Heterogeneous activation of a slow myosin gene in proliferating myoblasts and differentiated single myofibers.

ABSTRACT: Each skeletal muscle contains a fixed ratio of fast and slow myofibers that are distributed in a stereotyped pattern to achieve a specific motor function. How myofibers are specified during development and regeneration is poorly understood. Here we address this question using transgenic reporter mice that indelibly mark the myofiber lineages based on activation of fast or slow myosin. Lineage tracing indicates that during development all muscles have activated the fast myosin gene Myl1, but not the slow myosin gene Myh7, which is activated in all slow but a subset of fast myofibers. Similarly, most nascent myofibers do not activate Myh7 during fast muscle regeneration, but the ratio and pattern of fast and slow myofibers are restored at the completion of regeneration. At the single myofibe

SUBMITTER: Wang JH 

PROVIDER: S-EPMC4435531 | biostudies-literature | 2015 Jun

REPOSITORIES: biostudies-literature