Myostatin Gene Research Articles

Genome Editing Tools for Improved and Sustainable Livestock Production Systems

Genome editing has great potential to improve production traits such as dairy and meat quality, as well as wool production in livestock species. Some notable examples include the production of the β-lactoglobulin (BLG) knockout resulting in hypoallergenic milk, disruption of the myostatin (MSTN) gene leading to increased muscle mass, longer wool achieved by mutating the fibroblast growth factor 5 (FGF5) gene, and the development of porcine reproductive and respiratory syndrome (PRRS)-resistant pigs through the editing of the CD163 receptor. These advancements demonstrated the immense potential for enhancing productivity, animal health, and welfare to significant impact the economic benefits for farmers and industries. The regulatory landscape for gene-edited animals varies globally; the countries like Argentina, Australia, Brazil, Colombia, and Japan have adopted progressive policies by treating gene- edited animals similarly to those produced by conventional breeding. In conclusion, genome editing technologies have the potential to transform agriculture, promoting sustainability and efficiency in livestock production systems.

Serum level of myostatin and type I interferon-inducible gene expression in dermatomyositis patients and its relation to insulin resistance

BackgroundData regarding the relation between serum myostatin level, type I interferon-inducible gene expression and insulin resistance in dermatomyositis patients are limited. This study aimed to assess serum myostatin level, homeostatic model assessment of insulin resistance (HOMA-IR) and type I interferon-inducible gene expression in dermatomyositis patients. We evaluated the role of serum myostatin level, and type I interferon-inducible gene expression in the pathogenesis of dermatomyositis as well as the relation of serum myostatin level and type I interferon-inducible gene expression to the occurrence of insulin resistance. We evaluated serum levels of myostatin and HOMA-IR utilizing ELISA as well as IFIT1 and Mx1(MxA) gene expression with RT-PCR in 25 dermatomyositis patients (group A) and 25 obviously sound subjects as controls (group B).ResultsAmong group A, body mass index, serum levels of myostatin, fasting insulin, HOMA-IR, IFN-inducible genes Mx1 and IFIT1 were more significantly increased as well as; serum level of myostatin was positively correlated with age, gender, fasting insulin level, body mass index, and HOMA-IR.ConclusionsSerum level of myostatin, Mx1 and IFIT1 gene expression act as hazard factors of insulin resistance in group A.

Mammalian ubiquitous promoter isolated from proximal regulatory region of bovine MSTN gene

Gene therapy is a promising method for treating inherited diseases by directly delivering the correct genetic material into patient cells. However, the limited packaging capacity of vectors poses a challenge. Minimizing promoter size is a viable strategy among various approaches to address this issue. This study aims to optimize the bovine myostatin (MSTN) promoter, enhancing its utility in gene therapy applications. We identified the primary driver of activity as the proximal regulatory region. Isolated from the native promoter and termed M243, this 243-bp sequence was assessed for its potential as a ubiquitous promoter. In a variety of cell types, including bovine embryos and embryonic stem cells, the M243 promoter showed consistent expression, highlighting its suitability for applications requiring compact promoters. The isolation of a highly conserved, compact 243-bp sequence serving as a promoter suggests a solution for overcoming the size constraints of AAV vectors, suggesting potential contributions to the field of gene therapy.

Regulatory Role of Nfix Gene in Sheep Skeletal Muscle Cell Development and Its Interaction Mechanism with MSTN.

