The combined methodologies demonstrated the specificity of the mATPase staining patterns which correlated to the expression of distinct MyHC isoforms. In addition the results provide evidence that many fibres co-expressed different MyHC isoforms in variable relative amounts, forming a continuum. Staining intensities for mATPase, converted into optical density values by image analysis revealed that a relationship between mATPase and MyHC expression holds for hybrid fibres even when displaying one MyHC type with overwhelming dominance. The results also revealed that three MyHC isoforms I, IIA and IIB can be co-expressed on a single muscle fibre. In such a case mATPase alone, with the current protocols, does not allow an accurate characterization of the specific MyHC-based fibre type(s). Although some hybrid fibres may have displayed a non-uniform expression of myosins along their lengths, most fibres from the IIA/B group (type) remained very stable with respect to the relative amounts of the MyHCs expressed. Finally, a second slow MyHC isoform was recognized on immunoblots of a mixed muscle samples
Professor Anthony J Sargeant was the Head of Department and supervisor of Jose Sant’ana Pereira (very sadly now deceased) who carried out this meticulous work under his supervision in the early 1990s.
New method for the accurate characterization of single human skeletal muscle fibres demonstrates a relation between mATPase and MyHC expression in pure and hybrid fibre types
Journal of Muscle Research and Cell Motility
J Muscle Res Cell Motil. 1995 Feb;16(1):21-34