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Endo T. Postnatal skeletal muscle myogenesis governed by signal transduction networks: MAPKs and PI3K-Akt control multiple steps. Biochem Biophys Res Commun 2023; 682:223-243. [PMID: 37826946 DOI: 10.1016/j.bbrc.2023.09.048] [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: 07/19/2023] [Revised: 09/06/2023] [Accepted: 09/18/2023] [Indexed: 10/14/2023]
Abstract
Skeletal muscle myogenesis represents one of the most intensively and extensively examined systems of cell differentiation, tissue formation, and regeneration. Muscle regeneration provides an in vivo model system of postnatal myogenesis. It comprises multiple steps including muscle stem cell (or satellite cell) quiescence, activation, migration, myogenic determination, myoblast proliferation, myocyte differentiation, myofiber maturation, and hypertrophy. A variety of extracellular signaling and subsequent intracellular signal transduction pathways or networks govern the individual steps of postnatal myogenesis. Among them, MAPK pathways (the ERK, JNK, p38 MAPK, and ERK5 pathways) and PI3K-Akt signaling regulate multiple steps of myogenesis. Ca2+, cytokine, and Wnt signaling also participate in several myogenesis steps. These signaling pathways often control cell cycle regulatory proteins or the muscle-specific MyoD family and the MEF2 family of transcription factors. This article comprehensively reviews molecular mechanisms of the individual steps of postnatal skeletal muscle myogenesis by focusing on signal transduction pathways or networks. Nevertheless, no or only a partial signaling molecules or pathways have been identified in some responses during myogenesis. The elucidation of these unidentified signaling molecules and pathways leads to an extensive understanding of the molecular mechanisms of myogenesis.
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Affiliation(s)
- Takeshi Endo
- Department of Biology, Graduate School of Science, Chiba University, Yayoicho, Inageku, Chiba, Chiba 263-8522, Japan.
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2
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Militi S, Nibhani R, Jalali M, Pauklin S. RBL2-E2F-GCN5 guide cell fate decisions during tissue specification by regulating cell-cycle-dependent fluctuations of non-cell-autonomous signaling. Cell Rep 2023; 42:113146. [PMID: 37725511 DOI: 10.1016/j.celrep.2023.113146] [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: 01/15/2023] [Revised: 05/30/2023] [Accepted: 08/31/2023] [Indexed: 09/21/2023] Open
Abstract
The retinoblastoma family proteins (RBs) and E2F transcription factors are cell-autonomous regulators of cell-cycle progression, but they also impact fate choice in addition to tumor suppression. The range of mechanisms involved remains to be uncovered. Here, we show that RBs, particularly RBL2/p130, repress WNT ligands such as WNT4 and WNT8A, thereby directing ectoderm specification between neural crest to neuroepithelium. RBL2 achieves this function through cell-cycle-dependent cooperation with E2Fs and GCN5 on the regulatory regions of WNT loci, which direct neuroepithelial versus neural crest specification by temporal fluctuations of WNT/β-catenin and DLL/NOTCH signaling activity. Thus, the RB-E2F bona fide cell-autonomous axis controls cell fate decisions, and RBL2 regulates field effects via WNT ligands. This reveals a non-cell-autonomous function of RBL2-E2F in stem cell and tissue progenitor differentiation that has broader implications for cell-cycle-dependent cell fate specification in organogenesis, adult stem cells, tissue homeostasis, and tumorigenesis.
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Affiliation(s)
- Stefania Militi
- Botnar Research Centre, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Old Road, Headington, Oxford OX3 7LD, UK
| | - Reshma Nibhani
- Botnar Research Centre, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Old Road, Headington, Oxford OX3 7LD, UK
| | - Morteza Jalali
- Anne McLaren Laboratory for Regenerative Medicine, Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK
| | - Siim Pauklin
- Botnar Research Centre, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Old Road, Headington, Oxford OX3 7LD, UK.
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3
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Xiong Z, Wang M, Wu J, Shi X. Tceal7 Regulates Skeletal Muscle Development through Its Interaction with Cdk1. Int J Mol Sci 2023; 24:ijms24076264. [PMID: 37047236 PMCID: PMC10094454 DOI: 10.3390/ijms24076264] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/23/2023] [Accepted: 03/25/2023] [Indexed: 03/29/2023] Open
Abstract
We have previously reported Tceal7 as a muscle-specific gene that represses myoblast proliferation and promotes myogenic differentiation. The regulatory mechanism of Tceal7 gene expression has been well clarified recently. However, the underlying mechanism of Tceal7 function in skeletal muscle development remains to be elucidated. In the present study, we have generated an MCK 6.5 kb-HA-Tceal7 transgenic model. The transgenic mice are born normally, while they have displayed defects in the growth of body weight and skeletal muscle myofiber during postnatal development. Although four RxL motifs have been identified in the Tceal7 protein sequence, we have not detected any direct protein-protein interaction between Tceal7 and Cyclin A2, Cyclin B1, Cylin D1, or Cyclin E1. Further analysis has revealed the interaction between Tceal7 and Cdk1 instead of Cdk2, Cdk4, or Cdk6. Transgenic overexpression of Tceal7 reduces phosphorylation of 4E-BP1 Ser65, p70S6K1 Thr389, and Cdk substrates in skeletal muscle. In summary, these studies have revealed a novel mechanism of Tceal7 in skeletal muscle development.
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4
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Basuroy T, Dreier M, Baum C, Blomquist T, Trumbly R, Filipp FV, de la Serna IL. Epigenetic and pharmacological control of pigmentation via Bromodomain Protein 9 (BRD9). Pigment Cell Melanoma Res 2023; 36:19-32. [PMID: 36112085 PMCID: PMC10091956 DOI: 10.1111/pcmr.13068] [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: 05/25/2022] [Revised: 08/01/2022] [Accepted: 09/14/2022] [Indexed: 12/31/2022]
Abstract
Lineage-specific differentiation programs are activated by epigenetic changes in chromatin structure. Melanin-producing melanocytes maintain a gene expression program ensuring appropriate enzymatic conversion of metabolites into the pigment, melanin, and transfer to surrounding cells. During neuroectodermal development, SMARCA4 (BRG1), the catalytic subunit of SWItch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeling complexes, is essential for lineage specification. SMARCA4 is also required for development of multipotent neural crest precursors into melanoblasts, which differentiate into pigment-producing melanocytes. In addition to the catalytic domain, SMARCA4 and several SWI/SNF subunits contain bromodomains which are amenable to pharmacological inhibition. We investigated the effects of pharmacological inhibitors of SWI/SNF bromodomains on melanocyte differentiation. Strikingly, treatment of murine melanoblasts and human neonatal epidermal melanocytes with selected bromodomain inhibitors abrogated melanin synthesis and visible pigmentation. Using functional genomics, iBRD9, a small molecule selective for the bromodomain of BRD9 was found to repress pigmentation-specific gene expression. Depletion of BRD9 confirmed a requirement for expression of pigmentation genes in the differentiation program from melanoblasts into pigmented melanocytes and in melanoma cells. Chromatin immunoprecipitation assays showed that iBRD9 disrupts the occupancy of BRD9 and the catalytic subunit SMARCA4 at melanocyte-specific loci. These data indicate that BRD9 promotes melanocyte pigmentation whereas pharmacological inhibition of BRD9 is repressive.
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Affiliation(s)
- Tupa Basuroy
- Department of Cell and Cancer Biology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA
| | - Megan Dreier
- Department of Cell and Cancer Biology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA
| | - Caitlin Baum
- Department of Pathology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA
| | - Thomas Blomquist
- Department of Pathology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA
| | - Robert Trumbly
- Department of Cell and Cancer Biology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA.,Department of Medical Education, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA
| | - Fabian V Filipp
- Metaflux, Broadway, San Diego, California, USA.,Cancer Systems Biology, Institute for Diabetes and Cancer, Helmholtz Zentrum München, Munich, Germany.,School of Life Sciences Weihenstephan, Technical University München, Freising, Germany
| | - Ivana L de la Serna
- Department of Cell and Cancer Biology, University of Toledo College of Medicine and Life Sciences, Toledo, Ohio, USA
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5
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Yoo J, Kim GW, Jeon YH, Kim JY, Lee SW, Kwon SH. Drawing a line between histone demethylase KDM5A and KDM5B: their roles in development and tumorigenesis. Exp Mol Med 2022; 54:2107-2117. [PMID: 36509829 PMCID: PMC9794821 DOI: 10.1038/s12276-022-00902-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 09/29/2022] [Accepted: 10/13/2022] [Indexed: 12/14/2022] Open
Abstract
Distinct epigenetic modifiers ensure coordinated control over genes that govern a myriad of cellular processes. Growing evidence shows that dynamic regulation of histone methylation is critical for almost all stages of development. Notably, the KDM5 subfamily of histone lysine-specific demethylases plays essential roles in the proper development and differentiation of tissues, and aberrant regulation of KDM5 proteins during development can lead to chronic developmental defects and even cancer. In this review, we adopt a unique perspective regarding the context-dependent roles of KDM5A and KDM5B in development and tumorigenesis. It is well known that these two proteins show a high degree of sequence homology, with overlapping functions. However, we provide deeper insights into their substrate specificity and distinctive function in gene regulation that at times divert from each other. We also highlight both the possibility of targeting KDM5A and KDM5B to improve cancer treatment and the limitations that must be overcome to increase the efficacy of current drugs.
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Affiliation(s)
- Jung Yoo
- grid.15444.300000 0004 0470 5454College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, 21983 Republic of Korea
| | - Go Woon Kim
- grid.15444.300000 0004 0470 5454College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, 21983 Republic of Korea
| | - Yu Hyun Jeon
- grid.15444.300000 0004 0470 5454College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, 21983 Republic of Korea
| | - Ji Yoon Kim
- grid.15444.300000 0004 0470 5454College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, 21983 Republic of Korea
| | - Sang Wu Lee
- grid.15444.300000 0004 0470 5454College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, 21983 Republic of Korea
| | - So Hee Kwon
- grid.15444.300000 0004 0470 5454College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, 21983 Republic of Korea
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6
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Hou Y, Yoon Y, Oh E, Sung B, Kim Y. Effects of soy protein hydrolysates on antioxidant activity and inhibition of muscle loss. INTERNATIONAL FOOD RESEARCH JOURNAL 2022. [DOI: 10.47836/ifrj.29.6.22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Peptides show biological activity, and are more easily digested than complex proteins. In the present work, we evaluated the effects of soy hydrolysate on skeletal muscle. Soy protein isolate (SPI) was hydrolysed using 2% Alcalase (SPHA) and Flavourzyme (SPHF) at pH 8 for 3 h at 60°C, and at pH 7 for 3 h at 55°C, respectively. Antioxidant properties (total phenolic content and DPPH activity) and inhibition of muscle loss (myogenin, myosin heavy chain [MyHC], creatine kinase, and myostatin) by the SPI hydrolysates in C2C12 cells were compared with those of SPI. Alcalase produced more hydrolysed soy oligopeptides than Flavourzyme. Enzymatic hydrolysis increased the levels of essential amino acids, particularly in SPHF (2,466.85 mg/L) as compared to SPI (56.08 mg/L). The total phenolic contents of hydrolysates increased from 12.02 mg GAE/g in SPI to 22.87 and 18.67 mg GAE/g in SPHA and SPHF, respectively. The IC50 value of DPPH activity decreased four times after hydrolysis (SPI: 124.38, SPHA: 32.18, and SPHF: 30.21 mg/mL). SPHA and SPHF treatments increased the expression levels of both MyHC1 and MyHC3, as well as creatine kinase activity. A significant increase in MyHC3 expression was observed in SPHF at 10 µg/mL. Soy hydrolysates (SPHA: 93.5% and SPHF: 61%) induced a greater decrease in the expression of myostatin, a muscle reduction marker, than SPI (30.4%). In conclusion, soy hydrolysates may inhibit muscle loss, showing particularly better effects when Alcalase is used for hydrolysis.