Skeletal muscle development is crucial for livestock production, and understanding the molecular mechanisms involved is essential for enhancing muscle growth in sheep. This study aimed to investigate the role of Nfix, a member of the nuclear factor I (NFI) family, in regulating muscle development in sheep, filling a significant gap in the current understanding of Nfix deficiency and its impact on skeletal muscle growth, as no similar studies have been reported in this species. Bioinformatic analysis, including temporal analysis of transcriptome data, identified Nfix as a potential target gene for muscle growth regulation. The effects of Nfix overexpression and knockout on the proliferation and differentiation of sheep skeletal muscle cells were investigated. Changes in the expression of associated marker genes were assessed to explore the regulatory link between Nfix and the myostatin (MSTN) gene. Additionally, target miRNAs for Nfix and MSTN were predicted using online databases such as miRWalk, resulting in the construction of an Nfix-miRNA-MSTN interactive regulatory network. The findings revealed that Nfix promotes the proliferation and differentiation of sheep skeletal muscle cells, with further analysis indicating that Nfix may regulate muscle cell development by modulating MSTN expression. This study provides preliminary insights into the function of Nfix in sheep skeletal muscle development and its regulatory interactions, addressing a critical knowledge gap regarding Nfix deficiency and its implications for muscle growth. These findings contribute to a better understanding of muscle biology in sheep and provide a theoretical foundation for future research into the regulatory mechanisms governing muscle development.

The Multi-Loci Genotypes of the Myostatin Gene Associated with Growth Indicators of Intensively Fattened Lambs of Latvian Sheep.

Myostatin (MSTN), a member of the TGFβ superfamily, negatively affects skeletal muscle growth and controls muscle development at stages of pre-natal muscle growth. Marker-assisted selection with molecular markers of the MSTN gene can be used in animal husbandry for higher-quality and more economically profitable lambs. The study aims to identify multi-locus genotypes within the MSTN gene regions as molecular markers for fattening, feed efficiency, and carcass traits in Latvian sheep. This analysis was conducted on 76 intensively fattened male lambs representing six breeds in Latvia. Nine genotypes were identified based on four SNPs in the promoter and exon 1 regions, while six and four SNPs in introns 1 and 2 led to the formation of 14 and 10 genotypes, respectively. Six genotypes identified in the 3'UTR were significantly linked to traits such as birth weight, slaughter yield, muscle development, fat depth, average daily gain, dry matter intake, and feed efficiency. Genotypes of intron 1 were associated with slaughter yield, while genotypes of intron 2 were linked to fat depth, dry matter intake, and residual weight gain. The study concludes that MSTN gene SNPs can be used in selection to enhance sheep breeds in Latvia and improve economic outcomes for breeders.

The impact of myostatin variants on growth traits in South African Bonsmara beef cattle

Double muscling occurs when the myostatin (MSTN) gene is deactivated due to a series of mutations, leading to uncontrolled muscle growth and excessive muscle fiber accumulation, as the gene can no longer effectively regulate muscle development. This study aimed to assess the impact of MSTN variants and their combinations on growth traits, namely direct birth weight (BWDIR), direct weaning weight (WWDIR), average daily gain (ADG) and feed conversion ratio (FCR) in the South African (SA) Bonsmara. Genomically enhanced estimated breeding value (GEBVs) for traits of interest, and MTSN genotypes for SA Bonsmara animals were available for the study. Thirteen MSTN variants (Nt821, Q204X, F94L, E226X, E291X, C313Y, Nt419, S105C, D182N, Nt414, Nt324, Nt267, and Nt748) were routinely genotyped using the IDBv3 SNP array. Genotypic frequencies of MSTN variants ranged from 1.18% for Q204X to 35.02% for Nt748. No association was observed between the Nt267 variant and any growth traits, while both Nt748 and Nt414 variants affected WWDIR, ADG and FCR (p < 0.05). The results of the effect of multiple variants on growth traits indicated that there was an additive effect when more than one MSTN variant was present in an individual. This study is the first study to report the impact of MSTN variants on traits of economic importance in the SA Bonsmara breed.

Characterization of the myostatin gene in the neotropical species Piaractus mesopotamicus and the possibility of its use in genetic improvement programs.

