1
|
Chen Y, Qiu J, Wu Y, Jia H, Jiang Y, Jiang M, Wang Z, Sheng HB, Hu L, Zhang Z, Wang Z, Li Y, Huang Z, Wu H. Genetic findings of Sanger and nanopore single-molecule sequencing in patients with X-linked hearing loss and incomplete partition type III. Orphanet J Rare Dis 2022; 17:65. [PMID: 35189936 PMCID: PMC8862311 DOI: 10.1186/s13023-022-02235-7] [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: 05/06/2021] [Accepted: 02/06/2022] [Indexed: 12/01/2022] Open
Abstract
Background POU3F4 is the causative gene for X-linked deafness-2 (DFNX2), characterized by incomplete partition type III (IP-III) malformation of the inner ear. The purpose of this study was to investigate the clinical characteristics and molecular findings in IP-III patients by Sanger or nanopore single-molecule sequencing. Methods Diagnosis of IP-III was mainly based on clinical characteristics including radiological and audiological findings. Sanger sequencing of POU3F4 was carried out for these IP-III patients. For those patients with negative results for POU3F4 Sanger sequencing, nanopore long-read single-molecule sequencing was used to identify the possible pathogenic variants. Hearing intervention outcomes of hearing aids (HAs) fitting and cochlear implantation (CI) were also analyzed. Aided pure tone average (PTA) was further compared between two groups of patients according to their different locations of POU3F4 variants: in the exon region or in the upstream region. Results In total, 18 male patients from 14 unrelated families were diagnosed with IP-III. 10 variants were identified in POU3F4 by Sanger sequencing and 6 of these were reported for the first time (p.Gln181*, p.Val215Gly, p.Arg282Gln, p.Gln316*, c.903_912 delins TGCCA and p.Arg205del). Four different deletions that varied from 80 to 486 kb were identified 876–1503 kb upstream of POU3F4 by nanopore long-read single-molecule sequencing. De novo genetic mutations occurred in 21.4% (3/14) of patients with POU3F4 mutations. Among these 18 patients, 7 had bilateral HAs and 10 patients received unilateral CI. The mean aided PTA for HAs and CI users were 41.1 ± 5.18 and 40.3 ± 7.59 dB HL respectively. The mean PTAs for patients with the variants located in the exon and upstream regions were 39.6 ± 6.31 versus 43.0 ± 7.10 dB HL, which presented no significant difference (p = 0.342). Conclusions Among 14 unrelated IP-III patients, 28.6% (4/14) had no definite mutation in exon region of POU3F4. However, possible pathogenic deletions were identified in upstream region of this gene. De novo genetic mutations occurred in 21.4% (3/14) of patients with POU3F4 mutation. There was no significant difference of hearing intervention outcomes between the IP-III patients with variants located in the exon region and in the upstream region. Supplementary Information The online version contains supplementary material available at 10.1186/s13023-022-02235-7.
Collapse
|
2
|
Bademci G, Lasisi A, Yariz KO, Montenegro P, Menendez I, Vinueza R, Paredes R, Moreta G, Subasioglu A, Blanton S, Fitoz S, Incesulu A, Sennaroglu L, Tekin M. Novel domain-specific POU3F4 mutations are associated with X-linked deafness: examples from different populations. BMC MEDICAL GENETICS 2015; 16:9. [PMID: 25928534 PMCID: PMC4422282 DOI: 10.1186/s12881-015-0149-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 01/29/2015] [Indexed: 01/17/2023]
Abstract
Background Mutations in the POU3F4 gene cause X-linked deafness type 3 (DFN3), which is characterized by inner ear anomalies. Methods Three Turkish, one Ecuadorian, and one Nigerian families were included based on either inner ear anomalies detected in probands or X-linked family histories. Exome sequencing and/or Sanger sequencing were performed in order to identify the causative DNA variants in these families. Results Four novel, c.707A>C (p.(Glu236Ala)), c.772delG (p.(Glu258ArgfsX30)), c.902C>T (p.(Pro301Leu)), c.987T>C (p.(Ile308Thr)), and one previously reported mutation c.346delG (p.(Ala116ProfsX26)) in POU3F4, were identified. All mutations identified are predicted to affect the POU-specific or POU homeo domains of the protein and co-segregated with deafness in all families. Conclusions Expanding the spectrum of POU3F4 mutations in different populations along with their associated phenotypes provides better understanding of their clinical importance and will be helpful in clinical evaluation and counseling of the affected individuals. Electronic supplementary material The online version of this article (doi:10.1186/s12881-015-0149-2) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Guney Bademci
- John P. Hussmann Institute for Human Genomics and John T. Macdonald Foundation, Department of Human Genetics, Miller school of Medicine, University of Miami, 1501 NW 10th Avenue, BRB-610 (M-860), Miami, FL, 33136, USA.
