Expression of the bovine KLF6 gene polymorphisms and their association with carcass and body measures in Qinchuan cattle (Bos Taurus)

Investigating the Role of KLF6 in the Growth of Bovine Preadipocytes: Using Transcriptomic Analyses to Understand Beef Quality

Intramuscular fat is a crucial determinant of carcass quality traits like tenderness and taste, which in turn is influenced by the proliferation of intramuscular preadipocytes. This study aimed to investigate the Krüppel-like factor 6 (KLF6)-mediated proliferation of bovine preadipocytes and identify underlying molecular mechanisms. Down-regulation of KLF6 by siKLF6 resulted in a significant (p < 0.01) suppression of cell cycle-related genes including CDK1, MCM6, ZNF4, PCNA, CDK2, CCNB1, and CDK6. Conversely, the expression level of p27 was significantly (p < 0.01) increased. Moreover, EdU (5-ethynyl-20-deoxyuridine) staining revealed a significant decrease in EdU-labeled cells due to KLF6 down-regulation. Collectively, these findings indicate that KLF6 down-regulation inhibits adipocyte proliferation. Furthermore, RNA sequencing of preadipocytes transfected with siKLF6 and NC, followed by differential gene expression analysis, identified 100 up-regulated and 70 down-regulated genes. Additionally, the differentially expressed genes also significantly influenced various Gene Ontology (GO) terms related to cell cycle, nuclear chromosomes, and catalytic activity on DNA. Furthermore, the top 20 pathways enriched in these DEGs included cell cycle, DNA replication, cellular senescence, and homologous recombination. These GO terms and KEGG pathways play key roles in bovine preadipocyte proliferation. In conclusion, the results of this study suggest that KLF6 positively regulates the proliferation of bovine preadipocytes.

RNA-Seq explores the functional role of the fibroblast growth factor 10 gene in bovine adipocytes differentiation

OBJECTIVE

The present study was executed to explore the molecular mechanism of fibroblast growth factor 10 (FGF10) gene in bovine adipogenesis.

METHODS

The bovine FGF10 gene was overexpressed through Ad-FGF10 or inhibited through siFGF10 and their negative control (NC) in bovine adipocytes, and the multiplicity of infection, transfection efficiency, interference efficiency were evaluated through quantitative real-time polymerase chain reaction, western blotting and fluorescence microscopy. The lipid droplets, triglycerides (TG) content and the expression levels of adipogenic marker genes were measured during preadipocytes differentiation. The differentially expressed genes were explored through deep RNA sequencing.

RESULTS

The highest mRNA level was found in omasum, subcutaneous fat, and intramuscular fat. Moreover, the highest mRNA level was found in adipocytes at day 4 of differentiation. The results of red-oil o staining showed that overexpression (Ad-FGF10) of the FGF10 gene significantly (p<0.05) reduced the lipid droplets and TG content, and their downregulation (siFGF10) increased the measurement of lipid droplets and TG in differentiated bovine adipocytes. Furthermore, the overexpression of the FGF10 gene down regulated the mRNA levels of adipogenic marker genes such as CCAAT enhancer binding protein alpha (C/EBPα), fatty acid binding protein (FABP4), peroxisome proliferator-activated receptor-γ (PPARγ), lipoprotein lipase (LPL), and Fas cell surface death receptor (FAS), similarly, down-regulation of the FGF10 gene enriched the mRNA levels of C/EBPα, PPARγ, FABP4, and LPL genes (p<0.01). Additionally, the protein levels of PPARγ and FABP4 were reduced (p<0.05) in adipocytes infected with Ad-FGF10 gene and enriched in adipocytes transfected with siFGF10. Moreover, a total of 1,774 differentially expressed genes (DEGs) including 157 up regulated and 1,617 down regulated genes were explored in adipocytes infected with Ad-FGF10 or Ad-NC through deep RNA-sequencing. The top Kyoto encyclopedia of genes and genomes pathways regulated through DEGs were the PPAR signaling pathway, cell cycle, base excision repair, DNA replication, apoptosis, and regulation of lipolysis in adipocytes.

