stem cells (TSCs). The subcellular location of notch intracellular domain 1 (NICD1) appears to determine whether TGF-β signaling will be inhibited or not. Moreover, changes in NICD1 subcellular location are regulated by intracellular calcium distribution. Collectively, these results establish a potential mechanism whereby TSCs can balance growth and apoptosis, and thus guarantee the development of the fetus.
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Affiliation(s)
- Tao Tan
- 1 Yunnan Key Laboratory of Primate Biomedical Research , Kunming, Yunnan, China
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24
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Spindle formation in the mouse embryo requires Plk4 in the absence of centrioles. Dev Cell 2013; 27:586-97. [PMID: 24268700 PMCID: PMC3898710 DOI: 10.1016/j.devcel.2013.09.029] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 08/07/2013] [Accepted: 09/30/2013] [Indexed: 12/16/2022]
Abstract
During the first five rounds of cell division in the mouse embryo, spindles assemble in the absence of centrioles. Spindle formation initiates around chromosomes, but the microtubule nucleating process remains unclear. Here we demonstrate that Plk4, a protein kinase known as a master regulator of centriole formation, is also essential for spindle assembly in the absence of centrioles. Depletion of maternal Plk4 prevents nucleation and growth of microtubules and results in monopolar spindle formation. This leads to cytokinesis failure and, consequently, developmental arrest. We show that Plk4 function depends on its kinase activity and its partner protein, Cep152. Moreover, tethering Cep152 to cellular membranes sequesters Plk4 and is sufficient to trigger spindle assembly from ectopic membranous sites. Thus, the Plk4-Cep152 complex has an unexpected role in promoting microtubule nucleation in the vicinity of chromosomes to mediate bipolar spindle formation in the absence of centrioles. Plk4 is at acentriolar MTOCs and spindle poles in mouse embryos Plk4 is essential for acentriolar spindle assembly Depletion of maternal Plk4 prevents normal nucleation and growth of microtubules Plk4 MT-nucleating function depends on its kinase activity and its partner, Cep152
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25
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Li ZF, Liang YM, Lau PN, Shen W, Wang DK, Cheung WT, Xue CJ, Poon LM, Lam YW. Dynamic localisation of mature microRNAs in Human nucleoli is influenced by exogenous genetic materials. PLoS One 2013; 8:e70869. [PMID: 23940654 PMCID: PMC3735495 DOI: 10.1371/journal.pone.0070869] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2012] [Accepted: 06/26/2013] [Indexed: 11/18/2022] Open
Abstract
Although microRNAs are commonly known to function as a component of RNA-induced silencing complexes in the cytoplasm, they have been detected in other organelles, notably the nucleus and the nucleolus, of mammalian cells. We have conducted a systematic search for miRNAs in HeLa cell nucleoli, and identified 11 abundant miRNAs with a high level of nucleolar accumulation. Through in situ hybridisation, we have localised these miRNAs, including miR-191 and miR-484, in the nucleolus of a diversity of human and rodent cell lines. The nucleolar association of these miRNAs is resistant to various cellular stresses, but highly sensitive to the presence of exogenous nucleic acids. Introduction of both single- and double-stranded DNA as well as double stranded RNA rapidly induce the redistribution of nucleolar miRNAs to the cytoplasm. A similar change in subcellular distribution is also observed in cells infected with the influenza A virus. The partition of miRNAs between the nucleolus and the cytoplasm is affected by Leptomycin B, suggesting a role of Exportin-1 in the intracellular shuttling of miRNAs. This study reveals a previously unknown aspect of miRNA biology, and suggests a possible link between these small noncoding RNAs and the cellular management of foreign genetic materials.
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Affiliation(s)
- Zhou Fang Li
- Departments of Biology and Chemistry, City University of Hong Kong, Hong Kong, China
| | - Yi Min Liang
- Departments of Biology and Chemistry, City University of Hong Kong, Hong Kong, China
| | - Pui Ngan Lau
- Centre of Influenza Research and School of Public Health, The University of Hong Kong, Hong Kong, China
| | - Wei Shen
- Departments of Biology and Chemistry, City University of Hong Kong, Hong Kong, China
| | - Dai Kui Wang
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Wing Tai Cheung
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Chun Jason Xue
- Departments of Computer Science, City University of Hong Kong, Hong Kong, China
| | - Lit Man Poon
- Centre of Influenza Research and School of Public Health, The University of Hong Kong, Hong Kong, China
| | - Yun Wah Lam
- Departments of Biology and Chemistry, City University of Hong Kong, Hong Kong, China
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26
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Hu D, Scott IC, Snider F, Geary-Joo C, Zhao X, Simmons DG, Cross JC. The basic helix-loop-helix transcription factor Hand1 regulates mouse development as a homodimer. Dev Biol 2013; 382:470-81. [PMID: 23911935 DOI: 10.1016/j.ydbio.2013.07.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 07/04/2013] [Accepted: 07/28/2013] [Indexed: 10/26/2022]
Abstract
Hand1 is a basic helix-loop-helix transcription factor that is essential for development of the placenta, yolk sac and heart during mouse development. While Hand1 is essential for trophoblast giant cell (TGC) differentiation, its potential heterodimer partners are not co-expressed in TGCs. To test the hypothesis that Hand1 functions as homodimer, we generated knock-in mice in which the Hand1 gene was altered to encode a tethered homodimer (TH). Some Hand1(TH/-) conceptuses in which the only form of Hand1 is Hand1(TH) are viable and fertile, indicating that homodimer Hand1 is sufficient for mouse survival. ~2/3 of Hand1(TH/-) and all Hand1(TH/TH) mice died in utero and displayed severe placental defects and variable cardial and cranial-facial abnormalities, indicating a dosage-dependent effect of Hand1(TH). Meanwhile, expression of the Hand1(TH) protein did not have negative effects on viability or fertility in all Hand1(TH/+) mice. These data imply that Hand1 homodimer plays a dominant role during development and its expression dosage is critical for survival, whereas Hand1 heterodimers can be either dispensable or play a regulatory role to modulate the activity of Hand1 homodimer in vivo.