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7
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Pajalunga D, Crescenzi M. Restoring the Cell Cycle and Proliferation Competence in Terminally Differentiated Skeletal Muscle Myotubes. Cells 2021; 10:cells10102753. [PMID: 34685732 PMCID: PMC8534385 DOI: 10.3390/cells10102753] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 09/29/2021] [Accepted: 10/12/2021] [Indexed: 01/04/2023] Open
Abstract
Terminal differentiation is an ill-defined, insufficiently characterized, nonproliferation state. Although it has been classically deemed irreversible, it is now clear that at least several terminally differentiated (TD) cell types can be brought back into the cell cycle. We are striving to uncover the molecular bases of terminal differentiation, whose fundamental understanding is a goal in itself. In addition, the field has sought to acquire the ability to make TD cells proliferate. Attaining this end would probe the very molecular mechanisms we are trying to understand. Equally important, it would be invaluable in regenerative medicine, for tissues depending on TD cells and devoid of significant self-repair capabilities. The skeletal muscle has long been used as a model system to investigate the molecular foundations of terminal differentiation. Here, we summarize more than 50 years of studies in this field.
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Affiliation(s)
- Deborah Pajalunga
- Department of Oncology and Molecular Medicine, Italian National Institute of Health, 00161 Rome, Italy;
| | - Marco Crescenzi
- Core Facilities, Italian National Institute of Health, 00161 Rome, Italy
- Correspondence:
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8
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Pircher T, Wackerhage H, Aszodi A, Kammerlander C, Böcker W, Saller MM. Hypoxic Signaling in Skeletal Muscle Maintenance and Regeneration: A Systematic Review. Front Physiol 2021; 12:684899. [PMID: 34248671 PMCID: PMC8260947 DOI: 10.3389/fphys.2021.684899] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 05/26/2021] [Indexed: 12/26/2022] Open
Abstract
In skeletal muscle tissue, oxygen (O2) plays a pivotal role in both metabolism and the regulation of several intercellular pathways, which can modify proliferation, differentiation and survival of cells within the myogenic lineage. The concentration of oxygen in muscle tissue is reduced during embryogenesis and pathological conditions. Myogenic progenitor cells, namely satellite cells, are necessary for muscular regeneration in adults and are localized in a hypoxic microenvironment under the basal lamina, suggesting that the O2 level could affect their function. This review presents the effects of reduced oxygen levels (hypoxia) on satellite cell survival, myoblast regeneration and differentiation in vertebrates. Further investigations and understanding of the pathways involved in adult muscle regeneration during hypoxic conditions are maybe clinically relevant to seek for novel drug treatments for patients with severe muscle damage. We especially outlined the effect of hypoxia-inducible factor 1-alpha (HIF1A), the most studied transcriptional regulator of cellular and developmental response to hypoxia, whose investigation has recently been awarded with the Nobel price.
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Affiliation(s)
- Tamara Pircher
- Experimental Surgery and Regenerative Medicine, Department of General, Trauma and Reconstructive Surgery, Munich University Hospital, Munich, Germany
| | - Henning Wackerhage
- Faculty of Sport and Health Sciences, Technical University of Munich, Munich, Germany
| | - Attila Aszodi
- Experimental Surgery and Regenerative Medicine, Department of General, Trauma and Reconstructive Surgery, Munich University Hospital, Munich, Germany
| | - Christian Kammerlander
- Experimental Surgery and Regenerative Medicine, Department of General, Trauma and Reconstructive Surgery, Munich University Hospital, Munich, Germany
| | - Wolfgang Böcker
- Experimental Surgery and Regenerative Medicine, Department of General, Trauma and Reconstructive Surgery, Munich University Hospital, Munich, Germany
| | - Maximilian Michael Saller
- Experimental Surgery and Regenerative Medicine, Department of General, Trauma and Reconstructive Surgery, Munich University Hospital, Munich, Germany
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9
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Shinji S, Umezawa K, Nihashi Y, Nakamura S, Shimosato T, Takaya T. Identification of the Myogenetic Oligodeoxynucleotides (myoDNs) That Promote Differentiation of Skeletal Muscle Myoblasts by Targeting Nucleolin. Front Cell Dev Biol 2021; 8:616706. [PMID: 33585451 PMCID: PMC7874222 DOI: 10.3389/fcell.2020.616706] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/07/2020] [Indexed: 12/18/2022] Open
Abstract
Herein we report that the 18-base telomeric oligodeoxynucleotides (ODNs) designed from the Lactobacillus rhamnosus GG genome promote differentiation of skeletal muscle myoblasts which are myogenic precursor cells. We termed these myogenetic ODNs (myoDNs). The activity of one of the myoDNs, iSN04, was independent of Toll-like receptors, but dependent on its conformational state. Molecular simulation and iSN04 mutants revealed stacking of the 13-15th guanines as a core structure for iSN04. The alkaloid berberine bound to the guanine stack and enhanced iSN04 activity, probably by stabilizing and optimizing iSN04 conformation. We further identified nucleolin as an iSN04-binding protein. Results showed that iSN04 antagonizes nucleolin, increases the levels of p53 protein translationally suppressed by nucleolin, and eventually induces myotube formation by modulating the expression of genes involved in myogenic differentiation and cell cycle arrest. This study shows that bacterial-derived myoDNs serve as aptamers and are potential nucleic acid drugs directly targeting myoblasts.
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Affiliation(s)
- Sayaka Shinji
- Department of Agriculture, Graduate School of Science and Technology, Shinshu University, Nagano, Japan
| | - Koji Umezawa
- Department of Agricultural and Life Science, Faculty of Agriculture, Shinshu University, Nagano, Japan
- Department of Biomolecular Innovation, Institute for Biomedical Sciences, Shinshu University, Nagano, Japan
| | - Yuma Nihashi
- Department of Science and Technology, Graduate School of Medicine, Science and Technology, Shinshu University, Nagano, Japan
| | - Shunichi Nakamura
- Department of Agriculture, Graduate School of Science and Technology, Shinshu University, Nagano, Japan
| | - Takeshi Shimosato
- Department of Agriculture, Graduate School of Science and Technology, Shinshu University, Nagano, Japan
- Department of Agricultural and Life Science, Faculty of Agriculture, Shinshu University, Nagano, Japan
- Department of Biomolecular Innovation, Institute for Biomedical Sciences, Shinshu University, Nagano, Japan
- Department of Science and Technology, Graduate School of Medicine, Science and Technology, Shinshu University, Nagano, Japan
| | - Tomohide Takaya
- Department of Agriculture, Graduate School of Science and Technology, Shinshu University, Nagano, Japan
- Department of Agricultural and Life Science, Faculty of Agriculture, Shinshu University, Nagano, Japan
- Department of Biomolecular Innovation, Institute for Biomedical Sciences, Shinshu University, Nagano, Japan
- Department of Science and Technology, Graduate School of Medicine, Science and Technology, Shinshu University, Nagano, Japan
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Zluhan-Martínez E, Pérez-Koldenkova V, Ponce-Castañeda MV, Sánchez MDLP, García-Ponce B, Miguel-Hernández S, Álvarez-Buylla ER, Garay-Arroyo A. Beyond What Your Retina Can See: Similarities of Retinoblastoma Function between Plants and Animals, from Developmental Processes to Epigenetic Regulation. Int J Mol Sci 2020; 21:E4925. [PMID: 32664691 PMCID: PMC7404004 DOI: 10.3390/ijms21144925] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/29/2020] [Accepted: 07/07/2020] [Indexed: 12/15/2022] Open
Abstract
The Retinoblastoma protein (pRb) is a key cell cycle regulator conserved in a wide variety of organisms. Experimental analysis of pRb's functions in animals and plants has revealed that this protein participates in cell proliferation and differentiation processes. In addition, pRb in animals and its orthologs in plants (RBR), are part of highly conserved protein complexes which suggest the possibility that analogies exist not only between functions carried out by pRb orthologs themselves, but also in the structure and roles of the protein networks where these proteins are involved. Here, we present examples of pRb/RBR participation in cell cycle control, cell differentiation, and in the regulation of epigenetic changes and chromatin remodeling machinery, highlighting the similarities that exist between the composition of such networks in plants and animals.
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Affiliation(s)
- Estephania Zluhan-Martínez
- Laboratorio de Genética Molecular, Epigenética, Desarrollo y Evolución de Plantas, Instituto de Ecología, Universidad Nacional Autónoma de Mexico, 3er Circuito Ext. Junto a J. Botánico, Ciudad Universitaria, UNAM 04510, Mexico; (E.Z.-M.); (M.d.l.P.S.); (B.G.-P.)
- Posgrado en Ciencias Biomédicas, Universidad Nacional Autónoma de México, Av. Universidad 3000, Coyoacán 04510, Mexico
| | - Vadim Pérez-Koldenkova
- Laboratorio Nacional de Microscopía Avanzada, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Av. Cuauhtémoc, 330. Col. Doctores, Alc. Cuauhtémoc 06720, Mexico;
| | - Martha Verónica Ponce-Castañeda
- Unidad de Investigación Médica en Enfermedades Infecciosas, Centro Médico Nacional SXXI, Instituto Mexicano del Seguro Social, Mexico City 06720, Mexico;
| | - María de la Paz Sánchez
- Laboratorio de Genética Molecular, Epigenética, Desarrollo y Evolución de Plantas, Instituto de Ecología, Universidad Nacional Autónoma de Mexico, 3er Circuito Ext. Junto a J. Botánico, Ciudad Universitaria, UNAM 04510, Mexico; (E.Z.-M.); (M.d.l.P.S.); (B.G.-P.)
| | - Berenice García-Ponce
- Laboratorio de Genética Molecular, Epigenética, Desarrollo y Evolución de Plantas, Instituto de Ecología, Universidad Nacional Autónoma de Mexico, 3er Circuito Ext. Junto a J. Botánico, Ciudad Universitaria, UNAM 04510, Mexico; (E.Z.-M.); (M.d.l.P.S.); (B.G.-P.)
| | - Sergio Miguel-Hernández
- Laboratorio de Citopatología Ambiental, Departamento de Morfología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Campus Zacatenco, Calle Wilfrido Massieu Esquina Cda, Manuel Stampa 07738, Mexico;
| | - Elena R. Álvarez-Buylla
- Laboratorio de Genética Molecular, Epigenética, Desarrollo y Evolución de Plantas, Instituto de Ecología, Universidad Nacional Autónoma de Mexico, 3er Circuito Ext. Junto a J. Botánico, Ciudad Universitaria, UNAM 04510, Mexico; (E.Z.-M.); (M.d.l.P.S.); (B.G.-P.)
| | - Adriana Garay-Arroyo
- Laboratorio de Genética Molecular, Epigenética, Desarrollo y Evolución de Plantas, Instituto de Ecología, Universidad Nacional Autónoma de Mexico, 3er Circuito Ext. Junto a J. Botánico, Ciudad Universitaria, UNAM 04510, Mexico; (E.Z.-M.); (M.d.l.P.S.); (B.G.-P.)
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11
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Maugein A, Diedisheim M, Bailly K, Scharfmann R, Albagli O. The RB gene family controls the maturation state of the EndoC-βH2 human pancreatic β-cells. Differentiation 2020; 113:1-9. [PMID: 32120156 DOI: 10.1016/j.diff.2020.02.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/17/2020] [Accepted: 02/17/2020] [Indexed: 01/18/2023]
Abstract
The functional maturation of human pancreatic β-cells remains poorly understood. EndoC-βH2 is a human β-cell line with a reversible immortalized phenotype. Removal of the two oncogenes, SV40LT and hTERT introduced for its propagation, stops proliferation, triggers cell size increase and senescence, promotes mitochondrial activity and amplifies several β-cell traits and functions. Overall, these events recapitulate several aspects of functional β-cell maturation. We report here that selective depletion of SV40LT, but not of hTERT, is sufficient to revert EndoC-βH2 immortalization. SV40LT inhibits the activity of the RB family members and of P53. In EndoC-βH2 cells, the knock-down of RB itself, and, to a lesser extent, of its relative P130, precludes most events triggered by SV40LT depletion. In contrast, the knock-down of P53 does not prevent reversion of immortalization. Thus, an increase in RB and P130 activity, but not in P53 activity, is required for functional maturation of EndoC-βH2 cells upon SV40LT-depletion. In addition, RB and/or P130 depletion in SV40LT-expressing EndoC-βH2 cells decreases cell size, stimulates proliferation, and decreases the expression of key β-cell genes. Thus, despite SV40LT expression, EndoC-βH2 cells have a residual RB activity, which when suppressed reverts them to a more immature phenotype. These results show that the expression and activity levels of RB family members, especially RB itself, regulate the maturation state of EndoC-βH2 cells.
