1
|
Fontana J, López-Montero N, Elliott RM, Fernández JJ, Risco C. The unique architecture of Bunyamwera virus factories around the Golgi complex. Cell Microbiol 2008; 10:2012-28. [PMID: 18547336 PMCID: PMC7162186 DOI: 10.1111/j.1462-5822.2008.01184.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2008] [Accepted: 05/29/2008] [Indexed: 12/22/2022]
Abstract
Viral factories are novel structures built by viruses in infected cells. During their construction organelles are recruited and build a large scaffold for viral replication and morphogenesis. We have studied how a bunyavirus uses the Golgi to build the factory. With the help of confocal and 3D ultrastructural imaging together with molecular mapping in situ and in vitro we have characterized a tubular structure that harbours the viral replication complexes in a globular domain. Numerous ribonucleoproteins were released from purified tubes disrupted in vitro. Actin and myosin I were identified by peptide mass fingerprinting in isolated tubes while actin and the viral NSm non-structural protein were detected in the tubes' internal proteinaceous scaffold by immunogold labelling. Studies with NSm deletion mutants and drugs affecting actin showed that both NSm and actin are key factors for tube and virus assembly in Golgi. Three-dimensional reconstructions based on oriented serial sections of infected cells showed that tubes anchor cell organelles to Golgi stacks and make contacts with intracellular viruses. We propose that this new structure, unique among enveloped viruses, assembles in association with the most stable component of Golgi stacks, the actin-containing matrix scaffold, connecting viral replication and morphogenesis inside viral factories.
Collapse
Affiliation(s)
- Juan Fontana
- Cell Structure Laboratory, Centro Nacional de Biotecnología, CSIC, Campus Universidad Autónoma, Cantoblanco, 28049 Madrid, Spain
| | | | | | | | | |
Collapse
|
2
|
Pae EK, Hyatt JPK, Wu J, Chien P. Short-term electrical stimulation alters tongue muscle fibre type composition. Arch Oral Biol 2007; 52:544-51. [PMID: 17239813 DOI: 10.1016/j.archoralbio.2006.12.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2006] [Revised: 12/01/2006] [Accepted: 12/05/2006] [Indexed: 10/23/2022]
Abstract
OBJECTIVE To examine whether short-term exogenous activation of a tongue muscle induced a phenotypic shift from a fast to a slow fibre-type, and thus assess a potential therapeutic avenue to protect against obstructive sleep apnoea (OSA). METHODS New Zealand White rabbit genioglossus (GG) muscle, characteristically a fast muscle, was continuously stimulated at a frequency attributed to slow muscle (10Hz, 3V DC pulses) using an implanted micro-circuit for 7 days. Changes in muscle fibre types and aerobic capacity were assessed between stimulated and un-stimulated (control) groups using immunohistochemistry and electrophoresis for myosin heavy chain (MHC) and assayed for citrate synthase. RESULTS Compared to the un-stimulated control group, stimulated GG muscles had more (approximately 13%) type I MHC (slow-twitch) content; a proportional decrease in type II MHC (fast-twitch) isoform also occurred in the stimulated GG muscle (P<0.05). Electrophoresis analysis on whole muscle and single fibre MHC showed an increased type I expression in the stimulated GG muscle (P<0.01). A commensurate rise in citrate synthase activity, indicating a change in aerobic capacity, was also observed in the stimulated GG muscles. CONCLUSION Together, these results demonstrate a successful alteration in tongue muscle characteristics using exogenous electrical stimulation and perhaps a potential therapeutic application for OSA.
Collapse
Affiliation(s)
- Eung-Kwon Pae
- UCLA School of Dentistry, Los Angeles, CA 90095-1668, USA.
