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Li Q, Lin J, Rosen SM, Zhang T, Kazerounian S, Luo S, Agrawal PB. Striated Preferentially Expressed Protein Kinase (SPEG)-Deficient Skeletal Muscles Display Fewer Satellite Cells with Reduced Proliferation and Delayed Differentiation. THE AMERICAN JOURNAL OF PATHOLOGY 2020; 190:2453-2463. [PMID: 32919980 DOI: 10.1016/j.ajpath.2020.08.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 08/19/2020] [Accepted: 08/27/2020] [Indexed: 12/17/2022]
Abstract
Centronuclear myopathies (CNMs) are a subtype of congenital myopathies characterized by skeletal muscle weakness and an increase in the number of central myonuclei. SPEG (striated preferentially expressed protein kinase) has been identified as the sixth gene associated with CNM, and it has been shown that striated muscle-specific Speg-knockout (KO) mice have defective triad formation, abnormal excitation-contraction coupling, and calcium mishandling. The impact of SPEG deficiency on the survival and function of myogenic cells remains to be deciphered. In this study, the authors examined the overall population, proliferation, and differentiation of myogenic cells obtained from striated muscle-specific Speg-KO mice and compared them with wild-type (WT) controls. SPEG-deficient skeletal muscles contained fewer myogenic cells, which on further study demonstrated reduced proliferation and delayed differentiation compared with those from WT muscles. Regenerative response to skeletal muscle injury in Speg-KO mice was compared with that of WT mice, leading to the identification of similar abnormalities including fewer satellite cells, fewer dividing cells, and an increase in apoptotic cells in KO mice. Overall, these results reveal specific abnormalities in myogenic cell number and behavior associated with SPEG deficiency. Similar satellite cell defects have been reported in mouse models of MTM1- and DNM2-associated CNM, suggestive of shared underlying pathways.
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Affiliation(s)
- Qifei Li
- Division of Newborn Medicine, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts; Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts; The Manton Center for Orphan Disease Research, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Jasmine Lin
- Division of Newborn Medicine, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts; Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts; The Manton Center for Orphan Disease Research, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Samantha M Rosen
- Division of Newborn Medicine, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts; Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts; The Manton Center for Orphan Disease Research, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Tian Zhang
- Division of Newborn Medicine, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts; The Manton Center for Orphan Disease Research, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Shideh Kazerounian
- Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts; The Manton Center for Orphan Disease Research, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Shiyu Luo
- Division of Newborn Medicine, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts; Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts; The Manton Center for Orphan Disease Research, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Pankaj B Agrawal
- Division of Newborn Medicine, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts; Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts; The Manton Center for Orphan Disease Research, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts.
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Grogan A, Tsakiroglou P, Kontrogianni-Konstantopoulos A. Double the trouble: giant proteins with dual kinase activity in the heart. Biophys Rev 2020; 12:1019-1029. [PMID: 32638332 DOI: 10.1007/s12551-020-00715-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 07/02/2020] [Indexed: 12/12/2022] Open
Abstract
Obscurin and its homolog, striated muscle preferentially expressed gene (SPEG), constitute a unique group of proteins abundantly expressed in striated muscles that contain two tandemly arranged MLCK-like kinases. The physiological significance of the dual kinase motifs is largely understudied; however, a collection of recent studies characterizing their binding interactions, putative targets, and disease-linked mutations have begun to shed light on their potential roles in muscle pathophysiology. Specifically, obscurin kinase 1 is proposed to regulate cardiomyocyte adhesion via phosphorylating N-cadherin, whereas SPEG kinases 1 and 2 regulate Ca2+ cycling by phosphorylating junctophilin-2 and the sarcoendoplasmic Ca2+ ATPase 2 (SERCA2). Herein, we review what is currently known regarding the potential substrates, physiological roles, and disease associations of obscurin and SPEG tandem kinase domains and provide future directions that have yet to be investigated.
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Affiliation(s)
- Alyssa Grogan
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene St, Baltimore, MD, 21201, USA
| | - Panagiotis Tsakiroglou
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene St, Baltimore, MD, 21201, USA
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Tang J, Ma W, Chen Y, Jiang R, Zeng Q, Tan J, Jiang H, Li Q, Zhang VW, Wang J, Tang H, Luo L. Novel SPEG variant cause centronuclear myopathy in China. J Clin Lab Anal 2019; 34:e23054. [PMID: 31625632 PMCID: PMC7031609 DOI: 10.1002/jcla.23054] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 09/06/2019] [Accepted: 09/13/2019] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Centronuclear myopathy (CNM), a subtype of congenital myopathy (CM), is a group of clinical and genetically heterogeneous muscle disorders. Centronuclear myopathy is a kind of disease difficult to diagnose due to its genetic diversity. Since the discovery of the SPEG gene and disease-causing variants, only a few additional patients have been reported. METHODS A radiograph test, ultrasonic test, and biochemical tests were applied to clinical diagnosis of CNM. We performed trio medical exome sequencing of the family and conservation analysis to identify variants. RESULTS We report a pair of severe CNM twins with the same novel homozygous SPEG variant c. 8710A>G (p.Thr2904Ala) identified by clinical trio medical exome sequencing of the family and conservation analysis. The twins showed clinical symptoms of facial weakness, hypotonia, arthrogryposis, strephenopodia, patent ductus arteriosus, and pulmonary arterial hypertension. CONCLUSIONS Our report expands the clinical and molecular repertoire of CNM and enriches the variant spectrum of the SPEG gene in the Chinese population and helps us further understand the pathogenesis of CNM.