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Affiliation(s)
- Alicia Maugein
- Paris University, Institut Cochin, INSERM, U1016, CNRS, UMR8104, 75014, Paris, France
| | - Marc Diedisheim
- Assistance Publique - Hôpitaux de Paris, Diabetology Department, Paris University, Cochin Hospital, and INSERM, UMRS 1138, Centre de Recherche des Cordeliers, Paris University, 75006, Paris, France
| | - Karine Bailly
- Paris University, Institut Cochin, INSERM, U1016, CNRS, UMR8104, 75014, Paris, France
| | - Raphaël Scharfmann
- Paris University, Institut Cochin, INSERM, U1016, CNRS, UMR8104, 75014, Paris, France
| | - Olivier Albagli
- Paris University, Institut Cochin, INSERM, U1016, CNRS, UMR8104, 75014, Paris, France.
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12
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Ciuffoli V, Lena AM, Gambacurta A, Melino G, Candi E. Myoblasts rely on TAp63 to control basal mitochondria respiration. Aging (Albany NY) 2019; 10:3558-3573. [PMID: 30487319 PMCID: PMC6286837 DOI: 10.18632/aging.101668] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 11/15/2018] [Indexed: 12/15/2022]
Abstract
p53, with its family members p63 and p73, have been shown to promote myoblast differentiation by regulation of the function of the retinoblastoma protein and by direct activation of p21Cip/Waf1 and p57Kip2, promoting cell cycle exit. In previous studies, we have demonstrated that the TAp63γ isoform is the only member of the p53 family that accumulates during in vitro myoblasts differentiation, and that its silencing led to delay in myotube fusion. To better dissect the role of TAp63γ in myoblast physiology, we have generated both sh-p63 and Tet-On inducible TAp63γ clones. Gene array analysis of sh-p63 C2C7 clones showed a significant modulation of genes involved in proliferation and cellular metabolism. Indeed, we found that sh-p63 C2C7 myoblasts present a higher proliferation rate and that, conversely, TAp63γ ectopic expression decreases myoblasts proliferation, indicating that TAp63γ specifically contributes to myoblasts proliferation, independently of p53 and p73. In addition, sh-p63 cells have a defect in mitochondria respiration highlighted by a reduction in spare respiratory capacity and a decrease in complex I, IV protein levels. These results demonstrated that, beside contributing to cell cycle exit, TAp63γ participates to myoblasts metabolism control.
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Affiliation(s)
- Veronica Ciuffoli
- Department of Experimental Medicine and TOR, University of Rome "Tor Vergata", Rome, Italy
| | - Anna Maria Lena
- Department of Experimental Medicine and TOR, University of Rome "Tor Vergata", Rome, Italy
| | - Alessandra Gambacurta
- Department of Experimental Medicine and TOR, University of Rome "Tor Vergata", Rome, Italy
| | - Gerry Melino
- Department of Experimental Medicine and TOR, University of Rome "Tor Vergata", Rome, Italy.,MRC-Toxicology Unit, University of Cambridge, Cambridge, UK
| | - Eleonora Candi
- Department of Experimental Medicine and TOR, University of Rome "Tor Vergata", Rome, Italy.,IDI-IRCCS, Biochemistry laboratory, Rome, Italy
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13
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Lixin L, Juan W, Yun B, Jingwei L, Xiuju Y, Xiaomao L, Zhiwei Z, Xiaoyan H, Yanjun D, Hongquan L, Haidong W. Effect of Hypoxia on the Muscle Fiber Switching Signal Pathways CnA/NFATc1 and Myostatin in Mouse Myocytes. Acta Histochem 2019; 121:539-545. [PMID: 31047685 DOI: 10.1016/j.acthis.2019.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 03/16/2019] [Accepted: 04/01/2019] [Indexed: 12/13/2022]
Abstract
This study investigated the effects of a CoCl2-simulated hypoxic environment on the muscle fiber switching signaling pathways calcineurin A/nuclear factor of activated T cells cytoplasmic 1 (CnA/NFATc1) and myostatin. In this study, C2C12 muscle cells were cultured in vitro under CoCl2-simulated chemical hypoxic conditions, the expression levels of CnA and myostatin were detected through qRT-PCR and Western blot analyses, and a positioning study of NFATc1 was carried out by immunofluorescence labeling. Results showed that CoCl2 treatment significantly increased the expression levels of CnA and myostatin. Moreover, the position of NFATc1 expression changed; actually, its expression in the nucleus considerably increased. Furthermore, CoCl2-induced hypoxia inhibited the differentiation of C2C12 cells and reduced the expression levels of many slow- and fast-twitch muscles marker genes, but immunofluorescence staining results showed that the proportion of MyHC I type muscle fiber increased after CoCl2 treatment. The hypoxic environment simulated by CoCl2 can activate the signaling pathways CnA/NFATc1 and myostatin and increases the proportion of MyHC I type muscle fibers.
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Affiliation(s)
- Li Lixin
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu 030801, Shanxi, China.
| | - Wang Juan
- Department of Nephrology, Shanghai General Hosptial, Shanghai Jiaotong University, No. 100, Haining Road, Shanghai 200080, China.
| | - Bai Yun
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu 030801, Shanxi, China.
| | - Li Jingwei
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu 030801, Shanxi, China.
| | - Yu Xiuju
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu 030801, Shanxi, China.
| | - Luo Xiaomao
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu 030801, Shanxi, China.
| | - Zhu Zhiwei
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu 030801, Shanxi, China.
| | - He Xiaoyan
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu 030801, Shanxi, China.
| | - Dong Yanjun
- College of Veterinary Medicine, China Agricultural University, Haidian 100193, Beijing, China.
| | - Li Hongquan
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu 030801, Shanxi, China.
| | - Wang Haidong
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu 030801, Shanxi, China.
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14
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Takahashi K, Itakura E, Takano K, Endo T. DA-Raf, a dominant-negative regulator of the Ras–ERK pathway, is essential for skeletal myocyte differentiation including myoblast fusion and apoptosis. Exp Cell Res 2019; 376:168-180. [DOI: 10.1016/j.yexcr.2019.02.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 01/19/2019] [Accepted: 02/07/2019] [Indexed: 12/21/2022]
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15
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Brull A, Morales Rodriguez B, Bonne G, Muchir A, Bertrand AT. The Pathogenesis and Therapies of Striated Muscle Laminopathies. Front Physiol 2018; 9:1533. [PMID: 30425656 PMCID: PMC6218675 DOI: 10.3389/fphys.2018.01533] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 10/11/2018] [Indexed: 01/04/2023] Open
Abstract
Emery-Dreifuss muscular dystrophy (EDMD) is a genetic condition characterized by early contractures, skeletal muscle weakness, and cardiomyopathy. During the last 20 years, various genetic approaches led to the identification of causal genes of EDMD and related disorders, all encoding nuclear envelope proteins. By their respective localization either at the inner nuclear membrane or the outer nuclear membrane, these proteins interact with each other and establish a connection between the nucleus and the cytoskeleton. Beside this physical link, these proteins are also involved in mechanotransduction, responding to environmental cues, such as increased tension of the cytoskeleton, by the activation or repression of specific sets of genes. This ability of cells to adapt to environmental conditions is altered in EDMD. Increased knowledge on the pathophysiology of EDMD has led to the development of drug or gene therapies that have been tested on mouse models. This review proposed an overview of the functions played by the different proteins involved in EDMD and related disorders and the current therapeutic approaches tested so far.
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Affiliation(s)
- Astrid Brull
- Sorbonne Université, INSERM, Institut de Myologie, Center of Research in Myology, UMRS 974, Paris, France
| | - Blanca Morales Rodriguez
- Sorbonne Université, INSERM, Institut de Myologie, Center of Research in Myology, UMRS 974, Paris, France.,Sanofi R&D, Chilly Mazarin, France
| | - Gisèle Bonne
- Sorbonne Université, INSERM, Institut de Myologie, Center of Research in Myology, UMRS 974, Paris, France
| | - Antoine Muchir
- Sorbonne Université, INSERM, Institut de Myologie, Center of Research in Myology, UMRS 974, Paris, France
| | - Anne T Bertrand
- Sorbonne Université, INSERM, Institut de Myologie, Center of Research in Myology, UMRS 974, Paris, France
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16
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Luo W, Ren X, Chen J, Li L, Lu S, Chen T, Nie Q, Zhang X. TP63 Transcripts Play Opposite Roles in Chicken Skeletal Muscle Differentiation. Front Physiol 2018; 9:1298. [PMID: 30283353 PMCID: PMC6157316 DOI: 10.3389/fphys.2018.01298] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 08/29/2018] [Indexed: 11/18/2022] Open
Abstract
Tumor protein 63 (TP63) comprises multiple isoforms and plays an important role during embryonic development. It has been shown that TP63 knockdown inhibits myogenic differentiation, but which isoform is involved in the underlying myogenic regulation remains uncertain. Here, we found that two transcripts of TP63, namely, TAp63α and ΔNp63α, are expressed in chicken skeletal muscle. These two transcripts have distinct expression patterns and opposite functions in skeletal muscle development. TAp63 has higher expression in skeletal muscle than in other tissues, and its expression is gradually upregulated during chicken primary myoblast differentiation. ΔNp63 can be expressed in multiple tissues and exhibits stable expression during myoblast differentiation. TAp63α overexpression inhibits myoblast proliferation, induces cell cycle arrest, and enhances myoblast differentiation. However, although ΔNp63α has no significant effect on cell proliferation, the overexpression of ΔNp63α inhibits myoblast differentiation. Using isoform-specific overexpression assays following RNA-sequencing, we identified potential downstream genes of TAp63α and ΔNp63α in myoblast. Bioinformatics analyses and experimental verification results showed that the differentially expressed genes (DEGs) between the TAp63α and control groups were enriched in the cell cycle pathway, whereas the DEGs between the ΔNp63α and control groups were enriched in muscle system process, muscle contraction, and myopathy. These findings provide new insights into the function and expression of TP63 during skeletal muscle development, and indicate that one gene may play two opposite roles during a single cellular process.
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Affiliation(s)
- Wen Luo
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou, China
| | - Xueyi Ren
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou, China
| | - Jiahui Chen
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou, China
| | - Limin Li
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou, China
| | - Shiyi Lu
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou, China
| | - Tian Chen
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou, China
| | - Qinghua Nie
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou, China
| | - Xiquan Zhang
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural University, Guangzhou, China.,Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, South China Agricultural University, Guangzhou, China
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17
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Comprehensive analysis of lncRNAs and mRNAs with associated co-expression and ceRNA networks in C2C12 myoblasts and myotubes. Gene 2018; 647:164-173. [PMID: 29331478 DOI: 10.1016/j.gene.2018.01.039] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 12/29/2017] [Accepted: 01/09/2018] [Indexed: 12/30/2022]
Abstract
Long non-coding RNAs (lncRNAs) are emerging as important regulators in the modulation of muscle development and muscle-related diseases. To explore potential regulators of muscle differentiation, we determined the expression profiles of lncRNAs and mRNAs in C2C12 mouse myoblast cell line using microarray analysis. Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed to explore their function. We also constructed co-expression, cis/trans-regulation, and competing endogenous RNA (ceRNA) networks with bioinformatics methods. We found that 3067 lncRNAs and 3235 mRNAs were differentially regulated (fold change ≥2.0). Bioinformatics analysis indicated that the principal functions of the transcripts were related to muscle structure development and morphogenesis. Co-expression analysis showed 261 co-expression relationships between 233 lncRNAs and 10 mRNAs, and nine lncRNAs interacted with myog and MEF2C collectively. Cis/trans-regulation prediction revealed that lncRNA Myh6 could be a valuable gene via cis-regulation, and lncRNAs such as 2310043L19Ris, V00821, and AK139352 may participate in particular pathways regulated by transcription factors, including myog, myod1, and foxo1. The myog-specific ceRNA network covered 10 lncRNAs, 378 miRNAs, and 1960 edges. The upregulated lncRNAs Filip1, Myl1, and 2310043L19Rik may promote myog expression by acting as ceRNAs. Our results offer a new perspective on the modulation of lncRNAs in muscle differentiation.
