scholarly journals Effect of creatine on contents of myosin heavy chain and myosin-heavy-chain mRNA in steady-state chicken muscle-cell cultures

1984 ◽  
Vol 218 (3) ◽  
pp. 871-876 ◽  
Author(s):  
R B Young ◽  
R M Denome
Keyword(s):  
Steady State ◽  
Myosin Heavy Chain ◽  
Muscle Cell ◽  
Cell Cultures ◽  
Heavy Chain ◽  
Synthesis Rate ◽  
Adult Skeletal Muscle ◽  
Muscle Cultures ◽  
Chain Synthesis

Embryonic-chick muscle cells reach a steady state with respect to protein metabolism after approx. 1 week in cell culture. To determine if this steady state could be altered by the administration of agents that have been reported to stimulate myosin heavy-chain synthesis, 7-day muscle-cell cultures were treated with 0-1 mM-creatine. Incorporation of [3H]leucine into myosin heavy chain was stimulated by 30-40% at the optimum creatine concentration (0.2 mM), but this stimulation was blocked when actinomycin D (10 micrograms/ml) was also present. However, the quantity of myosin-heavy-chain mRNA as measured by hybridization in vitro was only 15% higher in creatine-treated cultures, and was therefore not entirely responsible for the observed effect. It is important to note that creatine only exerted its action on myosin-heavy-chain synthesis rate in steady-state cultures; creatine was ineffective in altering this rate in rapidly differentiating 3-day muscle cultures. Finally, muscle-cell cultures that had been grown for the entire 7-day culture period in the presence of 0.2 mM-creatine were assayed for quantity of myosin heavy chain. Control and creatine-treated cultures contained 12.7 +/- 1.5 and 20.5 +/- 1.8 micrograms/dish respectively. In conclusion, creatine apparently enhances the quantity of myosin heavy chain in steady-state embryonic muscle-cell cultures, but it probably does not mediate regulation of myosin content in adult skeletal muscle.

scholarly journals Metabolism of myosin heavy chain in steady-state chick skeletal muscle cultures

1981 ◽  
Vol 194 (1) ◽  
pp. 241-247 ◽  
Author(s):  
R B Young ◽  
O C Dombroske
Keyword(s):  
Steady State ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Horse Serum ◽  
Absolute Rate ◽  
Direct Proportion ◽  
Breakdown Rate ◽  
Breakdown Rates ◽  
Muscle Cultures ◽  
Chain Synthesis

Synthesis, accumulation and breakdown of the 200000-mol.wt. heavy subunit of myosin were analysed over an 11 day period in muscle cell cultures isolated from the leg muscle of 12-day chick embryos. Muscle cells accumulated myosin heavy chain rapidly from days 2 to 5 and maintained a maximum, constant myosin-heavy-chain concentration between days 7 and 11. Myosin-heavy-chain content and breakdown rate were compared in steady-state muscle cultures grown either in the presence of an optimum batch of horse serum (control) or in the presence of horse serum that had been pre-selected for its ability to inhibit several-fold the rate of synthesis of myosin heavy chain (inhibitory). The quantity of myosin heavy chain in the inhibited cultures was decreased in direct proportion to the decrease in the rate of synthesis of myosin heavy chain; however, the half-lives of myosin heavy chain (control, 17.7h; inhibitory, 17.0h) were virtually identical. In contrast, the absolute rate of breakdown of myosin heavy chain, expressed as molecules/min per nucleus, was approx. 5-fold lower in the inhibited cultures (4.3 × 10(3) molecules/min per nucleus) than in the control cultures (21.7 × 10(3) molecules/min per nucleus). Thus, inhibition of myosin-heavy-chain synthesis in this case was accompanied by diminished myosin-heavy-chain concentration and absolute breakdown rate at the altered steady state, but relative myosin-heavy-chain breakdown rates were unchanged.

Protein metabolism in chicken muscle cell cultures treated with cimaterol

1990 ◽  
Vol 68 (4) ◽  
pp. 1158-1169 ◽  
Author(s):  
R. B. Young ◽  
D. M. Moriarity ◽  
C. E. McGee ◽  
W. R. Farrar ◽  
H. E. Richter
Keyword(s):  
Protein Degradation ◽  
Myosin Heavy Chain ◽  
Muscle Cell ◽  
Cell Cultures ◽  
Heavy Chain ◽  
Protein Fraction ◽  
Myofibrillar Protein ◽  
Incorporation Rate ◽  
Synthesis Rate ◽  
Dot Blot

