SNP discovery and haplotype analysis in the bovine PRKAA2 gene

Polymorphism of sheep PRKAA2 gene and its association with growth traits

Small ruminants farming plays an important role in the livelihood of a large part of the population. Herein we aimed to analyze the effects of single nucleotide polymorphisms in PRKAA2 gene on the growth-related traits of Hu sheep and Dorper sheep. The body weight and body type of 1254 sheep were measured at 80, 100, 120, 140, 160 and 180d, and 37620 phenotypic data were collected. RT-qPCR analysis was performed to test PRKAA2 gene expressed in different tissues of sheep, with the highest expression level in spleen, followed by kidney. In the present study, the PRKAA2 gene sequencing revealed one polymorphism located on Chr1 (Oar_rambouillet_v1.0), termed as chr1:32832382 G > A, and were significantly associated with growth traits of sheep (p < 0.05). The body weight, body length, chest circumference, and cannon circumference of individuals with AA genotype were significantly higher than those with the GG and GA genotypes (p < 0.05). Our findings reveal that PRKAA2 gene could be used as a marker-assisted selection to improve the growth-related traits of sheep.

Association Analysis of PRKAA2 and MSMB Polymorphisms and Growth Traits of Xiangsu Hybrid Pigs

In this study, Xiangsu hybrid pig growth traits were evaluated via PRKAA2 and MSMB as candidate genes. Sanger sequencing revealed three mutation sites in PRKAA2, namely, g.42101G>T, g.60146A>T, and g.61455G>A, and all these sites were intronic mutations. Moreover, six mutation sites were identified in MSMB: intronic g.4374G>T, exonic g.4564T>C, exonic g.6378G>A, exonic g.6386C>T, intronic g.8643G>A, and intronic g.8857A>G. Association analysis revealed that g.42101G>T, g.60146A>T, g.61455G>A, g.4374G>T, g.4564T>C, g.6378G>A, g.6386C>T, g.8643G>A, and g.8857A>G showed different relationship patterns among body weight, body length, body height, chest circumference, abdominal circumference, tube circumference, and chest depth. Real-time polymerase chain reaction results revealed that the expression of PRKAA2 was highest in the longissimus dorsi muscle, followed by that in the heart, kidney, liver, lung, and spleen. The expression of MSMB was highest in the spleen, followed by that in the liver, kidney, lung, heart, and longissimus dorsi muscle. These results suggest that PRKAA2 and MSMB can be used in marker-assisted selection to improve growth related traits in Xiangsu hybrid pigs, providing new candidate genes for Pig molecular breeding.

Induction mechanism of cigarette smoke components (CSCs) on dyslipidemia and hepatic steatosis in rats

Objective

The purpose of this study was to explore the effect of cigarette smoke component (CSC) exposure on serum lipid levels in rats and the underlying molecular mechanism.

Methods

Male SPF-grade SD rats were randomly divided into a control group and a CSC exposure group, with the CSC group being exposed to CSC for 6 weeks. RT–PCR and Western blotting methods were used to detect lipid metabolism gene expression in rats, and 16S RNA gene sequencing was used to detect the gut microbiota in the rat cecum. Rat serum exosomes were prepared and identified, and the interaction of exosomal miR-291a-3p and miR-126a-5p with AMPK and CYP7A1 was detected by a dual luciferase reporter gene assay (DLRG).

Results

Serum indicators, including cholesterol levels and trimethylamine oxide (TMAO) content, were significantly affected in the CSC exposure group compared with the control group (P < 0.05), and the expression levels of adenylate-activated protein kinase (AMPK), acetyl-coenzyme A carboxylase (ACC) and HMG-CoA reductase (HMG-CoAR) genes were significantly increased (P < 0.05) in the liver, while the expression level of cholesterol 7α-hydroxylase (CYP7A1) was markedly decreased (P < 0.01). 16S rRNA gene sequencing of the gut microbiota in the rat cecum showed that the abundance of Firmicutes in the CSC group increased significantly at the phylum level, while the abundances of Bacteroidota and Spirochaetota were reduced significantly (P < 0.01). The relative abundance of Romboutsia, Turicibacter, and Clostridium sensu stricto increased significantly (P < 0.01), and the relative abundance of Prevotella, Muribaculaceae_norank, Lachnospiraceae NK4A136 group, Roseburia, Treponema, and Ruminococcus significantly decreased (P < 0.01) at the genus level. In addition, the exosome miR-291a-3p and miR-126a-5p levels were markedly regulated by CSC exposure (P < 0.01). The interactions of miR-291a-3p and miR-126a-5p with AMPK and CYP7A1 mRNA were also validated by the DLRG method.

Conclusions

In summary, the rat dyslipidemia induced by CSC exposure may be related to the interference of gut microbiota structure and interaction of miRNAs from serum exosomes with target mRNAs, which further regulated AMPK-ACC/CYP7A1 signaling in rats.

Study on the effect of CaMKKβ-mediated AMPK activation on the glycolysis and the quality of different altitude postmortem bovines longissimus muscle

This study investigated the activity of adenosine monophosphate-activated protein kinase (AMPK), glycolysis, and meat quality index in three altitude bovines during postmortem aging process. Local cattle (altitude:1,500 m), Gannan yak (3,000 m), and Yushu yak (4,500 m) postmortem Longissimus Dorsi (LD) muscle were used. Results indicated that CaCl₂ significantly increased the AMPK activity by increasing the calcium-regulated protein kinase kinase (CaMKKβ) activity. Besides, AMPK activation enhanced the activity of lactate dehydrogenase (LDH) and Ca²⁺ -ATPase and accelerated the rate of muscle maturation during postmortem aging. Moreover, the expression of HIF-1, PRKAA2, and GLUT4 genes in high-altitude Yushu yak was higher than that of low-altitude bovines. CaCl₂ activates AMPK by activating CaMKKβ cascade and accelerates postmortem glycolysis affecting the intramuscular environment, color, and muscle protein degradation to accelerate postmortem muscle maturation, suggesting that AMPK has essential effects on postmortem muscle glycolysis and quality, and can regulate muscle quality by regulating postmortem muscle AMPK activity. PRACTICAL APPLICATIONS: Insufficient postmortem glycolysis usually leads to DFD (dark, firm, and dry) meat. Beef have relatively high incidences of DFD meat, which has an unattractive dark color and causes significant loss to the meat industry. Therefore, AMPK, which can regulate postmortem glycolysis to affect meat quality, is a valid research target.

Polymorphisms in the Promoter Region of the Chinese Bovine PPARGC1A Gene

The peroxisome proliferator-activated receptor gamma coactivator-1 alpha protein, encoded by the PPARGC1A gene, plays an important role in energy homeostasis. The genetic variations within the PPARGC1A gene promoter region were scanned in 808 Chinese native bovines belonging to three cattle breeds and yaks. A total of 6 SNPs and one 4 bp insertion variation in the promoter region of the bovine PPARGC1A gene were identified: SNP -259 T>A, -301_-298insCTTT, -915 A>G, -1175 T>G, -1590 C>T, -1665 C>T and -1690 G>A, which are in the binding sites of some important transcription factors: sex-determining region Y (SRY), myeloid-specific zinc finger-1 (MZF-1) and octamer factor 1(Oct-1). It is expected that these polymorphisms may regulate PPARGC1A gene transcription and might have consequences at a regulatory level.