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18
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Hierarchical signaling transduction of the immune and muscle cell crosstalk in muscle regeneration. Cell Immunol 2017; 326:2-7. [PMID: 28867121 DOI: 10.1016/j.cellimm.2017.08.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Revised: 08/11/2017] [Accepted: 08/12/2017] [Indexed: 12/25/2022]
Abstract
The muscle regeneration is a complicated bioprocess that involved in many cell types, including necrotic muscle cells, satellite cells, mesenchymal cells, pericytes, immune cells, and other cell types present at the injury site. Immune cells involved in both innate and adaptive immune responses regulate the progress of muscle regeneration. In this review, we discussed the roles of different immune cells in muscle regeneration. The immune cells regulate muscle regeneration through cytokine production, cell-cell contacts, and general immune environment regulation. We also describe the current known mechanism of how immune cells regulating muscle regeneration.
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19
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Fischer M, Müller GA. Cell cycle transcription control: DREAM/MuvB and RB-E2F complexes. Crit Rev Biochem Mol Biol 2017; 52:638-662. [PMID: 28799433 DOI: 10.1080/10409238.2017.1360836] [Citation(s) in RCA: 148] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The precise timing of cell cycle gene expression is critical for the control of cell proliferation; de-regulation of this timing promotes the formation of cancer and leads to defects during differentiation and development. Entry into and progression through S phase requires expression of genes coding for proteins that function in DNA replication. Expression of a distinct set of genes is essential to pass through mitosis and cytokinesis. Expression of these groups of cell cycle-dependent genes is regulated by the RB pocket protein family, the E2F transcription factor family, and MuvB complexes together with B-MYB and FOXM1. Distinct combinations of these transcription factors promote the transcription of the two major groups of cell cycle genes that are maximally expressed either in S phase (G1/S) or in mitosis (G2/M). In this review, we discuss recent work that has started to uncover the molecular mechanisms controlling the precisely timed expression of these genes at specific cell cycle phases, as well as the repression of the genes when a cell exits the cell cycle.
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Affiliation(s)
- Martin Fischer
- a Molecular Oncology, Medical School, University of Leipzig , Leipzig , Germany.,b Department of Medical Oncology , Dana-Farber Cancer Institute , Boston , MA , USA.,c Department of Medicine, Brigham and Women's Hospital , Harvard Medical School , Boston , MA , USA
| | - Gerd A Müller
- a Molecular Oncology, Medical School, University of Leipzig , Leipzig , Germany
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20
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Abstract
Human retinoblastoma gene RB1 is the first tumor suppressor gene (TSG) isolated by positional cloning in 1986. RB is extensively studied for its ability to regulate cell cycle by binding to E2F1 and inhibiting the transcriptional activity of the latter. In human embryonic stem cells (ESCs), only a minute trace of RB is found in complex with E2F1. Increased activity of RB triggers differentiation, cell cycle arrest, and cell death. On the other hand, inactivation of the entire RB family (RB1, RBL1, and RBL2) in human ESC induces G2/M arrest and cell death. These observations indicate that both loss and overactivity of RB could be lethal for the stemness of cells. A question arises why inactive RB is required for the survival and stemness of cells? To shed some light on this question, we analyzed the RB-binding proteins. In this review we have focused on 27 RB-binding partners that may have potential roles in different aspects of stem cell biology.
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Affiliation(s)
- M Mushtaq
- Karolinska Institutet, Stockholm, Sweden
| | | | - E V Kashuba
- Karolinska Institutet, Stockholm, Sweden; R.E. Kavetsky Institute of Experimental Pathology, Oncology and Radiobiology, NASU, Kyiv, Ukraine.
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21
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Rao VK, Ow JR, Shankar SR, Bharathy N, Manikandan J, Wang Y, Taneja R. G9a promotes proliferation and inhibits cell cycle exit during myogenic differentiation. Nucleic Acids Res 2016; 44:8129-43. [PMID: 27229136 PMCID: PMC5041453 DOI: 10.1093/nar/gkw483] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 05/19/2016] [Indexed: 11/12/2022] Open
Abstract
Differentiation of skeletal muscle cells, like most other cell types, requires a permanent exit from the cell cycle. The epigenetic programming underlying these distinct cellular states is not fully understood. In this study, we provide evidence that the lysine methyltransferase G9a functions as a central axis to regulate proliferation and differentiation of skeletal muscle cells. Transcriptome analysis of G9a knockdown cells revealed deregulation of many cell cycle regulatory genes. We demonstrate that G9a enhances cellular proliferation by two distinct mechanisms. G9a blocks cell cycle exit via methylation-dependent transcriptional repression of the MyoD target genes p21(Cip/Waf1) and Rb1. In addition, it activates E2F1-target genes in a methyltransferase activity-independent manner. We show that G9a is present in the E2F1/PCAF complex, and enhances PCAF occupancy and histone acetylation marks at E2F1-target promoters. Interestingly, G9a preferentially associates with E2F1 at the G1/S phase and with MyoD at the G2/M phase. Our results provide evidence that G9a functions both as a co-activator and a co-repressor to enhance cellular proliferation and inhibit myogenic differentiation.
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Affiliation(s)
- Vinay Kumar Rao
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 117597, Singapore
| | - Jin Rong Ow
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 117597, Singapore
| | - Shilpa Rani Shankar
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 117597, Singapore
| | - Narendra Bharathy
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 117597, Singapore
| | - Jayapal Manikandan
- NanoString Technologies, 530 Fairview Ave N, Suite 2000 Seattle, WA, USA
| | - Yaju Wang
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 117597, Singapore
| | - Reshma Taneja
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 117597, Singapore
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22
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Osteosarcoma: prognosis plateau warrants retinoblastoma pathway targeted therapy. Signal Transduct Target Ther 2016; 1:16001. [PMID: 29263893 PMCID: PMC5657420 DOI: 10.1038/sigtrans.2016.1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 12/31/2015] [Accepted: 01/04/2016] [Indexed: 02/06/2023] Open
Abstract
Osteosarcoma (OS) is the most common primary bone cancer in children and adolescents, affecting ~560 young patients in the United States annually. The term OS describes a diverse array of subtypes with varying prognoses, but the majority of tumors are high grade and aggressive. Perhaps because the true etiology of these aggressive tumors remains unknown, advances in OS treatment have reached a discouraging plateau, with only incremental improvements over the past 40 years. Thus, research surrounding the pathogenesis of OS is essential, as it promises to unveil novel therapeutic targets that can attack tumor cells with greater specificity and lower toxicity. Among the candidate molecular targets in OS, the retinoblastoma (RB) pathway demonstrates the highest frequency of inactivation and thus represents a particularly promising avenue for molecular targeted therapy. This review examines the present thinking and practices in OS treatment and specifically highlights the relevance of the RB pathway in osteosarcomagenesis. Through further investigation into RB pathway-related novel therapeutic targets, we believe that a near-term breakthrough in improved OS prognosis is possible.
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23
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Negative regulation of initial steps in skeletal myogenesis by mTOR and other kinases. Sci Rep 2016; 6:20376. [PMID: 26847534 PMCID: PMC4742887 DOI: 10.1038/srep20376] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Accepted: 12/31/2015] [Indexed: 11/08/2022] Open
Abstract
The transition from a committed progenitor cell to one that is actively differentiating represents a process that is fundamentally important in skeletal myogenesis. Although the expression and functional activation of myogenic regulatory transcription factors (MRFs) are well known to govern lineage commitment and differentiation, exactly how the first steps in differentiation are suppressed in a proliferating myoblast is much less clear. We used cultured mammalian myoblasts and an RNA interference library targeting 571 kinases to identify those that may repress muscle differentiation in proliferating myoblasts in the presence or absence of a sensitizing agent directed toward CDK4/6, a kinase previously established to impede muscle gene expression. We identified 55 kinases whose knockdown promoted myoblast differentiation, either independently or in conjunction with the sensitizer. A number of the hit kinases could be connected to known MRFs, directly or through one interaction node. Focusing on one hit, Mtor, we validated its role to impede differentiation in proliferating myoblasts and carried out mechanistic studies to show that it acts, in part, by a rapamycin-sensitive complex that involves Raptor. Our findings inform our understanding of kinases that can block the transition from lineage commitment to a differentiating state in myoblasts and offer a useful resource for others studying myogenic differentiation.
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24
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Cefalù S, Lena AM, Vojtesek B, Musarò A, Rossi A, Melino G, Candi E. TAp63gamma is required for the late stages of myogenesis. Cell Cycle 2015; 14:894-901. [PMID: 25790093 DOI: 10.4161/15384101.2014.988021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
p53 family members, p63 and p73, play a role in controlling early stage of myogenic differentiation. We demonstrated that TAp63gamma, unlike the other p53 family members, is markedly up-regulated during myogenic differentiation in murine C2C7 cell line. We also found that myotubes formation was inhibited upon TAp63gamma knock-down, as also indicated by atrophyic myotubes and reduction of myoblasts fusion index. Analysis of TAp63gamma-dependend transcripts identified several target genes involved in skeletal muscle contractility energy metabolism, myogenesis and skeletal muscle autocrine signaling. These results indicate that TAp63gamma is a late marker of myogenic differentiation and, by controlling different sub-sets of target genes, it possibly contributes to muscle growth, remodeling, functional differentiation and tissue homeostasis.
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Affiliation(s)
- S Cefalù
- a Istututo Dermopatico dell'Immacolata ; IDI-IRCCS ; Rome , Italy
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25
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Váraljai R, Islam ABMMK, Beshiri ML, Rehman J, Lopez-Bigas N, Benevolenskaya EV. Increased mitochondrial function downstream from KDM5A histone demethylase rescues differentiation in pRB-deficient cells. Genes Dev 2015; 29:1817-34. [PMID: 26314709 PMCID: PMC4573855 DOI: 10.1101/gad.264036.115] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 08/06/2015] [Indexed: 12/18/2022]
Abstract
The retinoblastoma tumor suppressor protein pRb restricts cell growth through inhibition of cell cycle progression. Increasing evidence suggests that pRb also promotes differentiation, but the mechanisms are poorly understood, and the key question remains as to how differentiation in tumor cells can be enhanced in order to diminish their aggressive potential. Previously, we identified the histone demethylase KDM5A (lysine [K]-specific demethylase 5A), which demethylates histone H3 on Lys4 (H3K4), as a pRB-interacting protein counteracting pRB's role in promoting differentiation. Here we show that loss of Kdm5a restores differentiation through increasing mitochondrial respiration. This metabolic effect is both necessary and sufficient to induce the expression of a network of cell type-specific signaling and structural genes. Importantly, the regulatory functions of pRB in the cell cycle and differentiation are distinct because although restoring differentiation requires intact mitochondrial function, it does not necessitate cell cycle exit. Cells lacking Rb1 exhibit defective mitochondria and decreased oxygen consumption. Kdm5a is a direct repressor of metabolic regulatory genes, thus explaining the compensatory role of Kdm5a deletion in restoring mitochondrial function and differentiation. Significantly, activation of mitochondrial function by the mitochondrial biogenesis regulator Pgc-1α (peroxisome proliferator-activated receptor γ-coactivator 1α; also called PPARGC1A) a coactivator of the Kdm5a target genes, is sufficient to override the differentiation block. Overexpression of Pgc-1α, like KDM5A deletion, inhibits cell growth in RB-negative human cancer cell lines. The rescue of differentiation by loss of KDM5A or by activation of mitochondrial biogenesis reveals the switch to oxidative phosphorylation as an essential step in restoring differentiation and a less aggressive cancer phenotype.
