Co-expression of multiple myosin heavy chain genes, in addition to a tissue-specific one, in extraocular musculature.

Wieczorek, David F.; Periasamy, Muthu; Butler-Browne, Gillian; Whalen, Robert G.; Nadal-Ginard, B

doi:10.1083/jcb.101.2.618

Cited by 280 publications

(179 citation statements)

References 66 publications

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“…In limb muscles fetal MyHC is normally only expressed during early fetal muscle development. As the muscle differentiates and matures, the developmental MyHC isoforms are down regulated and replaced by the adult MyHC isoforms in limb muscles (Butler-Brown et al 1990 ;Barbet et al 1991) but persist in the human masseter (Sciote et al 1994 ;Sta/ l et al 1994 ;Monemi et al 1996 ;Butler-Brown et al 1988) and extraocular muscle fibres (Wieczorek et al 1985 ;Sartore et al 1987). No bands corresponding to the fetal MyHC were detected on the SDS-PAGE gels of the palate muscle samples, indicating that this isoform is of minor functional importance.…”

Section: Myosin Heavy Chain Compositionmentioning

confidence: 99%

Characterisation of human soft palate muscles with respect to fibre types, myosins and capillary supply

Stål

Lindman

2000

Journal of Anatomy

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Four human soft palate muscles, and palatopharyngeus, the uvula, the levator and tensor veli palatini were examined using enzyme-histochemical, immunohistochemical and biochemical methods and compared with human limb and facial muscles. Our results showed that each palate muscle had a distinct morphological identity and that they generally shared more similarities with facial than limb muscles. The palatopharyngeus and uvula muscles contained 2 of the highest proportions of type II fibres ever reported for human muscles. In contrast, the levator and tensor veli palatini muscles contained predominantly type I fibres. A fetal myosin heavy chain isoform (MyHC), not usually found in normal adult limb muscles, was present in a small number of fibres in all palate muscles. The mean muscle fibre diameter was smaller than in limb muscles and the individual and intramuscular variability in diameter and shape was considerable. All palate muscles had a high capillary density and an unusually high mitochondrial enzyme activity in the type II fibres, in comparison with limb muscles. No ordinary muscle spindles were observed. The fibre type and MyHC composition indicate that the palatopharyngeus and uvula muscles are functionally involved in quick movements whereas the levator and tensor veli palatini muscles perform slower and more continuous contractions. The high aerobic capacity and the rich capillarisation suggest that the palate muscles are relatively fatigue resistant. Absence of ordinary muscle spindles indicates a special proprioceptive control system. The special morphology of the palate muscles may be partly related to the unique anatomy with only one skeletal insertion, a feature consistent with muscle work at low load and tension and which may influence the cytoarchitecture of these muscles. Other important factors determining the special morphological characteristics might be specific functional requirements, distinct embryological origin and phylogenetic factors.

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Section: Myosin Heavy Chain Compositionmentioning

confidence: 99%

Characterisation of human soft palate muscles with respect to fibre types, myosins and capillary supply

Stål

Lindman

2000

Journal of Anatomy

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“…Two developmental MHC are expressed at specific stages during development: embryonic MHC "MHC emb" and foetal MHC "MHC foet" also called neonatal MHC "MHC neo". These developmental MHC usually disappear in adult muscles, except in particular muscles such as the extraocular muscle [98], masseter [17] and intrafusal fibres [51]. In avian species, at least seven fast MHC genes have been identified (see [4] for a review) which cannot be unambiguously assigned to the different subtypes of fast fibres.…”