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Affiliation(s)
- Dong Hu
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, Calgary, AB, Canada; Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada; Center for Stem Cell Application and Research, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
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27
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Perets R, Kaplan T, Stein I, Hidas G, Tayeb S, Avraham E, Ben-Neriah Y, Simon I, Pikarsky E. Genome-wide analysis of androgen receptor targets reveals COUP-TF1 as a novel player in human prostate cancer. PLoS One 2012; 7:e46467. [PMID: 23056316 PMCID: PMC3464259 DOI: 10.1371/journal.pone.0046467] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Accepted: 09/03/2012] [Indexed: 01/12/2023] Open
Abstract
Androgen activity plays a key role in prostate cancer progression. Androgen receptor (AR) is the main mediator of androgen activity in the prostate, through its ability to act as a transcription mediator. Here we performed a genome-wide analysis of human AR binding to promoters in the presence of an agonist or antagonist in an androgen dependent prostate cancer cell line. Many of the AR bound promoters are bound in all examined conditions while others are bound only in the presence of an agonist or antagonist. Several motifs are enriched in AR bound promoters, including the AR Response Element (ARE) half-site and recognition elements for the transcription factors OCT1 and SOX9. This suggests that these 3 factors could define a module of co-operating transcription factors in the prostate. Interestingly, AR bound promoters are preferentially located in AT rich genomic regions. Analysis of mRNA expression identified chicken ovalbumin upstream promoter-transcription factor 1 (COUP-TF1) as a direct AR target gene that is downregulated upon binding by the agonist liganded AR. COUP-TF1 immunostaining revealed nucleolar localization of COUP-TF1 in epithelium of human androgen dependent prostate cancer, but not in adjacent benign prostate epithelium. Stromal cells both in human and mouse prostate show nuclear COUP-TF1 staining. We further show that there is an inverse correlation between COUP-TF1 expression in prostate stromal cells and the rising levels of androgen with advancing puberty. This study extends the pool of recognized putative AR targets and identifies a negatively regulated target of AR – COUP-TF1 – which could possibly play a role in human prostate cancer.
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Affiliation(s)
- Ruth Perets
- Department of Pathology and Lautenberg center for immunology, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
- Division of Oncology, Rambam Health Care Campus, Haifa, Israel
| | - Tommy Kaplan
- Department of Molecular and Cell Biology, California Institute of Quantitative Biosciences, University of California, Berkeley, California, United States of America
- School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ilan Stein
- Department of Pathology and Lautenberg center for immunology, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Guy Hidas
- Department of Pathology and Lautenberg center for immunology, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
- Department of Urology, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Shay Tayeb
- Department of Pathology and Lautenberg center for immunology, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Eti Avraham
- Department of Pathology and Lautenberg center for immunology, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Yinon Ben-Neriah
- Department of Pathology and Lautenberg center for immunology, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Itamar Simon
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel Canada (IMRIC), The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Eli Pikarsky
- Department of Pathology and Lautenberg center for immunology, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
- * E-mail:
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28
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Ferraris SE, Isoniemi K, Torvaldson E, Anckar J, Westermarck J, Eriksson JE. Nucleolar AATF regulates c-Jun-mediated apoptosis. Mol Biol Cell 2012; 23:4323-32. [PMID: 22933572 PMCID: PMC3484108 DOI: 10.1091/mbc.e12-05-0419] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The AP-1 transcription factor c-Jun is essential for stress-induced apoptosis in several models. The apoptosis-antagonizing transcription factor is a novel nucleolar stress sensor, which is required as a cofactor for c-Jun–mediated apoptosis. The AP-1 transcription factor c-Jun has been shown to be essential for stress-induced apoptosis in several models. However, the molecular mechanisms underlying the proapoptotic activity of c-Jun are poorly understood. We identify the apoptosis-antagonizing transcription factor (AATF) as a novel nucleolar stress sensor, which is required as a cofactor for c-Jun–mediated apoptosis. Overexpression or down-regulation of AATF expression levels led to a respective increase or decrease in the amount of activated and phosphorylated c-Jun with a proportional alteration in the induction levels of the proapoptotic c-Jun target genes FasL and TNF-α. Accordingly, AATF promoted commitment of ultraviolet (UV)-irradiated cells to c-Jun-dependent apoptosis. Whereas AATF overexpression potentiated UV-induced apoptosis in wild-type cells, c-Jun–deficient mouse embryonic fibroblasts were resistant to AATF-mediated apoptosis induction. Furthermore, AATF mutants defective in c-Jun binding were also defective in inducing AP-1 activity and c-Jun–mediated apoptosis. UV irradiation induced a translocation of AATF from the nucleolus to the nucleus, thereby enabling its physical association to c-Jun. Analysis of AATF deletion mutants revealed that the AATF domains required for compartmentalization, c-Jun binding, and enhancement of c-Jun transcriptional activity were all also required to induce c-Jun–dependent apoptosis. These results identify AATF as a nucleolar-confined c-Jun cofactor whose expression levels and spatial distribution determine the stress-induced activity of c-Jun and the levels of c-Jun–mediated apoptosis.