The myostatin gene has played an important role in the genetic improvement of the main species of economic importance; however, it has not yet been described for some Neotropical fish essential for aquaculture. This study aimed to characterize the myostatin gene of pacu, Piaractus mesopotamicus, and investigate the association of a microsatellite marker in this gene with the weight of fish. The myostatin gene sequence was obtained after following a RACE-PCR strategy based on a partial mRNA sequence available in the GenBank database and the alignment of myostatin sequences from other fish species. The obtained sequence for the P. mesopotamicus gene was analyzed for short tandem repeats, and one dinucleotide was observed at the 3´untranslated region. A short tandem repeat polymorphism was verified in a wild population. Subsequently, the STR was evaluated in a test population of 232 animals in two 220m² concrete tanks at the Aquaculture Center of Unesp. Eight alleles and 22 genotype combinations were identified. A significant association was observed between microsatellite marker polymorphisms and the weight traits (WEIGHT1 and WEIGHT2). Alleles 210, 222, 226, and 230 were found to favor weight gain. In summary, this study contributes to the characterization of the myostatin gene in pacu fish and identifies an association between a STR and weight traits. Thus, this gene could be used as a target for genetic breeding using molecular strategies such as CRISPR and quantitative strategies such as marker-assisted selection, which would contribute to improving the production of the species.

Myostatin gene polymorphisms do not determine muscle hypertrophy in buffaloes: A case report

The aim of the study was to detect variations in the exonic and intronic regions of the myostatin gene in buffaloes with different body conformations. The regions of the gene were analyzed using the PCR-sequencing technique comparing an animal with muscle hypertrophy and ten animals with normal musculature. The hypertrophied buffalo sequence was compared to the others and no exclusive genotype was identified. It suggests that the found MSTN variants are not singly associated to muscle hypertrophy in buffaloes.

PSVII-4 A novel deletion in exon 3 of the myostatin (MSTN) gene is identified in a Raramuri criollo cattle herd

Abstract Several polymorphisms in the coding region of the myostatin (MSTN) gene have been associated with the double-muscled (DM) phenotype in different species. An experimental herd of purebred Raramuri criollo cattle in Chihuahua, Mexico, has been selectively managed for beef production during the last 15 yr. Recently, two calves where visually identified as DM animals. The aim of this study was to identify changes in the MSTN gene sequence, associated with the two DM individuals and to screen for carriers of the potential polymorphisms within this herd. The DM paternity of the calves was verified by the SeekSire bovine parentage testing of NEOGEN (Lincoln, NE). A 6.6 Kb fragment of the MSTN gene were amplified by PCR and sequenced using Illumina DNA prep kit in a MiniSeq platform. The resulting reads were analyzed using different bioinformatic programs. SNPs were generated in VCF files and filtered by the following criteria: variant confidence normalized by depth of variant samples (QD) &amp;lt; 2.0, mapping quality (MQ) &amp;lt; 40.0, strand bias(FS) &amp;gt; 60.0. The deduced myostatin protein and the three-dimensional model were obtained with bioinformatic tools. Once a novel variant was identified, a real-time PCR protocol was developed to genotype 100 and 97 herdmates, the allelic and genotypic frequencies were estimated. A 9-bp deletion was identified at the same position as the 11-bp deletion (g.821to 831del11) of the Belgian Blue MSTN allele (Figure 1). Although the latter allele has been found in three Spanish cattle breeds ancestrally related to Raramuri criollo, this is the first report of the 9-bp deletion in the MSTN gene. Such deletion results in the loss of three highly conserved amino acids residues (274, 275 and 276) in MSTN, but does not lead to a premature stop codon as in the case of the 11-bp deletion characteristic to DM Belgian Blue. The in silico three-dimensional MSTN conformation obtained for this allele has some structural differences compared with the protein reference model. The allelic frequencies were 0.85 and 0.15 for the MSTN+ and MSTNdel alleles, respectively, whereas the genotypic frequencies were 0.71, 0.01 and 0.28 for MSTN+/MSTN+, MSTNdel/MSTNdel MSTN+/MSTNdel genotypes, respectively. Controlled mattings to generate different genotypes in the research herd would allow to continue studying the effects of this MSTN gene variant on productive performance, forage behavior, husbandry and carcass and meat quality traits known to be affected by the DM phenotype in beef cattle.