| | - Akeem Lasisi
- John P. Hussmann Institute for Human Genomics and John T. Macdonald Foundation, Department of Human Genetics, Miller school of Medicine, University of Miami, 1501 NW 10th Avenue, BRB-610 (M-860), Miami, FL, 33136, USA. .,Department of Otorhinolaryngology, College of Medicine, University of Ibadan, Ibadan, Nigeria.
| | - Kemal O Yariz
- John P. Hussmann Institute for Human Genomics and John T. Macdonald Foundation, Department of Human Genetics, Miller school of Medicine, University of Miami, 1501 NW 10th Avenue, BRB-610 (M-860), Miami, FL, 33136, USA.
| | - Paola Montenegro
- Departamento de Genetica, Hospital de Especialidades FFAA, Quito, Ecuador.
| | - Ibis Menendez
- John P. Hussmann Institute for Human Genomics and John T. Macdonald Foundation, Department of Human Genetics, Miller school of Medicine, University of Miami, 1501 NW 10th Avenue, BRB-610 (M-860), Miami, FL, 33136, USA.
| | - Rodrigo Vinueza
- Departamento de Genetica, Hospital de Especialidades FFAA, Quito, Ecuador.
| | - Rosario Paredes
- Departamento de Genetica, Hospital de Especialidades FFAA, Quito, Ecuador.
| | - Germania Moreta
- Departamento de Genetica, Hospital de Especialidades FFAA, Quito, Ecuador.
| | - Asli Subasioglu
- John P. Hussmann Institute for Human Genomics and John T. Macdonald Foundation, Department of Human Genetics, Miller school of Medicine, University of Miami, 1501 NW 10th Avenue, BRB-610 (M-860), Miami, FL, 33136, USA. .,Department of Medical Genetics, Izmir Katip Celebi University, Ataturk Training and Research Hospital, Izmir, Turkey.
| | - Susan Blanton
- John P. Hussmann Institute for Human Genomics and John T. Macdonald Foundation, Department of Human Genetics, Miller school of Medicine, University of Miami, 1501 NW 10th Avenue, BRB-610 (M-860), Miami, FL, 33136, USA.
| | - Suat Fitoz
- Department of Radiodiagnostics, Ankara University School of Medicine, Ankara, Turkey.
| | - Armagan Incesulu
- Department of Otorhinolaryngology, Eskisehir Osmangazi University School of Medicine, Eskisehir, Turkey.
| | - Levent Sennaroglu
- Department of Otorhinolaryngology, Hacettepe University School of Medicine, Ankara, Turkey.
| | - Mustafa Tekin
- John P. Hussmann Institute for Human Genomics and John T. Macdonald Foundation, Department of Human Genetics, Miller school of Medicine, University of Miami, 1501 NW 10th Avenue, BRB-610 (M-860), Miami, FL, 33136, USA.