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Affiliation(s)
- Jia Tang
- Department of Medical Imaging Center, The First Affiliated Hospital of Jinan University, Jinan University, Guangzhou, China.,Medical Genetics Center, Jiangmen Maternity and Child health Care Hospital, Jiangmen, China
| | - Wei Ma
- Department of Biology, School of Basic Medicine, Jiamusi University, Jiamusi, China
| | - Yangran Chen
- Medical Genetics Center, Jiangmen Maternity and Child health Care Hospital, Jiangmen, China
| | - Runze Jiang
- Medical Genetics Center, Jiangmen Maternity and Child health Care Hospital, Jiangmen, China
| | - Qinlong Zeng
- Medical Genetics Center, Jiangmen Maternity and Child health Care Hospital, Jiangmen, China
| | - Jieliang Tan
- Medical Genetics Center, Jiangmen Maternity and Child health Care Hospital, Jiangmen, China
| | - Hongqing Jiang
- Medical Genetics Center, Jiangmen Maternity and Child health Care Hospital, Jiangmen, China
| | - Qing Li
- Medical Genetics Center, Jiangmen Maternity and Child health Care Hospital, Jiangmen, China
| | - Victor W Zhang
- AmCare Genomics Laboratory, International BioIsland, Guangzhou, China
| | - Jing Wang
- AmCare Genomics Laboratory, International BioIsland, Guangzhou, China
| | - Hui Tang
- Department of Medical Imaging Center, The First Affiliated Hospital of Jinan University, Jinan University, Guangzhou, China
| | - Liangping Luo
- Department of Medical Imaging Center, The First Affiliated Hospital of Jinan University, Jinan University, Guangzhou, China
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4
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Shu C, Huang H, Xu Y, Rota M, Sorrentino A, Peng Y, Padera RF, Huntoon V, Agrawal PB, Liu X, Perrella MA. Pressure Overload in Mice With Haploinsufficiency of Striated Preferentially Expressed Gene Leads to Decompensated Heart Failure. Front Physiol 2018; 9:863. [PMID: 30042693 PMCID: PMC6048438 DOI: 10.3389/fphys.2018.00863] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 06/18/2018] [Indexed: 01/20/2023] Open
Abstract
Striated preferentially expressed gene (Speg) is a member of the myosin light chain kinase family of proteins. Constitutive Speg deficient (Speg−/−) mice develop a dilated cardiomyopathy, and the majority of these mice die in utero or shortly after birth. In the present study we assessed the importance of Speg in adult mice. Speg−/− mice that survived to adulthood, or adult striated muscle-specific Speg knockout mice (Speg-KO), demonstrated cardiac dysfunction and evidence of increased left ventricular (LV) internal diameter and heart to body weight ratio. To determine whether heterozygosity of Speg interferes with the response of the heart to pathophysiologic stress, Speg+/− mice were exposed to pressure overload induced by transverse aortic constriction (TAC). At baseline, Speg+/+ and Speg+/− hearts showed no difference in cardiac function. However, 4 weeks after TAC, Speg+/− mice had a marked reduction in LV function. This defect was associated with an increase in LV internal diameter and enhanced heart weight to body weight ratio, compared with Speg+/+ mice after TAC. The response of Speg+/− mice to pressure overload also included increased fibrotic deposition in the myocardium, disruption of transverse tubules, and attenuation in cell contractility, compared with Speg+/+ mice. Taken together, these data demonstrate that Speg is necessary for normal cardiac function and is involved in the complex adaptation of the heart in response to TAC. Haploinsufficiency of Speg results in decompensated heart failure when exposed to pressure overload.
