TY  - JOUR
TI  - Myonuclear domain size varies along the lengths of maturing skeletal muscle fibers.
AU  - Rosser, Benjamin W C
AU  - Dean, Malcolm S
AU  - Bandman, Everett
T2  - The International Journal of Developmental Biology
AB  - In a skeletal muscle fiber, each myonucleus is responsible for gene expression in its surrounding cytoplasm. The region of cytoplasm associated with an individual myonucleus is termed myonuclear domain. However, little is known about domain size variation within individual muscle fibers. This study tests the hypothesis that myonuclear domains expressing neonatal myosin within end regions of maturing fibers will be smaller than domains elsewhere in the fibers. The model used is chicken pectoralis, where we have previously shown that during development repression of neonatal myosin radiates from the central region towards the fiber ends. Samples excised from birds aged nine through to 115 days after hatching were sectioned transversely. Using computer image analysis and immunocytochemistry, fiber profiles were classified as neonatal, transforming or adult. Each profile was also located in an adjacent dystrophin-labelled section, where myonuclei were visualized using haematoxylin and bisbenzamide. Variation in myonuclear length with age was not found to be significant (p = 0.925). Myonuclei were counted, and formulae used to calculate mean myonuclear domain size for each profile type. Myonuclear number/mm fiber was calculated to be adult (mean = 108.57 myonuclei/mm), transforming (65.82) and neonatal (25.23). Transforming profiles had significantly (p=0.027) more myonuclei/mm than neonatal, as did adult (p=0.005). Volume of cytoplasm/myonucleus was adult (mean = 16,132 microm3/myonucleus), transforming (12,899) and neonatal (8,130). Transforming and adult profiles had significantly (p
PY  - 2002
VL  - 46
IS  - 5
SP  - 747
EP  - 754
J2  - Int. J. Dev. Biol.
LA  - en
SN  - 0214-6282
SN  - 1696-3547
UR  - https://ijdb.ehu.eus/article/12216987
Y2  - 2024/11/23/16:08:01
ER  -