Electrophoretic separation of reptilian skeletal and cardiac muscle myosin heavy chain isoforms: Dependence on gel format

Abstract

This report provides a comparison of multiple gel formats to study myosin heavy chain (MHC) isoforms that are expressed in reptilian skeletal and cardiac muscles of five turtle species, water monitor, and prehensile tailed skink. Three gel formats were tested. The results identify one format that is superior, for the overall extent of electrophoretic separation and for the assessment of the number of MHC isoforms in reptilian striated muscles. The same format was shown previously to separate MHC isoforms that are expressed in American alligator. The results also show that another gel format reveals the distinct electrophoretic mobility of MHC isoforms in atrial, ventricular, and jaw adductor samples, compared to those expressed in skeletal muscles in the limbs and elsewhere in the body. In addition, the results reveal that the electrophoretic mobility of specific MHC isoforms, relative to other isoforms, depends on the gel format, as shown previously for mammalian and avian species. The discovery of the expression of masticatory MHC, which is abundantly expressed in jaw adductors of members of Carnivora and several other vertebrate orders, in the homologous muscles of prehensile tailed skink, an herbivore, and the carnivorous water monitor, was made during the course of this study.

Functional Segregation within the Muscles of Aquatic Propulsion in the Asiatic Water Monitor (Varanus salvator)

“…Except for one gel run (described below), all of the separating gels consisted of 7% acrylamide (50:1 acrylamide:bis cross-linking ratio) and 30% glycerol and were run at 8°C for 1.5 h at constant 275 V, then for another 25–27 h at constant 300 V in SE600 Hoefer gel units. This was the gel format that yielded the greatest number of MHC bands, in several reptilian species, with high resolution among multiple tested formats, as recently reported (Reiser and Bicer, 2014). All of the gels were silver-stained (Blough et al, 1996).…”

“…Differences in separating gel composition can alter the electrophoretic mobility of some MHC isoforms relative to others and can yield separation of some isoforms that are not separated from each other on other gel formats (e.g., Reiser and Bicer, 2014). Therefore, some samples were also run on separating gels that consisted of 9% acrylamide, 200:1 crosslinking, and 12% glycerol, to test whether any monitor MHC isoforms that co-migrated on one format could be separated from each other on a different format.…”

Fatigue resistant jaw muscles facilitate long-lasting courtship behaviour in the southern alligator lizard (Elgaria multicarinata)

“…The results based on single-fibre gel electrophoresis showed distinct 'jaw-fast' and 'jaw-slow' bands. Reiser & Bicer [41] tested various electrophoretic separation protocols on skeletal and cardiac muscle to identify MHC isoforms in reptilian muscles, including samples from four species of turtles (Chelydra serpentina, Apalone spinifera, Chrysemys picta, Graptemys geographica) and two species of lizards (Varanus salvator, Corucia zebrata). Notably, they found that the separation of the bands representing MHC isoforms distinctly differed between the jaw adductors and all other muscles tested in these reptiles.…”