DIFFERENTIAL EXPRESSION AND CYCLE THRESHOLD OF MYOSTATIN IN NIGERIAN LOCALLY ADAPTED AND EXOTIC TURKEYS

Myostatin (MSTN) gene plays a key role in the regulation of myogenesis. This study focused on the relative and differential expression of MSTN gene in Nigerian locally adapted and exotic turkeys. A total of two hundred turkeys comprising one hundred and fifty Nigerian locally adapted (fifty each of black, lavender and white colour variants) and fifty Hybrid converter (exotic) day-old poults were used for this study. The total RNA in liver, breast and thigh muscle tissues was extracted at six weeks (grower stage) and sixteen weeks (finisher stage) of age. The cycle threshold (CT), delta CT and relative expression (R) values of MSTN gene in Nigerian locally adapted and exotic turkeys were analyzed by real-time PCR and calculated using 2-△△Ct. The highest (p&lt;0.05) ΔCT (12.82) and R (1.38) were respectively found in the breast and liver tissues of local black turkey at 6 weeks while the highest (p&lt;0.05) ΔCT (10.60) and R (1.24) of MSTN gene were obtained from the breast and liver tissues of exotic turkey at 16 weeks. Generally, there was reduction in relative expression at finisher phase in the breast and thigh tissues of exotic and Nigerian locally adapted (black and lavender plumage variants) turkeys. This expression pattern provided useful information on the genetic basis for growth variation in exotic and Nigerian locally adapted turkeys and could be employed for genetic improvement of Nigeria locally adapted turkeys in a short period of time.

Dietary Supplementation with Nano-Curcumin Improves the Meat Quality and Nutrition Value of Largemouth Bass (Micropterus salmoides) Fed with a High-Carbohydrate Diet

This study investigated the effects of curcumin nanoparticles on the flesh quality of largemouth bass on a high-carbohydrate diet. A total of 180 fish (11.01 ± 0.02 g) were fed three semi-purified diets: the Control group (LC) were supplemented with standard carbohydrate (10%), the experimental group (HC) were supplemented with 15% carbohydrate, and the experimental group were supplemented with 0.2% nano-curcumin added to 15% carbohydrate (HCN) for 6 weeks. Results showed that a* value, taurine, valine, isoleucine, histidine, cystine, fatty acids (C17:0 and C20:2n6), MDA (malondialdehyde) content, and SOD (Superoxide dismutase) activity were significantly elevated (p &lt; 0.05) in HC. Muscle fibers showed significant increases in horizontal diameter, longitudinal diameter, and cross-sectional area (p &lt; 0.05), as well as up-regulated expression levels of the MRFS (myogenic regulatory factor) family gene and MSTN (myostatin) (p &lt; 0.05), and a significant decrease in C16:1n7 in HC (p &lt; 0.05). Importantly, the HCN group enhanced the muscle quality of largemouth bass by elevating the L* value, valine, isoleucine, arginine and cystine, C20:2n6, decreasing (p &lt; 0.05) refrigeration loss, chewability, firmness and hardness, then MDA content and SOD activity, and downregulating (p &lt; 0.05) MSTN and MRFS family gene expression levels to improve largemouth bass muscle quality.

Electroporation Delivery of Cas9 sgRNA Ribonucleoprotein-Mediated Genome Editing in Sheep IVF Zygotes.