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Affiliation(s)
- Chang Shu
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States.,Respiratory Center, Children's Hospital, Chongqing Medical University, Chongqing, China
| | - He Huang
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States.,Department of Anesthesiology, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Ying Xu
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States.,Department of Anesthesiology, Children's Hospital, Chongqing Medical University, Chongqing, China
| | - Marcello Rota
- Department of Anesthesia, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States.,Department of Physiology, New York Medical College, Valhalla, NY, United States.,Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Andrea Sorrentino
- Department of Anesthesia, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States.,Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Yuan Peng
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Robert F Padera
- Division of Health Sciences and Technology, Harvard-MIT Health Sciences and Technology, Cambridge, MA, United States.,Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Virginia Huntoon
- Divisions of Newborn Medicine and Genetics & Genomics, Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States
| | - Pankaj B Agrawal
- Divisions of Newborn Medicine and Genetics & Genomics, Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States
| | - Xiaoli Liu
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States.,Department of Pediatric Newborn Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Mark A Perrella
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States.,Department of Pediatric Newborn Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
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Renner M, Wolf T, Meyer H, Hartmann W, Penzel R, Ulrich A, Lehner B, Hovestadt V, Czwan E, Egerer G, Schmitt T, Alldinger I, Renker EK, Ehemann V, Eils R, Wardelmann E, Büttner R, Lichter P, Brors B, Schirmacher P, Mechtersheimer G. Integrative DNA methylation and gene expression analysis in high-grade soft tissue sarcomas. Genome Biol 2013; 14:r137. [PMID: 24345474 PMCID: PMC4054884 DOI: 10.1186/gb-2013-14-12-r137] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 12/17/2013] [Indexed: 12/13/2022] Open
Abstract
Background High-grade soft tissue sarcomas are a heterogeneous, complex group of aggressive malignant tumors showing mesenchymal differentiation. Recently, soft tissue sarcomas have increasingly been classified on the basis of underlying genetic alterations; however, the role of aberrant DNA methylation in these tumors is not well understood and, consequently, the usefulness of methylation-based classification is unclear. Results We used the Infinium HumanMethylation27 platform to profile DNA methylation in 80 primary, untreated high-grade soft tissue sarcomas, representing eight relevant subtypes, two non-neoplastic fat samples and 14 representative sarcoma cell lines. The primary samples were partitioned into seven stable clusters. A classification algorithm identified 216 CpG sites, mapping to 246 genes, showing different degrees of DNA methylation between these seven groups. The differences between the clusters were best represented by a set of eight CpG sites located in the genes SPEG, NNAT, FBLN2, PYROXD2, ZNF217, COL14A1, DMRT2 and CDKN2A. By integrating DNA methylation and mRNA expression data, we identified 27 genes showing negative and three genes showing positive correlation. Compared with non-neoplastic fat, NNAT showed DNA hypomethylation and inverse gene expression in myxoid liposarcomas, and DNA hypermethylation and inverse gene expression in dedifferentiated and pleomorphic liposarcomas. Recovery of NNAT in a hypermethylated myxoid liposarcoma cell line decreased cell migration and viability. Conclusions Our analysis represents the first comprehensive integration of DNA methylation and transcriptional data in primary high-grade soft tissue sarcomas. We propose novel biomarkers and genes relevant for pathogenesis, including NNAT as a potential tumor suppressor in myxoid liposarcomas.
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Liu X, Ramjiganesh T, Chen YH, Chung SW, Hall SR, Schissel SL, Padera RF, Liao R, Ackerman KG, Kajstura J, Leri A, Anversa P, Yet SF, Layne MD, Perrella MA. Disruption of striated preferentially expressed gene locus leads to dilated cardiomyopathy in mice. Circulation 2008; 119:261-8. [PMID: 19118250 DOI: 10.1161/circulationaha.108.799536] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
BACKGROUND The striated preferentially expressed gene (Speg) generates 4 different isoforms through alternative promoter use and tissue-specific splicing. Depending on the cell type, Speg isoforms may serve as markers of striated or smooth muscle differentiation. METHODS AND RESULTS To elucidate function of Speg gene isoforms, we disrupted the Speg gene locus in mice by replacing common exons 8, 9, and 10 with a lacZ gene. beta-Galactosidase activity was detected in cardiomyocytes of the developing heart starting at day 11.5 days post coitum (dpc). beta-Galactosidase activity in other cell types, including vascular smooth muscle cells, did not begin until 18.5 dpc. In the developing heart, protein expression of only Spegalpha and Spegbeta isoforms was present in cardiomyocytes. Homozygous Speg mutant hearts began to enlarge by 16.5 dpc, and by 18.5 dpc, they demonstrated dilation of right and left atria and ventricles. These cardiac abnormalities in the absence of Speg were associated with a cellular hypertrophic response, myofibril degeneration, and a marked decrease in cardiac function. Moreover, Speg mutant mice exhibited significant neonatal mortality, with increased death occurring by 2 days after birth. CONCLUSIONS These findings demonstrate that mutation of the Speg locus leads to cardiac dysfunction and a phenotype consistent with a dilated cardiomyopathy.
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Affiliation(s)
- Xiaoli Liu
- Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA 02115, USA
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7
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Tam JLY, Triantaphyllopoulos K, Todd H, Raguz S, de Wit T, Morgan JE, Partridge TA, Makrinou E, Grosveld F, Antoniou M. The human desmin locus: gene organization and LCR-mediated transcriptional control. Genomics 2006; 87:733-46. [PMID: 16545539 DOI: 10.1016/j.ygeno.2006.01.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2005] [Revised: 01/20/2006] [Accepted: 01/29/2006] [Indexed: 12/16/2022]
Abstract
Locus control regions (LCRs) are defined by their ability to confer reproducible physiological levels of transgene expression in mice and therefore thought to possess the ability to generate dominantly a transcriptionally active chromatin structure. We report the first characterization of a muscle-cell-specific LCR, which is linked to the human desmin gene (DES). The DES LCR consists of five regions of muscle-specific DNase I hypersensitivity (HS) localized between -9 and -18 kb 5' of DES and reproducibly drives full physiological levels of expression in all muscle cell types. The DES LCR DNase I HS regions are highly conserved between humans and other mammals and can potentially bind a broad range of muscle-specific and ubiquitous transcription factors. Bioinformatics and direct molecular analysis show that the DES locus consists of three muscle-specific (DES) or muscle preferentially expressed genes (APEG1 and SPEG, the human orthologue of murine striated-muscle-specific serine/threonine protein kinase, Speg). The DES LCR may therefore regulate expression of SPEG and APEG1 as well as DES.
