Limits...
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.

Show MeSH

Related in: MedlinePlus

Kyphosis in MyHC-IId/x  mice. Male mice at 12 wk  of age (wild-type) and 8 wk of age (MyHC-IId/x−/−) were anesthetized and x-rayed. (A) MyHC-IId/x wild-type +/+ male. (B)  MyHC-IId/x−/− male.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2140209&req=5

Figure 6: Kyphosis in MyHC-IId/x mice. Male mice at 12 wk of age (wild-type) and 8 wk of age (MyHC-IId/x−/−) were anesthetized and x-rayed. (A) MyHC-IId/x wild-type +/+ male. (B) MyHC-IId/x−/− male.

Mentions: Approximately one-third (8/26) of IId/x−/− knockout mice (males and females) developed kyphosis, a curvature of the spinal column that is commonly referred to as “hunchback.” This deformity is located in the thoracic vertebrae, and presented by as early as 6 wk of age and has been occasionally seen in heterozygous animals. No wild-type littermates developed this phenotype. This phenotype was detectable by visual examination (not shown) or by x-ray (Fig. 6).


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)

Kyphosis in MyHC-IId/x  mice. Male mice at 12 wk  of age (wild-type) and 8 wk of age (MyHC-IId/x−/−) were anesthetized and x-rayed. (A) MyHC-IId/x wild-type +/+ male. (B)  MyHC-IId/x−/− male.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 6: Kyphosis in MyHC-IId/x mice. Male mice at 12 wk of age (wild-type) and 8 wk of age (MyHC-IId/x−/−) were anesthetized and x-rayed. (A) MyHC-IId/x wild-type +/+ male. (B) MyHC-IId/x−/− male.
Mentions: Approximately one-third (8/26) of IId/x−/− knockout mice (males and females) developed kyphosis, a curvature of the spinal column that is commonly referred to as “hunchback.” This deformity is located in the thoracic vertebrae, and presented by as early as 6 wk of age and has been occasionally seen in heterozygous animals. No wild-type littermates developed this phenotype. This phenotype was detectable by visual examination (not shown) or by x-ray (Fig. 6).

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