The utilization of electroporation for delivering CRISPR/Cas9 system components has enabled efficient gene editing in mammalian zygotes, facilitating the development of genome-edited animals. In this study, our research focused on targeting the ACTG1 and MSTN genes in sheep, revealing a threshold phenomenon in electroporation with a voltage tolerance in sheep in vitro fertilization (IVF) zygotes. Various poring voltages near 40 V and pulse durations were examined for electroporating sheep zygotes. The study concluded that stronger electric fields required shorter pulse durations to achieve the optimal conditions for high gene mutation rates and reasonable blastocyst development. This investigation also assessed the quality of Cas9/sgRNA ribonucleoprotein complexes (Cas9 RNPs) and their influence on genome editing efficiency in sheep early embryos. It was highlighted that pre-complexation of Cas9 proteins with single-guide RNA (sgRNA) before electroporation was essential for achieving a high mutation rate. The use of suitable electroporation parameters for sheep IVF zygotes led to significantly high mutation rates and heterozygote ratios. By delivering Cas9 RNPs and single-stranded oligodeoxynucleotides (ssODNs) to zygotes through electroporation, targeting the MSTN (Myostatin) gene, a knock-in efficiency of 26% was achieved. The successful generation of MSTN-modified lambs was demonstrated by delivering Cas9 RNPs into IVF zygotes via electroporation.

Increased nanosphere size in the cuticle layer of Japanese quail egg by mutation in the myostatin gene

Cuticle quality can affect food safety by protecting poultry eggs from bacterial infection in the modern poultry industry. However, genetic factors related to cuticle nanostructure are not much reported due to limited bird models. In the current study, the genome-edited quail targeting myostatin (MSTN) gene was used to investigate the effect of MSTN mutation on the cuticle nanostructure and quality. To analyze nanostructure of the cuticle layer of the MSTN mutant and wild-type (WT) quail eggs, scanning electron microscope (SEM) images was taken. Thickness of the cuticle layer did not differ between the MSTN mutant and WT groups, but the size of the nanospheres in the surface of the cuticle layer was increased by MSTN mutation. In addition, increased size of the nanospheres in the MSTN mutant group was also shown in the upper region of the cross-sectional cuticle layer. Notably, both groups showed similar small-sized nanospheres in the lower region of the cuticle layer and the size was increased as they ascended to the upper region. The data suggested that MSTN mutation increased the size of the nanosphere in the upper region of the cuticle layer at a late phase rather than increasing the size of nanospheres in the lower region of the cuticle layer at an early phase of cuticle formation. However, the number of Escherichia coli attached to the surface did not differ between the two groups indicating no association between nanosphere size and bacterial attachment in quail eggs. The current study demonstrated a new function of the MSTN gene on regulation of cuticle nanostructure, for the first time. These results advanced our knowledge on the association between genetic factors and cuticle nanostructure and can be served as a reference to study the mechanism of cuticle formation in the future study.

CRISPR-Cas guide RNA indel analysis using CRISPResso2 with Nanopore sequencing data

ObjectiveInsertion and deletion (indel) analysis of CRISPR-Cas guide RNAs (gRNAs) is crucial in gene editing to assess gRNA efficiency and indel frequency. This study evaluates the utility of CRISPResso2 with Oxford Nanopore sequencing data (nCRISPResso2) for gRNA indel screening, compared to two common Sanger sequencing-based methods, TIDE and ICE. To achieve this, sheep and horse fibroblasts were transfected with Cas9 and a gRNA targeting the myostatin (MSTN) gene. DNA was subsequently extracted, and PCR products exceeding 600 bp were sequenced using both Sanger and Nanopore sequencing. Indel profiling was then conducted using TIDE, ICE, and nCRISPResso2.ResultsComparison revealed close correspondence in indel formation among methods. For the sheep MSTN gRNA, indel percentages were 52%, 58%, and 64% for TIDE, ICE, and nCRISPResso2, respectively. Horse MSTN gRNA showed 81%, 87%, and 86% edited amplicons for TIDE, ICE, and nCRISPResso2. The frequency of each type of indel was also comparable among the three methods, with nCRISPResso2 and ICE aligning the closest. nCRISPResso2 offers a viable alternative for CRISPR-Cas gRNA indel screening, especially with large amplicons unsuitable for Illumina sequencing. CRISPResso2’s compatibility with Nanopore data enables cost-effective and efficient indel profiling, yielding results comparable to common Sanger sequencing-based methods.

