• Korean Journal of Agricultural Science
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• v.31 no.2
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• pp.97-104
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• 2004

Myostatin is a transforming growth and differentiation factor-${\beta}$ family member that acts as a negative regulator of muscle growth. Previously, mutations in the myostatin gene were known to be related to double muscling phenotypes in cattle. Because myostatin gene is highly related to muscle mass, also meat quality, in cattle, we sequenced whole myostatin mRNA and investigated the SNPs (Single Nucleotide Polymorphisms) in Korean cattle (Hanwoo). The results indicated that Hanwoo had an SNP in nt2385 and this mutation can be a useful marker with further verifications. We also investigated expression patterns of the myostatin gene from various muscle tissues and organs. Northern blotting results indicated that myostatin expression was restricted in muscles with variable expression levels. The results presented here can be used as a valuable information for meat quality related traits and muscle mass in cattle.

• The Journal of Internal Korean Medicine
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• v.29 no.1
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• pp.243-257
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• 2008

Myostatin, a negative regulator of myogenesis, is shown to function by controlling the proliferation of myoblasts. In this study we show that myostatin is an inhibitor of myoblast differentiation and that this inhibition is mediated through Smad 3. To determine MyoD expression by Dodamtang treatment, we compared the expression pattern of $C_{2}C_{12}$ mouse myoblasts that constitutively express myostatin with control cells. In vitro, increasing concentrations of Dodamtang reversibly prevented the myogenic blockage of myoblasts by myostatin expression. ELISA assay, Western and confocal analysis indicated that treatment of Dodamtang to the low serum culture media increased the levels of MyoD leading to the inhibition of myogenic differentiation by myostatin. The stable transfection of $C_{2}C_{12}$ myoblasts with myostatin expressing constructs did rescue MyoD-induced myogenic differentiation. Consistent with this, the treatment of Dodamtang rescued the expression of a MyoD in $C_{2}C_{12}$ myoblasts treated with myostatin. Taken together, these results suggest that induction of MyoD by Dodamtang inhibits myostatin activity and expression via SMAD3 resulting in the rescue of the myoblasts to differentiate into myotubes. Thus we propose that myostatin action by Dodamtang plays a critical role in myogenic differentiation and that the muscular hyperplasia and hypertrophy seen in animals that blockage of functional myostatin is because of deregulated proliferation and differentiation of myoblasts.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.6
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• pp.827-831
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• 2007

Myostatin is a member of the transforming growth factor-${\beta}$(TGF-${\beta}$ super-family. It acts as a negative regulator for skeletal muscle growth. Myostatin mutations are characterized by a visible, generalized increase in muscle mass in double muscled cattle breeds. To understand the biochemistry and physiology of the Chinese Yellow bovine myostatin gene, we report here for the first time expression of the gene in Escherichia coli (E. coli). Primers of the myostatin gene of Chinese Yellow Cattle were designed on the basis of the reported bovine myostatin mRNA sequence (Gen-Bank Accession No. NM005259) and optimized for E. coli codon usage. XhoI and EcoRI restriction enzyme sites were incorporated in the primers, and then cloning vector and expression vector were constructed in a different host bacterium. The expressed protein had a molecule mass of about 16 kDa as determined by SDS-PAGE under reducing conditions. The expressed protein reacted specifically with myostatin monoclonal antibody on immunoblots. Our studies should lead to the investigation of the differences in myostatin genes of various cattle and could benefit human health and food animal agriculture.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.2
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• pp.275-281
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• 2009

Modification of thyroid hormone levels has a profound effect on skeletal muscle differentiation, predominantly through direct regulation involving thyroid hormone receptors. Nevertheless, little is known about the regulation of myostatin gene expression in skeletal muscle due to altered concentrations of thyroid hormone. Thus, the goal of our study was to find out whether altered thyroid states could change the gene expression of myostatin, the most powerful inhibitor of skeletal muscle development. A hyperthyroid state was induced in rats by daily injections of L-thyroxine 20 mg/100 g body weight for 14 days, while a hypothyroid state was induced in another group of rats by administering methimazole (0.04%) in drinking water for 14 days. After a period of 14 days of L-thyroxine treatment we observed a significant increase of myostatin expression both in mRNA and protein level. However, decreased expression of myostatin mRNA and protein were observed in hypothyroid rats. Furthermore, our studies demonstrated that the upregulation of myostatin gene expression might be responsible for the loss of body weight induced by altered thyroid hormone levels. We concluded that myostatin played a role in a metabolic process in muscle that was regulated by thyroid hormone.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.7
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• pp.1017-1021
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• 2005

Myostatin is a negative regulator of skeletal muscle growth and a loss of functional myostatin protein increases muscle hypertrophy and hyperplasia in cattle. The present study was conducted to investigate whether maternal passive immunization against myostatin would improve growth performance in chickens. A complete broiler myostatin cDNA was cloned and it was expressed into two transcripts as 1,128 bp and 985 bp by alternative splicing. A conjugated mature myostatin (350 bp) was used to induce autoimmunization and maternal passively immunized chickens was used for the experiment. It was confirmed that there was a maternal passive immunization against myostatin at zero weeks of age, but its effect was reduced by 6 weeks of age. The auto-immunized groups showed smaller body weights than those of control group during the growing period and the difference was getting bigger with time until 6 weeks of age. These results suggest that passive autoimmunization against myostatin used in this study is not potent enough to stimulate growth performance in chickens.

