ObjectiveThe objective of this study was to compare the DNA methylation profile in the longissimus dorsi muscle between Small Tailed Han and Dorper×Small Tailed Han crossbred sheep which were known to exhibit significant difference in meat-production.MethodsSix samples (three in each group) were subjected to the methylated DNA immunoprecipitation sequencing (MeDIP-seq) and subsequent bioinformatics analyses to detect differentially methylated regions (DMRs) between the two groups.Results23.08 Gb clean data from six samples were generated and 808 DMRs were identified in gene body or their neighboring up/downstream regions. Compared with Small Tailed Han sheep, we observed a tendency toward a global loss of DNA methylation in these DMRs in the crossbred group. Gene ontology enrichment analysis found several gene sets which were hypo-methylated in gene-body region, including nucleoside binding, motor activity, phospholipid binding and cell junction. Numerous genes were found to be differentially methylated between the two groups with several genes significantly differentially methylated, including transforming growth factor beta 3 (TGFB3), acyl-CoA synthetase long chain family member 1 (ACSL1), ryanodine receptor 1 (RYR1), acyl-CoA oxidase 2 (ACOX2), peroxisome proliferator activated receptor-gamma2 (PPARG2), netrin 1 (NTN1), ras and rab interactor 2 (RIN2), microtubule associated protein RP/EB family member 1 (MAPRE1), ADAM metallopeptidase with thrombospondin type 1 motif 2 (ADAMTS2), myomesin 1 (MYOM1), zinc finger, DHHC type containing 13 (ZDHHC13), and SH3 and PX domains 2B (SH3PXD2B). The real-time quantitative polymerase chain reaction validation showed that the 12 genes are differentially expressed between the two groups.ConclusionIn the current study, a tendency to a global loss of DNA methylation in these DMRs in the crossbred group was found. Twelve genes, TGFB3, ACSL1, RYR1, ACOX2, PPARG2, NTN1, RIN2, MAPRE1, ADAMTS2, MYOM1, ZDHHC13, and SH3PXD2B, were found to be differentially methylated between the two groups by gene ontology enrichment analysis. There are differences in the expression of 12 genes, of which ACSL1, RIN2, and ADAMTS2 have a negative correlation with methylation levels and the data suggest that DNA methylation levels in DMRs of the 3 genes may have an influence on the expression. These results will serve as a valuable resource for DNA methylation investigations on screening candidate genes which might be related to meat production in sheep.

Bovine calpastatin (CAST) gene polymorphisms have been associated with meat tenderness traits; however, little is known about how the CAST gene affects beef quality traits. In this study, 25 single nucleotide polymorphisms were detected in the CAST gene using polymerase chain reaction with single-strand conformation polymorphism and gene sequencing. Different preponderant genotypes were found at the corresponding gene locus. The E1-1, E1-2, and C3-1 loci were correlated with meat tenderness height and highly correlated with the fatty acid content and the amino acid content. The E4-2 locus was not correlated with meat tenderness, but it was correlated with cooking loss, brightness, and yellowness, among others. The CAST gene is a potential marker for these meat quality traits, but further research is required.

The calpain I (CAPN1) gene is an important marker for meat tenderness and marbling score in the bovine, but there were no studies to determine whether the CAPN1 gene had an association with other meat quality traits. In this study, we examined the relation between genetic polymorphisms of the CAPN1 gene and some meat quality traits in Yanbian Yellow Cattle of China. By PCR-SSCP and gene sequencing in 321 unrelated Yanbian yellow cattle, twenty seven single nucleotide polymorphisms (SNPs) were detected in CAPN1, two existed SNPs in exon 8 and exon 17 resulted in the change of AA at F311S and M599V, respectively, and the other polymorphisms were at intron 7, 8, 14, 16 and 17. There were different preponderant genotypes at the corresponding gene locus and all genotypes were not associated with tenderness but other meat traits. This is the first study of the relationship between CAPN1 and meat quality besides tenderness in Yanbian yellow cattle of China.

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Long-chain fatty acyl-CoA synthetase (ACSLs) is an essential enzyme for the synthesis of fatty acyl-CoA. ACSL1 plays a key role in the synthesis of triglycerides, phospholipids, and cholesterol esters. Background: In the current study, triglyceride content did not increase after overexpression of the ACSL1 gene. Methods: RNA-seq and lipid metabolome profiling were performed to determine why triglyceride levels did not change with ACSL1 overexpression. Results: Fatty acyl-CoA produced by ACSL1 was determined to be involved in the diglyceride synthesis pathway, and diglyceride content significantly increased when ACSL1 was overexpressed. Moreover, the arachidonic acid (AA) content in sheep adipocytes significantly increased, and the level of cyclooxygenase 2 (COX2) expression, the downstream metabolic gene, was significantly downregulated. Knocking down the ACSL1 gene was associated with an increase in COX2 mRNA expression, as well as an increase in prostaglandin content, which is the downstream metabolite of AA. Conclusions: The overexpression of the ACSL1 gene promotes the production of AA via downregulation of COX2 gene expression.