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Affiliation(s)
- Saima E Ferraris
- Department of Biosciences, Åbo Akademi University, FIN-20521 Turku, Finland
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29
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Baumbach J, Levesque MP, Raff JW. Centrosome loss or amplification does not dramatically perturb global gene expression in Drosophila. Biol Open 2012; 1:983-93. [PMID: 23213376 PMCID: PMC3507170 DOI: 10.1242/bio.20122238] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Accepted: 06/29/2012] [Indexed: 12/19/2022] Open
Abstract
Centrosome defects are a common feature of many cancers, and they can predispose fly brain cells to form tumours. In flies, centrosome defects perturb the asymmetric division of the neural stem cells, but it is unclear how this might lead to malignant transformation. One possibility is that centrosome defects might also perturb cellular homeostasis: for example, stress pathways are often activated in response to centrosome defects in cultured cells, and stress contributes to tumourigenesis in some fly models. Here we attempt to assess whether centrosome loss or centrosome amplification perturbs cell physiology in vivo by profiling the global transcriptome of Drosophila larval brains and imaginal discs that either lack centrosomes or have too many centrosomes. Surprisingly, we find that centrosome loss or amplification leads to few changes in the transcriptional profile of these cells, indicating that centrosome defects are surprisingly well tolerated by these cells. These observations indicate that centrosome defects can predispose fly brain cells to form tumours without, at least initially, dramatically altering their physiology.
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Affiliation(s)
- Janina Baumbach
- Sir William Dunn School of Pathology, University of Oxford , South Parks Road, Oxford OX1 3RE , UK
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30
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Vincentz JW, Barnes RM, Firulli AB. Hand factors as regulators of cardiac morphogenesis and implications for congenital heart defects. BIRTH DEFECTS RESEARCH. PART A, CLINICAL AND MOLECULAR TERATOLOGY 2011; 91:485-94. [PMID: 21462297 PMCID: PMC3119928 DOI: 10.1002/bdra.20796] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 01/06/2011] [Accepted: 02/02/2011] [Indexed: 11/08/2022]
Abstract
Almost 15 years of careful study have established the related basic Helix-Loop-Helix (bHLH) transcription factors Hand1 and Hand2 as critical for heart development across evolution. Hand factors make broad contributions, revealed through animal models, to the development of multiple cellular lineages that ultimately contribute to the heart. They perform critical roles in ventricular cardiomyocyte growth, differentiation, morphogenesis, and conduction. They are also important for the proper development of the cardiac outflow tract, epicardium, and endocardium. Molecularly, they function both through DNA binding and through protein-protein interactions, which are regulated transcriptionally, posttranscriptionally by microRNAs, and posttranslationally through phosphoregulation. Although direct Hand factor transcriptional targets are progressively being identified, confirmed direct targets of Hand factor transcriptional activity in the heart are limited. Identification of these targets will be critical to model the mechanisms by which Hand factor bHLH interactions affect developmental pathways. Improved understanding of Hand factor-mediated transcriptional cascades will be necessary to determine how Hand factor dysregulation translates to human disease phenotypes. This review summarizes the insight that animal models have provided into the regulation and function of these factors during heart development, in addition to the recent findings that suggest roles for HAND1 and HAND2 in human congenital heart disease.
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Affiliation(s)
- Joshua W. Vincentz
- Riley Heart Research Center, Wells Center for Pediatric Research, Division of Pediatric Cardiology, Departments of Anatomy, Biochemistry and Medical and Molecular Genetics, Indiana Medical School, 1044 W. Walnut St., Indianapolis, IN 46202-5225, USA
| | - Ralston M. Barnes
- Riley Heart Research Center, Wells Center for Pediatric Research, Division of Pediatric Cardiology, Departments of Anatomy, Biochemistry and Medical and Molecular Genetics, Indiana Medical School, 1044 W. Walnut St., Indianapolis, IN 46202-5225, USA
| | - Anthony B. Firulli
- Riley Heart Research Center, Wells Center for Pediatric Research, Division of Pediatric Cardiology, Departments of Anatomy, Biochemistry and Medical and Molecular Genetics, Indiana Medical School, 1044 W. Walnut St., Indianapolis, IN 46202-5225, USA
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31
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Lu S, Nie J, Luan Q, Feng Q, Xiao Q, Chang Z, Shan C, Hess D, Hemmings BA, Yang Z. Phosphorylation of the Twist1-family basic helix-loop-helix transcription factors is involved in pathological cardiac remodeling. PLoS One 2011; 6:e19251. [PMID: 21559426 PMCID: PMC3084786 DOI: 10.1371/journal.pone.0019251] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Accepted: 03/24/2011] [Indexed: 01/12/2023] Open
Abstract
Background The Twist1-family basic helix-loop-helix (bHLH) transcription factors including Twist1, Hand1 and Hand2, play an essential role in heart development and are implicated in pathological heart remodeling. Previously, it was reported that these bHLH transcription factors can be regulated by phosphorylation within the basic-helix I domain, which is involved in developmental processes such as limb formation and trophoblast differentiation. However, how phosphorylation of Twist1 family functions in post-natal heart is elusive. Principal Findings Here, we generated transgenic mice with over-expression of Hand1 and Twist1 mutants (to mimic or to abolish phosphorylation) in cardiomyocytes and found pathological cardiac remodeling leading to heart failure and sudden death. Gene expression profile analysis revealed up-regulation of growth-promoting genes and down-regulation of metabolic genes. It is well known that aberrant activation of Akt signaling causes pathological cardiac remodeling and results in heart failure. The basic-helix I domain of Twist1 family members contain Akt substrate consensus motif and may be downstream targets of Akt signaling. Using biochemical analysis, we demonstrated that Hand1 and Twist1 were phosphorylated by Akt in the basic-helix I domain. Phosphorylation of Hand1 regulated its transcriptional activation of luciferase reporter genes and DNA binding ability. Conclusions This study provides novel insights into the regulation of Twist1 family in cardiac remodeling and suggests that the Twist1 family can be regulated by Akt signaling.