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Affiliation(s)
- Jennifer L Y Tam
- Nuclear Biology Group, Department of Medical and Molecular Genetics, King's College London School of Medicine, King's College London-Guy's Campus, 8th Floor Guy's Tower, Guy's Hospital, London SE1 9RT, UK
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Manjasetty BA, Niesen FH, Scheich C, Roske Y, Goetz F, Behlke J, Sievert V, Heinemann U, Büssow K. X-ray structure of engineered human Aortic Preferentially Expressed Protein-1 (APEG-1). BMC STRUCTURAL BIOLOGY 2005; 5:21. [PMID: 16354304 PMCID: PMC1352370 DOI: 10.1186/1472-6807-5-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2005] [Accepted: 12/14/2005] [Indexed: 11/26/2022]
Abstract
Background Human Aortic Preferentially Expressed Protein-1 (APEG-1) is a novel specific smooth muscle differentiation marker thought to play a role in the growth and differentiation of arterial smooth muscle cells (SMCs). Results Good quality crystals that were suitable for X-ray crystallographic studies were obtained following the truncation of the 14 N-terminal amino acids of APEG-1, a region predicted to be disordered. The truncated protein (termed ΔAPEG-1) consists of a single immunoglobulin (Ig) like domain which includes an Arg-Gly-Asp (RGD) adhesion recognition motif. The RGD motif is crucial for the interaction of extracellular proteins and plays a role in cell adhesion. The X-ray structure of ΔAPEG-1 was determined and was refined to sub-atomic resolution (0.96 Å). This is the best resolution for an immunoglobulin domain structure so far. The structure adopts a Greek-key β-sandwich fold and belongs to the I (intermediate) set of the immunoglobulin superfamily. The residues lying between the β-sheets form a hydrophobic core. The RGD motif folds into a 310 helix that is involved in the formation of a homodimer in the crystal which is mainly stabilized by salt bridges. Analytical ultracentrifugation studies revealed a moderate dissociation constant of 20 μM at physiological ionic strength, suggesting that APEG-1 dimerisation is only transient in the cell. The binding constant is strongly dependent on ionic strength. Conclusion Our data suggests that the RGD motif might play a role not only in the adhesion of extracellular proteins but also in intracellular protein-protein interactions. However, it remains to be established whether the rather weak dimerisation of APEG-1 involving this motif is physiogically relevant.
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Affiliation(s)
- Babu A Manjasetty
- Protein Structure Factory, c/o BESSY GmbH, Albert-Einstein-Str. 15, 12489 Berlin, Germany
- Max-Delbrück-Centrum für Molekulare Medizin, Robert-Rössle-Str. 10, 13092 Berlin, Germany
- Case Centre for Proteomics, Case Western Reserve University, Upton, New York 11973, USA
| | - Frank H Niesen
- Protein Structure Factory, Heubnerweg 6, 14059 Berlin, Germany
- Charité Universitätsmedizin Berlin, Institut für Medizinische Physik & Biophysik, Ziegelstr. 5-9, 10098 Berlin, Germany
- Structural Genomics Consortium, University of Oxford, Botnar Research Centre, Oxford, OX3 7LD, UK
| | - Christoph Scheich
- Protein Structure Factory, Heubnerweg 6, 14059 Berlin, Germany
- Max-Planck-Institut für Molekulare Genetik, Ihnestr. 73, 14195 Berlin, Germany
| | - Yvette Roske
- Max-Delbrück-Centrum für Molekulare Medizin, Robert-Rössle-Str. 10, 13092 Berlin, Germany
- Protein Structure Factory, Heubnerweg 6, 14059 Berlin, Germany
| | - Frank Goetz
- Max-Delbrück-Centrum für Molekulare Medizin, Robert-Rössle-Str. 10, 13092 Berlin, Germany
- Protein Structure Factory, Heubnerweg 6, 14059 Berlin, Germany
| | - Joachim Behlke
- Max-Delbrück-Centrum für Molekulare Medizin, Robert-Rössle-Str. 10, 13092 Berlin, Germany
| | - Volker Sievert
- Protein Structure Factory, Heubnerweg 6, 14059 Berlin, Germany
- Max-Planck-Institut für Molekulare Genetik, Ihnestr. 73, 14195 Berlin, Germany
| | - Udo Heinemann
- Max-Delbrück-Centrum für Molekulare Medizin, Robert-Rössle-Str. 10, 13092 Berlin, Germany
- Institut für Chemie/Kristallographie, Freie Universität, Takustr. 6, 14195 Berlin, Germany
| | - Konrad Büssow
- Protein Structure Factory, Heubnerweg 6, 14059 Berlin, Germany
- Max-Planck-Institut für Molekulare Genetik, Ihnestr. 73, 14195 Berlin, Germany
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Kawai-Kowase K, Kumar MS, Hoofnagle MH, Yoshida T, Owens GK. PIAS1 activates the expression of smooth muscle cell differentiation marker genes by interacting with serum response factor and class I basic helix-loop-helix proteins. Mol Cell Biol 2005; 25:8009-23. [PMID: 16135793 PMCID: PMC1234309 DOI: 10.1128/mcb.25.18.8009-8023.2005] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Although a critical component of vascular disease is modulation of the differentiated state of vascular smooth muscle cells (SMC), the mechanisms governing SMC differentiation are relatively poorly understood. We have previously shown that E-boxes and the ubiquitously expressed class I basic helix-loop-helix (bHLH) proteins, including E2-2 and E12, are important in regulation of the SMC differentiation marker gene, the SM alpha-actin gene. The aim of the present study was to identify proteins that bind to class I bHLH proteins in SMC and modulate transcriptional regulation of SMC differentiation marker genes. Herein we report that members of the protein inhibitor of activated STAT (PIAS) family interact with class I bHLH factors as well as serum response factor (SRF). PIAS1 interacted with E2-2 and E12 based on yeast two-hybrid screens, mammalian two-hybrid assays, and/or coimmunoprecipitation assays. Overexpression of PIAS1 significantly activated the SM alpha-actin promoter and mRNA expression, as well as SM myosin heavy chain and SM22alpha, whereas a small interfering RNA for PIAS1 decreased activity of these promoters, as well as endogenous mRNA expression, and SRF binding to SM alpha-actin promoter within intact chromatin in cultured SMC. Of significance, PIAS1 bound to SRF and activated SM alpha-actin promoter expression in wild-type but not SRF(-/-) embryonic stem cells. These results provide novel evidence that PIAS1 modulates transcriptional activation of SMC marker genes through cooperative interactions with both SRF and class I bHLH proteins.