| |
Collapse
|
3
|
Cárdenas C, Juretić N, Bevilacqua JA, García IE, Figueroa R, Hartley R, Taratuto AL, Gejman R, Riveros N, Molgó J, Jaimovich E. Abnormal distribution of inositol 1,4,5‐trisphosphate receptors in human muscle can be related to altered calcium signals and gene expression in Duchenne dystrophy‐derived cells. FASEB J 2010; 24:3210-21. [DOI: 10.1096/fj.09-152017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- César Cárdenas
- Centro de Estudios Moleculares de la CélulaInstituto de Ciencias BiomédicasFacultad de MedicinaUniversidad de Chile Santiago Chile
- Department of PhysiologyUniversity of Pennsylvania Philadelphia Pennsylvania USA
- Centre National de la Recherche ScientifiqueInstitut de Neurobiologie Alfred FessardFRC2118Laboratoire de Neurobiologie Cellulaire et Moléculaire UPR9040 Gif sur Yvette France
| | - Nevenka Juretić
- Centro de Estudios Moleculares de la CélulaInstituto de Ciencias BiomédicasFacultad de MedicinaUniversidad de Chile Santiago Chile
- Centre National de la Recherche ScientifiqueInstitut de Neurobiologie Alfred FessardFRC2118Laboratoire de Neurobiologie Cellulaire et Moléculaire UPR9040 Gif sur Yvette France
| | - Jorge A. Bevilacqua
- Centro de Estudios Moleculares de la CélulaInstituto de Ciencias BiomédicasFacultad de MedicinaUniversidad de Chile Santiago Chile
- Programa de Anatomía y Biología del DesarrolloInstituto de Ciencias BiomédicasFacultad de MedicinaUniversidad de Chile Santiago Chile
- Departamento de Neurología y NeurocirugíaHospital Clínico Universidad de Chile Independencia Chile
- Centre National de la Recherche ScientifiqueInstitut de Neurobiologie Alfred FessardFRC2118Laboratoire de Neurobiologie Cellulaire et Moléculaire UPR9040 Gif sur Yvette France
| | - Isaac E. García
- Centro de Estudios Moleculares de la CélulaInstituto de Ciencias BiomédicasFacultad de MedicinaUniversidad de Chile Santiago Chile
- Centre National de la Recherche ScientifiqueInstitut de Neurobiologie Alfred FessardFRC2118Laboratoire de Neurobiologie Cellulaire et Moléculaire UPR9040 Gif sur Yvette France
| | - Reinaldo Figueroa
- Centro de Estudios Moleculares de la CélulaInstituto de Ciencias BiomédicasFacultad de MedicinaUniversidad de Chile Santiago Chile
- Centre National de la Recherche ScientifiqueInstitut de Neurobiologie Alfred FessardFRC2118Laboratoire de Neurobiologie Cellulaire et Moléculaire UPR9040 Gif sur Yvette France
| | - Ricardo Hartley
- Centro de Estudios Moleculares de la CélulaInstituto de Ciencias BiomédicasFacultad de MedicinaUniversidad de Chile Santiago Chile
- Centre National de la Recherche ScientifiqueInstitut de Neurobiologie Alfred FessardFRC2118Laboratoire de Neurobiologie Cellulaire et Moléculaire UPR9040 Gif sur Yvette France
| | - Ana L. Taratuto
- Departamento de NeuropatologíaInstituto de Investigaciones NeurológicasFLENI Buenos Aires Argentina
- Centre National de la Recherche ScientifiqueInstitut de Neurobiologie Alfred FessardFRC2118Laboratoire de Neurobiologie Cellulaire et Moléculaire UPR9040 Gif sur Yvette France
| | - Roger Gejman
- Departamento de Anatomía PatológicaFacultad de MedicinaPontificia Universidad Católica de Chile Santiago Chile
- Centre National de la Recherche ScientifiqueInstitut de Neurobiologie Alfred FessardFRC2118Laboratoire de Neurobiologie Cellulaire et Moléculaire UPR9040 Gif sur Yvette France
| | - Nora Riveros
- Centro de Estudios Moleculares de la CélulaInstituto de Ciencias BiomédicasFacultad de MedicinaUniversidad de Chile Santiago Chile
- Centre National de la Recherche ScientifiqueInstitut de Neurobiologie Alfred FessardFRC2118Laboratoire de Neurobiologie Cellulaire et Moléculaire UPR9040 Gif sur Yvette France
| | - Jordi Molgó
- Department of PhysiologyUniversity of Pennsylvania Philadelphia Pennsylvania USA
- Centre National de la Recherche ScientifiqueInstitut de Neurobiologie Alfred FessardFRC2118Laboratoire de Neurobiologie Cellulaire et Moléculaire UPR9040 Gif sur Yvette France
| | - Enrique Jaimovich
- Centro de Estudios Moleculares de la CélulaInstituto de Ciencias BiomédicasFacultad de MedicinaUniversidad de Chile Santiago Chile
- Centre National de la Recherche ScientifiqueInstitut de Neurobiologie Alfred FessardFRC2118Laboratoire de Neurobiologie Cellulaire et Moléculaire UPR9040 Gif sur Yvette France
| |
Collapse
|
4
|
Lee HK, Song MH, Kang M, Lee JT, Kong KA, Choi SJ, Lee KY, Venselaar H, Vriend G, Lee WS, Park HJ, Kwon TK, Bok J, Kim UK. Clinical and molecular characterizations of novel POU3F4 mutations reveal that DFN3 is due to null function of POU3F4 protein. Physiol Genomics 2009; 39:195-201. [DOI: 10.1152/physiolgenomics.00100.2009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
