Denervation-induced changes in myosin heavy chain expression in the rat diaphragm muscle

2003 ◽  
Vol 95 (2) ◽  
pp. 611-619 ◽  
Author(s):  
Paige C. Geiger ◽  
Jeffrey P. Bailey ◽  
Wen-Zhi Zhan ◽  
Carlos B. Mantilla ◽  
Gary C. Sieck
Keyword(s):  
Protein Expression ◽  
Mrna Expression ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Protein Isoforms ◽  
Diaphragm Muscle ◽  
Northern Analysis ◽  
Mrna Levels ◽  
Rat Diaphragm ◽  
Mrna Isoforms

Unilateral denervation (Dnv) of the rat diaphragm muscle (Diam) markedly alters expression of myosin heavy chain (MHC) isoforms. After 2 wk of Diam Dnv, MHC content per half-sarcomere decreases in fibers expressing MHC2X and MHC2B. We hypothesized that changes in MHC protein expression parallel changes in MHC mRNA expression. Relative MHC isoform mRNA levels were determined by Northern analysis after 1, 3, 7, and 14 days of Dnv of the rat Diam. MHC protein expression was determined by SDS-PAGE. Changes in MHC isoform protein and mRNA expression were not concurrent. Expression of MHCSlow and MHC2X mRNA isoforms decreased dramatically by 3 days of Dnv, whereas that of MHC2A and MHC2B did not change. Expression of all MHC protein isoforms decreased by 3 days of Dnv. We observed a differential effect of rat Diam Dnv on MHC isoform protein and mRNA expression. The time course of the changes in MHC isoform mRNA and protein expression suggests a predominant effect of altered protein turnover rates on MHC protein expression instead of altered transcription after Dnv.

Cloning and sequencing of myosin heavy chain isoform cDNAs in golden-mantled ground squirrels: effects of hibernation on mRNA expression

2004 ◽  
Vol 97 (5) ◽  
pp. 1985-1991 ◽  
Author(s):  
Bryan C. Rourke ◽  
Anqi Qin ◽  
Fadia Haddad ◽  
Kenneth M. Baldwin ◽  
Vincent J. Caiozzo
Keyword(s):  
Protein Expression ◽  
Mrna Expression ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Ground Squirrels ◽  
Small Rodent ◽  
Control Mechanisms ◽  
Mrna Levels ◽  
Myosin Heavy Chain Isoform ◽  
Cdna Sequences

The golden-mantled ground squirrel is a small rodent hibernator that demonstrates unusual myosin heavy chain (MHC) isoform plasticity during several months of torpor, punctuated by bouts of rewarming and shivering thermogenesis. We measured MHC mRNA levels to determine whether pretranslational control mechanisms were responsible for differences in MHC2x protein expression, as we previously observed between active and hibernating ground squirrels. We first cloned cDNA using the 3′ rapid amplification of cDNA ends (3′ RACE) technique and identified three sequences corresponding to MHC1, MHC2x, and MHC2b. A DNA control fragment was developed to be used in conjunction with a coupled RT-PCR reaction to simultaneously measure MHC mRNA levels for each isoform in the skeletal muscle of ground squirrels. MHC mRNA and protein expression were strongly correlated, and type IIx and IIb mRNA levels were significantly different between active and hibernating ground squirrels. Pretranslational control of MHC protein is apparently an important process during hibernation, although the exact stimulus is not known. The techniques presented can be used to obtain MHC cDNA sequences and to measure mRNA expression in many vertebrate groups.

Maximum specific force depends on myosin heavy chain content in rat diaphragm muscle fibers

2000 ◽  
Vol 89 (2) ◽  
pp. 695-703 ◽  
Author(s):  
Paige C. Geiger ◽  
Mark J. Cody ◽  
Rebecca L. Macken ◽  
Gary C. Sieck
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Fiber Type ◽  
Diaphragm Muscle ◽  
Specific Force ◽  
Rat Diaphragm ◽  
Cross Sectional ◽  
High Calcium ◽  
Cross Bridges ◽  
Triton X

In the present study, myosin heavy chain (MHC) content per half sarcomere, an estimate of the number of cross bridges available for force generation, was determined in rat diaphragm muscle (Diam) fibers expressing different MHC isoforms. We hypothesize that fiber-type differences in maximum specific force [force per cross-sectional area (CSA)] reflect the number of cross bridges present per CSA. Studies were performed on single, Triton X-100-permeabilized rat Diam fibers. Maximum specific force was determined by activation of single Diamfibers in the presence of a high-calcium solution (pCa, −log Ca2+ concentration of 4.0). SDS-PAGE and Western blot analyses were used to determine MHC isoform composition and MHC content per half sarcomere. Differences in maximum specific force across fast MHC isoforms were eliminated when controlled for half-sarcomere MHC content. However, the force produced by slow fibers remained below that of fast fibers when normalized for the number of cross bridges available. On the basis of these results, the lower force produced by slow fibers may be due to less force per cross bridge compared with fast fibers.

