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Regulation of Arp5 expression by alternative splicing coupled to nonsense-mediated RNA decay. Biochem Biophys Res Commun 2023; 657:50-58. [PMID: 36977368 DOI: 10.1016/j.bbrc.2023.03.047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 03/16/2023] [Indexed: 03/19/2023]
Abstract
Actin-related protein 5 (ARP5) inhibits the differentiation of skeletal, smooth, and cardiac muscle tissues, and ARP5 expression increases or decreases according to physiological and pathological changes in the muscle differentiation status. However, the regulatory mechanisms of ARP5 expression are largely unknown. Here, we identified a novel Arp5 mRNA isoform that contains premature termination codons in alternative exon 7b and is thus targeted by nonsense-mediated mRNA decay (NMD). In mouse skeletal muscle cells, switching from the canonical Arp5 isoform, i.e., Arp5(7a), to the NMD-targeted isoform Arp5(7b) occurred during differentiation, suggesting that Arp5 expression is regulated by alternative splicing coupled to NMD (AS-NMD). We developed an original method to accurately quantify the proportion of both Arp5 isoforms and measured higher levels of Arp5(7b) in muscle and brain tissues, where ARP5 is less expressed. The 3' splice site in Arp5 exon 7 has an unusual acceptor sequence that often leads to the skip of the authentic splice site and the use of the cryptic splice site localized 16 bases downstream. When the unusual acceptor sequence was mutated to the usual one, the Arp5(7b) isoform was barely detectable. The expression of several splicing factors involved in 3' splice site recognition was reduced after muscle differentiation. Additionally, knockdown of splicing factors increased the levels of Arp5(7b) and decreased the expression of Arp5(7a). Furthermore, strong positive correlations were found between Arp5 expression and the levels of these splicing factors in human skeletal and cardiac muscle tissues. Thus, Arp5 expression in muscle tissues is most likely regulated by the AS-NMD pathway.
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2
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Morita T, Hayashi K. Actin-related protein 5 suppresses the cooperative activation of cardiac gene transcription by myocardin and MEF2. FEBS Open Bio 2023; 13:363-379. [PMID: 36610028 PMCID: PMC9900090 DOI: 10.1002/2211-5463.13549] [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: 10/18/2022] [Revised: 12/15/2022] [Accepted: 01/05/2023] [Indexed: 01/08/2023] Open
Abstract
MYOCD is a transcription factor important for cardiac and smooth muscle development. We previously identified that actin-related protein 5 (ARP5) binds to the N-terminus of MYOCD. Here, we demonstrate that ARP5 inhibits the cooperative action of the cardiac-specific isoform of MYOCD with MEF2. ARP5 overexpression in murine hearts induced cardiac hypertrophy and fibrosis, whereas ARP5 knockdown in P19CL6 cells significantly increased cardiac gene expression. ARP5 was found to bind to a MEF2-binding motif of cardiac MYOCD and inhibit MEF2-mediated transactivation by MYOCD. RNA-seq analysis revealed 849 genes that are upregulated by MYOCD-MEF2 and 650 genes that are repressed by ARP5. ARP5 expression increased with cardiomyopathy and was negatively correlated with the expression of Tnnt2 and Ttn, which were regulated by cardiac MYOCD-MEF2. Overall, our data suggest that ARP5 is a potential suppressor of cardiac MYOCD during physiological and pathological processes.
