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Growth and muscle defects in mice lacking adult myosin heavy chain genes.

Acakpo-Satchivi LJ, Edelmann W, Sartorius C, Lu BD, Wahr PA, Watkins SC, Metzger JM, Leinwand L, Kucherlapati R - J. Cell Biol. (1997)

Bottom Line: The three adult fast myosin heavy chains (MyHCs) constitute the vast majority of the myosin in adult skeletal musculature, and are >92% identical.Both strains exhibit growth and muscle defects, but the defects are different between the two strains and do not correlate with the abundance or distribution of each gene product.Most striking is that while both strains exhibit physiological defects in isolated muscles, the defects are distinct.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Genetics, Albert Einstein College of Medicine, New York 10461, USA.

ABSTRACT
The three adult fast myosin heavy chains (MyHCs) constitute the vast majority of the myosin in adult skeletal musculature, and are >92% identical. We describe mice carrying mutations in each of two predominant adult fast MyHC genes, IIb and IId/x. Both strains exhibit growth and muscle defects, but the defects are different between the two strains and do not correlate with the abundance or distribution of each gene product. For example, despite the fact that MyHC-IIb accounts for >70% of the myosin in skeletal muscle and shows the broadest distribution of expression, the phenotypes of IIb mutants are generally milder than in the MyHC-IId/x strain. In addition, in a muscle which expresses both IIb and IId/x MyHC in wild-type mice, the histological defects are completely different for expression of the two genes. Most striking is that while both strains exhibit physiological defects in isolated muscles, the defects are distinct. Muscle from IIb mice has significantly reduced ability to generate force while IId mouse muscle generates normal amounts of force, but has altered kinetic properties. Many of the phenotypes demonstrated by these mice are typical in human muscle disease and should provide insight into their etiology.

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Histologic analysis  of tibialis anterior muscle  from MyHC-IId/x mice.  Cross-sections of tibialis anterior muscle from 6-wk-old  wild-type (A–C), MyHC-IIb−/− (D–F), and MyHC-IId/x−/− (G–I) mice were  stained with hematoxylin and  eosin (H&E) (A, D, and G),  Masson trichrome (B, E, and  H), and NADH-TR (C, F,  and I). Note the general disarray (MyHC-IId/x−/−, G),  change in fiber diameter in  H&E and NADH-TR stains  (F and I) and the interstitial  fibrosis visualized with Masson Trichrome staining (E  and H).
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Figure 7: Histologic analysis of tibialis anterior muscle from MyHC-IId/x mice. Cross-sections of tibialis anterior muscle from 6-wk-old wild-type (A–C), MyHC-IIb−/− (D–F), and MyHC-IId/x−/− (G–I) mice were stained with hematoxylin and eosin (H&E) (A, D, and G), Masson trichrome (B, E, and H), and NADH-TR (C, F, and I). Note the general disarray (MyHC-IId/x−/−, G), change in fiber diameter in H&E and NADH-TR stains (F and I) and the interstitial fibrosis visualized with Masson Trichrome staining (E and H).

Mentions: Tibialis anterior muscle was isolated from mice 4–6 wk of age, and analyzed histologically. This muscle was chosen because it expresses relatively high levels of both MyHC-IIb and IId/x and therefore would allow us to compare histological changes between the two strains (Pette and Staron, 1990). The results of this experiment are shown in Fig. 7, where sections were stained with hematoxylin and eosin, Masson trichrome and NADH-TR.


Growth and muscle defects in mice lacking adult myosin heavy chain genes.

Acakpo-Satchivi LJ, Edelmann W, Sartorius C, Lu BD, Wahr PA, Watkins SC, Metzger JM, Leinwand L, Kucherlapati R - J. Cell Biol. (1997)

Histologic analysis  of tibialis anterior muscle  from MyHC-IId/x mice.  Cross-sections of tibialis anterior muscle from 6-wk-old  wild-type (A–C), MyHC-IIb−/− (D–F), and MyHC-IId/x−/− (G–I) mice were  stained with hematoxylin and  eosin (H&E) (A, D, and G),  Masson trichrome (B, E, and  H), and NADH-TR (C, F,  and I). Note the general disarray (MyHC-IId/x−/−, G),  change in fiber diameter in  H&E and NADH-TR stains  (F and I) and the interstitial  fibrosis visualized with Masson Trichrome staining (E  and H).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2140209&req=5

Figure 7: Histologic analysis of tibialis anterior muscle from MyHC-IId/x mice. Cross-sections of tibialis anterior muscle from 6-wk-old wild-type (A–C), MyHC-IIb−/− (D–F), and MyHC-IId/x−/− (G–I) mice were stained with hematoxylin and eosin (H&E) (A, D, and G), Masson trichrome (B, E, and H), and NADH-TR (C, F, and I). Note the general disarray (MyHC-IId/x−/−, G), change in fiber diameter in H&E and NADH-TR stains (F and I) and the interstitial fibrosis visualized with Masson Trichrome staining (E and H).
Mentions: Tibialis anterior muscle was isolated from mice 4–6 wk of age, and analyzed histologically. This muscle was chosen because it expresses relatively high levels of both MyHC-IIb and IId/x and therefore would allow us to compare histological changes between the two strains (Pette and Staron, 1990). The results of this experiment are shown in Fig. 7, where sections were stained with hematoxylin and eosin, Masson trichrome and NADH-TR.

Bottom Line: The three adult fast myosin heavy chains (MyHCs) constitute the vast majority of the myosin in adult skeletal musculature, and are >92% identical.Both strains exhibit growth and muscle defects, but the defects are different between the two strains and do not correlate with the abundance or distribution of each gene product.Most striking is that while both strains exhibit physiological defects in isolated muscles, the defects are distinct.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Genetics, Albert Einstein College of Medicine, New York 10461, USA.

ABSTRACT
The three adult fast myosin heavy chains (MyHCs) constitute the vast majority of the myosin in adult skeletal musculature, and are >92% identical. We describe mice carrying mutations in each of two predominant adult fast MyHC genes, IIb and IId/x. Both strains exhibit growth and muscle defects, but the defects are different between the two strains and do not correlate with the abundance or distribution of each gene product. For example, despite the fact that MyHC-IIb accounts for >70% of the myosin in skeletal muscle and shows the broadest distribution of expression, the phenotypes of IIb mutants are generally milder than in the MyHC-IId/x strain. In addition, in a muscle which expresses both IIb and IId/x MyHC in wild-type mice, the histological defects are completely different for expression of the two genes. Most striking is that while both strains exhibit physiological defects in isolated muscles, the defects are distinct. Muscle from IIb mice has significantly reduced ability to generate force while IId mouse muscle generates normal amounts of force, but has altered kinetic properties. Many of the phenotypes demonstrated by these mice are typical in human muscle disease and should provide insight into their etiology.

Show MeSH
Related in: MedlinePlus