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Affiliation(s)
- Renáta Váraljai
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60607, USA
| | - Abul B M M K Islam
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60607, USA; Research Unit on Biomedical Informatics, Department of Experimental and Health Sciences, Barcelona Biomedical Research Park, Universitat Pompeu Fabra, Barcelona 08003, Spain; Department of Genetic Engineering and Biotechnology, University of Dhaka, Dhaka 1000, Bangladesh
| | - Michael L Beshiri
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60607, USA
| | - Jalees Rehman
- Section of Cardiology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612, USA; Department of Pharmacology, University of Illinois at Chicago, Chicago, Illinois 60612, USA
| | - Nuria Lopez-Bigas
- Research Unit on Biomedical Informatics, Department of Experimental and Health Sciences, Barcelona Biomedical Research Park, Universitat Pompeu Fabra, Barcelona 08003, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona 08010, Spain
| | - Elizaveta V Benevolenskaya
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60607, USA
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26
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An S, Chen Y, Gao C, Qin B, Du X, Meng F, Qi Y. Inactivation of INK4a and ARF induces myocardial proliferation and improves cardiac repair following ischemia‑reperfusion. Mol Med Rep 2015; 12:5911-6. [PMID: 26239104 DOI: 10.3892/mmr.2015.4133] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 04/10/2015] [Indexed: 11/05/2022] Open
Abstract
The growth of the heart during mammalian embryonic development is primarily dependent on an increase in the number of cardiomyocytes (CM). However, shortly following birth, CMs cease proliferating and further growth of the myocardium is achieved via hypertrophic expansion of the existing CM population. The cyclin-dependent kinase inhibitor 2A (Cdkn2a) locus encodes overlapping genes for two tumor suppressor proteins, p16INK4a and p19 alternative reading frame (ARF). To determine whether decreased Cdkn2a gene expression results in improved cardiac regeneration in vitro and in vivo following cardiac injury, the proliferation of CMs isolated from Cdkn2a knockout (KO) and wild‑type (WT) mice in vitro and in vivo were evaluated following generation of ischemia reperfusion (IR) injury. The KO mice demonstrated enhanced CM proliferation not only in vitro, but also in vivo. Furthermore, heart function was improved and scar size was decreased in the KO mice compared with that of the WT mice. The results also indicated that microRNA (miR)‑1 and miR‑195 expression levels associated with cell proliferation were reduced following IR injury in KO mice compared with those of WT mice. These results suggested that the inactivation of INK4a and ARF stimulated CM proliferation and promoted cardiac repair.
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Affiliation(s)
- Songtao An
- Department of Cardiology, People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, P.R. China
| | - Yan Chen
- Department of Cardiology, People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, P.R. China
| | - Chuanyu Gao
- Department of Cardiology, People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, P.R. China
| | - Bingyu Qin
- Department of Anesthesia, People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, P.R. China
| | - Xianhui Du
- Department of Anesthesia, People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, P.R. China
| | - Fanmin Meng
- Department of Anesthesia, People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, P.R. China
| | - Yanyan Qi
- Department of Anesthesia, People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, P.R. China
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Sung B, Hwang SY, Kim MJ, Kim M, Jeong JW, Kim CM, Chung HY, Kim ND. Loquat leaf extract enhances myogenic differentiation, improves muscle function and attenuates muscle loss in aged rats. Int J Mol Med 2015; 36:792-800. [PMID: 26178971 DOI: 10.3892/ijmm.2015.2286] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Accepted: 07/03/2015] [Indexed: 11/06/2022] Open
Abstract
A main characteristic of aging is the debilitating, progressive and generalized impairment of biological functions, resulting in an increased vulnerability to disease and death. Skeletal muscle comprises approximately 40% of the human body; thus, it is the most abundant tissue. At the age of 30 onwards, 0.5‑1% of human muscle mass is lost each year, with a marked acceleration in the rate of decline after the age of 65. Thus, novel strategies that effectively attenuate skeletal muscle loss and enhance muscle function are required to improve the quality of life of older subjects. The aim of the present study was to determine whether loquat (Eriobotrya japonica) leaf extract (LE) can prevent the loss of skeletal muscle function in aged rats. Young (5-month-old) and aged (18‑19-month-old) rats were fed LE (50 mg/kg/day) for 35 days and the changes in muscle mass and strength were evaluated. The age‑associated loss of grip strength was attenuated, and muscle mass and muscle creatine kinase (CK) activity were enhanced following the administration of LE. Histochemical analysis also revealed that LE abrogated the age‑associated decrease in cross‑sectional area (CSA) and decreased the amount of connective tissue in the muscle of aged rats. To investigate the mode of action of LE, C2C12 murine myoblasts were used to evaluate the myogenic potential of LE. The expression levels of myogenic proteins (MyoD and myogenin) and functional myosin heavy chain (MyHC) were measured by western blot analysis. LE enhanced MyoD, myogenin and MyHC expression. The changes in the expression of myogenic genes corresponded with an increase in the activity of CK, a myogenic differentiation marker. Finally, LE activated the Akt/mammalian target of rapamycin (mTOR) signaling pathway, which is involved in muscle protein synthesis during myogenesis. These findings suggest that LE attenuates sarcopenia by promoting myogenic differentiation and subsequently promoting muscle protein synthesis.
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Affiliation(s)
- Bokyung Sung
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan 609‑735, Republic of Korea
| | - Seong Yeon Hwang
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan 609‑735, Republic of Korea
| | - Min Jo Kim
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan 609‑735, Republic of Korea
| | - Minjung Kim
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan 609‑735, Republic of Korea
| | - Ji Won Jeong
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan 609‑735, Republic of Korea
| | - Cheol Min Kim
- Research Center for Anti‑Aging Technology Development, Pusan National University, Busan 609‑735, Republic of Korea
| | - Hae Young Chung
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan 609‑735, Republic of Korea
| | - Nam Deuk Kim
- Department of Pharmacy, College of Pharmacy, Pusan National University, Busan 609‑735, Republic of Korea
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28
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Abstract
DNA damage is induced in many types of cells by internal and external cell stress. When DNA is damaged, DNA Damage Response (DDR) programs are activated to repair the DNA lesions in order to preserve genomic integrity and suppress subsequent malignant transformation. Among these programs is cell cycle checkpoint that ensures cell cycle arrest and subsequent repair of the damaged DNA, apoptosis and senescence in various phases of the cell cycle. Moreover, recent studies have established the cell differentiation checkpoint, the other type of the checkpoint that is specifically activated in the course of differentiation. We will discuss the evidences that support the link between DNA damage proteins and C2C12 cell differentiation.
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Affiliation(s)
- Sara Cuesta Sancho
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, NY14263, USA
| | - Toru Ouchi
- Department of Cancer Genetics, Roswell Park Cancer Institute, Buffalo, NY14263, USA
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29
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Albini S, Coutinho Toto P, Dall'Agnese A, Malecova B, Cenciarelli C, Felsani A, Caruso M, Bultman SJ, Puri PL. Brahma is required for cell cycle arrest and late muscle gene expression during skeletal myogenesis. EMBO Rep 2015; 16:1037-50. [PMID: 26136374 DOI: 10.15252/embr.201540159] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 05/25/2015] [Indexed: 02/03/2023] Open
Abstract
Although the two catalytic subunits of the SWI/SNF chromatin-remodeling complex--Brahma (Brm) and Brg1--are almost invariably co-expressed, their mutually exclusive incorporation into distinct SWI/SNF complexes predicts that Brg1- and Brm-based SWI/SNF complexes execute specific functions. Here, we show that Brg1 and Brm have distinct functions at discrete stages of muscle differentiation. While Brg1 is required for the activation of muscle gene transcription at early stages of differentiation, Brm is required for Ccnd1 repression and cell cycle arrest prior to the activation of muscle genes. Ccnd1 knockdown rescues the ability to exit the cell cycle in Brm-deficient myoblasts, but does not recover terminal differentiation, revealing a previously unrecognized role of Brm in the activation of late muscle gene expression independent from the control of cell cycle. Consistently, Brm null mice displayed impaired muscle regeneration after injury, with aberrant proliferation of satellite cells and delayed formation of new myofibers. These data reveal stage-specific roles of Brm during skeletal myogenesis, via formation of repressive and activatory SWI/SNF complexes.
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Affiliation(s)
- Sonia Albini
- Sanford-Burnham Institute for Medical Research, La Jolla, CA, USA
| | | | | | - Barbora Malecova
- Sanford-Burnham Institute for Medical Research, La Jolla, CA, USA
| | | | - Armando Felsani
- CNR-Istituto di Biologia Cellulare e Neurobiologia Fondazione Santa Lucia, Rome, Italy
| | - Maurizia Caruso
- CNR-Istituto di Biologia Cellulare e Neurobiologia Fondazione Santa Lucia, Rome, Italy
| | - Scott J Bultman
- Department of Genetics, Lineberger Comprehensive Cancer Center University of North Carolina, Chapel Hill, NC, USA
| | - Pier Lorenzo Puri
- Sanford-Burnham Institute for Medical Research, La Jolla, CA, USA IRCCS Fondazione Santa Lucia, Rome, Italy
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Schaal C, Pillai S, Chellappan SP. The Rb-E2F transcriptional regulatory pathway in tumor angiogenesis and metastasis. Adv Cancer Res 2015; 121:147-182. [PMID: 24889531 DOI: 10.1016/b978-0-12-800249-0.00004-4] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The retinoblastoma tumor suppressor protein Rb plays a major role in regulating G1/S transition and is a critical regulator of cell proliferation. Rb protein exerts its growth regulatory properties mainly by physically interacting with the transcriptionally active members of the E2F transcription factor family, especially E2Fs 1, 2, and 3. Given its critical role in regulating cell proliferation, it is not surprising that Rb is inactivated in almost all tumors, either through the mutation of Rb gene itself or through the mutations of its upstream regulators including K-Ras and INK4. Recent studies have revealed a significant role for Rb and its downstream effectors, especially E2Fs, in regulating various aspects of tumor progression, angiogenesis, and metastasis. Thus, components of the Rb-E2F pathway have been shown to regulate the expression of genes involved in angiogenesis, including VEGF and VEGFR, genes involved in epithelial-mesenchymal transition including E-cadherin and ZEB proteins, and genes involved in invasion and migration like matrix metalloproteinases. Rb has also been shown to play a major role in the functioning of normal and cancer stem cells; further, Rb and E2F appear to play a regulatory role in the energy metabolism of cancer cells. These findings raise the possibility that mutational events that initiate tumorigenesis by inducing uncontrolled cell proliferation might also contribute to the progression and metastasis of cancers through the mediation of the Rb-E2F transcriptional regulatory pathway. This review highlights these recent studies on tumor promoting functions of the Rb-E2F pathway.
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Affiliation(s)
- Courtney Schaal
- Department of Tumor Biology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida, USA
| | - Smitha Pillai
- Department of Tumor Biology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida, USA
| | - Srikumar P Chellappan
- Department of Tumor Biology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida, USA.