Evaluating the Potential of Double-Muscled Angus Sires to Produce Progeny from Dairy Cows to Meet Premium Beef Brand Specifications

In response to the increasing global demand for sustainable beef production, this review of the literature was undertaken to explore the possibility of using the progeny of cows in the pasture-based New Zealand dairy production system that are mainly of the Holstein–Friesian, Jersey, and Holstein–Friesian × Jersey-cross breeds, to produce beef that meets the standards demanded by the Certified Angus Beef® (CAB) standard. CAB is a United States of America (USA) benchmark for beef quality. Traditionally, the offspring of dairy breeds have not been suitable for producing high-quality beef due to their genetic makeup and physical characteristics. However, in the USA, breeding programmes have used genetic strategies to boost muscle meat yield in terminal-sire breeds like the Lim-Flex® and NuEra Genetics® T14 cattle lines. In these lines, selection has focused on enhancing muscling and other Angus traits, including ensuring the cattle are homozygous polled and black-coloured. The overall aim has been to alter the phenotypic characteristics of the offspring of dairy cows by terminal-sire crosses, so they resemble the phenotype of purebred Angus cattle and meet the CAB standard. The approach can involve using different alleles of the myostatin gene (MSTN) carried by the terminal Angus sires to increase carcass value from the dairy cow-derived male progeny (including the MSTN c.821(del11) allele or the myostatin protein p.F94L leucine-containing allele) to increase meat yield and eating characteristics. It is concluded that a targeted selection and mating strategy could provide another source of high-quality beef production, and one that also meets societal demands for better animal welfare and increased sustainability.

Myostatin serum levels depends on age and diet in athletic and no athletic dogs

Myostatin is a growth factor related to muscular mass atrophy via mTOR pathway inhibition. Mutations in this gene have been correlated with high muscular mass development in different species of mammals, including human and dogs. Different studies have shown that sport practice increases myostatin gene expression. Some of them were conducted in canine breeds selected for different sport practices, including mushing sports. In this study, body weight, muscular mass, and serum levels of myostatin were analysed in different canine breeds, selected, and not selected for sprint and middle-distance racing, and the effect on epidemiological factors was evaluated. Sex, reproductive status, and canine breed affects body weight and muscular mass, being higher in males, and in sled canine breed. Age has an effect in body weight and myostatin serum levels, being lower in elder dogs. Sport practice and type of diet had an effect in muscular mass development but not in myostatin serum levels. Results showed a high positive correlation between muscular mass and body weight but not with myostatin levels. These results suggest that independent-myostatin mechanisms of mTOR pathway regulation could be related to muscular mass development in dogs.

Polymorphisms of the myostatin gene in animals (overreview)

Polymorphisms of the myostatin gene in animals (overreview)

Research Note: Sexual dimorphic effect of myostatin mutation on fat accumulation in Japanese quail

As an anti-myogenic factor, the myostatin (MSTN) gene was mainly considered as a genetic marker to improve meat production. Moreover, an additional effect of the MSTN mutation on reducing fat deposition in various farm animals suggested a potential application of the MSTN gene on regulating fat deposition in poultry species. Although increase in muscle mass resulted from muscle hyperplasia in the MSTN mutant quail, cellular mechanism behind the decrease in fat deposition was not investigated in the quail model. In the current study, to investigate sexual dimorphic association between fat deposition and Mstn mutation in quail, leg and abdominal fat pads from 4-month-old male and female quail were histologically analyzed. Interestingly, abdominal and leg fat pad weights were significantly decreased by the MSTN mutation only in female quail, but not in male quail, showing sexual dimorphism in regulating fat deposition by the MSTN mutation in quail. Histological analysis also revealed that fat cell sizes of leg and abdominal fats were significantly reduced only in female groups aligning with the decreased fat pad weights. Sexual dimorphic effect of the MSTN mutation on fat cell hypotrophy and reduced fat pad weights in quail provided an important scientific finding to be considered on the usage of the MSTN gene as a genetic marker to reduce fat deposition in poultry species.

Nutritional synergy: optimizing growth in Siruvidai chicken via diverse dietary energy and protein strategies and gene expression analysis - brooder phase.