• Fisheries and Aquatic Sciences
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• v.12 no.3
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• pp.185-193
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• 2009

A complete cDNA, which encodes for a myostatin-like protein (Es-MSTN), was isolated from the Chinese mitten crab, Eriocheir sinensis. Es-MSTN was composed of 2,397 nucleotides and the open reading frame (ORF) specified a protein containing 468 amino acids. Es-MSTN exhibited 32% amino acid sequence identity and 52% similarity to human myostatin. Multiple sequence alignment analysis indicated that Es-MSTN possessed the conserved proteolytic cleavage site (RXXR) for maturation of the protein and nine cysteine residues for disulfide bridges. Besides the conserved structural features, Es-MSTN also exhibits its unique characters; a longer N-terminal domain which is involved in protein folding and latent form of myostatin and absence of the cleavage site for BMP-1/tolloid family of metalloproteinase to activate mature myostatin. Phylogenetic analysis suggests that Es-MSTN showed the closely related to both vertebrate myostatin and GDF11. Es-MSTN is expressed highly in the claw muscle, leg muscle, thoracic muscle and heart, and moderately in the hindgut suggesting that Es-MSTN may play important roles in the muscle tissues. As homolog of mammalian myostatin and GDF11, Es-MSTN may be involved in development of muscular tissue and further study will help to produce high-quality seafood.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2000.11a
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• pp.78-80
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• 2000

A new murine TGF-$\beta$ family member, myostatin(growth/differentiation factor-8) is expressed specifically in developing and adult skeletal muscle and may be a negative regulator of skeletal muscle development. This study aims at characterization and identification of genomic organization of chicken myostatin gene. In thi study, we identified the genomic organization and sequence of chicken myostatin gene. Results of RT-PCR and Northern blots from various tissues showed different mRNA expression levels in developmental stages of chick embryos and demonstrated strong expression of myostatin mRNA in skeletal muscle. These facts suggest that chicken myostatin gene would play an important role not only in skeletal muscle cell but also in other tissues.

• Molecules and Cells
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• v.37 no.4
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• pp.302-306
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• 2014

Myostatin represses muscle growth by negatively regulating the number and size of muscle fibers. Myostatin loss-of-function can result in the double-muscling phenotype and increased muscle mass. Thus, knockout of myostatin gene could improve the quality of meat from mammals. In the present study, zinc finger nucleases, a useful tool for generating gene knockout animals, were designed to target exon 1 of the myostatin gene. The designed ZFNs were introduced into porcine primary fibroblasts and early implantation embryos via electroporation and microinjection, respectively. Mutations around the ZFNs target site were detected in both primary fibroblasts and blastocysts. The proportion of mutant fibroblast cells and blastocyst was 4.81% and 5.31%, respectively. Thus, ZFNs can be used to knockout myostatin in porcine primary fibroblasts and early implantation embryos.

• Journal of Life Science
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• v.21 no.8
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• pp.1149-1155
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• 2011

Myostatin (MSTN) belongs to the transforming growth factor-${\beta}$ superfamily or growth and differentiation factor 8 (GDF-8), and functions as a negative regulator of skeletal muscle development and growth. Previous studies in mammals have suggested that myostatin knock-out increased muscle mass and decreased fat content compared to those of the wide type. Recently, several studies on myostatin have beenconducted on the block myostatin signal pathway with myostatin antagonists and the MSTN regulation with RNAi to control myostatin function. This study was performed to analyze growth and muscle alteration of Oncorhychus masou by treatment with recombinant myostatin prodomains derived from fish. We designed myostatin prodomains derived from P. olivaceus (pMALc2x-poMSTNpro) and S. schlegeli (pMALc2x-sMSTNpro) in a pMALc2x expression vector, and then purified the recombinant proteins using affinity chromatography. The purified recombinant proteins were treated in O. masou through an immersion method. Recombinant protein treated groups did not show a significant difference in weight, protein, or lipid composition compared to the control. However, there was a difference in the average number and area for histological analyses in the muscle fiber. At twelve and twenty-two weeks from the initial treatment, there were differences in averagefiber number and area between the 0.05 mg/l treated-group and the control, but the numbers were similar to those of the control during the same time period. At twelve weeks, however, 0.2 mg/l treated-group had an increase in average fiber number and decrease in average fiber area compared to the control. At twenty-two weeks, the pMALc2x-sMSTNpro 0.2 mg/l treated-group was induced and showed a decrease in average fiber number and increase in average fiber area. The results between twelve and twenty-two weeks showed that the fiber numbers had decreased, whereas average fiberarea had increased due to sMSTNpro. It is understood that the sMSTNpro induced only hyperplasia at twelve weeks, after which it induced hypertrophy. Recombinant myostatin prodomains derived from fish may induce hyperplasia and hypertrophy in O. masou depending upon the time that has elapsed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.2
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• pp.139-145
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• 2009

We cloned and sequenced the open reading frame (ORF) cDNA encoding myostatin from the muscle of abalone (Haliotis discus hannai). The ORF cDNA of the abalone myostatin is 1134 bp and encoded 377 amino acid residues that were 60-96% homologous with the amino acids of other organism myostatins. In addition, the ORF contained a conserved proteolytic cleavage site (RXRR) and nine conserved cysteine residues in the C-terminus. Semi-quantitative RT-PCR revealed the presence of myostatin mRNA in various tissues. The strongest expression was observed in the mantle of female abalone, and the gills and heart of male abalone.