Fast Skeletal Myosin Isoforms in Thermally Acclimated Carp1

396

333

SummaryTeleost 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 growth, ectothermy and paralogue preservation have resulted in modifications of the genetic pathways regulating muscle growth in teleosts compared to mammals largely remains unknown. This review describes the use of compensatory growth models, transgenesis and tissue culture to explore the mechanisms of muscle growth in teleosts and provides some perspectives on future research directions.

Section: Plasticity Of the Myogenic Phenotypementioning

confidence: 99%

Growth and the regulation of myotomal muscle mass in teleost fish

Johnston

Bower

Macqueen

2011

396

333

“…The chymotryptic fragments of myosin were fractionated according to Watabe and colleagues (Watabe et al, 1992), separated on SDS-PAGE and transferred to polyvinylidene difluoride membranes (Millipore, Billerica, MA, USA). The fragment bands were analyzed for their N-terminal amino acid sequences with an Applied Biosystems Procise 492HT protein sequencer.…”

Section: Purification Of Myosin and N-terminal Amino Acid Sequencingmentioning

confidence: 99%

Fibre type-specific expression patterns of myosin heavy chain genes in adult torafugu Takifugu rubripes muscles

Akolkar

Kinoshita

Yasmin

et al. 2010

SUMMARYComprehensive in silico studies, based on the total fugu genome database, which was the first to appear in fish, revealed that torafugu Takifugu rubripes contains 20 sarcomeric myosin heavy chain (MYH) genes (MYH genes) (Ikeda et al., 2007). The present study was undertaken to identify MYH genes that would be expressed in adult muscles. In total, seven MYH genes were found by screening cDNA clone libraries constructed from fast, slow and cardiac muscles. Three MYH genes, fast-type MYH M86-1 , slow-type MYH M8248 and slow/cardiac-type MYH M880 , were cloned exclusively from fast, slow and cardiac muscles, respectively. Northern blot hybridization substantiated their specific expression, with the exception of MYH M880 . In contrast, transcripts of fast-type MYH M2528-1 and MYH M1034 were found in both fast and slow muscles as revealed by cDNA clone library and northern blot techniques. This result was supported by in situ hybridization analysis using specific RNA probes, where transcripts of fast-type MYH M2528-1 were expressed in fast fibres with small diameters as well as in fibres of superficial slow muscle with large diameters adjacent to fast muscle. Transcripts of fast-type MYH M86-1 were expressed in all fast fibres with different diameters, whereas transcripts of slow-type MYH M8248 were restricted to fibres with small diameters located in a superficial part of slow muscle. Interestingly, histochemical analyses showed that fast fibres with small diameters and slow fibres with large diameters both contained acid-stable myofibrillar ATPase, suggesting that these fibres have similar functions, possibly in the generation of muscle fibres irrespective of their fibre types. Supplementary material available online at

“…Studies with fully activated skinned fibers found that maximum tension and shortening speed increased at low temperatures in both fast and slow muscles following a period of cold acclimation (Johnston et al, 1985). We have shown that changes in the expression of MYH isoforms play a key role in the plasticity of myofibrillar ATPase activity and contractile properties with temperature acclimation (Hwang et al, 1990;Watabe et al, 1992Watabe et al, , 1995Guo et al, 1994). Three distinct MYH DNAs were cloned from the fast myotomal muscle of carp acclimated to either 10°C or 30°C for a minimum of 6·weeks (Imai et al, 1997;Hirayama and Watabe, 1997).…”

Section: Introductionmentioning

confidence: 99%

Molecular cloning and mRNA expression analysis of carp embryonic, slow and cardiac myosin heavy chain isoforms

Nihei

Kobiyama

Ikeda

et al. 2006

Self Cite

SUMMARY Three embryonic class II myosin heavy chains (MYHs) were cloned from the common carp (Cyprinus carpio L.), MYHemb1,MYHemb2 and MYHemb3. MYH DNA clones were also isolated from the slow muscle of adult carp acclimated to 10°C (MYHS10)and 30°C (MYHS30). Phylogenetic analysis demonstrated that MYHemb1 and MYHemb2 belonged to the fast skeletal muscle MYH clade. By contrast, the sequence of MYHemb3 was similar to the adult slow muscle isoforms, MYHS10 and MYHS30. MYHemb1 and MYHemb2 transcripts were first detected by northern blot analysis in embryos 61 h post-fertilization (h.p.f.) at the heartbeat stage, with peak expression occurring in 1-month-old juveniles. MYHemb1 continued to be expressed at low levels in 7-month-old juveniles when MYHemb2 was not detectable. MYHemb3transcripts appeared at almost the same stage as MYHemb1transcripts did (61 h.p.f.), and these genes showed a similar pattern of expression. Whole mount in situ hybridization analysis revealed that the transcripts of MYHemb1 and MYHemb2 were expressed in the inner part of myotome, whereas MYHemb3 was expressed in the superficial compartment. MYHS10 and MYHS30 mRNAs were first detected at hatching. In adult stages, the expression of slow muscle MYH mRNAs was dependent on acclimation temperature. MYHS10 mRNA was expressed at an acclimation temperature of 10 and 20°C, but not at 30°C. In contrast, MYHS30 mRNA was strongly expressed at all acclimation temperatures. The predominant MYH transcripts found in adult slow muscle and in embryos at hatching were expressed in adult fast muscle at some acclimation temperatures but not others. A MYH DNA clone was isolated from the cardiac muscle of 10°C-acclimated adult fish (MYHcard). MYHcard mRNA was first detected at 61 h.p.f., but strong signals were only observed in the adult myocardium. The present study has therefore revealed a complex pattern of expression of MYH genes in relation to developmental stage, muscle type and acclimation temperature. None of the skeletal muscle MYHs identified so far was strongly expressed during the late juvenile stage, indicating further developmentally regulated members of the MYH II gene family remain to be discovered.