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Affiliation(s)
- Shuangshuang Lu
- The Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Junwei Nie
- The Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Qing Luan
- The Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Qiuting Feng
- The Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Qi Xiao
- The Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Zai Chang
- The Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Congjia Shan
- The Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing, China
| | - Daniel Hess
- The Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Brian A. Hemmings
- The Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Zhongzhou Yang
- The Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing, China
- * E-mail:
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32
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Hoya-Arias R, Tomishima M, Perna F, Voza F, Nimer SD. L3MBTL1 deficiency directs the differentiation of human embryonic stem cells toward trophectoderm. Stem Cells Dev 2011; 20:1889-900. [PMID: 21341991 DOI: 10.1089/scd.2010.0437] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Human embryonic stem cells (hESCs) can be used to study the early events in human development and, hopefully, to understand how to differentiate human pluripotent cells for clinical use. To define how L3MBTL1, a chromatin-associated polycomb group protein with transcriptional repressive activities, regulates early events in embryonic cell differentiation, we created hESC lines that constitutively express shRNAs directed against L3MBTL1. The L3MBTL1 knockdown (KD) hESCs maintained normal morphology, proliferation, cell cycle kinetics, cell surface markers, and karyotype after 40 passages. However, under conditions that promote spontaneous differentiation, the L3MBTL1 KD cells differentiated into a relatively homogeneous population of large, flat trophoblast-like cells, unlike the multilineage differentiation seen with the control cells. The differentiated L3MBTL1 KD cells expressed numerous trophoblast markers and secreted placental hormones. Although the L3MBTL1 KD cells could be induced to differentiate into various embryonic lineages, they adopted an exclusive trophoblast fate during spontaneous differentiation. Our data demonstrate that depletion of L3MBTL1 does not affect hESC self-renewal, rather it enhances differentiation toward extra-embryonic trophoblast tissues.
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Affiliation(s)
- Ruben Hoya-Arias
- Molecular Pharmacology and Chemistry Program, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, New York 10065, USA
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Abstract
When cells are observed by phase contrast microscopy, nucleoli are among the most conspicuous structures. The nucleolus was formally described between 1835 and 1839, but it was another century before it was discovered to be associated with a specific chromosomal locus, thus defining it as a cytogenetic entity. Nucleoli were first isolated in the 1950s, from starfish oocytes. Then, in the early 1960s, a boomlet of studies led to one of the epochal discoveries in the modern era of genetics and cell biology: that the nucleolus is the site of ribosomal RNA synthesis and nascent ribosome assembly. This epistemologically repositioned the nucleolus as not merely an aspect of nuclear anatomy but rather as a cytological manifestation of gene action-a major heuristic advance. Indeed, the finding that the nucleolus is the seat of ribosome production constitutes one of the most vivid confluences of form and function in the history of cell biology. This account presents the nucleolus in both historical and contemporary perspectives. The modern era has brought the unanticipated discovery that the nucleolus is plurifunctional, constituting a paradigm shift.
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Affiliation(s)
- Thoru Pederson
- Program in Cell and Developmental Dynamics, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, 01605, USA.
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Sakaue-Sawano A, Kobayashi T, Ohtawa K, Miyawaki A. Drug-induced cell cycle modulation leading to cell-cycle arrest, nuclear mis-segregation, or endoreplication. BMC Cell Biol 2011; 12:2. [PMID: 21226962 PMCID: PMC3277280 DOI: 10.1186/1471-2121-12-2] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Accepted: 01/13/2011] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Cancer cell responses to chemotherapeutic agents vary, and this may reflect different defects in DNA repair, cell-cycle checkpoints, and apoptosis control. Cytometry analysis only quantifies dye-incorporation to examine DNA content and does not reflect the biological complexity of the cell cycle in drug discovery screens. RESULTS Using population and time-lapse imaging analyses of cultured immortalized cells expressing a new version of the fluorescent cell-cycle indicator, Fucci (Fluorescent Ubiquitination-based Cell Cycle Indicator), we found great diversity in the cell-cycle alterations induced by two anticancer drugs. When treated with etoposide, an inhibitor of DNA topoisomerase II, HeLa and NMuMG cells halted at the G2/M checkpoint. HeLa cells remained there, but NMuMG cells then overrode the checkpoint and underwent nuclear mis-segregation or avoided the checkpoint and entered the endoreplication cycle in a drug concentration dependent manner. In contrast, an inhibitor of Cdk4 led to G1 arrest or endoreplication in NMuMG cells depending upon the initial cell-cycle phase of drug exposure. CONCLUSIONS Drug-induced cell cycle modulation varied not only between different cell types or following treatment with different drugs, but also between cells treated with different concentrations of the same drug or following drug addition during different phases of the cell cycle. By combining cytometry analysis with the Fucci probe, we have developed a novel assay that fully integrates the complexity of cell cycle regulation into drug discovery screens. This assay system will represent a powerful drug-discovery tool for the development of the next generation of anti-cancer therapies.