Abstract Primary muscle cell cultures were prepared from the leg muscle of 12-d broiler chicken embryos. The partitioning agent cimaterol (10−6 to 10−10M) was added on d 1 and each day thereafter, and cells were studied after 7 d in culture. Cimaterol had no effect at any level either on the percentage of nuclei within multinucleated myotubes or on the total number of nuclei within myotubes. At 10−7M cimaterol, the quantity of the myofibrillar protein fraction was increased by 25.1 ± 8.0% (P <.05) and the quantity of myosin heavy chain was increased by 30.9 ± 4.5% (P < .05). To understand the basis for the increase in myofibrillar protein, the incorporation rate of [3H]Leu was measured in pulse labeling experiments. The apparent synthesis rate of the soluble protein fraction and the crude myofibrillar fraction was not significantly increased by cimaterol; however, cimaterol levels greater than 10−8M caused a 10 to 12% increase (P < .05) in the incorporation rate of [3H]Leu into myosin heavy chain. The effect of cimaterol on release of [3H]Leu from prelabeled protein also was assessed in pulse-chase experiments; the apparent rate of protein degradation was inhibited by 10 to 15% (P < .05) at the higher levels of cimaterol. Dot blot analysis indicated that the quantity of myosin heavy chain mRNA was elevated in cimaterol-treated cultures. Thus, the increased quantity of myofibrillar proteins in embryonic broiler muscle cell cultures is the combined result of a stimulation in the rate of protein synthesis and an inhibition in the rate of protein degradation.

scholarly journals Contractile activity is required for the expression of neonatal myosin heavy chain in embryonic chick pectoral muscle cultures.

1986 ◽  
Vol 103 (6) ◽  
pp. 2153-2161 ◽  
Author(s):  
L C Cerny ◽  
E Bandman
Keyword(s):  
Monoclonal Antibody ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Contractile Activity ◽  
Pectoral Muscle ◽  
Chicken Muscle ◽  
High K ◽  
Muscle Cultures ◽  
Spontaneous Contractions

The expression of neonatal myosin heavy chain (MHC) was examined in developing embryonic chicken muscle cultures using a monoclonal antibody (2E9) that has been shown to be specific for that isoform (Bandman, E., 1985, Science (Wash. DC), 227: 780-782). After 1 wk in vitro some myotubes could be stained with the antibody, and the number of cells that reacted with 2E9 increased with time in culture. All myotubes always stained with a second monoclonal antibody that reacted with all MHC isoforms (AG19) or with a third monoclonal antibody that reacted with the embryonic but not the neonatal MHC (EB165). Quantitation by ELISA of an extract from 2-wk cultures demonstrated that the neonatal MHC represented between 10 and 15% of the total myosin. The appearance of the neonatal isoform was inhibited by switching young cultures to medium with a higher [K+] which has been shown to block spontaneous contractions of myotubes in culture. Furthermore, if mature cultures that reacted with the neonatal antibody were placed into high [K+] medium, neonatal MHC disappeared from virtually all myotubes within 3 d. The effect of high [K+] medium was reversible. When cultures maintained in high [K+] medium for 2 wk were placed in standard medium, which permitted the resumption of contractile activity, within 24 h cells began to react with the neonatal specific antibody, and by 72 h many myotubes were strongly positive. Since similar results were also obtained by inhibiting spontaneous contractions with tetrodotoxin, we suggest that the development of contractile activity is not only associated with the maturation of myotubes in culture, but may also be the signal that induces the expression of the neonatal MHC.

Effects of aging on in vivo synthesis of skeletal muscle myosin heavy-chain and sarcoplasmic protein in humans

1997 ◽  
Vol 273 (4) ◽  
pp. E790-E800 ◽  
Author(s):  
P. Balagopal ◽  
Olav E. Rooyackers ◽  
Deborah B. Adey ◽  
Philip A. Ades ◽  
K. Sreekumaran Nair
Keyword(s):  
Myosin Heavy Chain ◽  
Old Age ◽  
Muscle Mass ◽  
Heavy Chain ◽  
Contractile Function ◽  
Contractile Protein ◽  
Whole Body ◽  
Synthesis Rate ◽  
Sarcoplasmic Protein ◽  
Chain Synthesis