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Affiliation(s)
- Keiko Kawai-Kowase
- Department of Molecular Physiology and Biological Physics, University of Virginia, 415 Lane Road, MR5, Room 1220, P.O. Box 801394, Charlottesville, VA 22908, USA
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Arvanitis DA, Flouris GA, Spandidos DA. Genomic rearrangements on VCAM1, SELE, APEG1and AIF1 loci in atherosclerosis. J Cell Mol Med 2005; 9:153-9. [PMID: 15784173 PMCID: PMC6741330 DOI: 10.1111/j.1582-4934.2005.tb00345.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
The inflammatory nature of atherosclerosis has been well established. However, the initial steps that trigger this response in the arterial intima remain obscure. Previous studies reported a significant rate of genomic alterations in human atheromas. The accumulation of genomic rearrangements in vascular endothelium and smooth muscle cells may be important for disease development. To address this issue, 78 post-mortem obtained aortic atheromas were screened for microsatellite DNA alterations versus correspondent venous blood. To evaluate the significance of these observations, 33 additional histologically normal aortic specimens from age and sex-matched cases were examined. Loss of heterozygosity (LOH) was found in 47,4% of the cases and in 18,2% of controls in at least one locus. The LOH occurrence in aortic tissue is associated to atherosclerosis risk (OR 4,06, 95% CI 1,50 to 10,93). Significant genomic alterations were found on 1p32-p31, 1q22-q25, 2q35 and 6p21.3 where VCAM1, SELE, APEG1 and AIF1 genes have been mapped respectively. Our data implicate somatic DNA rearrangements, on loci associated to leukocyte adhesion, vascular smooth muscle cells growth, differentiation and migration, to atherosclerosis development as an inflammatory condition.
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Affiliation(s)
- D A Arvanitis
- Department of Virology, Medical School, University of Crete, Heraklion, Crete, Greece
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11
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Kumar MS, Hendrix JA, Johnson AD, Owens GK. Smooth muscle alpha-actin gene requires two E-boxes for proper expression in vivo and is a target of class I basic helix-loop-helix proteins. Circ Res 2003; 92:840-7. [PMID: 12663487 DOI: 10.1161/01.res.0000069031.55281.7c] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Changes in the differentiated state of smooth muscle cells (SMCs) play a key role in vascular diseases, yet the mechanisms controlling SMC differentiation are still largely undefined. We addressed the role of basic helix-loop-helix (bHLH) proteins in SMC differentiation by first determining the role of two E-box (CAnnTG) motifs, binding sites for bHLH proteins, in the transcriptional regulation of the SMC differentiation marker gene, smooth muscle alpha-actin (SM alpha-actin), in vivo. Mutation of one or both E-boxes significantly reduced the expression of a -2560- to 2784-bp SM alpha-actin promoter/LacZ reporter gene in vivo in transgenic mice. We then determined the potential role of class I bHLH proteins, E12, E47, HEB, and E2-2, in SM alpha-actin regulation. In cotransfection experiments, E12, HEB, and E2-2 activated the SM alpha-actin promoter. Activation by HEB and E2-2 was synergistic with serum response factor. Additionally, the dominant-negative/inhibitory HLH proteins, Id2, Id3, and Twist, inhibited both the E12 and serum response factor-induced activations of the SM alpha-actin promoter. Finally, we demonstrated that E2A proteins (E12/E47) specifically bound the E-box-containing region of the SM alpha-actin promoter in vivo in the context of intact chromatin in SMCs. Taken together, these results provide the first evidence of E-box-dependent regulation of a SMC differentiation marker gene in vivo in transgenic mice. Moreover, they demonstrate a potential role for class I bHLH factors and their inhibitors, Id and Twist, in SM alpha-actin regulation and suggest that these factors may play an important role in control of SMC differentiation and phenotypic modulation.