Nutrient supply regulates overall body growth directly or indirectly through its influence on regulatory factors optimizing nutrient requirements becomes crucial before embarking on genetic improvements. Hence this study addresses this gap by evaluating the effect of feeding varying energy and crude protein levels on growth performance and gene expression related to the growth of indigenous Siruvidai chicken from 0 to 12 weeks. A 360-day-old straight-run Siruvidai chick were randomly distributed into six experimental groups with three replicates of each 20 chicks. The birds were fed corn-soy-based diets formulated with two levels of energy (2500 and 2700kcal ME/kg) each with three levels of crude protein (16, 18, and 20%) during the brooder stage (0-12 weeks) in 2 × 3 factorial design. Results revealed that there was no significant effect on the energy and protein interaction levels on average feed intake, body weight gain and feed conversion ratio in Siruvidai chicken at 12 weeks. The results showed significantly (P < 0.05) lower feed intake in 18% protein fed groups and significantly (P < 0.01) lower feed intake in higher energy 2700kcal ME/kg fed groups. A better feed conversion ratio (4.06 and 4.21) was observed on the effect of protein levels in bird diets with 18% and 20% protein fed groups. The Growth Hormone (GH) and Myostatin (MSTN) gene expression were significantly (P < 0.01) higher in 16% CP and 2500kcal ME/kg in hepatic tissue. The high protein and low energy diet up-regulated the Insulin-like Growth Factor-1 (IGF-1) gene expression in hepatic tissue. The study concluded that Siruvidai chicken fed with 18% crude protein and 2500kcal ME/kg is optimum for 0-12 weeks of age.

Myostatin gene invalidation does not prevent skeletal muscle mass loss during experimental sepsis in mice.

Loss of muscle mass and function induced by sepsis contributes to physical inactivity and disability in intensive care unit patients. Limiting skeletal muscle deconditioning may thus be helpful in reducing the long-term effect of muscle wasting in patients. We tested the hypothesis that invalidation of the myostatin gene, which encodes a powerful negative regulator of skeletal muscle mass, could prevent or attenuate skeletal muscle wasting and improve survival of septic mice. Sepsis was induced by caecal ligature and puncture (CLP) in 13-week-old C57BL/6J wild-type and myostatin knock-out male mice. Survival rates were similar in wild-type and myostatin knock-out mice seven days after CLP. Loss in muscle mass was also similar in wild-type and myostatin knock-out mice 4 and 7 days after CLP. The loss in muscle mass was molecularly supported by an increase in the transcript level of E3-ubiquitin ligases and autophagy-lysosome markers. This transcriptional response was blunted in myostatin knock-out mice. No change was observed in the protein level of markers of the anabolic insulin/IGF1-Akt-mTOR pathway. Muscle strength was similarly decreased in wild-type and myostatin knock-out mice 4 and 7 days after CLP. This was associated with a modified expression of genes involved in ion homeostasis and excitation-contraction coupling, suggesting that a long-term functional recovery following experimental sepsis may be impaired by a dysregulated expression of molecular determinants of ion homeostasis and excitation-contraction coupling. In conclusion, myostatin gene invalidation does not provide any benefit in preventing skeletal muscle mass loss and strength in response to experimental sepsis. KEY POINTS: Survival rates are similar in wild-type and myostatin knock-out mice seven days after the induction of sepsis. Loss in muscle mass and muscle strength are similar in wild-type and myostatin knock-out mice 4 and 7 days after the induction of an experimental sepsis. Despite evidence of a transcriptional regulation, the protein level of markers of the anabolic insulin/IGF1-Akt-mTOR pathway remained unchanged. RT-qPCR analysis of autophagy-lysosome pathway markers indicates that activity of the pathway may be altered by experimental sepsis in wild-type and myostatin knock-out mice. Experimental sepsis induces greater variations in the mRNA levels of wild-type mice than those of myostatin knock-out mice, without providing any significant catabolic resistance or functional benefits.