A decline in muscle mass and contractile function are prominent features of the sarcopenia of old age. Because myosin heavy chain is an important contractile protein, it was hypothesized that synthesis of this protein decreases in sarcopenia. The fractional synthesis rate of myosin heavy chain was measured simultaneously with rates of mixed muscle and sarcoplasmic proteins from the increment of [13C]leucine in these proteins purified from serial needle biopsy samples taken from 24 subjects (age: from 20 to 92 yr) during a primed continuous infusion ofl-[1-13C]leucine. A decline in synthesis rate of mixed muscle protein ( P < 0.01) and whole body protein ( P < 0.01) was observed from young to middle age with no further change with advancing age. An age-related decline of myosin heavy-chain synthesis rate was also observed ( P < 0.01), with progressive decline occurring from young, through middle, to old age. However, sarcoplasmic protein synthesis did not decline with age. Myosin heavy-chain synthesis rate was correlated with measures of muscle strength ( P < 0.05), circulating insulin-like growth factor I ( P < 0.01), and dehydroepiandrosterone sulfate ( P < 0.05) in men and women and free testosterone levels in men ( P < 0.01). A decline in the synthesis rate of myosin heavy chain implies a decreased ability to remodel this important muscle contractile protein and likely contributes to the declining muscle mass and contractile function in the elderly.

scholarly journals Control of immunoglobulin secretion in the murine plasmacytoma line MOPC 315.

1978 ◽  
Vol 148 (1) ◽  
pp. 301-312 ◽  
Author(s):  
G E Sonenshein ◽  
M Siekevitz ◽  
G R Siebert ◽  
M L Gefter
Keyword(s):  
Heavy Chain ◽  
Wheat Germ ◽  
Secretory Protein ◽  
Synthesis Rate ◽  
Free System ◽  
Alpha Chain ◽  
Chain Synthesis ◽  
Variant Line

Cells of the 315LV-1 (derived from NP1) variant line of MOPC 315 contain approximately 1% the normal intracellular level of the heavy (alpha) chain of IgA and no detectable light (lambda2) chain. The synthesis rate of alpha-chain in the variant, however, is similar to that in cells of the parent line. Moreover the relative amount of translatable alpha-chain mRNA that can be extracted from 315LV-1 cells is about the same as for parental cells. No light-chain synthesis can be detected either in vivo or in vitro in a wheat germ cell-free system. The 315LV-1 heavy chain synthesized in vivo or in vitro has slightly greater electrophoretic mobility than normal H chain and turns over rapidly intracellularly. The variant fails to secrete any of its heavy chain, despite the fact that its H chain mRNA is bound to membranes, as one would expect for a secretory protein message. Fusion of 315LV-1 cells with cells of a kappa-producing MPC 11 variant line leads to stabilization of the intracellular H chain and also to full recovery of secretion of the H chain as an H2L2 molecule.

scholarly journals Acute changes in myosin heavy chain synthesis rate in pressure versus volume overload.

1994 ◽  
Vol 75 (3) ◽  
pp. 418-425 ◽  
Author(s):  
T Imamura ◽  
P J McDermott ◽  
R L Kent ◽  
M Nagatsu ◽  
G Cooper ◽  
...  
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Volume Overload ◽  
Synthesis Rate ◽  
Chain Synthesis ◽  
Acute Changes

scholarly journals A screen for genetic loci required for body-wall muscle development during embryogenesis in Caenorhabditis elegans.

Genetics ◽  
1994 ◽  
Vol 137 (2) ◽  
pp. 483-498
Author(s):  
J Ahnn ◽  
A Fire
Keyword(s):  
Caenorhabditis Elegans ◽  
Myosin Heavy Chain ◽  
Muscle Cell ◽  
Heavy Chain ◽  
Body Wall ◽  
Muscle Development ◽  
Contractile Function ◽  
The Body ◽  
Body Wall Muscle ◽  
Genetic Loci

Abstract We have used available chromosomal deficiencies to screen for genetic loci whose zygotic expression is required for formation of body-wall muscle cells during embryogenesis in Caenorhabditis elegans. To test for muscle cell differentiation we have assayed for both contractile function and the expression of muscle-specific structural proteins. Monoclonal antibodies directed against two myosin heavy chain isoforms, the products of the unc-54 and myo-3 genes, were used to detect body-wall muscle differentiation. We have screened 77 deficiencies, covering approximately 72% of the genome. Deficiency homozygotes in most cases stain with antibodies to the body-wall muscle myosins and in many cases muscle contractile function is observed. We have identified two regions showing distinct defects in myosin heavy chain gene expression. Embryos homozygous for deficiencies removing the left tip of chromosome V fail to accumulate the myo-3 and unc-54 products, but express antigens characteristic of hypodermal, pharyngeal and neural development. Embryos lacking a large region on chromosome III accumulate the unc-54 product but not the myo-3 product. We conclude that there exist only a small number of loci whose zygotic expression is uniquely required for adoption of a muscle cell fate.

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