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Affiliation(s)
- Meena S Kumar
- Department of Molecular Physiology and Biological Physics, University of Virginia, 415 Lane Rd, MR5 Room 1220, PO Box 801394, Charlottesville, Va 22908, USA
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12
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Abstract
Alterations in the differentiated state of vascular smooth muscle cells (SMCs) are known to play a key role in vascular diseases, yet the mechanisms controlling SMC differentiation are still poorly understand. In this review, we discuss our present knowledge of control of SMC differentiation at the transcriptional level, pointing out some common themes, important paradigms, and unresolved issues in SMC-specific gene regulation. We focus primarily on the serum response factor-CArG box-dependent pathway, because it has been shown to play a critical role in regulation of multiple SMC marker genes. However, we also highlight several other important regulatory elements, such as a transforming growth factor beta control element, E-boxes, and MCAT motifs. We present evidence in support of the notion that SMC-specific gene regulation is not controlled by a few SMC-specific transcription factors but rather by complex combinatorial interactions between multiple general and tissue-specific proteins. Finally, we discuss the implications of chromatin remodeling on SMC differentiation.
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Affiliation(s)
- Meena S Kumar
- Department of Molecular Physiology and Biological Physics, University of Virginia, 415 Lane Rd, MR5 Room 1220, PO Box 801394, Charlottesville, VA 22908, USA.
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13
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Leach KM, Vieira KF, Kang SHL, Aslanian A, Teichmann M, Roeder RG, Bungert J. Characterization of the human beta-globin downstream promoter region. Nucleic Acids Res 2003; 31:1292-301. [PMID: 12582249 PMCID: PMC150227 DOI: 10.1093/nar/gkg209] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The human beta-globin gene is abundantly expressed specifically in adult erythroid cells. Stage-specific transcription is regulated principally by promoter proximal cis-regulatory elements. The basal promoter contains a non-canonical TATA-like motif as well as an initiator element. These two elements have been shown to interact with the TFII-D complex. Here we show that in addition to the TATA and initiator elements, conserved E-box motifs are located in the beta-globin downstream promoter. One of the E-box motifs overlaps the initiator and this composite element interacts with USF1 and TFII-I in vitro. Another E-box, located 60 bp 3' to the transcription initiation site, interacts with USF1 and USF2. Mutations of either the initiator or the downstream E-box impair transcription of the beta-globin gene in vitro. Mutations of a putative NF-E2-binding site in the downstream promoter region do not affect transcription in vitro. USF1, USF2, TFII-I and p45 can be crosslinked to a beta-globin promoter fragment in MEL cells in vivo, whereas only TFII-I and USF2 crosslink to the beta-globin gene in K562 cells. The summary data demonstrate that in addition to the well-characterized interactions of the TFII-D complex with the basal promoter, E-box motifs contribute to the efficient formation of transcription complexes on the adult beta-globin gene.
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Affiliation(s)
- Kelly M Leach
- Center for Mammalian Genetics, Powell Gene Therapy Center, Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, 1600 SW Archer Road, PO 100245, Gainesville, FL 32610, USA
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14
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Zingg JM, Ricciarelli R, Andorno E, Azzi A. Novel 5' exon of scavenger receptor CD36 is expressed in cultured human vascular smooth muscle cells and atherosclerotic plaques. Arterioscler Thromb Vasc Biol 2002; 22:412-7. [PMID: 11884283 DOI: 10.1161/hq0302.104517] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
CD36, a member of the scavenger receptor family, is centrally involved in the uptake of oxidized low density lipoproteins (oxLDLs) from the bloodstream. During the atherosclerotic process, the lipid cargo of oxLDL accumulates in macrophages and smooth muscle cells (SMCs), inducing their pathological conversion to foam cells. Increased expression of CD36 occurs in human atherosclerotic lesions, and CD36 knockout mice show reduced uptake of modified LDLs and reduced atherosclerosis. Here, we describe a novel exon 1b and extended CD36 promoter in human SMCs. Exon 1b is specifically transcribed in activated aortic SMCs and mainly expressed in atherosclerotic plaques. Thus, switching to exon 1b transcription may be an important step for the activation of SMCs and their conversion to foam cells. Using an antisense oligonucleotide to exon 1b, we inhibit CD36 translation and highly reduce oxLDL uptake. The antisense to exon 1b does not affect CD36 in cell lines not expressing the new exon. The possibility of a novel antiatherosclerotic therapy and the use of exon 1b as a marker of atherosclerosis are discussed.