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Affiliation(s)
| | - Ken'ichiro Hayashi
- Department of OphthalmologyYamaguchi University Graduate School of MedicineJapan,Department of RNA Biology and NeuroscienceOsaka University Graduate School of MedicineJapan
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3
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Khachigian LM, Black BL, Ferdinandy P, De Caterina R, Madonna R, Geng YJ. Transcriptional regulation of vascular smooth muscle cell proliferation, differentiation and senescence: Novel targets for therapy. Vascul Pharmacol 2022; 146:107091. [PMID: 35896140 DOI: 10.1016/j.vph.2022.107091] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 07/21/2022] [Accepted: 07/21/2022] [Indexed: 10/16/2022]
Abstract
Vascular smooth muscle cells (SMC) possess a unique cytoplasticity, regulated by transcriptional, translational and phenotypic transformation in response to a diverse range of extrinsic and intrinsic pathogenic factors. The mature, differentiated SMC phenotype is physiologically typified transcriptionally by expression of genes encoding "contractile" proteins, such as SMα-actin (ACTA2), SM-MHC (myosin-11) and SM22α (transgelin). When exposed to various pathological conditions (e.g., pro-atherogenic risk factors, hypertension), SMC undergo phenotypic modulation, a bioprocess enabling SMC to de-differentiate in immature stages or trans-differentiate into other cell phenotypes. As recent studies suggest, the process of SMC phenotypic transformation involves five distinct states characterized by different patterns of cell growth, differentiation, migration, matrix protein expression and declined contractility. These changes are mediated via the action of several transcriptional regulators, including myocardin and serum response factor. Conversely, other factors, including Kruppel-like factor 4 and nuclear factor-κB, can inhibit SMC differentiation and growth arrest, while factors such as yin yang-1, can promote SMC differentiation whilst inhibiting proliferation. This article reviews recent advances in our understanding of regulatory mechanisms governing SMC phenotypic modulation. We propose the concept that transcription factors mediating this switching are important biomarkers and potential pharmacological targets for therapeutic intervention in cardiovascular disease.
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Affiliation(s)
- Levon M Khachigian
- Vascular Biology and Translational Research, Department of Pathology, Faculty of Medicine and Health, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Brian L Black
- Cardiovascular Research Institute, University of California, San Francisco, CA, United States of America
| | - Péter Ferdinandy
- Cardiovascular and Metabolic Research Group, Department of Pharmacology and Pharmacotherapy, Semmelweis University, 1089 Budapest, Hungary; Pharmahungary Group, 6722 Szeged, Hungary
| | - Raffaele De Caterina
- Cardiovascular Division, Pisa University Hospital & University of Pisa, Via Paradisa, 2, Pisa 56124, Italy
| | - Rosalinda Madonna
- Cardiovascular Division, Pisa University Hospital & University of Pisa, Via Paradisa, 2, Pisa 56124, Italy; Division of Cardiovascular Medicine, Department of Internal Medicine, The Center for Cardiovascular Biology and Atherosclerosis Research, McGovern School of Medicine, University of Texas Health Science Center at Houston, Houston, TX, United States of America
| | - Yong-Jian Geng
- Division of Cardiovascular Medicine, Department of Internal Medicine, The Center for Cardiovascular Biology and Atherosclerosis Research, McGovern School of Medicine, University of Texas Health Science Center at Houston, Houston, TX, United States of America
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4
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Morita T, Hayashi K. Actin-related protein 5 functions as a novel modulator of MyoD and MyoG in skeletal muscle and in rhabdomyosarcoma. eLife 2022; 11:77746. [PMID: 35348112 PMCID: PMC8983046 DOI: 10.7554/elife.77746] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 03/28/2022] [Indexed: 11/13/2022] Open
Abstract
Myogenic regulatory factors (MRFs) are pivotal transcription factors in myogenic differentiation. MyoD commits cells to the skeletal muscle lineage by inducing myogenic genes through recruitment of chromatin remodelers to its target loci. This study showed that Actin-related protein 5 (Arp5) acts as an inhibitory regulator of MyoD and MyoG by binding to their cysteine-rich (CR) region, which overlaps with the region essential for their epigenetic functions. Arp5 expression was faint in skeletal muscle tissues. Excessive Arp5 in mouse hind limbs caused skeletal muscle fiber atrophy. Further, Arp5 overexpression in myoblasts inhibited myotube formation by diminishing myogenic gene expression, whereas Arp5 depletion augmented myogenic gene expression. Arp5 disturbed MyoD-mediated chromatin remodeling through competition with the three-amino-acid-loop-extension-class homeodomain transcription factors the Pbx1–Meis1 heterodimer for binding to the CR region. This antimyogenic function was independent of the INO80 chromatin remodeling complex, although Arp5 is an important component of that. In rhabdomyosarcoma (RMS) cells, Arp5 expression was significantly higher than in normal myoblasts and skeletal muscle tissue, probably contributing to MyoD and MyoG activity dysregulation. Arp5 depletion in RMS partially restored myogenic properties while inhibiting tumorigenic properties. Thus, Arp5 is a novel modulator of MRFs in skeletal muscle differentiation.