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31
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Nagano H, Yamagishi N, Tomida C, Yano C, Aibara K, Kohno S, Abe T, Ohno A, Hirasaka K, Okumura Y, Mills EM, Nikawa T, Teshima-Kondo S. A novel myogenic function residing in the 5' non-coding region of Insulin receptor substrate-1 (Irs-1) transcript. BMC Cell Biol 2015; 16:8. [PMID: 25887310 PMCID: PMC4373113 DOI: 10.1186/s12860-015-0054-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 02/16/2015] [Indexed: 11/20/2022] Open
Abstract
Background There is evidence that several messenger RNAs (mRNAs) are bifunctional RNAs, i.e. RNA transcript carrying both protein-coding capacity and activity as functional non-coding RNA via 5′ and 3′ untranslated regions (UTRs). Results In this study, we identified a novel bifunctional RNA that is transcribed from insulin receptor substrate-1 (Irs-1) gene with full-length 5′UTR sequence (FL-Irs-1 mRNA). FL-Irs-1 mRNA was highly expressed only in skeletal muscle tissue. In cultured skeletal muscle C2C12 cells, the FL-Irs-1 transcript functioned as a bifunctional mRNA. The FL-Irs-1 transcript produced IRS-1 protein during differentiation of myoblasts into myotubes; however, this transcript functioned as a regulatory RNA in proliferating myoblasts. The FL-Irs-1 5′UTR contains a partial complementary sequence to Rb mRNA, which is a critical factor for myogenic differentiation. The overexpression of the 5′UTR markedly reduced Rb mRNA expression, and this reduction was fully dependent on the complementary element and was not compensated by IRS-1 protein. Conversely, knockdown of FL-Irs-1 mRNA increased Rb mRNA expression and enhanced myoblast differentiation into myotubes. Conclusions Our findings suggest that the FL-Irs-1 transcript regulates myogenic differentiation as a regulatory RNA in myoblasts. Electronic supplementary material The online version of this article (doi:10.1186/s12860-015-0054-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hikaru Nagano
- Department of Nutritional Physiology, Institute of Health Biosciences, Tokushima University Graduate School, Tokushima, 770-8503, Japan. .,Facalty of Nutritional Science, Sagami Women's University, Sagamihara, 252-0383, Japan.
| | - Naoko Yamagishi
- Department of Nutritional Physiology, Institute of Health Biosciences, Tokushima University Graduate School, Tokushima, 770-8503, Japan.
| | - Chisato Tomida
- Department of Nutritional Physiology, Institute of Health Biosciences, Tokushima University Graduate School, Tokushima, 770-8503, Japan.
| | - Chiaki Yano
- Department of Nutritional Physiology, Institute of Health Biosciences, Tokushima University Graduate School, Tokushima, 770-8503, Japan.
| | - Kana Aibara
- Department of Nutritional Physiology, Institute of Health Biosciences, Tokushima University Graduate School, Tokushima, 770-8503, Japan.
| | - Shohei Kohno
- Department of Nutritional Physiology, Institute of Health Biosciences, Tokushima University Graduate School, Tokushima, 770-8503, Japan.
| | - Tomoki Abe
- Department of Nutritional Physiology, Institute of Health Biosciences, Tokushima University Graduate School, Tokushima, 770-8503, Japan.
| | - Ayako Ohno
- Department of Nutritional Physiology, Institute of Health Biosciences, Tokushima University Graduate School, Tokushima, 770-8503, Japan.
| | - Katsuya Hirasaka
- Graduate school of Fisheries Science and Environmental Studies, Nagasaki University, Nagasaki, 852-8521, Japan.
| | - Yuushi Okumura
- Facalty of Nutritional Science, Sagami Women's University, Sagamihara, 252-0383, Japan.
| | - Edward M Mills
- Division of Pharmacology/Toxicology, College of Pharmacy, University of Texas at Austin, Austin, Texas.
| | - Takeshi Nikawa
- Department of Nutritional Physiology, Institute of Health Biosciences, Tokushima University Graduate School, Tokushima, 770-8503, Japan.
| | - Shigetada Teshima-Kondo
- Department of Nutritional Physiology, Institute of Health Biosciences, Tokushima University Graduate School, Tokushima, 770-8503, Japan.
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32
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Harada A, Mallappa C, Okada S, Butler JT, Baker SP, Lawrence JB, Ohkawa Y, Imbalzano AN. Spatial re-organization of myogenic regulatory sequences temporally controls gene expression. Nucleic Acids Res 2015; 43:2008-21. [PMID: 25653159 PMCID: PMC4344497 DOI: 10.1093/nar/gkv046] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 11/05/2014] [Accepted: 01/13/2015] [Indexed: 12/14/2022] Open
Abstract
During skeletal muscle differentiation, the activation of some tissue-specific genes occurs immediately while others are delayed. The molecular basis controlling temporal gene regulation is poorly understood. We show that the regulatory sequences, but not other regions of genes expressed at late times of myogenesis, are in close physical proximity in differentiating embryonic tissue and in differentiating culture cells, despite these genes being located on different chromosomes. Formation of these inter-chromosomal interactions requires the lineage-determinant MyoD and functional Brg1, the ATPase subunit of SWI/SNF chromatin remodeling enzymes. Ectopic expression of myogenin and a specific Mef2 isoform induced myogenic differentiation without activating endogenous MyoD expression. Under these conditions, the regulatory sequences of late gene loci were not in close proximity, and these genes were prematurely activated. The data indicate that the spatial organization of late genes contributes to temporal regulation of myogenic transcription by restricting late gene expression during the early stages of myogenesis.
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Affiliation(s)
- Akihito Harada
- Department of Advanced Medical Initiatives, JST-CREST, Faculty of Medicine, Kyushu University, Fukuoka 812-8582, Japan
| | - Chandrashekara Mallappa
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Seiji Okada
- Department of Advanced Medical Initiatives, JST-CREST, Faculty of Medicine, Kyushu University, Fukuoka 812-8582, Japan
| | - John T Butler
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Stephen P Baker
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA Department of Quantitative Health Sciences, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Jeanne B Lawrence
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Yasuyuki Ohkawa
- Department of Advanced Medical Initiatives, JST-CREST, Faculty of Medicine, Kyushu University, Fukuoka 812-8582, Japan Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Anthony N Imbalzano
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
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33
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Satellite cells: regenerative mechanisms and applicability in muscular dystrophy. Stem Cells Int 2015; 2015:487467. [PMID: 25763072 PMCID: PMC4339711 DOI: 10.1155/2015/487467] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 12/17/2014] [Accepted: 01/08/2015] [Indexed: 11/17/2022] Open
Abstract
The satellite cells are long regarded as heterogeneous cell population, which is intimately linked to the processes of muscular recovery. The heterogeneous cell population may be classified by specific markers. In spite of the significant amount of variation amongst the satellite cell populations, it seems that their activity is tightly bound to the paired box 7 transcription factor expression, which is, therefore, used as a canonical marker for these cells. Muscular dystrophic diseases, such as Duchenne muscular dystrophy, elicit severe tissue injuries leading those patients to display a very specific pattern of muscular recovery abnormalities. There have been works on the application of precursors cells as a therapeutic alternative for Duchenne muscular dystrophy and initial attempts have proven the cells inefficient; however later endeavours have proposed solutions for the experiments improving significantly the results. The presence of a range of satellite cells populations indicates the existence of specific cells with enhanced capability of muscular recovery in afflicted muscles.
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34
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Flowers S, Patel PJ, Gleicher S, Amer K, Himelman E, Goel S, Moran E. p107-Dependent recruitment of SWI/SNF to the alkaline phosphatase promoter during osteoblast differentiation. Bone 2014; 69:47-54. [PMID: 25182511 PMCID: PMC5222550 DOI: 10.1016/j.bone.2014.08.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 08/11/2014] [Accepted: 08/16/2014] [Indexed: 12/28/2022]
Abstract
The retinoblastoma protein family is intimately involved in the regulation of tissue specific gene expression during mesenchymal stem cell differentiation. The role of the following proteins, pRB, p107 and p130, is particularly significant in differentiation to the osteoblast lineage, as human germ-line mutations of RB1 greatly increase susceptibility to osteosarcoma. During differentiation, pRB directly targets certain osteogenic genes for activation, including the alkaline phosphatase-encoding gene Alpl. Chromatin immunoprecipitation (ChIP) assays indicate that Alpl is targeted by p107 in differentiating osteoblasts selectively during activation with the same dynamics as pRB, which suggests that p107 helps promote Alpl activation. Mouse models indicate overlapping roles for pRB and p107 in bone and cartilage formation, but very little is known about direct tissue-specific gene targets of p107, or the consequences of targeting by p107. Here, the roles of p107 and pRB were compared using shRNA-mediated knockdown genetics in an osteoblast progenitor model, MC3T3-E1 cells. The results show that p107 has a distinct role along with pRB in induction of Alpl. Deficiency of p107 does not impede recruitment of transcription factors recognized as pRB co-activation partners at the promoter; however, p107 is required for the efficient recruitment of an activating SWI/SNF chromatin-remodeling complex, an essential event in Alpl induction.
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Affiliation(s)
- Stephen Flowers
- Department of Orthopaedics, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ 07103, USA
| | - Parth J Patel
- Department of Orthopaedics, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ 07103, USA
| | - Stephanie Gleicher
- Department of Orthopaedics, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ 07103, USA
| | - Kamal Amer
- Department of Orthopaedics, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ 07103, USA
| | - Eric Himelman
- Department of Orthopaedics, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ 07103, USA
| | - Shruti Goel
- Department of Orthopaedics, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ 07103, USA
| | - Elizabeth Moran
- Department of Orthopaedics, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ 07103, USA.
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35
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Popov B, Petrov N. pRb-E2F signaling in life of mesenchymal stem cells: Cell cycle, cell fate, and cell differentiation. Genes Dis 2014; 1:174-187. [PMID: 30258863 PMCID: PMC6150080 DOI: 10.1016/j.gendis.2014.09.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 09/14/2014] [Indexed: 02/07/2023] Open
Abstract
Mesenchymal stem cells (MSCs) are multipotent cells that can differentiate into various mesodermal lines forming fat, muscle, bone, and other lineages of connective tissue. MSCs possess plasticity and under special metabolic conditions may transform into cells of unusual phenotypes originating from ecto- and endoderm. After transplantation, MSCs release the humoral factors promoting regeneration of the damaged tissue. During last five years, the numbers of registered clinical trials of MSCs have increased about 10 folds. This gives evidence that MSCs present a new promising resource for cell therapy of the most dangerous diseases. The efficacy of the MSCs therapy is limited by low possibilities to regulate their conversion into cells of damaged tissues that is implemented by the pRb-E2F signaling. The widely accepted viewpoint addresses pRb as ubiquitous regulator of cell cycle and tumor suppressor. However, current publications suggest that basic function of the pRb-E2F signaling in development is to regulate cell fate and differentiation. Through facultative and constitutive chromatin modifications, pRb-E2F signaling promotes transient and stable cells quiescence, cell fate choice to differentiate, to senesce, or to die. Loss of pRb is associated with cancer cell fate. pRb regulates cell fate by retaining quiescence of one cell population in favor of commitment of another or by suppression of genes of different cell phenotype. pRb is the founder member of the "pocket protein" family possessing functional redundancy. Critical increase in the efficacy of the MSCs based cell therapy will depend on precise understanding of various aspects of the pRb-E2F signaling.
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Affiliation(s)
- Boris Popov
- Institute of Cytology, Russian Academy of Sciences, St.Petersburg, 4, Tikhoretsky Av., 194064, Russia
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36
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Rajabi HN, Takahashi C, Ewen ME. Retinoblastoma protein and MyoD function together to effect the repression of Fra-1 and in turn cyclin D1 during terminal cell cycle arrest associated with myogenesis. J Biol Chem 2014; 289:23417-27. [PMID: 25006242 DOI: 10.1074/jbc.m113.532572] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The acquisition of skeletal muscle-specific function and terminal cell cycle arrest represent two important features of the myogenic differentiation program. These cellular processes are distinct and can be separated genetically. The lineage-specific transcription factor MyoD and the retinoblastoma protein pRb participate in both of these cellular events. Whether and how MyoD and pRb work together to effect terminal cell cycle arrest is uncertain. To address this question, we focused on cyclin D1, whose stable repression is required for terminal cell cycle arrest and execution of myogenesis. MyoD and pRb are both required for the repression of cyclin D1; their actions, however, were found not to be direct. Rather, they operate to regulate the immediate early gene Fra-1, a critical player in mitogen-dependent induction of cyclin D1. Two conserved MyoD-binding sites were identified in an intronic enhancer of Fra-1 and shown to be required for the stable repression of Fra-1 and, in turn, cyclin D1. Localization of MyoD alone to the intronic enhancer of Fra-1 in the absence of pRb was not sufficient to elicit a block to Fra-1 induction; pRb was also recruited to the intronic enhancer in a MyoD-dependent manner. These observations suggest that MyoD and pRb work together cooperatively at the level of the intronic enhancer of Fra-1 during terminal cell cycle arrest. This work reveals a previously unappreciated link between a lineage-specific transcription factor, a tumor suppressor, and a proto-oncogene in the control of an important facet of myogenic differentiation.
