Transcriptional regulation of the bovine FGFR1 gene facilitates myoblast proliferation under hypomethylation of the promoter.

DNA methylation, which can affect the expression level of genes, is one of the most vital epigenetic modifications in mammals. Fibroblast growth factor receptor 1 (FGFR1) plays an important role in muscle development; however, DNA methylation of the FGFR1 promoter has not been studied to date in cattle. Our study focused on methylation of the FGFR1 promoter and its effect on bovine myoblast proliferation and differentiation. We identified the FGFR1 core promoter by using luciferase reporter assays; we then studied FGFR1 expression by reverse transcription quantitative polymerase chain reaction, and the methylation pattern in the FGFR1 core promoter by bisulfite sequencing polymerase chain reaction in bovine muscle tissue at three different developmental stages. We used RNAi strategy to investigate the function of FGFR1 in myoblast proliferation and differentiation. Results showed that the FGFR1 core promoters were located at the R2 (-509 to ~-202 bp) and R4 (-1295 to ~-794 bp) regions upstream of the FGFR1 gene. FGFR1 expression level was negatively associated with the degree of methylation of the FGFR1 core promoter during the developmental process. In addition, we found that FGFR1 can promote myoblast proliferation, but had no effect on myoblast differentiation. In conclusion, our results suggest that FGFR1 can promote myoblast proliferation and its transcription can be regulated by the methylation level of the core promoter. Our findings provide a mechanistic basis for the improvement of animal breeding.

Integrative analysis of APOL3 gene CNV for adult cattle stature.

Copy number variations (CNVs) have been identified as another important structural variation of genome. In recent years, a large amount of CNVRs have been identified in humans and animals. However, association and dosage effects studies of CNVs are very limited. Apolipoprotein L3 (APOL3) gene plays a central role in modulating gene transcription and is located within a CNVR that encompasses quantitative trait locis (QTLs) for economic traits like meat quality. Herein, we analyzed the CNV polymorphism of APOL3 in 421 individuals from five distinct cattle breeds, and then correlated their genotypes with growth traits. Association analysis revealed that the APOL3 CNV was significantly associated with hip height and cannon circumference of Xianan (XN) cattle (P < .01), and visibly associated with body slanting length and hucklebone width of Pinan (PN) cattle (P < .05). Overall, the data provide evidence for the functional role of APOL3 CNV and a basis for future applications in cattle breeding.

Growth Performance and Meat Quality Evaluations in Three-Way Cross Cattle Developed for the Tibetan Plateau and their Molecular Understanding by Integrative Omics Analysis.

Despite of favorable characteristics of high protein, low fat, and free-pollution, yak meat has intrinsically poor performance in tenderness and color, which is ever challenging yak sector. To this end, a three-way cross system was first developed for high quality beef of the Tibetan Plateau using Angus cattle ( Bos taurus) as terminal sire to mate with 1/2 yak (F1) generated from♂Qaidam cattle ( Bos taurus) × â™€yak ( Bos grunniens). The withers height, chest girth, and body weight of 1/4 yak (F2) were all great higher than that of yak and 1/2 yak ( P < 0.01), especially at later period, suggesting the faster growth rate of 1/4 yak. Also the dressing percentage was much better in 1/4 yak ( P < 0.01). Tenderness and meat color were both significantly improved in 1/4 yak with some unpleasant sacrifice of PUFAs, such as EPA and DHA, and meat protein, given the significantly lower shear force and higher L* ( P < 0.01). A total of 769 genes, including SREBF1, GHR, and FASN, the widely recognized causal genes of meat quality, were identified from 11947 differently expressed genes by the data integration of transcriptome, GWAS and QTL. These genes were significantly enriched for important pathway and GO terms, such as insulin signaling pathway, fatty acid biosynthesis, calcium signaling pathway, metabolic pathway, and cellular response to stress ( P < 0.01). And 12 promising candidates were exemplified with annotation of H3K4me3 data from divergent meat quality, such as OSTF1, NRAS1, and KCNJ11. Interestingly, 75 high-altitude adaptive candidate genes were also detected in the list. This study is a first step toward high quality beef of the Tibetan Plateau and provides useful information for their molecular understanding.

Distribution and association study in copy number variation of KCNJ12 gene across four Chinese cattle populations.

Copy number variation is a large genome variation which usually happens in the noncoding-region, and it may occur at the locus associated with the functional gene to further influence the phenotype. Potassium inwardly-rectifying channel, subfamily J 12 (KCNJ12) gene expressed widely in cardiomyocytes and neurons, plays an important role in tumor therapy and muscle movement regulation. In this study, we detected the distribution of CNVs for KCNJ12 gene in 404 individuals belonging to four Chinese cattle breeds (NY, JX, JA and GF). We also investigated the KCNJ12 gene expression in different tissues of JX cattle. Additionally, we examined the association of two CNV regions (CNV1: 1,600 bp, intron 1; CNV2: 4,800 bp, intergenic) with growth traits. The statistical analyses indicated that the CNV1 is associated with the body length, rump length and weight in JX cattle population (P < 0.05); and there has a significant association with the body length, chest circumference, and body weight in GF cattle (P < 0.05).The CNV2 had a significant effect on the body length and body weight in JX cattle (P < 0.05); the body length, chest circumference, rump length and body weight in GF cattle (P < 0.01 or P < 0.05). The copy numbers of KCNJ12 gene presented the negative correlations with the transcript level of gene in skeletal muscles (P < 0.05). Our results provide evidence that CNV1 and CNV 2 in KCNJ12 are associated with growth traits in two cattle populations and may be used as candidates for marker-assisted selection and breeding management in cattle.

DNA methylation status of CRABP2 promoter down-regulates its expression.

As an important epigenetic modification DNA methylation is catalyzed by DNA methylation transferases (DNMTs) and occurs mainly in CpG islands. DNA methylation plays an important role in regulates gene expression, cell differentiation, genetic imprinting and tumor therapy. Retinoic acid-binding proteins (RAC) is vital for the absorption, transport, metabolism and maintenance of homeostasis of retinoic acid, which in turn regulates the differentiation and proliferation of cells by regulating the transcription of many target genes, therefore, these proteins influence differentiation and proliferation of adipocytes and muscle fibroblasts. Thus, cellular retinoic acid binding protein 2 (CRABP2) may be a candidate gene which affects beef quality, yield and fat deposition. The aim of this study was to evaluate the expression and the methylation pattern on the differentially methylated region (DMR) of the promoter of CRABP2. The DNA methylation pattern was tested by bisulfite sequencing polymerase chain reaction (BSP), the quantitative real-time PCR (qPCR) was used to analysis the expression of CRABP2 gene. The results showed that the DNA methylation level was higher in purebred cattle breed than that in hybrid cattle breeds which was negative correlation with the expression of the gen. These results indicate that the methylation status of the CRABP2 DMR can regulate mRNA expression. What's more, there are different methylation and expression patterns in different breeds and tissues which may influence the phenotype, and the results may be a useful parameter to investigate the function of CRABP2 in muscle and fat developmental in Chinese cattle.