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Purine-rich element binding protein B attenuates the coactivator function of myocardin by a novel molecular mechanism of smooth muscle gene repression. Mol Cell Biochem 2021; 476:2899-2916. [PMID: 33743134 DOI: 10.1007/s11010-021-04117-1] [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: 07/29/2020] [Accepted: 02/20/2021] [Indexed: 10/21/2022]
Abstract
Myocardin is a potent transcriptional coactivator protein, which functions as the master regulator of vascular smooth muscle cell differentiation. The cofactor activity of myocardin is mediated by its physical interaction with serum response factor, a ubiquitously expressed transactivator that binds to CArG boxes in genes encoding smooth muscle-restricted proteins. Purine-rich element binding protein B (Purβ) represses the transcription of the smooth muscle α-actin gene (Acta2) in fibroblasts and smooth muscle cells by interacting with single-stranded DNA sequences flanking two 5' CArG boxes in the Acta2 promoter. In this study, the ability of Purβ to modulate the cofactor activity of myocardin was investigated using a combination of cellular and biochemical approaches. Results of smooth muscle gene promoter-reporter assays indicated that Purβ specifically inhibits the coactivator function of myocardin in a manner requiring the presence of all three single-stranded DNA binding domains in the Purβ homodimer. DNA binding analyses demonstrated that Purβ interacts with CArG-containing DNA elements with a much lower affinity compared to other purine-rich target sequences present in the Acta2 promoter. Co-immunoprecipitation and DNA pull-down assays revealed that Purβ associates with myocardin and serum response factor when free or bound to duplex DNA containing one or more CArG boxes. Functional analysis of engineered Purβ point mutants identified several amino acid residues essential for suppression of myocardin activity. Collectively, these findings suggest an inhibitory mechanism involving direct protein-protein interaction between the homodimeric Purβ repressor and the myocardin-serum response factor-CArG complex.
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A differentiated Ca 2+ signalling phenotype has minimal impact on myocardin expression in an automated differentiation assay using A7r5 cells. Cell Calcium 2021; 96:102369. [PMID: 33677175 DOI: 10.1016/j.ceca.2021.102369] [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: 08/27/2020] [Revised: 02/06/2021] [Accepted: 02/08/2021] [Indexed: 01/12/2023]
Abstract
Vascular smooth muscle cells are unusual in that differentiated, contractile cells possess the capacity to "de-differentiate" into a synthetic phenotype that is characterized by being replicative, secretory, and migratory. One aspect of this phenotypic modulation is a shift from voltage-gated Ca2+ signalling in electrically coupled, differentiated cells to increased dependence on store-operated Ca2+ entry and sarcoplasmic reticulum Ca2+ release in synthetic cells. Conversely, an increased voltage-gated Ca2+ entry is seen when proliferating A7r5 smooth muscle cells quiesce. We asked whether this change in Ca2+ signalling was linked to changes in the expression of the phenotype-regulating transcriptional co-activator myocardin or α-smooth muscle actin, using correlative epifluorescence Ca2+ imaging and immunocytochemistry. Cells were cultured in growth media (DMEM, 10% serum, 25 mM glucose) or differentiation media (DMEM, 1% serum, 5 mM glucose). Coinciding with growth arrest, A7r5 cells became electrically coupled, and spontaneous Ca2+ signalling showed increasing dependence on L-type voltage-gated Ca2+ channels that were blocked with nifedipine (5 μM). These synchronized oscillations were modulated by ryanodine receptors, based on their sensitivity to dantrolene (5 μM). Actively growing cultures had spontaneous Ca2+ transients that were insensitive to nifedipine and dantrolene but were blocked by inhibition of the sarco-endoplasmic reticulum ATPase with cyclopiazonic acid (10 μM). In cells treated with differentiation media, myocardin and αSMA immunoreactivity increased prior to changes in the Ca2+ signalling phenotype, while chronic inhibition of voltage-gated Ca2+ entry modestly increased immunoreactivity of myocardin. Stepwise regression analyses suggested that changes in myocardin expression had a weak relationship with Ca2+ signalling synchronicity, but not frequency or amplitude. In conclusion, we report a 96-well assay and analytical pipeline to study the link between Ca2+ signalling and smooth muscle differentiation. This assay showed that changes in the expression of two molecular differentiation markers (myocardin and αSMA) tended to precede changes in the Ca2+ signalling phenotype.