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Affiliation(s)
- Asako Sakaue-Sawano
- Life Function and Dynamics, ERATO, JST, 2-1 Hirosawa, Wako-city, Saitama 351-0198, Japan
- Laboratory for Cell Function and Dynamics, Advanced Technology Development Group, Brain Science Institute, RIKEN, 2-1 Hirosawa, Wako-city, Saitama 351-0198, Japan
| | - Tamiyo Kobayashi
- MIS Division, Olympus Corp., 2-3 Kuboyama-cho, Hachioji, Tokyo 192-8512, Japan
| | - Kenji Ohtawa
- Brain Science Research Division, Brain Science and Life Technology, Research Foundation, 1-28-12 Narimasu, Itabashi, Tokyo 175-0094, Japan
| | - Atsushi Miyawaki
- Life Function and Dynamics, ERATO, JST, 2-1 Hirosawa, Wako-city, Saitama 351-0198, Japan
- Laboratory for Cell Function and Dynamics, Advanced Technology Development Group, Brain Science Institute, RIKEN, 2-1 Hirosawa, Wako-city, Saitama 351-0198, Japan
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Xie Y, Awonuga AO, Zhou S, Puscheck EE, Rappolee DA. Interpreting the stress response of early mammalian embryos and their stem cells. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2011; 287:43-95. [PMID: 21414586 DOI: 10.1016/b978-0-12-386043-9.00002-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
This review analyzes and interprets the normal, pathogenic, and pathophysiological roles of stress and stress enzymes in mammalian development. Emerging data suggest that stem cells from early embryos are induced by stress to perform stress-enzyme-mediated responses that use the strategies of compensatory, prioritized, and reversible differentiation. These strategies have been optimized during evolution and in turn have aspects of energy conservation during stress that optimize and maximize the efficacy of the stress response. It is likely that different types of stem cells have varying degrees of flexibility in mediating compensatory and prioritized differentiation. The significance of this analysis and interpretation is that it will serve as a foundation for yielding tools for diagnosing, understanding normal and pathophysiological mechanisms, and providing methods for managing stress enzymes to improve short- and long-term reproductive outcomes.
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Affiliation(s)
- Y Xie
- CS Mott Center for Human Growth and Development, Wayne State University School of Medicine, Detroit, Michigan, USA
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Abstract
Cell specification and differentiation of cardiomyocytes from mesodermal precursors is orchestrated by epigenetic and transcriptional inputs throughout heart formation. Of the many transcription factor super families that play a role in this process, the basic Helix-loop Helix (bHLH) family of proteins is well represented. The bHLH protein by design allows for dimerization-both as homodimers and heterodimers with other proteins within the family. Although DNA binding is mediated via a short variable cis-element termed an E-box, it is clear that DNA-affinity for these elements as well as the transcriptional input conveyed is dictated largely by the transcriptional partners within the dimer complex. Dimer partner choice has a number of inputs requiring co-expression within a given cell nucleus and dimerization modulation by the level of protein present, and post-translational modifications that can both enhance or reduce protein-protein interactions. Due to these complex interrelationships, it has been difficult to identity bona-fide downstream transcriptional targets and define the molecular pathways regulated of bHLH factors within cardiogenesis, despite the clear roles suggested via loss-of-function animals models. This review focuses on the Hand bHLH proteins-key members of the Twist-family of bHLH factors. Despite over a decade of investigation, questions regarding functional redundancy, downstream targets, and biological role during heart specification and differentiation have still not been fully addressed. Our goal is to review what is currently known and address strategies for gaining further understanding of Hand/Twist gene dosage and functional redundancy relationships within the developing heart that may underlie congenital heart defect pathogenesis.
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Affiliation(s)
- Simon J Conway
- Division of Pediatric Cardiology, Department Anatomy, Riley Heart Research Center, Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, 1044 W. Walnut St, Indianapolis, IN 46202-5225, USA
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Meteleva-Fischer YV, Von Hauff E, Parisi J. Electrochemical synthesis of polypyrrole layers doped with glutamic ions. J Appl Polym Sci 2009. [DOI: 10.1002/app.31079] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Torres R, Ramirez JC. A chemokine targets the nucleus: Cxcl12-gamma isoform localizes to the nucleolus in adult mouse heart. PLoS One 2009; 4:e7570. [PMID: 19859557 PMCID: PMC2762742 DOI: 10.1371/journal.pone.0007570] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Accepted: 10/01/2009] [Indexed: 12/18/2022] Open
Abstract
Chemokines are extracellular mediators of complex regulatory circuits involved principally in cell-to-cell communication. Most studies to date of the essential chemokine Cxcl12 (Sdf-1) have focused on the ubiquitously expressed secreted isoforms α and β. Here we show that, unlike these isoforms and all other known chemokines, the alternatively transcribed γ isoform is an intracellular protein that localizes to the nucleolus in differentiated mouse Cardiac tissue. Our results demonstrate that nucleolar transportation is encoded by a nucleolar-localization signal in the unique carboxy-terminal region of Sdf-1γ, and is competent both in vivo and in vitro. The molecular mechanism underlying these unusual chemokine properties involves cardiac-specific transcription of an mRNA containing a unique short-leader sequence lacking the signal peptide and translation from a non-canonical CUG codon. Our results provide an example of genome economy even for essential and highly conserved genes such as Cxcl12, and suggest that chemokines can exert tissue specific functions unrelated to cell-to-cell communication.
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Affiliation(s)
- Raul Torres
- Viral Vector Facility, Technical Unit of Gene Targeting, Fundacion CNIC National Centre for Cardiovascular Research, Madrid, Spain
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Abstract
The 35S ribosomal RNA genes (rDNA) are organized as repeated arrays in many organisms. Epigenetic regulation of transcription of the rRNA results in only a subset of copies being transcribed, making rDNA an important model for understanding epigenetic chromatin modification. We have created an allelic series of deletions within the rDNA array of the Drosophila Y chromosome that affect nucleolus size and morphology, but do not limit steady-state rRNA concentrations. These rDNA deletions result in reduced heterochromatin-induced gene silencing elsewhere in the genome, and the extent of the rDNA deletion correlates with the loss of silencing. Consistent with this, chromosomes isolated from strains mutated in genes required for proper heterochromatin formation have very small rDNA arrays, reinforcing the connection between heterochromatin and the rDNA. In wild-type cells, which undergo spontaneous natural rDNA loss, we observed the same correlation between loss of rDNA and loss of heterochromatin-induced silencing, showing that the volatility of rDNA arrays may epigenetically influence gene expression through normal development and differentiation. We propose that the rDNA contributes to a balance between heterochromatin and euchromatin in the nucleus, and alterations in rDNA--induced or natural--affect this balance.
