Scd1 mammary-specific vector constructed and overexpressed in goat fibroblast cells resulting in an increase of palmitoleic acid and oleic acid

Identification of Susceptibility Genes Underlying Bovine Respiratory Disease in Xinjiang Brown Cattle Based on DNA Methylation

DNA methylation is a form of epigenetic regulation, having pivotal parts in controlling cellular expansion and expression levels within genes. Although blood DNA methylation has been studied in humans and other species, its prominence in cattle is largely unknown. This study aimed to methodically probe the genomic methylation map of Xinjiang brown (XJB) cattle suffering from bovine respiratory disease (BRD), consequently widening cattle blood methylome ranges. Genome-wide DNA methylation profiling of the XJB blood was investigated through whole-genome bisulfite sequencing (WGBS). Many differentially methylated regions (DMRs) obtained by comparing the cases and controls groups were found within the CG, CHG, and CHH (where H is A, T, or C) sequences (16,765, 7502, and 2656, respectively), encompassing 4334 differentially methylated genes (DMGs). Furthermore, GO/KEGG analyses showed that some DMGs were involved within immune response pathways. Combining WGBS-Seq data and existing RNA-Seq data, we identified 71 significantly differentially methylated (DMGs) and expressed (DEGs) genes (p < 0.05). Next, complementary analyses identified nine DMGs (LTA, STAT3, IKBKG, IRAK1, NOD2, TLR2, TNFRSF1A, and IKBKB) that might be involved in the immune response of XJB cattle infected with respiratory diseases. Although further investigations are needed to confirm their exact implication in the involved immune processes, these genes could potentially be used for a marker-assisted selection of animals resistant to BRD. This study also provides new knowledge regarding epigenetic control for the bovine respiratory immune process.

Overproduction of palmitoleic acid from corn stover hydrolysate by engineered Saccharomyces cerevisiae

Palmitoleic acid (POA) has been widely applied to nutrition and pharmaceutical industry. However, high cost of scale-up fermentation restricts the extensive application of POA. Hence, we investigated the availability of corn stover hydrolysate (CSH) as carbon source in POA production by engineered S. cerevisiae. Although the yeast growth was inhibited to some extent by CSH, the POA production with CSH was slightly higher than that with pure glucose. The C/N ratio of 120 and addition of 1 g/L lysine raised the POA titer up to 2.19 g/L and 2.05 g/L, respectively. Two-stage cultivation could increase the POA titer by upregulating the gene expression of key enzymes in fatty acid synthesis pathway. A high POA content of 57.5% (v/v) and a highest POA titer of 6.56 g/L were achieved under the optimized conditions. These findings provide a feasible approach for sustainable production of POA or its derivatives from CSH.

Proteomics Insights into the Gene Network of cis9, trans11-Conjugated Linoleic Acid Biosynthesis in Bovine Mammary Gland Epithelial Cells

The objective of the study was to elucidate the stearoyl-coenzyme A desaturase (SCD1)-dependent gene network of c9, t11-CLA biosynthesis in MAC-T cells from an energy metabolism perspective. The cells were divided into the CAY group (firstly incubated with CAY10566, a chemical inhibitor of SCD1, then incubated with trans-11-octadecenoic acid, (TVA)), the TVA group (only TVA), and the control group (without CAY, TVA). The c9, t11-CLA, and TVA contents were determined by gas chromatography. The mRNA levels of SCD1 and candidate genes were analyzed via real-time PCR. Tandem mass tag (TMT)-based quantitative proteomics, bioinformatic analysis, parallel reaction monitoring (PRM), and small RNA interference were used to explore genes involved in the SCD1-dependent c9, t11-CLA biosynthesis. The results showed that the SCD1 deficiency led by CAY10566 blocked the biosynthesis of c9, t11-CLA. In total, 60 SCD1-related proteins mainly involved in energy metabolism pathways were primarily screened by TMT-based quantitative proteomics analysis. Moreover, 17 proteins were validated using PRM analysis. Then, 11 genes were verified to have negative relationships with SCD1 after the small RNA interference analysis. Based on the above results, we concluded that genes involved in energy metabolism pathways have an impact on the SCD1-dependent molecular mechanism of c9, t11-CLA biosynthesis.

Analysis of DNA methylation profiles during sheep skeletal muscle development using whole-genome bisulfite sequencing

BACKGROUND

DNA methylation is an epigenetic regulatory form that plays an important role in regulating the gene expression and the tissues development.. However, DNA methylation regulators involved in sheep muscle development remain unclear. To explore the functional importance of genome-scale DNA methylation during sheep muscle growth, this study systematically investigated the genome-wide DNA methylation profiles at key stages of Hu sheep developmental (fetus and adult) using deep whole-genome bisulfite sequencing (WGBS).

RESULTS

Our study found that the expression levels of DNA methyltransferase (DNMT)-related genes were lower in fetal muscle than in the muscle of adults. The methylation levels in the CG context were higher than those in the CHG and CHH contexts, and methylation levels were highest in introns, followed by exons and downstream regions. Subsequently, we identified 48,491, 17, and 135 differentially methylated regions (DMRs) in the CG, CHG, and CHH sequence contexts and 11,522 differentially methylated genes (DMGs). The results of bisulfite sequencing PCR (BSP) correlated well with the WGBS-Seq data. Moreover, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional annotation analysis revealed that some DMGs were involved in regulating skeletal muscle development and fatty acid metabolism. By combining the WGBS-Seq and previous RNA-Seq data, a total of 159 overlap genes were obtained between differentially expressed genes (DEGs) and DMGs (FPKM > 10 and fold change > 4). Finally, we found that 9 DMGs were likely to be involved in muscle growth and metabolism of Hu sheep.

CONCLUSIONS

We systemically studied the global DNA methylation patterns of fetal and adult muscle development in Hu sheep, which provided new insights into a better understanding of the epigenetic regulation of sheep muscle development.

The Lentiviral System Construction for Highly Expressed Porcine Stearoyl-CoA Desaturase-1 and Functional Characterization in Stably Transduced Porcine Swine Kidney Cells

The most highly regulated and abundant fatty acid in animal tissue is oleic acid (18:1n9). Oleic acid is synthesized by the Δ9 desaturase, stearoyl-CoA desaturase-1 (SCD1), which is responsible for the synthesis of the putative cytokine palmitoleic acid (16:1n7) and 18:2 cis-9, trans-11 conjugated linoleic acid. Owing to the importance of SCD1 in lipid metabolism, we generated porcine swine kidney (SK6) transgenic cell lines for sustained overexpression or knockdown of porcine stearoyl-CoA desaturase-1 (pSCD1) in an inducible manner by utilizing a lentiviral expression system. We successfully validated these cell culture models for expression and functionality of pSCD1 by documenting that the pSCD-transduced cells overexpressed pSCD1 protein and mRNA. Additionally, the pSCD1-transduced cells increased the conversion of palmitate (16:0) to palmitoleic acid nearly fourfold. The lentiviral vectors utilized in this study can be further used to generate transgenic animals to document the effects of the overexpression of SCD1 on obesity and steatosis.