Effects of perinatal undernutrition on elimination of immature myosin isoforms in the rat diaphragm

1991 ◽  
Vol 261 (2) ◽  
pp. L49-L54 ◽  
Author(s):  
B. S. Brozanski ◽  
M. J. Daood ◽  
W. A. LaFramboise ◽  
J. F. Watchko ◽  
T. P. Foley ◽  
...  
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Time Course ◽  
Myosin Light Chain ◽  
Diaphragm Muscle ◽  
Myosin Isoforms ◽  
Rat Diaphragm ◽  
Two Dimensional Gel Electrophoresis ◽  
Significant Difference ◽  
Immunocytochemical Techniques

The effect of perinatal undernutrition on the postnatal elimination of immature myosin isoforms in rat diaphragm muscle was examined using electrophoretic and immunocytochemical techniques. Electrophoresis of native myosin showed that neonatal bands were present in diaphragm muscles of both control and undernourished rats on day 4. By day 21, the neonatal bands were diminished in the control diaphragm compared with the diaphragm of the undernourished rats. Neonatal bands persisted on postnatal day 30 in the diaphragm of the undernourished rats but not in the diaphragm of control rats. No significant difference in the time course of elimination of embryonic myosin light chain (LCemb) was observed between the diaphragm muscles of control and undernourished rats with two-dimensional gel electrophoresis. Immunocytochemical analysis demonstrated embryonic myosin heavy chain (MHCemb) in all myofibers of the diaphragm muscle of both groups at day 4, but this isoform was not detected in either group by day 14. Reactivity with anti-neonatal myosin heavy chain (MHCneo) indicated that rate of elimination of the MHCneo was delayed in the undernourished state as compared with the normal rats (P less than 0.001). Serum triiodothyronine levels were measured at 14, 21, and 30 days and were significantly lower in the undernourished rats compared with age-matched controls. These data demonstrate that the normal postnatal decrease in MHCneo, but not MHCemb or LCemb, is affected by the nutritional state of the animal. We speculate that these alterations in myosin isoform transitions are induced by hypothyroidism associated with undernutrition.

ATP consumption rate per cross bridge depends on myosin heavy chain isoform

2003 ◽  
Vol 94 (6) ◽  
pp. 2188-2196 ◽  
Author(s):  
Young-Soo Han ◽  
Paige C. Geiger ◽  
Mark J. Cody ◽  
Rebecca L. Macken ◽  
Gary C. Sieck
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Consumption Rate ◽  
Diaphragm Muscle ◽  
Rat Diaphragm ◽  
Myosin Heavy Chain Isoform ◽  
Standard Curve ◽  
Cross Bridge ◽  
Sds Page ◽  
Triton X

In the present study, we tested the hypothesis that intrinsic differences in ATP consumption rate per cross bridge exist across rat diaphragm muscle (Diam) fibers expressing different myosin heavy chain (MHC) isoforms. During maximum Ca2+ activation (pCa 4.0) of single, Triton X-permeabilized Diam fibers, isometric ATP consumption rate was determined by using an NADH-linked fluorometric technique. The MHC concentration in single Diam fibers was determined by densitometric analysis of SDS-PAGE gels and comparison to a standard curve of known MHC concentrations. Isometric ATP consumption rate varied across Diam fibers expressing different MHC isoforms, being highest in fibers expressing MHC2X (1.14 ± 0.08 nmol · mm−3 · s−1) and/or MHC2B (1.33 ± 0.08 nmol · mm−3 · s−1), followed by fibers expressing MHC2A (0.77 ± 0.11 nmol · mm−3 · s−1) and MHCSlow (0.46 ± 0.03 nmol · mm−3 · s−1). These differences in ATP consumption rate also persisted when it was normalized for MHC concentration in single Diam fibers. Normalized ATP consumption rate for MHC concentration varied across Diam fibers expressing different MHC isoforms, being highest in fibers expressing MHC2X (2.02 ± 0.19 s−1) and/or MHC2B (2.64 ± 0.15 s−1), followed by fibers expressing MHC2A(1.57 ± 0.16 s−1) and MHCSlow (0.77 ± 0.05 s−1). On the basis of these results, we conclude that there are intrinsic differences in ATP consumption rate per cross bridge in Diam fibers expressing MHC isoforms.