| | | | | | | |
Collapse
|
3
|
Sokoloff AJ, Yang B, Li H, Burkholder TJ. Immunohistochemical characterization of slow and fast myosin heavy chain composition of muscle fibres in the styloglossus muscle of the human and macaque (Macaca rhesus). Arch Oral Biol 2007; 52:533-43. [PMID: 17210117 PMCID: PMC1991289 DOI: 10.1016/j.archoralbio.2006.11.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2006] [Revised: 10/09/2006] [Accepted: 11/16/2006] [Indexed: 11/23/2022]
Abstract
OBJECTIVE Muscle fibre contractile diversity is thought to be increased by the hybridization of multiple myosin heavy chain (MHC) isoforms in single muscle fibres. Reports of hybrid fibres composed of MHCI and MHCII isoforms in human, but not macaque, tongue muscles, suggest a human adaptation for increased tongue muscle contractile diversity. Here we test whether hybrid fibres composed of MHCI and MHCII are unique to human tongue muscles or are present as well in the macaque. METHODS MHC composition of the macaque and human styloglossus was characterized with antibodies that allowed identification of three muscle fibre phenotypes, a slow phenotype composed of MHCI, a fast phenotype composed of MHCII and a hybrid phenotype composed of MHCI and MHCII. RESULTS The fast phenotype constitutes 68.5% of fibres in the macaque and 43.4% of fibres in the human (P<0.0001). The slow phenotype constitutes 20.2% of fibres in the macaque and 39.3% of fibres in the human (P<0.0001). The hybrid phenotype constitutes 11.2% of fibres in the macaque and 17.3% of fibres in the human (P=0.0002). Macaques and humans do not differ in fiber size (cross-sectional area, diameter). However, measures of fibre size differ by phenotype such that fast>hybrid>slow (P<0.05). CONCLUSION These data demonstrate differences in the relative percent of muscle fibre phenotypes in the macaque and human styloglossus but also demonstrate that all three phenotypes are present in both species. These data suggest a similar range of mechanical properties in styloglossus muscle fibres of the macaque and human.
Collapse
Affiliation(s)
- Alan J Sokoloff
- Department of Physiology, Emory University School of Medicine, Atlanta, GA 30322, USA.
| | | | | | | |
Collapse
|
4
|
Lim D, Beitzel F, Lynch G, Woods MG. Myosin heavy chain isoform composition of human masseter muscle from subjects with different mandibular plane angles. Aust Orthod J 2006; 22:105-14. [PMID: 17203573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
AIM To investigate the presence of myosin heavy chain isoforms in human masseter muscle and to describe any differences in orthognathic surgery patients with different mandibular plane angles. METHOD Biopsies were obtained from the anterior border of the superficial masseter muscle in 18 patients undergoing various orthognathic procedures. Myosin heavy chain isoforms were isolated and analysed by SDS-PAGE gel electrophoresis. Steiner's mandibular plane angles were measured from pretreatment lateral cephalometric radiographs and used to classify the vertical dimension of each subject. RESULTS Despite the fact that there was wide individual variation, there appeared to be no direct association between the presence of myosin heavy chain isoforms and specific vertical facial patterns. Type I myosin heavy chain isoform was the most common isoform found in all subjects. More Type IIA myosin heavy chain isoforms were observed in dolichofacial subjects. There were no differences between genders in myosin heavy chain expression. CONCLUSION A wide variation of myosin heavy chain isoforms exists in the masseter muscle of individuals with different mandibular plane angles. Further investigations involving larger sample sizes and the incorporation of bite-force measurements may help to clarify the relationship between mandibular muscle characteristics and the vertical facial dimension.
Collapse
Affiliation(s)
- Donna Lim
- School of Dental Science, The University of Melbourne, Melbourne, Australia
| | | | | | | |
Collapse
|
5
|
Sumoza-Toledo A, Gillespie PG, Romero-Ramirez H, Ferreira-Ishikawa HC, Larson RE, Santos-Argumedo L. Differential localization of unconventional myosin I and nonmuscle myosin II during B cell spreading. Exp Cell Res 2006; 312:3312-22. [PMID: 16919270 DOI: 10.1016/j.yexcr.2006.07.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2006] [Revised: 07/01/2006] [Accepted: 07/07/2006] [Indexed: 02/06/2023]
Abstract
Cross-linking of CD44 in vitro promotes chemokinesis and actin-based dendrite formation in T and B cells. However, the mechanisms by which the adhesion molecule CD44 induces cytoskeleton activation in lymphocytes are still poorly understood. In this study, we have investigated whether myosin isoforms are involved in CD44-dependent dendrite formation in activated B cells. Pharmacological inhibition of myosin with 2,3-butanedione monoxime strongly affected spreading and dendrite formation, suggesting that these cellular motors may participate in these phenomena. Furthermore, immunofluorescence analysis showed differences in subcellular localization of class I and class II myosin during B cell spreading. In response to CD44 cross-linking, myosin-1c was polarized to lamellipodia, where F-actin was high. In contrast, the distribution of cytosplasmic nonmuscle class II myosin was not altered. Expressions of myosin-1c and II were also demonstrated in B cells by Western blot. Although the inhibition of PLCgamma, PI3K and MEK-1 activation affected the spreading and dendrite formation in activated B cells, only PLCgamma and MEK-1 inhibition correlated with absence of myosin-1c polarization. Additionally, myosin-1c polarization was observed upon cross-linking of other surface molecules, suggesting a common mechanism for B cell spreading. This work shows that class I and class II myosin are expressed in B cells, are differentially distributed, and may participate in the morphological changes of these cells.
