Growth and the regulation of myotomal muscle mass in teleost fish

• Published in: Journal of Experimental Biology
• Main Authors: Johnston, Ian A., Bower, Neil I., Macqueen, Daniel J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2011
• Subjects: muscle fibre; myogenic precursor cell; myoblast fusion; muscle gene paralogue; muscle protein synthesis; muscle protein breakdown; muscle growth model; TROUT ONCORHYNCHUS-MYKISS; THICK FILAMENT FORMATION; ZEBRAFISH DANIO-RERIO; IN-VITRO ASSESSMENT; SALMON SALMO-SALAR; HEAVY-CHAIN GENES; SKELETAL-MUSCLE; ATLANTIC SALMON; SIGNALING PATHWAYS; Salmo salar
• Online Access: https://research-portal.st-andrews.ac.uk/en/publications/5601789f-d2ca-4637-84af-ca8c5f3a1e5b; https://doi.org/10.1242/jeb.038620

Teleost muscle first arises in early embryonic life and its development is driven by molecules present in the egg yolk and modulated by environmental stimuli including temperature and oxygen. Several populations of myogenic precursor cells reside in the embryonic somite and external cell layer and contribute to muscle fibres in embryo, larval, juvenile and adult stages. Many signalling proteins and transcription factors essential for these events are known. In all cases, myogenesis involves myoblast proliferation, migration, fusion and terminal differentiation. Maturation of the embryonic muscle is associated with motor innervation and the development of a scaffold of connective tissue and complex myotomal architecture needed to generate swimming behaviour. Adult muscle is a heterogeneous tissue composed of several cell types that interact to affect growth patterns. The development of capillary and lymphatic circulations and extramuscular organs - notably the gastrointestinal, endocrine, neuroendocrine and immune systems - serves to increase information exchange between tissues and with the external environment, adding to the complexity of growth regulation. Teleosts often exhibit an indeterminate growth pattern, with body size and muscle mass increasing until mortality or senescence occurs. The dramatic increase in myotomal muscle mass between embryo and adult requires the continuous production of muscle fibres until 40-50% of the maximum body length is reached. Sarcomeric proteins can be mobilised as a source of amino acids for energy metabolism by other tissues and for gonad generation, requiring the dynamic regulation of muscle mass throughout the life cycle. The metabolic and contractile phenotypes of muscle fibres also show significant plasticity with respect to environmental conditions, migration and spawning. Many genes regulating muscle growth are found as multiple copies as a result of paralogue retention following whole-genome duplication events in teleost lineages. The extent to which indeterminate ...