X-linked deafness type 3 (DFN3), the most prevalent X-linked form of hereditary deafness, is caused by mutations in the POU3F4 locus, which encodes a member of the POU family of transcription factors. Despite numerous reports on clinical evaluations and genetic analyses describing novel POU3F4 mutations, little is known about how such mutations affect normal functions of the POU3F4 protein and cause inner ear malformations and deafness. Here we describe three novel mutations of the POU3F4 gene and their clinical characterizations in three Korean families carrying deafness segregating at the DFN3 locus. The three mutations cause a substitution (p.Arg329Pro) or a deletion (p.Ser310del) of highly conserved amino acid residues in the POU homeodomain or a truncation that eliminates both DNA-binding domains (p.Ala116fs). In an attempt to better understand the molecular mechanisms underlying their inner ear defects, we examined the behavior of the normal and mutant forms of the POU3F4 protein in C3H/10T1/2 mesodermal cells. Protein modeling as well as in vitro assays demonstrated that these mutations are detrimental to the tertiary structure of the POU3F4 protein and severely affect its ability to bind DNA. All three mutated POU3F4 proteins failed to transactivate expression of a reporter gene. In addition, all three failed to inhibit the transcriptional activity of wild-type proteins when both wild-type and mutant proteins were coexpressed. Since most of the mutations reported for DFN3 thus far are associated with regions that encode the DNA binding domains of POU3F4, our results strongly suggest that the deafness in DFN3 patients is largely due to the null function of POU3F4.
Collapse
Affiliation(s)
- Hee Keun Lee
- Department of Biology, Kyungpook National University, Daegu
| | - Mee Hyun Song
- Department of Otorhinolaryngology, Kwandong University College of Medicine, Goyang
- Department of Otorhinolaryngology, Yonsei University College of Medicine; and
| | - Myengmo Kang
- Department of Anatomy, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul
| | - Jung Tae Lee
- Department of Immunology, Keimyung University School of Medicine
| | - Kyoung-Ah Kong
- Department of Anatomy, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul
| | - Su-Jin Choi
- Department of Biology, Kyungpook National University, Daegu
| | - Kyu Yup Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, College of Medicine, Kyungpook National University, Daegu, South Korea
| | - Hanka Venselaar
- Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Gert Vriend
- Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Won-Sang Lee
- Department of Otorhinolaryngology, Yonsei University College of Medicine; and
| | | | - Taeg Kyu Kwon
- Department of Immunology, Keimyung University School of Medicine
| | - Jinwoong Bok
- Department of Anatomy, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul
| | - Un-Kyung Kim
- Department of Biology, Kyungpook National University, Daegu
| |
Collapse
|
5
|
Minczuk M, Lilpop J, Boros J, Stepien PP. The 5′ region of the human hSUV3 gene encoding mitochondrial DNA and RNA helicase: Promoter characterization and alternative pre-mRNA splicing. ACTA ACUST UNITED AC 2005; 1729:81-7. [PMID: 15919122 DOI: 10.1016/j.bbaexp.2005.04.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2005] [Revised: 04/19/2005] [Accepted: 04/20/2005] [Indexed: 10/25/2022]
Abstract
The human nuclear hSUV3 gene encodes ATP-dependent RNA and DNA helicase, which predominantly localizes in the mitochondria. In yeast, the Suv3 helicase is a component of mitochondrial degradosome, a two-subunit complex, which degrades aberrant mtRNAs. In contrast to the well-documented physiological role of the yeast SUV3, the function of its human orthologue remains unknown. In this report, we have analyzed the hSUV3 5' genomic region. Our data suggest that hSUV3 is a housekeeping gene. Deletion analysis and in vitro mutagenesis revealed the presence of an enhancer region and regulatory elements in basal promoter including: (i) direct 10-bp-long repeats, which share significant sequence similarity with the consensus for the NF-kappaB/Rel family transcription factors, (ii) Sp1 general transcription factor binding site, and (iii) NRF-1 transcription factor binding sites, the latter typical for nuclear-encoded mitochondrial genes. Furthermore, we show that the 5' region of the hSUV3 pre-mRNA can be alternatively spliced.