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Tucker T, Tsukasaki Y, Sakai T, Mitsuhashi S, Komatsu S, Jeffers A, Idell S, Ikebe M. Myocardin Is Involved in Mesothelial-Mesenchymal Transition of Human Pleural Mesothelial Cells. Am J Respir Cell Mol Biol 2020; 61:86-96. [PMID: 30605348 DOI: 10.1165/rcmb.2018-0121oc] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Pleural fibrosis is characterized by severe inflammation of the pleural space and pleural reorganization. Subsequent thickening of the visceral pleura contributes to lung stiffness and impaired lung function. Pleural mesothelial cells (PMCs) can become myofibroblasts via mesothelial-mesenchymal transition (MesoMT) and contribute to pleural organization, fibrosis, and rind formation. However, the mechanisms that underlie MesoMT remain unclear. Here, we investigated the role of myocardin in the induction of MesoMT. Transforming growth factor β (TGF-β) and thrombin induced MesoMT and markedly upregulated the expression of myocardin, but not myocardin-related transcription factor A (MRTF-A) or MRTF-B, in human PMCs (HPMCs). TGF-β stimulation notably induced the nuclear translocation of myocardin in HPMCs, whereas nuclear translocation of MRTF-A and MRTF-B was not observed. Several genes under the control of myocardin were upregulated in cells undergoing MesoMT, an effect that was accompanied by a dramatic cytoskeletal reorganization of HPMCs consistent with a migratory phenotype. Myocardin gene silencing blocked TGF-β- and thrombin-induced MesoMT. Although myocardin upregulation was blocked, MRTF-A and MRTF-B were unchanged. Myocardin, α-SMA, calponin, and smooth muscle myosin were notably upregulated in the thickened pleura of carbon black/bleomycin and empyema mouse models of fibrosing pleural injury. Similar results were observed in human nonspecific pleuritis. In a TGF-β mouse model of pleural fibrosis, PMC-specific knockout of myocardin protected against decrements in lung function. Further, TGF-β-induced pleural thickening was abolished by PMC-specific myocardin knockout, which was accompanied by a marked reduction of myocardin, calponin, and α-SMA expression compared with floxed-myocardin controls. These novel results show that myocardin participates in the development of MesoMT in HPMCs and contributes to the pathogenesis of pleural organization and fibrosis.