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MESH Headings
- 5' Flanking Region
- Arteriosclerosis/genetics
- Arteriosclerosis/metabolism
- Arteriosclerosis/pathology
- Base Sequence
- CD36 Antigens/biosynthesis
- CD36 Antigens/genetics
- Cell Line
- Cell Line, Transformed
- Cells, Cultured
- Exons
- Genes, Reporter
- Humans
- Membrane Proteins
- Molecular Sequence Data
- Muscle, Smooth, Vascular/metabolism
- Oligonucleotides, Antisense/pharmacology
- Promoter Regions, Genetic
- RNA, Messenger/biosynthesis
- Receptors, Immunologic/biosynthesis
- Receptors, Immunologic/genetics
- Receptors, Lipoprotein
- Receptors, Scavenger
- Scavenger Receptors, Class B
- Transcription, Genetic
- Tumor Cells, Cultured
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Affiliation(s)
- Jean-Marc Zingg
- Institute of Biochemistry and Molecular Biology, University of Bern, Bern, Switzerland
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15
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Chen YH, Layne MD, Watanabe M, Yet SF, Perrella MA. Upstream stimulatory factors regulate aortic preferentially expressed gene-1 expression in vascular smooth muscle cells. J Biol Chem 2001; 276:47658-63. [PMID: 11606591 DOI: 10.1074/jbc.m108678200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The phenotypic modulation of vascular smooth muscle cells (VSMC) plays a central role in the pathogenesis of arteriosclerosis. Aortic preferentially expressed gene-1 (APEG-1), a VSMC-specific gene, is expressed highly in differentiated but not in dedifferentiated VSMC. Previously, we identified an E-box element in the mouse APEG-1 proximal promoter, which is essential for VSMC reporter activity. In this study, we investigated the role of upstream stimulatory factors (USF) in the regulation of APEG-1 transcription via this E-box element. By electrophoretic mobility shift assays, recombinant USF1 and USF2 homo- and heterodimers bound specifically to the APEG-1 E-box. Nuclear extracts prepared from primary cultures of rat aortic smooth muscle cells exhibited specific USF1 and USF2 binding to the APEG-1 E-box. To investigate the binding properties of USF during VSMC differentiation, nuclear extracts were prepared from the neural crest cell line, MONC-1, which differentiates into VSMC in culture. Maximal USF1 and USF2 protein levels and binding to the APEG-1 E-box occurred 3 h after the differentiation of MONC-1 cells was initiated. Co-transfection experiments demonstrated that dominant negative USF repressed APEG-1 promoter activity, and USF1, but not USF2, transactivated the APEG-1 promoter. Our studies demonstrate that USF factors contribute to the regulation of APEG-1 expression and may influence the differentiation of VSMC.
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MESH Headings
- Animals
- Aorta/metabolism
- Aorta, Thoracic/cytology
- Aorta, Thoracic/metabolism
- Blotting, Northern
- Blotting, Western
- Cell Differentiation
- Cell Nucleus/metabolism
- Cells, Cultured
- DNA-Binding Proteins
- Dimerization
- Dose-Response Relationship, Drug
- Gene Expression Regulation
- Genes, Dominant
- Luciferases/metabolism
- Male
- Muscle, Smooth/cytology
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/metabolism
- Phenotype
- Promoter Regions, Genetic
- Protein Binding
- Protein Biosynthesis
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Time Factors
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Transcription, Genetic
- Transfection
- Upstream Stimulatory Factors
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Affiliation(s)
- Y H Chen
- Pulmonary and Critical Care and Cardiovascular Divisions, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
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16
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Manabe I, Owens GK. The smooth muscle myosin heavy chain gene exhibits smooth muscle subtype-selective modular regulation in vivo. J Biol Chem 2001; 276:39076-87. [PMID: 11489897 DOI: 10.1074/jbc.m105402200] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Previous studies in our laboratory demonstrated that the transgene consisting of the -4.2 to +11.6 kilobase (kb) region of the smooth muscle (SM) myosin heavy chain (MHC) gene was expressed in virtually all SM tissue types in vivo in transgenic mice and that the multiple CArG elements within this region were differentially required in SMC subtypes, implying that the SM-MHC gene was controlled by multiple transcriptional regulatory modules. To investigate this hypothesis, we analyzed specific regulatory regions within the SM-MHC -4.2 to +11.6 kb region by a combination of deletion analyses of various SM-MHC transgenes as well as by DNaseI hypersensitivity assays and in vivo footprinting in intact SMC tissues. The results showed that SM-MHC transgene expression depended on a large number of required regulatory modules that were widely spread over the -4.2 to +11.6 region. Moreover, the results revealed several unexpected novel features of regulation of the SM-MHC gene including: 1) unique combinations of regulatory modules were required for SM-MHC expression in different SMC-subtypes; 2) repressor modules as well as activator modules were both critical for SMC specificity of the gene; 3) certain modules were required in certain contexts but were dispensable in others within a given SMC-subtype (i.e. the net activity of the module was determined by interaction between modules not simply by the sum of module activities); and 4) we identified a highly conserved 200-base pair transcriptional regulatory module at +8 kb that was required in the large arteries but dispensable in the coronary arteries and airways in transgenic mice and contained multiple potential cis-elements that were occupied by nuclear proteins in the intact aorta based on in vivo footprinting. Taken together, the results suggest a model of complex modular control of expression of the SM-MHC gene that varies between SMC subtypes. Moreover, the studies establish the possibility of designing derivatives of the SM-MHC promoter that might be used for targeting gene expression to specific SMC subtypes in vivo.
