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Spatial and temporal changes in myosin heavy chain gene expression in skeletal muscle development
B D Lu1, D L Allen, L A Leinwand
1Department of Microbiology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York, 10461, USA.
Developmental Biology
|December 10, 1999
Summary
During mouse development, adult fast myosin heavy chain (MyHC) RNAs show distinct temporal and spatial expression patterns. Postnatally, MyHC RNA and protein changes vary by muscle, not always matching adult distributions.
Area of Science:
- Muscle physiology
- Developmental biology
- Molecular genetics
Background:
- Mammalian skeletal muscle expresses seven myosin heavy chains (MyHCs) with regulated patterns.
- Understanding MyHC expression during development is crucial for muscle biology.
Purpose of the Study:
- To detail the timing, distribution, and quantitation of MyHC expression in developing and early postnatal mouse skeletal muscle.
- To investigate the relationship between MyHC RNA and protein expression during mouse development.
Main Methods:
- In situ hybridization to analyze mRNA distribution.
- Ribonuclease protection assays to quantify mRNA levels.
- Analysis of MyHC protein expression.
Main Results:
- Three adult fast MyHC RNAs (IIa, IIb, IId/x) are expressed in mouse embryos with distinct temporal and spatial patterns.
- IIb mRNA appears by 14.5 days postcoitum (dpc), followed by IId/x and IIa mRNAs.
- Postnatally, significant changes in MyHC RNA and protein proportions occur, varying by muscle and region, and RNA and protein expression are coincident.
Conclusions:
- MyHC expression is tightly regulated during mouse development, with distinct patterns for different isoforms.
- Postnatal MyHC expression undergoes dynamic changes that are muscle-specific and regionally restricted.
- Developmental MyHC expression patterns do not always predict adult muscle fiber composition.