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Affiliation(s)
- Torry Tucker
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas
| | - Yoshikazu Tsukasaki
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas
| | - Tsuyoshi Sakai
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas
| | - Shinya Mitsuhashi
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas
| | - Satoshi Komatsu
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas
| | - Ann Jeffers
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas
| | - Steven Idell
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas
| | - Mitsuo Ikebe
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas
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8
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Venit T, Mahmood SR, Endara-Coll M, Percipalle P. Nuclear actin and myosin in chromatin regulation and maintenance of genome integrity. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2020; 355:67-108. [DOI: 10.1016/bs.ircmb.2020.05.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/06/2022]
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9
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Klages-Mundt NL, Kumar A, Zhang Y, Kapoor P, Shen X. The Nature of Actin-Family Proteins in Chromatin-Modifying Complexes. Front Genet 2018; 9:398. [PMID: 30319687 PMCID: PMC6167448 DOI: 10.3389/fgene.2018.00398] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 08/31/2018] [Indexed: 01/25/2023] Open
Abstract
Actin is not only one of the most abundant proteins in eukaryotic cells, but also one of the most versatile. In addition to its familiar involvement in enabling contraction and establishing cellular motility and scaffolding in the cytosol, actin has well-documented roles in a variety of processes within the confines of the nucleus, such as transcriptional regulation and DNA repair. Interestingly, monomeric actin as well as actin-related proteins (Arps) are found as stoichiometric subunits of a variety of chromatin remodeling complexes and histone acetyltransferases, raising the question of precisely what roles they serve in these contexts. Actin and Arps are present in unique combinations in chromatin modifiers, helping to establish structural integrity of the complex and enabling a wide range of functions, such as recruiting the complex to nucleosomes to facilitate chromatin remodeling and promoting ATPase activity of the catalytic subunit. Actin and Arps are also thought to help modulate chromatin dynamics and maintain higher-order chromatin structure. Moreover, the presence of actin and Arps in several chromatin modifiers is necessary for promoting genomic integrity and an effective DNA damage response. In this review, we discuss the involvement of actin and Arps in these nuclear complexes that control chromatin remodeling and histone modifications, while also considering avenues for future study to further shed light on their functional importance.
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Affiliation(s)
- Naeh L Klages-Mundt
- Science Park Research Division, Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, United States.,Program in Genetics & Epigenetics, The University of Texas MD Anderson Cancer Center, UTHealth Graduate School of Biomedical Sciences, Houston, TX, United States
| | - Ashok Kumar
- Department of Cellular and Molecular Biology, The University of Texas Health Science Center at Tyler, Tyler, TX, United States
| | - Yuexuan Zhang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Prabodh Kapoor
- Department of Cellular and Molecular Biology, The University of Texas Health Science Center at Tyler, Tyler, TX, United States
| | - Xuetong Shen
- Science Park Research Division, Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, United States.,Program in Genetics & Epigenetics, The University of Texas MD Anderson Cancer Center, UTHealth Graduate School of Biomedical Sciences, Houston, TX, United States
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10
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Lyu Q, Dhagia V, Han Y, Guo B, Wines-Samuelson ME, Christie CK, Yin Q, Slivano OJ, Herring P, Long X, Gupte SA, Miano JM. CRISPR-Cas9-Mediated Epitope Tagging Provides Accurate and Versatile Assessment of Myocardin-Brief Report. Arterioscler Thromb Vasc Biol 2018; 38:2184-2190. [PMID: 29976770 PMCID: PMC6204210 DOI: 10.1161/atvbaha.118.311171] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 06/22/2018] [Indexed: 11/16/2022]
Abstract
Objective- Unreliable antibodies often hinder the accurate detection of an endogenous protein, and this is particularly true for the cardiac and smooth muscle cofactor, MYOCD (myocardin). Accordingly, the mouse Myocd locus was targeted with 2 independent epitope tags for the unambiguous expression, localization, and activity of MYOCD protein. Approach and Results- 3cCRISPR (3-component clustered regularly interspaced short palindromic repeat) was used to engineer a carboxyl-terminal 3×FLAG or 3×HA epitope tag in mouse embryos. Western blotting with antibodies to each tag revealed a MYOCD protein product of ≈150 kDa, a size considerably larger than that reported in virtually all publications. MYOCD protein was most abundant in some adult smooth muscle-containing tissues with surprisingly low-level expression in the heart. Both alleles of Myocd are active in aorta because a 2-fold increase in protein was seen in mice homozygous versus heterozygous for FLAG-tagged Myocd. ChIP (chromatin immunoprecipitation)-quantitative polymerase chain reaction studies provide proof-of-principle data demonstrating the utility of this mouse line in conducting genome-wide ChIP-seq studies to ascertain the full complement of MYOCD-dependent target genes in vivo. Although FLAG-tagged MYOCD protein was undetectable in sections of adult mouse tissues, low-passaged vascular smooth muscle cells exhibited expected nuclear localization. Conclusions- This report validates new mouse models for analyzing MYOCD protein expression, localization, and binding activity in vivo and highlights the need for rigorous authentication of antibodies in biomedical research.
