Electrophoretic analysis of proteins from single bovine muscle fibres

Abstract

A number of single fibres were isolated by dissection of four bovine masseter (ma) muscles, three rectus abdominis (ra) muscles and eight sternomandibularis (sm) muscles. By histochemical criteria these muscles contain respectively, solely slow fibres (often called type I), predominantly fast fibres (type II), and a mixture of fast and slow. The fibres were analysed by conventional sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and the gels stained with Coomassie Blue. Irrespective of the muscle, every fibre could be classed into one of two broad groups based on the mobility of proteins in the range 135000-170000 daltons. When zones containing myosin heavy chain were cut from the single-fibre gel tracks and ‘mapped’ [Cleveland, Fischer, Kirschner & Laemmli (1977) J. Biol. Chem. 252, 1102-1106] with Staphylococcus proteinase, it was found that one group always contained fast myosin heavy chain, whereas the second group always contained the slow form. Moreover, a relatively fast-migrating alpha-tropomyosin was associated with the fast myosin group and a slow-migrating form with the slow myosin group. All fibres also contained beta-tropomyosin; the coexistence of alpha- and beta-tropomyosin is at variance with evidence that alpha-tropomyosin is restricted to fast fibres [Dhoot & Perry (1979) Nature (London) 278, 714-718]. Fast fibres containing the expected fast light chains and troponins I and C fast were identified in the three ra muscles, but in only four sm muscles. In three other sm muscles, all the fast fibres contained two troponins I and an additional myosin light chain that was more typical of myosin light chain 1 slow. The remaining sm muscle contained a fast fibre type that was similar to the first type, except that its myosin light chain 1 was more typical of the slow polymorph. Troponin T was bimorphic in all fast fibres from a ra muscles and in at least some fast fibres from one sm muscle. Peptide ‘mapping’ revealed two forms of fast myosin heavy chain distributed among fast fibres. Each form was associated with certain other proteins. Slow myosin heavy chain was unvarying in three slow fibre types identified. Troponin I polymorphs were the principal indicator of slow fibre types. The myofibrillar polymorphs identified presumably contribute to contraction properties, but beyond cud chewing involving ma muscle, nothing is known of the conditions that gave rise to the variable fibre composites in sm and ra muscles.

Bovine Skeletal Muscle Cells Predominantly Express a Vascular Cell Adhesion Molecule-1 Seven-Ig Domain Splice Form

“…In the present study, MyHC isoform composition differed among the ten skeletal muscles, as shown in previous studies of protein level (Young and Davey, 1981;Young, 1982;Manabe et al ., 1995) and mRNA level determined by multiplex RT-PCR (Tanabe et al ., 1998). Although three fast-type MyHC isoforms have not been distinguished from each other in terms of protein level, the previous studies also showed good correlation of expression between the mRNA level and the protein level of MyHC slow or fast isoforms.…”

“…The difference in the expression of MyHC isoforms among muscles varies among mammalian species (Manabe et al ., 1995;Tanabe et al ., 1998). The exclusive expression of MyHC-slow observed in bovine MS is a characteristic of ruminant animals (Young and Davey, 1981;Manabe et al ., 1995), presumably because of their sustained chewing behavior. These observations suggest the flexibility of expression pattern of MyHC isoforms in each muscle in response to a specific physiological condition.…”

Enzyme-linked immunosorbent assay for myosin heavy chains in the horse

“…The separation gel had a 5-8% polyacrylamide gradient (Bar and Pette, 1988) and the stacking gel was at 3.5%. To improve resolution, the separation gel also contained a 40% glycerol gradient (Sugiura and Murakami, 1990 (Suzuki, 1977;Young and Davey, 1981;Picard et al, 1994). In the present study, the electrophoresis showed the same MHC 1 content in the equine masseter as in the bovine masseter.…”

A possible role for myosin light chain 1 slow of bovine muscle

“…Fast-contracting fibres and muscles are additionally recruited as locomotion begins and speed increases. Although Armstrong's model for division of labour is widely accepted, at least one mammalian muscle, the bovine masseter, contains only slow fibres (Young & Davey, 1981;Talmant et al, 1986) yet is not postural. Instead, the masseter is rhythmically active in chewing.…”