CONCLUSION

Therefore, we can conclude that the FGF10 gene is a negative regulator of bovine adipogenesis and could be used as a candidate gene in marker-assisted selection.

Transcriptome analysis of adipose tissue in grazing cattle: Identifying key regulators of fat metabolism

The taste and tenderness of meat are the main determinants of carcass quality in many countries. This study aimed to discuss the mechanisms of intramuscular fat deposition in grazing and house-breeding cattle. We performed transcriptome analysis to characterize messenger RNA and microRNA (miRNA) expression profiles. A total of 456 and 66 differentially expressed genes (DEGs) and differentially expressed (DE) miRNAs were identified in the adipose tissue of grazing and house-breeding cattle. Kyoto Encyclopedia of Genes and Genomes pathway analysis identified the association of DEGs with fatty acid metabolism, fatty acid degradation, peroxisome proliferator-activated receptors signaling pathway, adenosine monophosphate-activated protein kinase signaling pathway, adipocytokine signaling pathway, and the association of DE miRNAs with mitogen-activated protein kinase signaling pathway. Apolipoprotein L domain containing 1, pyruvate dehydrogenase kinase 4, and sphingosine-1-phosphate lyase 1 genes may be the key regulators of fat metabolism in grazing cattle. Finally, we found that miR-211 and miR-331-5p were negatively correlated with the elongation of very long-chain fatty acids protein 6 (ELOVL6), and miR-331-5p might be the new regulator involved in fat metabolism. The results indicated that ELOVL6 participated in various functions and pathways related to fat metabolism. Meanwhile, miR-331-5p, as a new regulator, might play an essential role in this process. Our findings laid a more in-depth and systematic research foundation for the formation mechanism and characteristics of adipose tissue in grazing cattle.

Characterizing structural variants based on graph-genotyping provides insights into pig domestication and local adaption

Structural variants (SVs), such as deletions (DELs) and insertions (INSs), contribute substantially to pig genetic diversity and phenotypic variation. Using a library of SVs discovered from long-read primary assemblies and short-read sequenced genomes, we map pig genomic SVs with a graph-based method for re-genotyping SVs in 402 genomes. Our results demonstrate that those SVs harboring specific trait-associated genes may greatly shape pig domestication and local adaptation. Further characterization of SVs reveals that some population-stratified SVs may alter the transcription of genes by affecting regulatory elements. We identify that the genotypes of two DELs (296-bp DEL, chr7: 52,172,101-52,172,397; 278-bp DEL, chr18: 23,840,143-23,840,421) located in muscle-specific enhancers are associated with the expression of target genes related to meat quality (FSD2) and muscle fiber hypertrophy (LMOD2 and WASL) in pigs. Our results highlight the role of SVs in domestic porcine evolution, and the identified candidate functional genes and SVs are valuable resources for future genomic research and breeding programs in pigs.

The kruppel-like factor (KLF) family, diseases, and physiological events

The Kruppel-Like Factor family of regulatory proteins, which has 18 members, is transcription factors. This family contains zinc finger proteins, regulates the activation and suppression of transcription, and binds to DNA, RNA, and proteins. Klfs related to the immune system are Klf1, Klf2, Klf3, Klf4, Klf6, and Klf14. Klfs related to adipose tissue development and/or glucose metabolism are Klf3, Klf7, Klf9, Klf10, Klf11, Klf14, Klf15, and Klf16. Klfs related to cancer are Klf3, Klf4, Klf5, Klf6, Klf7, Klf8, Klf9, Klf10, Klf11, Klf12, Klf13, Klf14, Klf16, and Klf17. Klfs related to the cardiovascular system are Klf4, Klf5, Klf10, Klf13, Klf14, and Klf15. Klfs related to the nervous system are Klf4, Klf7, Klf8, and Klf9. Klfs are associated with diseases such as carcinogenesis, oxidative stress, diabetes, liver fibrosis, thalassemia, and the metabolic syndrome. The aim of this review is to provide information about the relationship of Klfs with some diseases and physiological events and to guide future studies.