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Affiliation(s)
- Qing Lyu
- Aab Cardiovascular Research Institute, University of
Rochester Medical Center, Rochester, NY
| | - Vidhi Dhagia
- Department of Pharmacology, New York Medical College,
Valhalla NY
| | - Yu Han
- Aab Cardiovascular Research Institute, University of
Rochester Medical Center, Rochester, NY
| | - Bing Guo
- Aab Cardiovascular Research Institute, University of
Rochester Medical Center, Rochester, NY
| | - Mary E. Wines-Samuelson
- Aab Cardiovascular Research Institute, University of
Rochester Medical Center, Rochester, NY
| | - Christine K. Christie
- Aab Cardiovascular Research Institute, University of
Rochester Medical Center, Rochester, NY
| | - Qiangzong Yin
- Aab Cardiovascular Research Institute, University of
Rochester Medical Center, Rochester, NY
| | - Orazio J. Slivano
- Aab Cardiovascular Research Institute, University of
Rochester Medical Center, Rochester, NY
| | - Paul Herring
- Department of Cellular and Integrative Physiology, Indiana
University School of Medicine, Indianapolis, IN
| | - Xiaochun Long
- Department of Molecular and Cellular Physiology, Albany
Medical College, Albany, NY 12208
| | - Sachin A. Gupte
- Department of Pharmacology, New York Medical College,
Valhalla NY
| | - Joseph M. Miano
- Aab Cardiovascular Research Institute, University of
Rochester Medical Center, Rochester, NY
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Morrison AJ. Genome maintenance functions of the INO80 chromatin remodeller. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0289. [PMID: 28847826 DOI: 10.1098/rstb.2016.0289] [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] [Accepted: 06/06/2017] [Indexed: 12/15/2022] Open
Abstract
Chromatin modification is conserved in all eukaryotes and is required to facilitate and regulate DNA-templated processes. For example, chromatin manipulation, such as histone post-translational modification and nucleosome positioning, play critical roles in genome stability pathways. The INO80 chromatin-remodelling complex, which regulates the abundance and positioning of nucleosomes, is particularly important for proper execution of inducible responses to DNA damage. This review discusses the participation and activity of the INO80 complex in DNA repair and cell cycle checkpoint pathways, with emphasis on the Saccharomyces cerevisiae model system. Furthermore, the role of ATM/ATR kinases, central regulators of DNA damage signalling, in the regulation of INO80 function will be reviewed. In addition, emerging themes of chromatin remodelling in mitotic stability pathways and chromosome segregation will be introduced. These studies are critical to understanding the dynamic chromatin landscape that is rapidly and reversibly modified to maintain the integrity of the genome.This article is part of the themed issue 'Chromatin modifiers and remodellers in DNA repair and signalling'.