Section: Myofibre Diversitymentioning

confidence: 99%

Muscle fibre ontogenesis in farm animal species

et al. 2002

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“…The developmental MHC isoforms (i.e., embryonic and neonatal), which are normally expressed in developing muscle fibers and completely substituted by the adult isoforms in limb muscles, still persist in some adult cranial muscles, including the extraocular muscles (Wieczorek et al, 1985;Sartore et al, 1987;Rubinstein and Hoh, 2000), masseter (d 'Albis et al, 1986;Butler-Browne et al, 1988;Eriksson et al, 1994;Sciote et al, 1994;Stal et al, 1994;Korfage et al, 2000) and laryngeal muscles (Jung et al, 1999), and in the muscle spindles (Rowlerson et al, 1985).…”

mentioning

confidence: 99%

“…In addition, muscle-specific MHC isoforms have been revealed in the jaw-closing muscles of most carnivores (called IIM or type II masticatory MHC) , extraocular muscles (called MHC-EO) (Wieczorek et al, 1985;Sartore et al, 1987;Rubinstein and Hoh, 2000), and laryngeal muscles (called MHC-IIL or type II laryngeal MHC) (DelGaudio et al, 1995;Jung et al, 1999).…”

mentioning

confidence: 99%

Adult human mylohyoid muscle fibers express slow‐tonic, α‐cardiac, and developmental myosin heavy‐chain isoforms

Wang

et al. 2004

Anat. Rec.

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Some adult cranial muscles have been reported to contain unusual myosin heavy-chain (MHC) isoforms (i.e., slow-tonic, ␣-cardiac, embryonic, and neonatal), which exhibit distinct contractile properties. In this study, adult human mylohyoid (MH) muscles obtained from autopsies were investigated to detect the unusual MHC isoforms. For comparison, the biceps brachii and masseter muscles of the same subjects were also examined. Serial cross-sections from the muscles studied were incubated with a panel of isoform-specific anti-MHC monoclonal antibodies that distinguish major and unusual MHC isoforms. On average, the slow type I and fast type II MHC-containing fibers in the MH muscle accounted for 54% and 46% of the fibers, respectively. In contrast to limb and trunk muscles, the adult human MH muscle was characterized by a large proportion of hybrid fibers (85%) and a small percentage of pure fibers (15%; P Ͻ 0.01). Of the fast fiber types, the proportion of the type IIa MHC-containing fibers (92%) was much greater than that of the type IIx MHC-containing fibers (8%; P Ͻ 0.01). Our data demonstrated that the adult human MH fibers expressed the unusual MHC isoforms that were also identified in the masseter, but not in the biceps brachii. These isoforms were demonstrated by immunocytochemistry and confirmed by electrophoretic immunoblotting. Fiber-to-fiber comparisons showed that the unusual MHC isoforms were coexpressed with the major MHC isoforms (i.e., MHCI, IIa, and IIx), thus forming various major/unusual (or m/u) MHC hybrid fiber types. Interestingly, the unusual MHC isoforms were expressed in a fiber type-specific manner. The slow-tonic and ␣-cardiac MHC isoforms were coexpressed predominantly with slow type I MHC isoform, whereas the developmental MHC isoforms (i.e., embryonic and neonatal) coexisted primarily with fast type IIa MHC isoform. There were no MH fibers that expressed exclusively unusual MHC isoforms. Approximately 81% of the slow type I MHC-containing fibers expressed slow-tonic and ␣-cardiac MHC isoforms, whereas 80% of the fast type IIa MHC-containing fibers expressed neonatal MHC isoform. The m/u hybrid fibers (82% of the total fiber population) were found to constitute the predominant fiber types in the adult human MH muscle. At least seven m/u MHC hybrid fiber types were identified in the adult human MH muscle. The most common m/u hybrid fiber types were found to be the MHCI/slow-tonic/␣-cardiac and MHCIIa/neonatal, which accounted for 39% and 33% of the total fiber population, respectively. The multiplicity of MHC isoforms in the adult MH fibers is believed to be related to embryonic origin, innervation pattern, and unique functional requirements.

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Co-expression of multiple myosin heavy chain genes, in addition to a tissue-specific one, in extraocular musculature.

Cited by 280 publications

References 66 publications

Characterisation of human soft palate muscles with respect to fibre types, myosins and capillary supply

Characterisation of human soft palate muscles with respect to fibre types, myosins and capillary supply

Muscle fibre ontogenesis in farm animal species

Adult human mylohyoid muscle fibers express slow‐tonic, α‐cardiac, and developmental myosin heavy‐chain isoforms

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