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Affiliation(s)
- Hasan N Rajabi
- From the Dana-Farber Cancer Institute, Boston, Massachusetts 02215
| | - Chiaki Takahashi
- From the Dana-Farber Cancer Institute, Boston, Massachusetts 02215, the Cancer Research Institute of Kanazawa University, 13-1 Takara-machi, Kanazawa 920-0934, Japan, and
| | - Mark E Ewen
- From the Dana-Farber Cancer Institute, Boston, Massachusetts 02215, the Molecular Oncology Research Institute, Tufts Medical Center, Boston, Massachusetts 02111
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37
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Arginine-glycine-glutamine and serine-isoleucine-lysine-valine-alanine-valine modified poly(l-lactide) films: Bioactive molecules used for surface grafting to guide cellular contractile phenotype. Biointerphases 2014; 9:029002. [DOI: 10.1116/1.4864432] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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38
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Ajioka I. Coordination of proliferation and neuronal differentiation by the retinoblastoma protein family. Dev Growth Differ 2014; 56:324-34. [PMID: 24697649 DOI: 10.1111/dgd.12127] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 02/13/2014] [Accepted: 02/16/2014] [Indexed: 12/23/2022]
Abstract
Once neurons enter the post-mitotic G0 phase during central nervous system (CNS) development, they lose their proliferative potential. When neurons re-enter the cell cycle during pathological situations such as neurodegeneration, they undergo cell death after S phase progression. Thus, the regulatory networks that drive cell proliferation and maintain neuronal differentiation are highly coordinated. In this review, the coordination of cell cycle control and neuronal differentiation during development are discussed, focusing on regulation by the Rb family of tumor suppressors (including p107 and p130), and the Cip/Kip family of cyclin dependent kinase (Cdk) inhibitors. Based on recent findings suggesting roles for these families in regulating neurogenesis and neuronal differentiation, I propose that the Rb family is essential for daughter cells of neuronal progenitors to enter the post-mitotic G0 phase without affecting the initiation of neuronal differentiation in most cases, while the Cip/Kip family regulates the timing of neuronal progenitor cell cycle exit and the initiation of neuronal differentiation at least in the progenitor cells of the cerebral cortex and the retina. Rb's lack of involvement in regulating the initiation of neuronal differentiation may explain why Rb family-deficient retinoblastomas characteristically exhibit neuronal features.
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Affiliation(s)
- Itsuki Ajioka
- Center for Brain Integration Research, Tokyo Medical and Dental University, 1-5-45 Yushima, Tokyo, 113-8510, Japan
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39
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A retinoblastoma allele that is mutated at its common E2F interaction site inhibits cell proliferation in gene-targeted mice. Mol Cell Biol 2014; 34:2029-45. [PMID: 24662053 DOI: 10.1128/mcb.01589-13] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The retinoblastoma protein (pRB) is best known for regulating cell proliferation through E2F transcription factors. In this report, we investigate the properties of a targeted mutation that disrupts pRB interactions with the transactivation domain of E2Fs. Mice that carry this mutation endogenously (Rb1(ΔG)) are defective for pRB-dependent repression of E2F target genes. Except for an accelerated entry into S phase in response to serum stimulation, cell cycle regulation in Rb1(ΔG/ΔG) mouse embryonic fibroblasts (MEFs) strongly resembles that of the wild type. In a serum deprivation-induced cell cycle exit, Rb1(ΔG/ΔG) MEFs display a magnitude of E2F target gene derepression similar to that of Rb1(-/-) cells, even though Rb1(ΔG/ΔG) cells exit the cell cycle normally. Interestingly, cell cycle arrest in Rb1(ΔG/ΔG) MEFs is responsive to p16 expression and gamma irradiation, indicating that alternate mechanisms can be activated in G1 to arrest proliferation. Some Rb1(ΔG/ΔG) mice die neonatally with a muscle degeneration phenotype, while the others live a normal life span with no evidence of spontaneous tumor formation. Most tissues appear histologically normal while being accompanied by derepression of pRB-regulated E2F targets. This suggests that non-E2F-, pRB-dependent pathways may have a more relevant role in proliferative control than previously identified.
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Abstract
Lamins A and C, encoded by LMNA, are constituent of the nuclear lamina, a meshwork of proteins underneath the nuclear envelope first described as scaffolding proteins of the nucleus. Since the discovery of LMNA mutations in highly heterogeneous human disorders (including cardiac and muscular dystrophies, lipodystrophies and progeria), the number of functions described for lamin A/C has expanded. Lamin A/C is notably involved in the regulation of chromatin structure and gene transcription, and in the resistance of cells to mechanical stress. This review focuses on studies performed on knock-out and knock-in Lmna mouse models, which have led to decipher some of the lamin A/C functions in striated muscles and to the first preclinical trials of pharmaceutical therapies.
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Perilli S, Perez-Perez JM, Di Mambro R, Peris CL, Díaz-Triviño S, Del Bianco M, Pierdonati E, Moubayidin L, Cruz-Ramírez A, Costantino P, Scheres B, Sabatini S. RETINOBLASTOMA-RELATED protein stimulates cell differentiation in the Arabidopsis root meristem by interacting with cytokinin signaling. THE PLANT CELL 2013; 25:4469-78. [PMID: 24285791 PMCID: PMC3875730 DOI: 10.1105/tpc.113.116632] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 11/04/2013] [Accepted: 11/14/2013] [Indexed: 05/23/2023]
Abstract
Maintenance of mitotic cell clusters such as meristematic cells depends on their capacity to maintain the balance between cell division and cell differentiation necessary to control organ growth. In the Arabidopsis thaliana root meristem, the antagonistic interaction of two hormones, auxin and cytokinin, regulates this balance by positioning the transition zone, where mitotically active cells lose their capacity to divide and initiate their differentiation programs. In animals, a major regulator of both cell division and cell differentiation is the tumor suppressor protein RETINOBLASTOMA. Here, we show that similarly to its homolog in animal systems, the plant RETINOBLASTOMA-RELATED (RBR) protein regulates the differentiation of meristematic cells at the transition zone by allowing mRNA accumulation of AUXIN RESPONSE FACTOR19 (ARF19), a transcription factor involved in cell differentiation. We show that both RBR and the cytokinin-dependent transcription factor ARABIDOPSIS RESPONSE REGULATOR12 are required to activate the transcription of ARF19, which is involved in promoting cell differentiation and thus root growth.
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Affiliation(s)
- Serena Perilli
- Department of Biology and Biotechnology, Laboratories of Functional Genomics and Proteomics of Model Systems, University of Rome Sapienza, 00185 Rome, Italy
| | - José Manuel Perez-Perez
- Molecular Genetics, Department of Biology, University of Utrecht, 3584 CH Utrecht, The Netherlands
| | - Riccardo Di Mambro
- Department of Biology and Biotechnology, Laboratories of Functional Genomics and Proteomics of Model Systems, University of Rome Sapienza, 00185 Rome, Italy
| | - Cristina Llavata Peris
- Department of Biology and Biotechnology, Laboratories of Functional Genomics and Proteomics of Model Systems, University of Rome Sapienza, 00185 Rome, Italy
| | - Sara Díaz-Triviño
- Molecular Genetics, Department of Biology, University of Utrecht, 3584 CH Utrecht, The Netherlands
| | - Marta Del Bianco
- Department of Biology and Biotechnology, Laboratories of Functional Genomics and Proteomics of Model Systems, University of Rome Sapienza, 00185 Rome, Italy
| | - Emanuela Pierdonati
- Department of Biology and Biotechnology, Laboratories of Functional Genomics and Proteomics of Model Systems, University of Rome Sapienza, 00185 Rome, Italy
| | - Laila Moubayidin
- Department of Biology and Biotechnology, Laboratories of Functional Genomics and Proteomics of Model Systems, University of Rome Sapienza, 00185 Rome, Italy
| | - Alfredo Cruz-Ramírez
- Molecular Genetics, Department of Biology, University of Utrecht, 3584 CH Utrecht, The Netherlands
| | - Paolo Costantino
- Department of Biology and Biotechnology, Laboratories of Functional Genomics and Proteomics of Model Systems, University of Rome Sapienza, 00185 Rome, Italy
| | - Ben Scheres
- Molecular Genetics, Department of Biology, University of Utrecht, 3584 CH Utrecht, The Netherlands
| | - Sabrina Sabatini
- Department of Biology and Biotechnology, Laboratories of Functional Genomics and Proteomics of Model Systems, University of Rome Sapienza, 00185 Rome, Italy
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Abstract
Tumor suppressors are so named because cancers occur in their absence, but these genes also have important functions in development, metabolism and tissue homeostasis. Here, we discuss known and potential functions of tumor suppressor genes during tissue regeneration, focusing on the evolutionarily conserved tumor suppressors pRb1, p53, Pten and Hippo. We propose that their activity is essential for tissue regeneration. This is in contrast to suggestions that tumor suppression is a trade-off for regenerative capacity. We also hypothesize that certain aspects of tumor suppressor pathways inhibit regenerative processes in mammals, and that transient targeted modification of these pathways could be fruitfully exploited to enhance processes that are important to regenerative medicine.
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Affiliation(s)
- Jason H Pomerantz
- Department of Surgery, Division of Plastic and Reconstructive Surgery, University of California, San Francisco, CA 94143, USA.
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Sdek P, Oyama K, Angelis E, Chan SS, Schenke-Layland K, MacLellan WR. Epigenetic regulation of myogenic gene expression by heterochromatin protein 1 alpha. PLoS One 2013; 8:e58319. [PMID: 23505487 PMCID: PMC3594309 DOI: 10.1371/journal.pone.0058319] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 02/02/2013] [Indexed: 12/17/2022] Open
Abstract
Heterochromatin protein 1 (HP1) is an essential heterochromatin-associated protein typically involved in the epigenetic regulation of gene silencing. However, recent reports have demonstrated that HP1 can also activate gene expression in certain contexts including differentiation. To explore the role of each of the three mammalian HP1 family members (α, β and γ) in skeletal muscle, their expression was individually disrupted in differentiating skeletal myocytes. Among the three isoforms of HP1, HP1α was specifically required for myogenic gene expression in myoblasts only. Knockdown of HP1α led to a defect in transcription of skeletal muscle-specific genes including Lbx1, MyoD and myogenin. HP1α binds to the genomic region of myogenic genes and depletion of HP1α results in a paradoxical increase in histone H3 lysine 9 trimethylation (H3K9me3) at these sites. JHDM3A, a H3K9 demethylase also binds to myogenic gene's genomic regions in myoblasts in a HP1α-dependent manner. JHDM3A interacts with HP1α and knockdown of JHDM3A in myoblasts recapitulates the decreased myogenic gene transcription seen with HP1α depletion. These results propose a novel mechanism for HP1α-dependent gene activation by interacting with the demethylase JHDM3A and that HP1α is required for maintenance of myogenic gene expression in myoblasts.