Collapse
Affiliation(s)
- Michal Minczuk
- Department of Genetics, University of Warsaw, Pawinskiego 5A, 02-106 Warsaw, Poland.
| | | | | | | |
Collapse
|
6
|
Dominov JA, Kravetz AJ, Ardelt M, Kostek CA, Beermann ML, Miller JB. Muscle-specific BCL2 expression ameliorates muscle disease in laminin {alpha}2-deficient, but not in dystrophin-deficient, mice. Hum Mol Genet 2005; 14:1029-40. [PMID: 15757977 DOI: 10.1093/hmg/ddi095] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
To examine the role of apoptosis in neuromuscular disease progression, we have determined whether pathogenesis in dystrophin-deficient (mdx) and laminin alpha2-deficient (Lama2-null) mice is ameliorated by overexpression of the anti-apoptosis protein BCL2 in diseased muscles. The mdx mice are a model for the human disease, Duchenne muscular dystrophy (DMD), and the Lama2-null mice are a model for human congenital muscular dystrophy type 1A (MDC1A). For these studies, we generated transgenic mice that overexpressed human BCL2 under control of muscle-specific MyoD or MRF4 promoter fragments. We then used cross-breeding to introduce the transgenes into diseased mdx or Lama2-null mice. In mdx mice, we found that overexpression of BCL2 failed to produce any significant differences in muscle pathology. In contrast, in the Lama2-null mice, we found that muscle-specific expression of BCL2 led to a several-fold increase in lifespan and an increased growth rate. Thus, BCL2-mediated apoptosis appears to play a significant role in pathogenesis of laminin alpha2 deficiency, but not of dystrophin deficiency, suggesting that therapies designed to ameliorate disease by inhibition of apoptosis are more likely to succeed in MDC1A than in DMD.
Collapse
Affiliation(s)
- Janice A Dominov
- Boston Biomedical Research Institute, 64 Grove Street, Watertown, MA 02472, USA.
| | | | | | | | | | | |
Collapse
|
7
|
Relaix F, Molinari S, Lemonnier M, Schäfer B, Buckingham M. The in vivo form of the murine class VI POU protein Emb is larger than that encoded by previously described transcripts. Gene 2004; 333:35-46. [PMID: 15177678 DOI: 10.1016/j.gene.2004.02.047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2003] [Revised: 11/28/2003] [Accepted: 02/05/2004] [Indexed: 11/25/2022]
Abstract
The class VI POU domain family member known as Emb in the mouse (rat Brn5 or human mPOU/TCFbeta1) is present in vivo as a protein migrating at about 80 kDa on western blots, considerably larger than that predicted (about 42 kDa) from previously cloned coding sequences. By RT-PCR and 5' RACE strategies a full-length Emb sequence, Emb FL, is now identified. Shorter sequences encoding the -COOH terminal, and an -NH(2) terminal isoform, EmbN, were also isolated. Comparisons of Emb coding sequences between species, including the full-length zebra fish, POU(c), are presented, together with a compilation of the multiple transcripts produced by alternative splicing and the presence of different transcriptional start and stop sites, from the Emb gene.
Collapse
Affiliation(s)
- F Relaix
- C.N.R.S. URA 2578, Department of Developmental Biology, Pasteur Institute, 75724 Paris Cedex 15, France
| | | | | | | | | |
Collapse
|
8
|
Molinari S, Relaix F, Lemonnier M, Kirschbaum B, Schäfer B, Buckingham M. A novel complex regulates cardiac actin gene expression through interaction of Emb, a class VI POU domain protein, MEF2D, and the histone transacetylase p300. Mol Cell Biol 2004; 24:2944-57. [PMID: 15024082 PMCID: PMC371105 DOI: 10.1128/mcb.24.7.2944-2957.2004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2002] [Revised: 10/23/2002] [Accepted: 01/06/2004] [Indexed: 11/20/2022] Open
Abstract
Expression of the mouse cardiac actin gene depends on a distal enhancer (-7 kbp) which has been shown, in transgenic mice, to direct expression to embryonic skeletal muscle. The presence of this distal sequence is also associated with reproducible expression of cardiac actin transgenes. In differentiated skeletal muscle cells, activity of the enhancer is driven by an E box, binding MyoD family members, and by a 3' AT-rich sequence which is in the location of a DNase I-hypersensitive site. This sequence does not bind MEF2 proteins, or other known muscle transcription factors, directly. Oct1 and Emb, a class VI POU domain protein, bind to consensus sites on the DNA, and it is the binding of Emb which is important for activity. Emb binds as a major complex with MEF2D and the histone transacetylase p300. The form of Emb present in this complex and as a major form in muscle cell extracts is longer (80 kDa) than that previously described. These results demonstrate the importance of this novel complex in the transcriptional regulation of the cardiac actin gene and suggest a potential role in chromatin remodeling associated with muscle gene activation.