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Affiliation(s)
- I Manabe
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia 22908, USA
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17
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Dhulipala PD, Lianos EA, Kotlikoff MI. Regulation of human P2X1 promoter activity by beta helix-loop-helix factors in smooth muscle cells. Gene 2001; 269:167-75. [PMID: 11376948 DOI: 10.1016/s0378-1119(01)00442-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We isolated and characterized genomic clones of the human P2X1 receptor (hP2X1) gene in an effort to understand its tissue specific expression. The hP2X1 gene contains 12 exons spanning 20 kb, with exon sizes ranging from 59 to 143 bp. A 385 bp upstream fragment promoted hP2X1 gene expression in smooth muscle (A7R5 and primary trachealis) and fibroblast (NIH3T3) cell lines, and mutation of a consensus E box sequence (CACCTG) within this fragment (-340 to -345) did not alter basal promoter activity. However, co-transfected bHLH factors regulated activity of the 385 bp minimal P2X1 promoter in a tissue-specific manner. E12 expression inhibited and ITF2b augmented activity in A7R5 cells, but had no effect in NIH3T3 cells. ITF2a, Myo-D, and Id1 proteins had no effect on either cell line, but co-expression of ITF2a blocked E12 inhibition in A7R5 cells, while ITF2b failed to reverse the inhibition. Northern analysis of A7R5 RNA identified high levels of E12 and ITF2b transcripts, and gel shift assays using A7R5 and NIH3T3 nuclear extracts indicated the formation of a protein-DNA complex with an oligonucleotide corresponding to -330 and -348, which was abolished by base substitutions within the E box motif. Our results identify a critical E box response element in the hP2X1 promoter that binds bHLH factors and demonstrate smooth muscle specific transcriptional regulation by E proteins.
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MESH Headings
- 3T3 Cells
- Amino Acid Sequence
- Animals
- Base Sequence
- Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
- Binding Sites
- Cloning, Molecular
- DNA, Complementary
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Gene Expression Profiling
- Gene Expression Regulation
- Helix-Loop-Helix Motifs
- Humans
- Inhibitor of Differentiation Protein 1
- Mice
- Molecular Sequence Data
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/metabolism
- MyoD Protein/genetics
- MyoD Protein/metabolism
- Nerve Tissue Proteins
- Promoter Regions, Genetic
- Receptors, Purinergic P2/genetics
- Receptors, Purinergic P2X
- Repressor Proteins
- TCF Transcription Factors
- Trans-Activators/genetics
- Trans-Activators/metabolism
- Transcription Factor 4
- Transcription Factor 7-Like 1 Protein
- Transcription Factor 7-Like 2 Protein
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Transcription, Genetic
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Affiliation(s)
- P D Dhulipala
- Department of Medicine, Division of Nephrology, UMDNJ-Robert Wood Johnson Medical School, New Brunswick, NJ, USA
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18
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Hsieh CM, Fukumoto S, Layne MD, Maemura K, Charles H, Patel A, Perrella MA, Lee ME. Striated muscle preferentially expressed genes alpha and beta are two serine/threonine protein kinases derived from the same gene as the aortic preferentially expressed gene-1. J Biol Chem 2000; 275:36966-73. [PMID: 10973969 DOI: 10.1074/jbc.m006028200] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Aortic preferentially expressed gene (APEG)-1 is a 1.4-kilobase pair (kb) mRNA expressed in vascular smooth muscle cells and is down-regulated by vascular injury. An APEG-1 5'-end cDNA probe identified three additional isoforms. The 9-kb striated preferentially expressed gene (SPEG)alpha and the 11-kb SPEGbeta were found in skeletal muscle and heart. The 4-kb brain preferentially expressed gene was detected in the brain and aorta. We report here cloning of the 11-kb SPEGbeta cDNA. SPEGbeta encodes a 355-kDa protein that contains two serine/threonine kinase domains and is homologous to proteins of the myosin light chain kinase family. At least one kinase domain is active and capable of autophosphorylation. In the genome, all four isoforms share the middle three of the five exons of APEG-1, and they differ from each other by using different 5'- and 3'-ends and alternative splicing. We show that the expression of SPEGalpha and SPEGbeta is developmentally regulated in the striated muscle during C2C12 myoblast to myotube differentiation in vitro and cardiomyocyte maturation in vivo. This developmental regulation suggests that both SPEGalpha and SPEGbeta can serve as sensitive markers for striated muscle differentiation and that they may be important for adult striated muscle function.
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Affiliation(s)
- C M Hsieh
- Cardiovascular and the Pulmonary and Critical Care Divisions, Brigham and Women's Hospital, and the Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115, USA
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19
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Miano JM, Carlson MJ, Spencer JA, Misra RP. Serum response factor-dependent regulation of the smooth muscle calponin gene. J Biol Chem 2000; 275:9814-22. [PMID: 10734136 DOI: 10.1074/jbc.275.13.9814] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Smooth muscle calponin is a multifunctional, thin filament-associated protein whose expression is restricted to smooth muscle cell lineages in developing and postnatal tissues. Although the physiology of smooth muscle calponin has been studied extensively, the cis-elements governing its restricted pattern of expression have yet to be identified. Here we report on smooth muscle-specific enhancer activity within the first intron of smooth muscle calponin. Sequence analysis revealed a proximal consensus intronic CArG box and two distal intronic CArG-like elements, each of which bound recombinant serum response factor (SRF) as well as immunoreactive SRF from smooth muscle nuclear extracts. Site-directed mutagenesis studies suggested that the consensus CArG box mediates much of the intronic enhancer activity; mutating all three CArG elements abolished the ability of SRF to confer enhancer activity on the smooth muscle calponin promoter. Cotransfecting a dominant-negative SRF construct attenuated smooth muscle-specific enhancer activity, and transducing smooth muscle cells with adenovirus harboring the dominant-negative SRF construct selectively reduced steady-state expression of endogenous smooth muscle calponin. These results demonstrate an important role for intronic CArG boxes and the SRF protein in the transcriptional control of smooth muscle calponin in vitro.
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Affiliation(s)
- J M Miano
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
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