Sarcomeric myosin heavy chain is coded by a highly conserved multigene family

Area of Science:

• Molecular Biology
• Genetics
• Evolutionary Biology

Background:

• Myosin heavy chain (MHC) is crucial for muscle contraction.
• Understanding MHC gene family structure and conservation is vital for muscle biology research.

Purpose of the Study:

• To characterize the myosin heavy chain (MHC) gene family using the pMHC25 plasmid.
• To investigate the evolutionary conservation and genomic organization of sarcomeric MHC genes.
• To determine if MHC genes undergo rearrangement during muscle differentiation.

Main Methods:

• Hybridization of the pMHC25 plasmid to L6E9 rat cell line myotube mRNA and genomic DNA.
• Analysis of restriction endonuclease-digested genomic DNA from various species.
• Assessment of MHC gene sequences in differentiated and undifferentiated muscle cells.

Main Results:

• The pMHC25 plasmid specifically hybridizes to sarcomeric MHC mRNAs and multiple genomic DNA fragments, indicating a sarcomeric MHC multigene family.
• This multigene family comprises at least seven genes with sequence homology and some polymorphisms.
• Sarcomeric MHC genes are conserved across diverse species with striated muscle, suggesting horizontal and vertical evolutionary conservation.
• MHC genes do not exhibit rearrangement or amplification during muscle cell differentiation.

Conclusions:

• The pMHC25 plasmid is a valuable tool for studying the sarcomeric MHC multigene family.
• Sarcomeric MHC genes represent an evolutionarily conserved multigene family.
• Muscle cell differentiation does not involve MHC gene rearrangement or amplification.