Collapse
Affiliation(s)
- Adriana Sumoza-Toledo
- Department of Molecular Biomedicine, Centro de Investigación y Estudios Avanzados, Av. IPN #2508. Col. Zacatenco. CP 07360, México, D.F., México
| | | | | | | | | | | |
Collapse
|
6
|
Puhke R, Aunola S, Surakka J, Venojärvi M, Alev K, Seene T, Rusko H. The profile and distribution of myosin heavy chain isoforms in middle-aged sedentary persons. J Sports Med Phys Fitness 2006; 46:176-82. [PMID: 16823344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
AIM Human lifestyle has drastically changed during the past century as the share of physical work in daily life has decreased. The purpose of the present study was to examine the distribution of myosin heavy chain (MHC) isoforms in middle-aged sedentary persons, to compare the proportion of MHC isoforms of middle-aged and young sedentary persons and to demonstrate the effect of physical activity of MHC isoforms in middle-aged sedentary persons. METHODS Eighty-nine middle-aged sedentary and 13 young sedentary persons volunteered for the study. Thirty middle-aged sedentary subjects participated in strength-conditional exercise program during 9 months. Vertical jumping height and maximal anaerobic work capacity were measured. Muscle samples were taken from vastus lateralis muscle. MHC isoform composition was determined by SDS-PAGE. RESULTS Variation of MHC I and MHC IIa isoforms in middle-age sedentary persons demonstrated normal distribution. Significant differences of MHC isoform proportions between middle-aged and young sedentary participants were not observed. The proportion of MHC IIx decreased significantly after the exercise period that significantly improved the maximal anaerobic power and jumping height of participants. CONCLUSIONS Normal distribution illustrated the proportion of MHC I and MHC IIa isoforms in 89 middle-aged sedentary persons while significant differences of MHC isoforms proportion between young and middle-aged sedentary persons were not observed. Even small increase of physical activity improved physical performance and decrease the MHC IIx proportion of middle-aged sedentary persons. Physically active lifestyle in middle age, when age-related changes have not started yet, may delay age-related changes in skeletal muscle.
Collapse
Affiliation(s)
- R Puhke
- Institute of Exercise Biology and Physiotherapy, University of Tartu, Tartu, Estonia.
| | | | | | | | | | | | | |
Collapse
|
7
|
Friedmann B, Kinscherf R, Vorwald S, Müller H, Kucera K, Borisch S, Richter G, Bärtsch P, Billeter R. Muscular adaptations to computer-guided strength training with eccentric overload. ACTA ACUST UNITED AC 2004; 182:77-88. [PMID: 15329060 DOI: 10.1111/j.1365-201x.2004.01337.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS In order to investigate the muscular adaptations to a novel form of strength training, 18 male untrained subjects performed 4 weeks of low resistance-high repetition knee extension exercise. METHODS Nine of them trained on a conventional weight resistance device (Leg curler, CON/ECC group), with loads equivalent to 30% of the concentric one-repetition maximum (1RM) for both the concentric and eccentric phase of movement. The other nine trained on a newly developed computer-driven device (CON/ECC-OVERLOAD group) with the concentric load equivalent to 30% of the concentric 1RM and the eccentric load equivalent to 30% of the eccentric 1RM. RESULTS Training resulted in significantly (P < or = 0.05) increased peak torque and a tendency (P=0.092) to increased muscle cross-sectional area for the CON/ECC-OVERLOAD but not the CON/ECC group, while strength endurance capacity was significantly (P < or = 0.05) increased in the CON/ECC group only. RT-PCR revealed significantly increased myosin heavy chain (MHC) IIa and lactate dehydrogenase (LDH) A mRNAs, a tendency for increased MHC IIx mRNA (P = 0.056) and high correlations between the changes in MHC IIx and LDH A mRNAs (r=0.97, P=0.001) in the CON/ECC-OVERLOAD group. CONCLUSIONS These results indicate a shift towards a more type II dominated gene expression pattern in the vasti laterales muscles of the CON/ECC-OVERLOAD group in response to training. We suggest that the increased eccentric load in the CON/ECC-OVERLOAD training leads to distinct adaptations towards a stronger, faster muscle.