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Affiliation(s)
- Patima Sdek
- Departments of Medicine/Cardiology, Center for Cardiovascular Biology, Institute for Stem Cell Research, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Kyohei Oyama
- Departments of Medicine/Cardiology, Center for Cardiovascular Biology, Institute for Stem Cell Research, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Ekaterini Angelis
- Departments of Medicine/Cardiology, Center for Cardiovascular Biology, Institute for Stem Cell Research, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Shing S. Chan
- Departments of Medicine/Cardiology, Center for Cardiovascular Biology, Institute for Stem Cell Research, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Katja Schenke-Layland
- Departments of Medicine/Cardiology, Center for Cardiovascular Biology, Institute for Stem Cell Research, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - W. Robb MacLellan
- Departments of Medicine/Cardiology, Center for Cardiovascular Biology, Institute for Stem Cell Research, University of Washington School of Medicine, Seattle, Washington, United States of America
- * E-mail:
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Abstract
Adult skeletal muscle in mammals is a stable tissue under normal circumstances but has remarkable ability to repair after injury. Skeletal muscle regeneration is a highly orchestrated process involving the activation of various cellular and molecular responses. As skeletal muscle stem cells, satellite cells play an indispensible role in this process. The self-renewing proliferation of satellite cells not only maintains the stem cell population but also provides numerous myogenic cells, which proliferate, differentiate, fuse, and lead to new myofiber formation and reconstitution of a functional contractile apparatus. The complex behavior of satellite cells during skeletal muscle regeneration is tightly regulated through the dynamic interplay between intrinsic factors within satellite cells and extrinsic factors constituting the muscle stem cell niche/microenvironment. For the last half century, the advance of molecular biology, cell biology, and genetics has greatly improved our understanding of skeletal muscle biology. Here, we review some recent advances, with focuses on functions of satellite cells and their niche during the process of skeletal muscle regeneration.
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Affiliation(s)
- Hang Yin
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
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Indovina P, Marcelli E, Casini N, Rizzo V, Giordano A. Emerging roles of RB family: new defense mechanisms against tumor progression. J Cell Physiol 2013; 228:525-35. [PMID: 22886479 DOI: 10.1002/jcp.24170] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 07/31/2012] [Indexed: 12/14/2022]
Abstract
The retinoblastoma (RB) family of proteins, including RB1/p105, retinoblastoma-like 1 (RBL1/p107), and retinoblastoma-like 2 (RBL2/p130), is principally known for its central role on cell cycle regulation. The inactivation of RB proteins confers a growth advantage and underlies multiple types of tumors. Recently, it has been shown that RB proteins have other important roles, such as preservation of chromosomal stability, induction and maintenance of senescence and regulation of apoptosis, cellular differentiation, and angiogenesis. RB proteins are involved in many cellular pathways and act as transcriptional regulators able to bind several transcription factors, thus antagonizing or potentiating their functions. Furthermore, RB proteins might control the expression of specific target genes by recruiting chromatin remodeling enzymes. Although many efforts have been made to dissect the different functions of RB proteins, it remains still unclear which are necessary for cancer suppression and the role they play at distinct steps of carcinogenesis. Moreover, RB proteins can behave differently in various cell types or cell states. Elucidating the intricate RB protein network in regulating cell fate might provide the knowledge necessary to explain their potent tumor suppressor activity and to design novel therapeutic strategies.
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Affiliation(s)
- Paola Indovina
- Department of Human Pathology and Oncology, University of Siena, Siena, Italy
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Abstract
The retinoblastoma tumor suppressor protein pRB is conventionally regarded as an inhibitor of the E2F family of transcription factors. Conversely, pRB is also recognized as an activator of tissue-specific gene expression along various lineages including osteoblastogenesis. During osteoblast differentiation, pRB directly targets Alpl and Bglap, which encode the major markers of osteogenesis alkaline phosphatase and osteocalcin. Surprisingly, p130 and repressor E2Fs were recently found to cooccupy and repress Alpl and Bglap in proliferating osteoblast precursors before differentiation. This raises the further question of whether these genes convert to E2F activation targets when differentiation begins, which would constitute a remarkable situation wherein pRB and E2F would be cotargeting genes for activation. Chromatin immunoprecipitation analysis in an osteoblast differentiation model shows that Alpl and Bglap are indeed targeted by an activator E2F, i.e., is E2F1. Promoter occupation of Alpl and Bglap by E2F1 occurs specifically during activation, and depletion of E2F1 severely impairs their induction. Mechanistically, promoter occupation by E2F1 and pRB is mutually dependent, and without this cooperative effect, activation steps previously shown to be dependent on pRB, including recruitment of RNA polymerase II, are impaired. Myocyte- and adipocyte-specific genes are also cotargeted by E2F1 and pRB during differentiation along their respective lineages. The finding that pRB and E2F1 cooperate to activate expression of tissue-specific genes is a paradigm distinct from the classical concept of pRB as an inhibitor of E2F1, but is consistent with the observed roles of these proteins in physiological models.
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Affiliation(s)
- Stephen Flowers
- Department of Orthopaedics, New Jersey Medical School-University Hospital Cancer Center, UMDNJ, Newark, NJ 07103, USA
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Gurung R, Parnaik VK. Cyclin D3 promotes myogenic differentiation and Pax7 transcription. J Cell Biochem 2012; 113:209-19. [PMID: 21898542 DOI: 10.1002/jcb.23346] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Differentiation of skeletal muscle myoblasts involves activation of muscle-specific markers such as MyoD, Myf5, MRF4, and myogenin, followed by exit from the cell cycle, expression of structural proteins, and fusion into multinucleated myotubes. Cyclin D3 is upregulated during muscle differentiation, and expression of cyclin D3 in proliferating myoblasts causes early activation of myogenesis. In this study, we have identified the genes activated by cyclin D3 expression in C2C12 myoblasts and differentiated cells by real-time PCR analysis. Cyclin D3 expression induced faster differentiation kinetics and increase in levels of myogenic genes such as MyoD, Myf5, and myogenin at an early stage during the differentiation process, although long-term myogenic differentiation was not affected. Transcript levels of the transcription factor Pax7 that is expressed in muscle progenitors were enhanced by cyclin D3 expression in myoblasts. Components of a histone methyltransferase complex recruited by Pax7 to myogenic gene promoters were also regulated by cyclin D3. Further, the Pax7 promoter was upregulated in myoblasts expressing cyclin D3. Myoblasts that expressed cyclin D3 showed moderately higher levels of the cyclin-dependent kinase inhibitor p21 and were stalled in G2/M phase of the cell cycle. Our findings suggest that cyclin D3 primes myoblasts for differentiation by enhancing muscle specific gene expression and cell cycle exit.
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Affiliation(s)
- Ritika Gurung
- Centre for Cellular and Molecular Biology, Hyderabad, India
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Al-Tahan A, Sarkis O, Harajly M, Baghdadi OK, Zibara K, Boulos F, Dighe D, Kregel S, Bazarbachi A, El-Sabban M, Skapek SX, Saab R. Retinoic acid fails to induce cell cycle arrest with myogenic differentiation in rhabdomyosarcoma. Pediatr Blood Cancer 2012; 58:877-84. [PMID: 21755593 DOI: 10.1002/pbc.23246] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Accepted: 05/26/2011] [Indexed: 12/16/2022]
Abstract
BACKGROUND Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children. Current treatment strategies do not cure most children with recurrent or high-risk disease, underlying the need for novel therapeutic approaches. Retinoic acid has been shown to induce differentiation in a variety of cells including skeletal myoblasts and neuroblasts. In the setting of minimal residual disease, retinoic acid improves survival in neuroblastoma, another poorly differentiated childhood tumor. Whether such an approach is useful for rhabdomyosarcoma has not yet been investigated. Several in vitro studies have demonstrated an appreciable effect of retinoic acid on human RMS cellular proliferation and differentiation. PROCEDURE We assessed the efficacy of ATRA on rhabdomyosarcoma, in vitro and in vivo, using cell lines and xenografts. RESULTS ATRA slowed RMS cell proliferation, and promoted a more differentiated myogenic phenotype in both alveolar and embryonal RMS cell lines. Treatment of cultured murine myoblasts with retinoids increased Myogenin expression, but did not induce cell cycle arrest. Despite the favorable in vitro effects, ATRA failed to delay relapse of minimal residual disease using human RMS xenografts in immuno-suppressed NOD-SCID (NSG) mice. Interestingly, tumors that recurred after ATRA treatment showed evidence of enhanced muscle differentiation. CONCLUSION Our results indicate that ATRA could increase the expression of some genes associated with muscle differentiation in rhabdomyosarcoma cells, but there was no benefit of single-agent therapy in an MRD model, likely because cell cycle arrest was uncoupled from the pro-differentiation effects of retinoids.
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Affiliation(s)
- Alaa Al-Tahan
- Department of Pediatrics, American University of Beirut, Beirut, Lebanon
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A shared role for RBF1 and dCAP-D3 in the regulation of transcription with consequences for innate immunity. PLoS Genet 2012; 8:e1002618. [PMID: 22496667 PMCID: PMC3320600 DOI: 10.1371/journal.pgen.1002618] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Accepted: 02/08/2012] [Indexed: 12/27/2022] Open
Abstract
Previously, we discovered a conserved interaction between RB proteins and the Condensin II protein CAP-D3 that is important for ensuring uniform chromatin condensation during mitotic prophase. The Drosophila melanogaster homologs RBF1 and dCAP-D3 co-localize on non-dividing polytene chromatin, suggesting the existence of a shared, non-mitotic role for these two proteins. Here, we show that the absence of RBF1 and dCAP-D3 alters the expression of many of the same genes in larvae and adult flies. Strikingly, most of the genes affected by the loss of RBF1 and dCAP-D3 are not classic cell cycle genes but are developmentally regulated genes with tissue-specific functions and these genes tend to be located in gene clusters. Our data reveal that RBF1 and dCAP-D3 are needed in fat body cells to activate transcription of clusters of antimicrobial peptide (AMP) genes. AMPs are important for innate immunity, and loss of either dCAP-D3 or RBF1 regulation results in a decrease in the ability to clear bacteria. Interestingly, in the adult fat body, RBF1 and dCAP-D3 bind to regions flanking an AMP gene cluster both prior to and following bacterial infection. These results describe a novel, non-mitotic role for the RBF1 and dCAP-D3 proteins in activation of the Drosophila immune system and suggest dCAP-D3 has an important role at specific subsets of RBF1-dependent genes. The retinoblastoma protein (pRB) is a tumor suppressor protein known for its ability to repress transcription of E2F-dependent genes and induce cell cycle arrest. We have previously shown that RB proteins in Drosophila and human cells interact with the Condensin II subunit, CAP-D3, in an E2F-independent manner. Condensins promote condensation of chomosomes in mitosis. Our previous studies suggested that the Drosophila pRB and CAP-D3 homologs, RBF1 and dCAP-D3, co-localize on DNA and may share a function in cells that never undergo mitosis. In this study, we show that one non-mitotic function shared between RBF1 and dCAP-D3 is the regulation of many non-cell-cycle-related, clustered, and cell-type-specific transcripts including a conserved family of genes that are important for the immune response in the fly. In fact, results show that normal levels of dCAP-D3 and RBF1 expression are necessary for the ability of the fly to clear infection with human bacterial pathogens. This work demonstrates that dCAP-D3 proteins can regulate a unique subset of RBF1-dependent transcripts in vivo and identifies a novel role for both RBF1 and dCAP-D3 protein in activation of innate immune genes, which may be conserved in human cells.
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Abstract
The RB1 gene is the first tumor suppressor gene identified whose mutational inactivation is the cause of a human cancer, the pediatric cancer retinoblastoma. The 25 years of research since its discovery has not only illuminated a general role for RB1 in human cancer, but also its critical importance in normal development. Understanding the molecular function of the RB1 encoded protein, pRb, is a long-standing goal that promises to inform our understanding of cancer, its relationship to normal development, and possible therapeutic strategies to combat this disease. Achieving this goal has been difficult, complicated by the complexity of pRb and related proteins. The goal of this review is to explore the hypothesis that, at its core, the molecular function of pRb is to dynamically regulate the location-specific assembly or disassembly of protein complexes on the DNA in response to the output of various signaling pathways. These protein complexes participate in a variety of molecular processes relevant to DNA including gene transcription, DNA replication, DNA repair, and mitosis. Through regulation of these processes, RB1 plays a uniquely prominent role in normal development and cancer.
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Affiliation(s)
- Meenalakshmi Chinnam
- Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, New York, USA
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