Muscle profiles

Different skeletal myofibre types are known to express distinct muscle myosin isoforms. In the Early Edition of the Proceedings of the National Academy of Sciences, Porter et al., from Case Western Reserve University, Cleveland, USA, describe a genomics approach to exploring the molecular signatures underlying skeletal muscle biology (Proc Natl Acad Sci USA 2001, 10.1073/pnas.211257298). They used high-density oligonucleotide arrays (from Affymetrix) to measure gene expression profiles in the extraocular muscle (EOM), jaw and hindlimb muscles of mice. A third of the genes examined were expressed in each muscle type. Profile analysis indicated that EOM is a distinct muscle allotype defined by the expression of 400 EOM-specific genes. These include genes implicated in sarcomeric organisation and excitation-contraction coupling. Thus, microarrays can be used to define the molecular basis for myofibre classes and to characterize genes contributing to skeletal muscle biology.