Collapse
Affiliation(s)
- B Friedmann
- Department of Sports Medicine, Medical Clinic and Policlinic, University of Heidelberg, Heidelberg, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Abstract
Diversity in muscle contractile properties is based on the variability of contractile properties of single muscle fibers which in turn is related to the presence of different myosin heavy-chain (MyHC) isoforms. Human jaw muscles are featured by many hybrid fibers expressing more than one MyHC isoform. The purpose of this study was to determine the proportion of each isoform within these fibers for evaluation of the fiber's capacity of producing a large diversity in contractile properties. Electrophoretic separation of MyHC isoforms was performed on 218 single fibers of the temporalis and digastric muscles. Of these fibers, 100 were classified as hybrid fibers. Most hybrid fibers co-expressed MyHC-IIA and -IIX (n = 62); a smaller number co-expressed MyHC-I and -IIA (n = 14), MyHC-I and -IIX (n = 12), and MyHC-I, -IIA, and -IIX (n = 12). The proportions of the individual MyHC isoforms in the hybrid fibers varied highly, suggesting a large range of contractile properties among these fibers.
Collapse
Affiliation(s)
- J A M Korfage
- Department of Functional Anatomy, Academic Center for Dentistry Amsterdam (ACTA), Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands.
| | | |
Collapse
|
9
|
Abstract
Type IIB fast fibres are typically demonstrated in human skeletal muscle by histochemical staining for the ATPase activity of myosin heavy-chain (MyHC) isoforms. However, the monoclonal antibody specific for the mammalian IIB isoform does not detect MyHC IIB protein in man and MyHC IIX RNA is found in histochemically identified IIB fibres, suggesting that the IIB protein isoform may not be present in man; if this is not so, jaw-closing muscles, which express a diversity of isoforms, are likely candidates for their presence. ATPase histochemistry, immunohistochemistry polyacrylamide gel electrophoresis and in situ hybridization, which included a MyHC IIB-specific mRNA riboprobe, were used to compare the composition and RNA expression of MyHC isoforms in a human jaw-closing muscle, the masseter, an upper limb muscle, the triceps, an abdominal muscle, the external oblique, and a lower limb muscle, the gastrocnemius. The external oblique contained a mixture of histochemically defined type I, IIA and IIB fibres distributed in a mosaic pattern, while the triceps and gastrocnemius contained only type I and IIA fibres. Typical of limb muscle fibres, the MyHC I-specific mRNA probes hybridized with histochemically defined type I fibres, the IIA-specific probes with type IIA fibres and the IIX-specific probes with type IIB fibres. The MyHC IIB mRNA probe hybridized only with a few histochemically defined type I fibres in the sample from the external oblique; in addition to this IIB message, these fibres also expressed RNAs for MyHC I, IIA and IIX. MyHC IIB RNA was abundantly expressed in histochemical and immunohistochemical type IIA fibres of the masseter, together with transcripts for IIA and in some cases IIX. No MyHC IIB protein was detected in fibres and extracts of either the external oblique or masseter by immunohistochemistry, immunoblotting and electrophoresis. Thus, IIB RNA, but not protein, was found in the fibres of two different human skeletal muscles. It is believed this is the first report of the substantial expression of IIB mRNA in man as demonstrated in a subset of masseter fibres, but rarely in limb muscle, and in only a few fibres of the external oblique. These findings provide further evidence for the complexity of myosin gene expression, especially in jaw-closing muscles.