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El-Hashash AHK, Warburton D, Kimber SJ. Genes and signals regulating murine trophoblast cell development. Mech Dev 2009; 127:1-20. [PMID: 19755154 DOI: 10.1016/j.mod.2009.09.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2009] [Revised: 09/05/2009] [Accepted: 09/08/2009] [Indexed: 11/25/2022]
Abstract
A fundamental step in embryonic development is cell differentiation whereby highly specialised cell types are developed from a single undifferentiated, fertilised egg. One of the earliest lineages to form in the mammalian conceptus is the trophoblast, which contributes exclusively to the extraembryonic structures that form the placenta. Trophoblast giant cells (TGCs) in the rodent placenta form the outermost layer of the extraembryonic compartment, establish direct contact with maternal cells, and produce a number of pregnancy-specific cytokine hormones. Giant cells differentiate from proliferative trophoblasts as they exit the cell cycle and enter a genome-amplifying endocycle. Normal differentiation of secondary TGCs is a critical step toward the formation of the placenta and normal embryonic development. Trophoblast development is also of particular interest to the developmental biologist and immunobiologist, as these cells constitute the immediate cellular boundary between the embryonic and maternal tissues. Abnormalities in the development of secondary TGCs results in severe malfunction of the placenta. Herein we review new information that has been accumulated recently regarding the molecular and cellular regulation of trophoblast and placenta development. In particular, we discuss the molecular aspects of murine TGC differentiation. We also focus on the role of growth and transcription factors in TGC development.
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Affiliation(s)
- Ahmed H K El-Hashash
- Developmental Biology, Saban Research Institute, Children's Hospital Los Angeles, Keck School of Medicine of University of Southern California, Los Angeles, CA 90027, USA
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Pitulescu ME, Teichmann M, Luo L, Kessel M. TIPT2 and geminin interact with basal transcription factors to synergize in transcriptional regulation. BMC BIOCHEMISTRY 2009; 10:16. [PMID: 19515240 PMCID: PMC2702275 DOI: 10.1186/1471-2091-10-16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Accepted: 06/10/2009] [Indexed: 12/20/2022]
Abstract
BACKGROUND The re-replication inhibitor Geminin binds to several transcription factors including homeodomain proteins, and to members of the polycomb and the SWI/SNF complexes. RESULTS Here we describe the TATA-binding protein-like factor-interacting protein (TIPT) isoform 2, as a strong binding partner of Geminin. TIPT2 is widely expressed in mouse embryonic and adult tissues, residing both in cyto- and nucleoplasma, and enriched in the nucleolus. Like Geminin, also TIPT2 interacts with several polycomb factors, with the general transcription factor TBP (TATA box binding protein), and with the related protein TBPL1 (TRF2). TIPT2 synergizes with geminin and TBP in the activation of TATA box-containing promoters, and with TBPL1 and geminin in the activation of the TATA-less NF1 promoter. Geminin and TIPT2 were detected in the chromatin near TBP/TBPL1 binding sites. CONCLUSION Together, our study introduces a novel transcriptional regulator and its function in cooperation with chromatin associated factors and the basal transcription machinery.
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Affiliation(s)
- Mara E Pitulescu
- Department of Molecular Cell Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.
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Yang Z, MacQuarrie KL, Analau E, Tyler AE, Dilworth FJ, Cao Y, Diede SJ, Tapscott SJ. MyoD and E-protein heterodimers switch rhabdomyosarcoma cells from an arrested myoblast phase to a differentiated state. Genes Dev 2009; 23:694-707. [PMID: 19299559 DOI: 10.1101/gad.1765109] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Rhabdomyosarcomas are characterized by expression of myogenic specification genes, such as MyoD and/or Myf5, and some muscle structural genes in a population of cells that continues to replicate. Because MyoD is sufficient to induce terminal differentiation in a variety of cell types, we have sought to determine the molecular mechanisms that prevent MyoD activity in human embryonal rhabdomyosarcoma cells. In this study, we show that a combination of inhibitory Musculin:E-protein complexes and a novel splice form of E2A compete with MyoD for the generation of active full-length E-protein:MyoD heterodimers. A forced heterodimer between MyoD and the full-length E12 robustly restores differentiation in rhabdomyosarcoma cells and broadly suppresses multiple inhibitory pathways. Our studies indicate that rhabdomyosarcomas represent an arrested progress through a normal transitional state that is regulated by the relative abundance of heterodimers between MyoD and the full-length E2A proteins. The demonstration that multiple inhibitory mechanisms can be suppressed and myogenic differentiation can be induced in the RD rhabdomyosarcomas by increasing the abundance of MyoD:E-protein heterodimers suggests a central integrating function that can be targeted to force differentiation in muscle cancer cells.
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Affiliation(s)
- Zhihong Yang
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
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43
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Pederson T, Tsai RY. In search of nonribosomal nucleolar protein function and regulation. J Cell Biol 2009; 184:771-6. [PMID: 19289796 PMCID: PMC2699146 DOI: 10.1083/jcb.200812014] [Citation(s) in RCA: 126] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Accepted: 01/30/2009] [Indexed: 01/15/2023] Open
Abstract
The life of the nucleolus has proven to be more colorful and multifaceted than had been envisioned a decade ago. A large number of proteins found in this subnuclear compartment have no identifiable tie either to the ribosome biosynthetic pathway or to the other newly established activities occurring within the nucleolus. The questions of how and why these proteins end up in this subnuclear compartment remain unanswered and are the focus of intense current interest. This review discusses our thoughts on the discovery of nonribosomal proteins in the nucleolus.