Collapse
Affiliation(s)
- S Molinari
- CNRS URA 2578, Department of Developmental Biology, Pasteur Institute, 75724 Paris Cedex 15, France
| | | | | | | | | | | |
Collapse
|
9
|
Pavlath GK, Dominov JA, Kegley KM, Miller JB. Regeneration of transgenic skeletal muscles with altered timing of expression of the basic helix-loop-helix muscle regulatory factor MRF4. THE AMERICAN JOURNAL OF PATHOLOGY 2003; 162:1685-91. [PMID: 12707053 PMCID: PMC1851175 DOI: 10.1016/s0002-9440(10)64303-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In regenerating muscle cells, muscle regulatory factor (MRF) 4 is normally the last of the four MRFs to be expressed. To analyze how the timing of MRF4 expression affects muscle regeneration, we compared regeneration after local freeze injury of muscles from wild-type mice with muscles from transgenic mice in which MRF4 expression was under control of an approximately 1.6-kb fragment of the myogenin promoter. Three days after injury, masseter and tibialis anterior (TA) muscles in wild-type mice expressed little or no MRF4 mRNA; whereas these muscles in transgenic mice expressed abundant MRF4 mRNA from both the transgene and the endogenous gene. Thus, MRF4 up-regulation was accelerated in transgenic compared to wild-type regenerating muscles, and expression of the transgene appeared to activate, perhaps indirectly, expression of the endogenous MRF4 gene. At 11 days after injury, regeneration, as measured by cross-sectional area and density of regenerated fibers, was significantly impaired in transgenic TA compared to wild-type TA, whereas at 19 days after injury both transgenic and TA muscle fibers had fully recovered to preinjury values. Regeneration of masseter muscles, which normally regenerate much less completely than TA muscles, was unaffected by the transgene. Thus, the timing of MRF4 up-regulation, as well as additional muscle-specific factors, can determine the progress of muscle regeneration.
Collapse
Affiliation(s)
- Grace K Pavlath
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia, USA
| | | | | | | |
Collapse
|
10
|
Zoeller RT. Challenges confronting risk analysis of potential thyroid toxicants. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2003; 23:143-162. [PMID: 12635729 DOI: 10.1111/1539-6924.00296] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Screening and testing for potential thyroid toxicants using endpoints of thyroid function, including circulating levels of thyroid hormones and thyrotropin, will not capture toxicants that directly interfere with thyroid hormone action at the receptor. The goals of the present review are to provide a critique of the literature focused on thyroid hormone and brain development as it relates to testing and evaluating thyroid toxicants, and to propose possible solutions to this perceived dilemma.
Collapse
Affiliation(s)
- R Thomas Zoeller
- Biology Department, Morrill Science Center, University of Massachusetts, Amherst, MA 01003, USA.
| |
Collapse
|
11
|
Dominov JA, Houlihan-Kawamoto CA, Swap CJ, Miller JB. Pro- and anti-apoptotic members of the Bcl-2 family in skeletal muscle: a distinct role for Bcl-2 in later stages of myogenesis. Dev Dyn 2001; 220:18-26. [PMID: 11146504 DOI: 10.1002/1097-0177(2000)9999:9999<::aid-dvdy1088>3.0.co;2-#] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Apoptotic myonuclei appear during myogenesis and in diseased muscles. To investigate cell death regulation in skeletal muscle, we examined how members of the Bcl-2 family of apoptosis regulators are expressed and function in the C2C12 muscle cell line and in primary muscle cells at different stages of development. Both anti-apoptotic (Bcl-W, Bcl-X(L)) and pro-apoptotic (Bad, Bak, Bax) members of the Bcl-2 family were expressed in developing skeletal muscle in vivo. Each was also expressed in embryonic (E11-12), fetal (E15-16), and neonatal muscle stem cells, myoblasts, and myotubes in vitro. In contrast, Bcl-2 expression was limited to a small group of mononucleate, desmin-positive, myogenin-negative muscle cells that were seen in fetal and neonatal, but not embryonic, muscle cell cultures. The cell surface protein Sca-1, which is associated with muscle and blood stem cells, was found on approximately 1/2 of these Bcl-2-positive cells. Loss of Bcl-2 did not affect expression of other family members, because neonatal muscles of wild-type and Bcl-2-null mice had similar amounts of Bcl-X(L), Bcl-W, Bad, Bak, and Bax mRNAs. Loss of Bcl-2 did have functional consequences; however, because neonatal muscles of Bcl-2-null mice had only approximately 2/3 as many fast muscle fibers as muscles in wild-type mice. Thus, Bcl-2 function is required for particular stages of fetal and postnatal myogenesis.