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Affiliation(s)
- Ashby J Morrison
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA 94305, USA
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12
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Morita T, Hayashi K. Tumor Progression Is Mediated by Thymosin-β4 through a TGFβ/MRTF Signaling Axis. Mol Cancer Res 2018; 16:880-893. [DOI: 10.1158/1541-7786.mcr-17-0715] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 12/21/2017] [Accepted: 12/26/2017] [Indexed: 11/16/2022]
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13
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Zhang HB, Wang ZQ, Chen FZ, Ding W, Liu WB, Chen ZR, He SH, Wei AY. Maintenance of the contractile phenotype in corpus cavernosum smooth muscle cells by Myocardin gene therapy ameliorates erectile dysfunction in bilateral cavernous nerve injury rats. Andrology 2017; 5:798-806. [PMID: 28544569 DOI: 10.1111/andr.12375] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 03/02/2017] [Accepted: 04/05/2017] [Indexed: 12/18/2022]
Abstract
The pathophysiology of erectile dysfunction post radical prostatectomy is not clearly clarified, and the low efficacy of traditional PDE5i treatment remains a major complaint in contemporary practice. This study aimed to demonstrate phenotypic modulation in bilateral cavernous nerve injury (BCNI) rats within 7 days, and subsequently validate gene therapy with Myocardin (Mycod) by maintaining a contractile phenotype in corpus cavernosum smooth muscle cells. Initially, 36 male rats were randomly divided into BCNI and negative control (NC) groups for histological and phenotypic molecular measurements at 3, 5, and 7 days. Afterwards, an additional 30 rats received a single intra-cavernous injection of 50 μL PBS, Ad-Myocd (1 × 1011 pfu/ml) or Ad-vector for 10 animals each, namely the NC+PBS, BCNI+Ad-Myocd, and BCNI+Ad-vector groups. Finally, the validity and mechanism of Myocd transfection was explored at 21 days in vivo and 48 h in vitro. Western blotting showed canonical declines in Myocd, α-SMA, and Calponin expression, as well as elevated Osteopontin (OPN) expression, before corporeal morphological and SM-to-collagen ratio changes at day 5 after injury. Overexpression of Myocd maintained the contractile phenotype of corpus cavernosum smooth muscle cells, ameliorated bilateral cavernous nerve injury rat erectile dysfunction, as well as promoted cell contractility and suppressed proliferative capacity. Simultaneously, confocal imaging revealed up-regulation and co-localization of serum response factor in gene-transferred cells. In conclusion, our study is the first to investigate corpus cavernosum smooth muscle cells phenotypes in the early stages of cavernous injury model rats, and Myocd reversed phenotypic modulation by activating serum response factor. The experimental results demonstrated the validity of gene therapy for erectile dysfunction.
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Affiliation(s)
- H-B Zhang
- Department of Urology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Z-Q Wang
- Department of Urology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - F-Z Chen
- Department of Urology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - W Ding
- Department of Urology, Nanfang Hospital, Southern Medical University, Guangzhou, China
- Department of Urology, The First Affiliated Hospital of Guiyang College of Traditional Chinese Medicine, Guiyang, China
| | - W-B Liu
- Department of Urology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Z-R Chen
- Department of Urology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - S-H He
- Department of Urology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - A-Y Wei
- Department of Urology, Nanfang Hospital, Southern Medical University, Guangzhou, China
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14
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Bengal E. TAZ is involved in transcriptional complexes regulating smooth muscle cell differentiation. FEBS J 2017; 284:1628-1630. [PMID: 28581256 DOI: 10.1111/febs.14079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
TGFβ signaling plays an important role in the differentiation of vascular smooth muscle cells (VSMCs), yet the mechanism remains largely unknown. The study by Pagiatakis et al. identifies the transcriptional coactivator TAZ as a mediator of TGFβ signaling in VSMC-specific transcription. TAZ is involved in the formation of stable ternary complexes of SRF/Myocardin on CArG elements that are required for the transcription of VSMC structural genes.
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Affiliation(s)
- Eyal Bengal
- Department of Biochemistry, The Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
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15
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Xia XD, Zhou Z, Yu XH, Zheng XL, Tang CK. Myocardin: A novel player in atherosclerosis. Atherosclerosis 2017; 257:266-278. [DOI: 10.1016/j.atherosclerosis.2016.12.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Revised: 11/29/2016] [Accepted: 12/01/2016] [Indexed: 12/21/2022]
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16
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Abstract
A majority of messenger RNA precursors (pre-mRNAs) in the higher eukaryotes undergo alternative splicing to generate more than one mature product. By targeting the open reading frame region this process increases diversity of protein isoforms beyond the nominal coding capacity of the genome. However, alternative splicing also frequently controls output levels and spatiotemporal features of cellular and organismal gene expression programs. Here we discuss how these non-coding functions of alternative splicing contribute to development through regulation of mRNA stability, translational efficiency and cellular localization.