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Affiliation(s)
- Thoru Pederson
- Program in Cell Dynamics, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Robert Y.L. Tsai
- Center for Cancer and Stem Cell Biology, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX 77030
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Salichs E, Ledda A, Mularoni L, Albà MM, de la Luna S. Genome-wide analysis of histidine repeats reveals their role in the localization of human proteins to the nuclear speckles compartment. PLoS Genet 2009; 5:e1000397. [PMID: 19266028 PMCID: PMC2644819 DOI: 10.1371/journal.pgen.1000397] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2008] [Accepted: 01/30/2009] [Indexed: 12/20/2022] Open
Abstract
Single amino acid repeats are prevalent in eukaryote organisms, although the role of many such sequences is still poorly understood. We have performed a comprehensive analysis of the proteins containing homopolymeric histidine tracts in the human genome and identified 86 human proteins that contain stretches of five or more histidines. Most of them are endowed with DNA- and RNA-related functions, and, in addition, there is an overrepresentation of proteins expressed in the brain and/or nervous system development. An analysis of their subcellular localization shows that 15 of the 22 nuclear proteins identified accumulate in the nuclear subcompartment known as nuclear speckles. This localization is lost when the histidine repeat is deleted, and significantly, closely related paralogous proteins without histidine repeats also fail to localize to nuclear speckles. Hence, the histidine tract appears to be directly involved in targeting proteins to this compartment. The removal of DNA-binding domains or treatment with RNA polymerase II inhibitors induces the re-localization of several polyhistidine-containing proteins from the nucleoplasm to nuclear speckles. These findings highlight the dynamic relationship between sites of transcription and nuclear speckles. Therefore, we define the histidine repeats as a novel targeting signal for nuclear speckles, and we suggest that these repeats are a way of generating evolutionary diversification in gene duplicates. These data contribute to our better understanding of the physiological role of single amino acid repeats in proteins. Single amino acid repeats are common in eukaryotic proteins. Some of them are associated with developmental and neurodegenerative disorders in humans, suggesting that they play important functions. However, the role of many of these repeats is unknown. Here, we have studied histidine repeats from a bioinformatics as well as a functional point of view. We found that only 86 proteins in the human genome contain stretches of five or more histidines, and that most of these proteins have functions related with RNA synthesis. When studying where these proteins localize in the cell, we found that a significant proportion accumulate in a subnuclear organelle known as nuclear speckles, via the histidine repeat. This is a structure where proteins related to the synthesis and processing of RNA accumulate. In some cases, the localization is transient and depends on the transcriptional requirements of the cell. Our findings are important because they identify a common cellular function for stretches of histidine residues, and they support the notion that histidine repeats contribute to generate evolutionary diversification. Finally, and considering that some of the proteins with histidine stretches are key elements in essential developmental processes, variation in these repeats would be expected to contribute to human disease.
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Affiliation(s)
- Eulàlia Salichs
- Genes and Disease Program, Centre de Regulació Genòmica (CRG), Barcelona, Spain
- El Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Barcelona, Spain
| | - Alice Ledda
- Biomedical Informatics Research Program, Institut Municipal d'Investigació Mèdica-IMIM, Barcelona, Spain
| | - Loris Mularoni
- Biomedical Informatics Research Program, Institut Municipal d'Investigació Mèdica-IMIM, Barcelona, Spain
| | - M. Mar Albà
- Biomedical Informatics Research Program, Institut Municipal d'Investigació Mèdica-IMIM, Barcelona, Spain
- Universitat Pompeu Fabra, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Susana de la Luna
- Genes and Disease Program, Centre de Regulació Genòmica (CRG), Barcelona, Spain
- El Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Barcelona, Spain
- Universitat Pompeu Fabra, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
- * E-mail:
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Immink RGH, Tonaco IAN, de Folter S, Shchennikova A, van Dijk ADJ, Busscher-Lange J, Borst JW, Angenent GC. SEPALLATA3: the 'glue' for MADS box transcription factor complex formation. Genome Biol 2009; 10:R24. [PMID: 19243611 PMCID: PMC2688274 DOI: 10.1186/gb-2009-10-2-r24] [Citation(s) in RCA: 200] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2008] [Revised: 12/16/2008] [Accepted: 02/25/2009] [Indexed: 11/10/2022] Open
Abstract
A yeast 3-hybrid screen in Arabidopsis reveals MADS box protein complexes: SEP3 is shown to mediate complex formation and floral timing. Background Plant MADS box proteins play important roles in a plethora of developmental processes. In order to regulate specific sets of target genes, MADS box proteins dimerize and are thought to assemble into multimeric complexes. In this study a large-scale yeast three-hybrid screen is utilized to provide insight into the higher-order complex formation capacity of the Arabidopsis MADS box family. SEPALLATA3 (SEP3) has been shown to mediate complex formation and, therefore, special attention is paid to this factor in this study. Results In total, 106 multimeric complexes were identified; in more than half of these at least one SEP protein was present. Besides the known complexes involved in determining floral organ identity, various complexes consisting of combinations of proteins known to play a role in floral organ identity specification, and flowering time determination were discovered. The capacity to form this latter type of complex suggests that homeotic factors play essential roles in down-regulation of the MADS box genes involved in floral timing in the flower via negative auto-regulatory loops. Furthermore, various novel complexes were identified that may be important for the direct regulation of the floral transition process. A subsequent detailed analysis of the APETALA3, PISTILLATA, and SEP3 proteins in living plant cells suggests the formation of a multimeric complex in vivo. Conclusions Overall, these results provide strong indications that higher-order complex formation is a general and essential molecular mechanism for plant MADS box protein functioning and attribute a pivotal role to the SEP3 'glue' protein in mediating multimerization.