Mechanisms underlying myosin heavy chain expression during development of the rat diaphragm muscle

2006 ◽  
Vol 101 (6) ◽  
pp. 1546-1555 ◽  
Author(s):  
Paige C. Geiger ◽  
Jeffrey P. Bailey ◽  
Carlos B. Mantilla ◽  
Wen-Zhi Zhan ◽  
Gary C. Sieck
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Diaphragm Muscle ◽  
Rat Diaphragm

scholarly journals Myosin Heavy Chain Isoforms in Equine Gluteus Medius Muscle: Comparison of mRNA and Protein Expression Profiles

2005 ◽  
Vol 53 (11) ◽  
pp. 1383-1390 ◽  
Author(s):  
Karin Eizema ◽  
Maarten M.M. van den Burg ◽  
Henriëtte W. de Jonge ◽  
Elizabeth G. Dingboom ◽  
Wim A. Weijs ◽  
...  
Keyword(s):  
Protein Expression ◽  
Mrna Expression ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Expression Profiles ◽  
Gluteus Medius ◽  
Fine Tuning ◽  
Skeletal Muscle Myosin ◽  
Gluteus Medius Muscle ◽  
Mrna And Protein Expression

The major structural protein in skeletal muscle, myosin heavy chain (MyHC), is primarily transcriptionally controlled. We compared the expression of MyHC isoforms on the mRNA and protein level in biopsies from the m. gluteus medius from adult untrained horses. In transverse sections, the majority of fibers showed qualitatively identical mRNA and protein expression patterns. However, coexpression of 2a and 2d/x MyHCs was substantially more common at the protein than at the mRNA level, suggesting a fine-tuning of these two genes in normal muscle not subjected to any training protocol. Because transverse sections give a limited sampling of mRNA expression in the case of uneven distribution of transcripts in a muscle fiber, we also analyzed longitudinal sections. We present, for the first time, evidence that expression of MyHC mRNA and protein was equal along the length of the fiber. Hence, mRNA expression is not regulated by differential expression of isoforms by separate myonuclei. It is concluded that the number of protein hybrid fibers in equine gluteus medius muscle is controlled by alteration of the transcription pattern uniformly along the fiber, rather than by simultaneous transcription of genes. The differences with the results in muscle of small animals and humans are discussed.

scholarly journals Myosin heavy chain changes in heart failure‐rat diaphragm muscle are not related to myogenic regulatory factors expression

2011 ◽  
Vol 25 (S1) ◽  
Author(s):  
Aline Regina Ruiz Lima ◽  
Paula F Martinez ◽  
Ricardo L Damatto ◽  
Marcelo D M Cezar ◽  
Daniele M Guizoni ◽  
...  
Keyword(s):  
Heart Failure ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Diaphragm Muscle ◽  
Rat Diaphragm ◽  
Myogenic Regulatory Factors ◽  
Regulatory Factors

Force-calcium relationship depends on myosin heavy chain and troponin isoforms in rat diaphragm muscle fibers

1999 ◽  
Vol 87 (5) ◽  
pp. 1894-1900 ◽  
Author(s):  
Paige C. Geiger ◽  
Mark J. Cody ◽  
Gary C. Sieck
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Fiber Type ◽  
Muscle Fibers ◽  
Diaphragm Muscle ◽  
Rat Diaphragm ◽  
Single Fibers ◽  
Maximal Force ◽  
Sds Page ◽  
Triton X

The present study examined Ca2+ sensitivity of diaphragm muscle (Diam) fibers expressing different myosin heavy chain (MHC) isoforms. We hypothesized that Diam fibers expressing the MHCslow isoform have greater Ca2+ sensitivity than fibers expressing fast MHC isoforms and that this fiber-type difference in Ca2+ sensitivity reflects the isoform composition of the troponin (Tn) complex (TnC, TnT, and TnI). Studies were performed in single Triton-X-permeabilized Diam fibers. The Ca2+ concentration at which 50% maximal force was generated (pCa50) was determined for each fiber. SDS-PAGE and Western analyses were used to determine the MHC and Tn isoform composition of single fibers. The pCa50 for Diam fibers expressing MHCslow was significantly greater than that of fibers expressing fast MHC isoforms, and this greater Ca2+ sensitivity was associated with expression of slow isoforms of the Tn complex. However, some Diam fibers expressing MHCslow contained the fast TnC isoform. These results suggest that the combination of TnT, TnI, and TnC isoforms may determine Ca2+ sensitivity in Diam fibers.

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