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Yao W, Beckwith SL, Zheng T, Young T, Dinh VT, Ranjan A, Morrison AJ. Assembly of the Arp5 (Actin-related Protein) Subunit Involved in Distinct INO80 Chromatin Remodeling Activities. J Biol Chem 2015; 290:25700-9. [PMID: 26306040 DOI: 10.1074/jbc.m115.674887] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Indexed: 11/06/2022] Open
Abstract
ATP-dependent chromatin remodeling, which repositions and restructures nucleosomes, is essential to all DNA-templated processes. The INO80 chromatin remodeling complex is an evolutionarily conserved complex involved in diverse cellular processes, including transcription, DNA repair, and replication. The functional diversity of the INO80 complex can, in part, be attributed to specialized activities of distinct subunits that compose the complex. Furthermore, structural analyses have identified biochemically discrete subunit modules that assemble along the Ino80 ATPase scaffold. Of particular interest is the Saccharomyces cerevisiae Arp5-Ies6 module located proximal to the Ino80 ATPase and the Rvb1-Rvb2 helicase module needed for INO80-mediated in vitro activity. In this study we demonstrate that the previously uncharacterized Ies2 subunit is required for Arp5-Ies6 association with the catalytic components of the INO80 complex. In addition, Arp5-Ies6 module assembly with the INO80 complex is dependent on distinct conserved domains within Arp5, Ies6, and Ino80, including the spacer region within the Ino80 ATPase domain. Arp5-Ies6 interacts with chromatin via assembly with the INO80 complex, as IES2 and INO80 deletion results in loss of Arp5-Ies6 chromatin association. Interestingly, ectopic addition of the wild-type Arp5-Ies6 module stimulates INO80-mediated ATP hydrolysis and nucleosome sliding in vitro. However, the addition of mutant Arp5 lacking unique insertion domains facilitates ATP hydrolysis in the absence of nucleosome sliding. Collectively, these results define the requirements of Arp5-Ies6 assembly, which are needed to couple ATP hydrolysis to productive nucleosome movement.
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Affiliation(s)
- Wei Yao
- From the Department of Biology, Stanford University, Stanford California 94305 and
| | - Sean L Beckwith
- From the Department of Biology, Stanford University, Stanford California 94305 and
| | - Tina Zheng
- From the Department of Biology, Stanford University, Stanford California 94305 and
| | - Thomas Young
- From the Department of Biology, Stanford University, Stanford California 94305 and
| | - Van T Dinh
- From the Department of Biology, Stanford University, Stanford California 94305 and
| | - Anand Ranjan
- Laboratory of Biochemistry and Molecular Biology, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Ashby J Morrison
- From the Department of Biology, Stanford University, Stanford California 94305 and
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Abstract
Myocardin (MYOCD) is a potent transcriptional coactivator that functions primarily in cardiac muscle and smooth muscle through direct contacts with serum response factor (SRF) over cis elements known as CArG boxes found near a number of genes encoding for contractile, ion channel, cytoskeletal, and calcium handling proteins. Since its discovery more than 10 years ago, new insights have been obtained regarding the diverse isoforms of MYOCD expressed in cells as well as the regulation of MYOCD expression and activity through transcriptional, post-transcriptional, and post-translational processes. Curiously, there are a number of functions associated with MYOCD that appear to be independent of contractile gene expression and the CArG-SRF nucleoprotein complex. Further, perturbations in MYOCD gene expression are associated with an increasing number of diseases including heart failure, cancer, acute vessel disease, and diabetes. This review summarizes the various biological and pathological processes associated with MYOCD and offers perspectives to several challenges and future directions for further study of this formidable transcriptional coactivator.
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Affiliation(s)
- Joseph M Miano
- Aab Cardiovascular Research Institute, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
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