PURPOSE: To examine and characterize the expression of M-bands (or M-lines) in the orbital layer (OL) and global layer (GL) of adult rat extraocular muscles (EOMs). METHODS: Semiquantitative polymerase chain reaction (PCR), quantitative (q)PCR, immunohistochemistry, and confocal microscopy were used to analyze expression of the major gene and protein constituents of M-bands in freshly dissected and cryosectioned rectus extraocular muscles (EOMs) and tibialis anterior (TA) muscles. Electron microscopy (EM) was performed on perfusion-fixed EOMs and TA muscles in a layer-specific manner, to determine, characterize, and quantify laminar-specific differences in M-band expression. RESULTS: These studies demonstrate EOM layer-specific differences in the expression of M-bands and their major constituents, myomesin1 (Myom1) and myomesin2 (Myom2 or M-protein) at the structural, mRNA, and protein levels by using EM, semiquantitative PCR, qPCR, immunohistochemistry, and confocal microscopy. Differences in thick filament lattice order were quantified by using EM-based inter-thick-filament distance and variance measurements and were found to be TA > GL > OL. CONCLUSIONS: The expression pattern of M-bands and their constituents in EOMs provides mechanistic insight for their allotypic and layer-specific viscoelastic properties. Modeling the differential expression of M-bands between EOMs and TA predicts increased elasticity but reduced force and eccentric contraction (ECC)-mediated damage in EOMs and suggests a potential mechanism for the clinical sparing of EOMs noted in Duchenne's muscular dystrophy (DMD).
PURPOSE: To examine and characterize the expression of M-bands (or M-lines) in the orbital layer (OL) and global layer (GL) of adult rat extraocular muscles (EOMs). METHODS: Semiquantitative polymerase chain reaction (PCR), quantitative (q)PCR, immunohistochemistry, and confocal microscopy were used to analyze expression of the major gene and protein constituents of M-bands in freshly dissected and cryosectioned rectus extraocular muscles (EOMs) and tibialis anterior (TA) muscles. Electron microscopy (EM) was performed on perfusion-fixed EOMs and TA muscles in a layer-specific manner, to determine, characterize, and quantify laminar-specific differences in M-band expression. RESULTS: These studies demonstrate EOM layer-specific differences in the expression of M-bands and their major constituents, myomesin1 (Myom1) and myomesin2 (Myom2 or M-protein) at the structural, mRNA, and protein levels by using EM, semiquantitative PCR, qPCR, immunohistochemistry, and confocal microscopy. Differences in thick filament lattice order were quantified by using EM-based inter-thick-filament distance and variance measurements and were found to be TA > GL > OL. CONCLUSIONS: The expression pattern of M-bands and their constituents in EOMs provides mechanistic insight for their allotypic and layer-specific viscoelastic properties. Modeling the differential expression of M-bands between EOMs and TA predicts increased elasticity but reduced force and eccentric contraction (ECC)-mediated damage in EOMs and suggests a potential mechanism for the clinical sparing of EOMs noted in Duchenne's muscular dystrophy (DMD).
Authors: Miranda D Grounds; Hannah G Radley; Gordon S Lynch; Kanneboyina Nagaraju; Annamaria De Luca Journal: Neurobiol Dis Date: 2008-04-09 Impact factor: 5.996
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Authors: Roman Schoenauer; Maximilian Y Emmert; Allison Felley; Elisabeth Ehler; Chad Brokopp; Benedikt Weber; Mohamed Nemir; Giuseppe G Faggian; Thierry Pedrazzini; Volkmar Falk; Simon P Hoerstrup; Irina Agarkova Journal: Basic Res Cardiol Date: 2010-11-11 Impact factor: 17.165
Authors: Rafael R Oexner; David Pla-Martín; Thomas Paß; Martin H J Wiesen; Peter Zentis; Astrid Schauss; Olivier R Baris; Sammy Kimoloi; Rudolf J Wiesner Journal: Invest Ophthalmol Vis Sci Date: 2020-10-01 Impact factor: 4.799