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Affiliation(s)
- Richard G H Immink
- Plant Research International, Bioscience, Droevendaalsesteeg 1, Wageningen, the Netherlands.
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Amon A. A decade of Cdc14--a personal perspective. Delivered on 9 July 2007 at the 32nd FEBS Congress in Vienna, Austria. FEBS J 2009; 275:5774-84. [PMID: 19021755 DOI: 10.1111/j.1742-4658.2008.06693.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
In budding yeast, the protein phosphatase Cdc14 is a key regulator of late mitotic events. Research over the last decade has revealed many of its functions and today we know that this protein phosphatase orchestrates several aspects of chromosome segregation and is the key trigger of exit from mitosis. Elucidation of the mechanisms controlling Cdc14 activity through nucleolar sequestration now serves as a paradigm for how regulation of the subcellular localization of proteins regulates protein function. Here I review these findings focusing on how discoveries in my laboratory helped elucidate the function and regulation of Cdc14.
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Affiliation(s)
- Angelika Amon
- David H. Koch Institute for Integrative Cancer Research, Cambridge, MA, USA.
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Activation of an endogenous suicide response after perturbation of rRNA synthesis leads to neurodegeneration in mice. J Neurosci 2009; 28:12759-64. [PMID: 19036968 DOI: 10.1523/jneurosci.2439-08.2008] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Transcription of rRNA genes is essential for maintaining nucleolar integrity, a hallmark for the healthy state and proliferation rate of a cell. Inhibition of rRNA synthesis leads to disintegration of the nucleolus, elevated levels of p53, and induction of cell suicide, identifying the nucleolus as a critical stress sensor. Whether deregulation of rRNA synthesis is causally involved in neurodegeneration by promoting cell death and/or by inhibiting cellular growth has however not been addressed. The transcription factor TIF-IA plays a central role in mammalian rRNA synthesis, regulating the transcriptional activity of RNA polymerase I. To investigate the consequences of nucleolar perturbation in the nervous system, we have chosen to specifically ablate the gene encoding the transcription factor TIF-IA in two different contexts: neural progenitors and hippocampal neurons. Here, we show that ablation of TIF-IA leads to impaired nucleolar activity and results in increased levels of the proapoptotic transcription factor p53 in both neural progenitors and hippocampal neurons but induces rapid apoptosis only in neural progenitors. Nondividing cells of the adult hippocampus are more refractory to loss of rRNA transcription and face a protracted degeneration. Our study provides an unexploited strategy to initiate neurodegeneration based on perturbation of nucleolar function and underscores a novel perspective to study the cellular and molecular changes involved in the neurodegenerative processes.
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Abstract
The rDNA arrays in Drosophila contain the cis-acting nucleolus organizer regions responsible for forming the nucleolus and the genes for the 28S, 18S, and 5.8S/2S RNA components of the ribosomes and so serve a central role in protein synthesis. Mutations or alterations that affect the nucleolus organizer region have pleiotropic effects on genome regulation and development and may play a role in genomewide phenomena such as aging and cancer. We demonstrate a method to create an allelic series of graded deletions in the Drosophila Y-linked rDNA of otherwise isogenic chromosomes, quantify the size of the deletions using real-time PCR, and monitor magnification of the rDNA arrays as their functions are restored. We use this series to define the thresholds of Y-linked rDNA required for sufficient protein translation, as well as establish the rate of Y-linked rDNA magnification in Drosophila. Finally, we show that I-CreI expression can revert rDNA deletion phenotypes, suggesting that double-strand breaks are sufficient to induce rDNA magnification.
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50
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Funato N, Chapman SL, McKee MD, Funato H, Morris JA, Shelton JM, Richardson JA, Yanagisawa H. Hand2 controls osteoblast differentiation in the branchial arch by inhibiting DNA binding of Runx2. Development 2009; 136:615-25. [PMID: 19144722 DOI: 10.1242/dev.029355] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Members of the basic helix-loop-helix (bHLH) family of transcription factors regulate the specification and differentiation of numerous cell types during embryonic development. Hand1 and Hand2 are expressed by a subset of neural crest cells in the anterior branchial arches and are involved in craniofacial development. However, the precise mechanisms by which Hand proteins mediate biological actions and regulate downstream target genes in branchial arches is largely unknown. Here, we report that Hand2 negatively regulates intramembranous ossification of the mandible by directly inhibiting the transcription factor Runx2, a master regulator of osteoblast differentiation. Hand proteins physically interact with Runx2, suppressing its DNA binding and transcriptional activity. This interaction is mediated by the N-terminal domain of the Hand protein and requires neither dimerization with other bHLH proteins nor DNA binding. We observed partial colocalization of Hand2 and Runx2 in the mandibular primordium of the branchial arch, and downregulation of Hand2 precedes Runx2-driven osteoblast differentiation. Hand2 hypomorphic mutant mice display insufficient mineralization and ectopic bone formation in the mandible due to accelerated osteoblast differentiation, which is associated with the upregulation and ectopic expression of Runx2 in the mandibular arch. Here, we show that Hand2 acts as a novel inhibitor of the Runx2-DNA interaction and thereby regulates osteoblast differentiation in branchial arch development.
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Affiliation(s)
- Noriko Funato
- Department of Molecular Biology, McGill University, Montreal, Quebec H3A 2B2, Canada
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