title: M line appearance in developing striated muscle.
abstract: Myofilament assembly occurs in a definite sequence. Myofibrils first appear within embryonic myotomes as non-striated, linear arrangements of parallel thick and thin myofilaments (crude sarcomeres) with periodic dense cross bands (Z lines). In the center of sarcomeres within these early myofibrils, faint M lines are often detected. In older embryos, after typical cross striations became apparent, the M lines can be detected bisecting each A band.
authors.affiliation: Department of Anatomy and Cell Biology, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania.
authors.forename: Raworth
authors.initials: R
authors.lastname: Allen
authors.affiliation: Department of Anatomy and Cell Biology, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania.
authors.forename: John
authors.initials: J
authors.lastname: Grisnik