Collapse
MESH Headings
- Abdominal Muscles/metabolism
- Abdominal Muscles/ultrastructure
- Adenosine Triphosphatases
- Adolescent
- Adult
- Electrophoresis, Polyacrylamide Gel
- Female
- Gene Expression
- Humans
- Immunoblotting
- In Situ Hybridization
- Male
- Masseter Muscle/metabolism
- Masseter Muscle/ultrastructure
- Middle Aged
- Muscle Fibers, Fast-Twitch/metabolism
- Muscle Fibers, Fast-Twitch/ultrastructure
- Muscle Fibers, Skeletal/metabolism
- Muscle Fibers, Skeletal/ultrastructure
- Muscle Fibers, Slow-Twitch/metabolism
- Muscle Fibers, Slow-Twitch/ultrastructure
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/ultrastructure
- Myosin Heavy Chains/analysis
- Myosin Heavy Chains/genetics
- Myosin Type I/analysis
- Myosin Type I/genetics
- Myosin Type II/analysis
- Myosin Type II/genetics
- Nonmuscle Myosin Type IIA/analysis
- Nonmuscle Myosin Type IIA/genetics
- Nonmuscle Myosin Type IIB/analysis
- Nonmuscle Myosin Type IIB/genetics
- Phenotype
- Protein Isoforms/analysis
- Protein Isoforms/genetics
- RNA Probes
- RNA, Messenger/analysis
- RNA, Messenger/genetics
Collapse
Affiliation(s)
- Michael J. Horton
- Department of Orthodontics, School of Dental Medicine, University of Pittsburgh, 3501 Terrace Street, Pittsburgh, PA 15261, USA
| | - Carla A. Brandon
- Department of Orthodontics, School of Dental Medicine, University of Pittsburgh, 3501 Terrace Street, Pittsburgh, PA 15261, USA
| | - Terence J. Morris
- Department of Orthodontics, School of Dental Medicine, University of Pittsburgh, 3501 Terrace Street, Pittsburgh, PA 15261, USA
| | - Thomas W. Braun
- Department of Oral Surgery, School of Dental Medicine, University of Pittsburgh, 3501 Terrace Street, Pittsburgh, PA 15261, USA
| | - Kenneth M. Yaw
- Department of Orthopaedic Surgery, University of Pittsburgh Medical Center, 3471 Fifth Ave., Pittsburgh, PA 15213, USA
| | - James J. Sciote
- Department of Orthodontics, School of Dental Medicine, University of Pittsburgh, 3501 Terrace Street, Pittsburgh, PA 15261, USA
- Corresponding author. Tel.: +1-412-648-8419; fax: +1-412-648-8817. (J.J. Sciote)
| |
Collapse
|
10
|
Abstract
While human masseter muscle is known to have unusual co-expression of myosin heavy-chain proteins, cellular kinetics of individual fibers has not yet been tested. Here we examine if myosin heavy-chain protein content is closely correlated to fiber-shortening speed, as previously reported in other human muscles, or if these proteins do not correlate well to shortening speeds, as has been demonstrated previously in rat muscle. Slack-test recordings of single, skinned human masseter fibers at 15 degrees C revealed maximum shortening velocities generally slower and much more variable than those recorded in human limb muscle. The slowest fiber recorded had a maximum shortening velocity (V0) value of 0.027 muscle lengths x s(-1), several times slower than the slowest type I fibers previously measured in humans. By contrast, human limb muscle controls produced V0 measurements comparable with previously published results. Analysis by gel electrophoresis found 63% of masseter fibers to contain pure type I MyHC and the remainder to co-express mostly type I in various combinations with IIA and IIX isoforms. V0 in masseter fibers forms a continuum in which no clear relationship to MyHC isoform content is apparent.
Collapse
Affiliation(s)
- T. J. Morris
- The Department of Orthodontics & Dentofacial Orthopedics, University of Pittsburgh, 3501 Terrace Street, Pittsburgh, PA 15261-1932
| | - C. A. Brandon
- The Department of Orthodontics & Dentofacial Orthopedics, University of Pittsburgh, 3501 Terrace Street, Pittsburgh, PA 15261-1932
| | - M. J. Horton
- The Department of Orthodontics & Dentofacial Orthopedics, University of Pittsburgh, 3501 Terrace Street, Pittsburgh, PA 15261-1932
| | - D. S. Carlson
- Baylor College of Dentistry, Texas A&M University System Health Science Center
| | - J. J. Sciote
- The Department of Orthodontics & Dentofacial Orthopedics, University of Pittsburgh, 3501 Terrace Street, Pittsburgh, PA 15261-1932
- corresponding author,
| |
Collapse
|