Collapse
Affiliation(s)
- J A Dominov
- Myogenesis Research Laboratory, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
| | | | | | | |
Collapse
|
12
|
Dominov JA, Dunn JJ, Miller JB. Bcl-2 expression identifies an early stage of myogenesis and promotes clonal expansion of muscle cells. J Cell Biol 1998; 142:537-44. [PMID: 9679150 PMCID: PMC2133046 DOI: 10.1083/jcb.142.2.537] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
We show that Bcl-2 expression in skeletal muscle cells identifies an early stage of the myogenic pathway, inhibits apoptosis, and promotes clonal expansion. Bcl-2 expression was limited to a small proportion of the mononucleate cells in muscle cell cultures, ranging from approximately 1-4% of neonatal and adult mouse muscle cells to approximately 5-15% of the cells from the C2C12 muscle cell line. In rapidly growing cultures, some of the Bcl-2-positive cells coexpressed markers of early stages of myogenesis, including desmin, MyoD, and Myf-5. In contrast, Bcl-2 was not expressed in multinucleate myotubes or in those mononucleate myoblasts that expressed markers of middle or late stages of myogenesis, such as myogenin, muscle regulatory factor 4 (MRF4), and myosin. The small subset of Bcl-2-positive C2C12 cells appeared to resist staurosporine-induced apoptosis. Furthermore, though myogenic cells from genetically Bcl-2-null mice formed myotubes normally, the muscle colonies produced by cloned Bcl-2-null cells contained only about half as many cells as the colonies produced by cells from wild-type mice. This result suggests that, during clonal expansion from a muscle progenitor cell, the number of progeny obtained is greater when Bcl-2 is expressed.
Collapse
Affiliation(s)
- J A Dominov
- Myogenesis Research Laboratory, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
| | | | | |
Collapse
|
13
|
Abstract
MRF4, myogenin, MyoD, and Myf-5 are the four members of the basic helix-loop-helix family of muscle-specific regulatory factors (MRFs). We examined whether MRF4 could substitute for myogenin in vivo by determining if the myofiber- and MRF4-deficient phenotype of myogenin (-/-) mice could be rescued by a myogenin promoter-MRF4 transgene. When the transgene was expressed at a physiological level in myogenin-deficient fetuses, we found that expression of the endogenous MRF4 gene was restored to normal levels, whereas MyoD levels were unchanged. Thus, MRF4 can participate in a positive autoregulatory loop and can substitute for myogenin to activate its own promoter. Myogenin-deficient fetuses that expressed the transgene also had more myosin, more and larger myofibers, and a more normal ribcage morphology than myogenin-deficient littermates without the transgene. The transgene failed, however, to restore normal numbers of myofibers or viability to myogenin-deficient mice, because the approximately 1.6 kb myogenin promoter fragment was not expressed in most late-forming myofibers. These results demonstrate that MRF4 is able to substitute for myogenin to activate MRF4 expression and promote myofiber formation during the early stages of myogenesis.
Collapse
Affiliation(s)
- Z Zhu
- Neuromuscular Laboratory, Massachusetts General Hospital, Charlestown 02129, USA
| | | |
Collapse
|
14
|
Ryan AK, Rosenfeld MG. POU domain family values: flexibility, partnerships, and developmental codes. Genes Dev 1997; 11:1207-25. [PMID: 9171367 DOI: 10.1101/gad.11.10.1207] [Citation(s) in RCA: 404] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- A K Ryan
- Howard Hughes Medical Institute, Department and School of Medicine, University of California at San Diego, La Jolla 92093-0648, USA
| | | |
Collapse
|
15
|
Affiliation(s)
- A Buonanno
- National Institutes of Health, Bethesda, Maryland 20892, USA
| | | |
Collapse
|