Roles of MEF2A and HOXA5 in the transcriptional regulation of the bovine FoxO1 gene

The Forkhead box factor 1 (FoxO1) gene plays a vital role in the growth and development of skeletal muscle. In the present study, expression analysis of the bovine FoxO1 gene exhibited the highest expression in longissimus dorsi muscle followed by its expression in adipose tissue. Moreover, high mRNA expression of FoxO1 gene was found in differentiated bovine myoblasts and adipocytes at day 6 of induced differentiation (p < 0.05). The regulatory pattern of the bovine FoxO1 gene was investigated through screening and dual-luciferase activity of the 1.7 kb 5'UTR (untranslated region) within pGL3-basic vector and a core promoter region was explored at (-285/-27) upstream of the transcription start site. The transcription factors (TFs) MEF2A and HOXA5 within the core promoter region (-285/-27) were found as the regulatory cis-acting element. The siRNA interference of the TFs, chromatin immunoprecipitation (ChIP) assay, and site-directed mutation validated that MEF2A and HOXA5 binding occurs in the region -285/-27 bp and performs an essential role in the transcriptional regulation of bovine FoxO1 gene. These findings explored the regulatory network mechanism of the FoxO1 gene in skeletal muscle development and adipogenesis for the bovine breed improvement program.

Genetic variants of TORC1 gene promoter and their association with carcass quality and body measurement traits in Qinchuan beef cattle

In the present study, sequencing of TORC1 prompter region explored three SNPs at loci g.80G>T, g.93A>T, and g.1253G>A. The SNP1 produced GG, GT and TT, SNP2 AA, AT and TT, and SNP3 produced GG, GA and AA genotypes. Allelic and genotypic frequencies analysis exhibited that SNP1 is within Hardy-Weinberg equilibrium (HWE). All three SNPs were found highly polymorphic as PIC value (0.25 < PIC < 0.50). At loci g.80G>T the cattle with genotype GG showed significantly (P <0.01) larger body length (BL), Wither height (WH), Hip height (HH), Rump length (RL), Hip width (HW), Chest depth (CD), and Chest circumference (CC). The genotype AA at g.93A>T showed significantly (P< 0.01 and 0.05) Larger body length (BL), Wither height (WH), Hip height, Rump length (RL), Hip width (HW), Chest depth (CD), and Chest circumference (CC). Interestingly, the carcass quality parameters such as Ultrasound loin area (ULA) and Intramuscular fat percentage (IF%) was highest in genotype GG at loci g.1253G>A. These findings conclude that genotype GG at loci g.80 G>T and AA at loci g.93A>T could be used as genetic markers for body measurement and genotype GG at loci g.1253G>A for carcass quality traits of TORC1 gene in Qinchuan beef cattle.

Identification of genetic associations and functional SNPs of bovine KLF6 gene on milk production traits in Chinese holstein

BACKGROUND

Our previous research identified the Kruppel like factor 6 (KLF6) gene as a prospective candidate for milk production traits in dairy cattle. The expression of KLF6 in the livers of Holstein cows during the peak of lactation was significantly higher than that during the dry and early lactation periods. Notably, it plays an essential role in activating peroxisome proliferator-activated receptor α (PPARα) signaling pathways. The primary aim of this study was to further substantiate whether the KLF6 gene has significant genetic effects on milk traits in dairy cattle.

RESULTS

Through direct sequencing of PCR products with pooled DNA, we totally identified 12 single nucleotide polymorphisms (SNPs) within the KLF6 gene. The set of SNPs encompasses 7 located in 5' flanking region, 2 located in exon 2 and 3 located in 3' untranslated region (UTR). Of these, the g.44601035G > A is a missense mutation that resulting in the replacement of arginine (CGG) with glutamine (CAG), consequently leading to alterations in the secondary structure of the KLF6 protein, as predicted by SOPMA. The remaining 7 regulatory SNPs significantly impacted the transcriptional activity of KLF6 following mutation (P < 0.005), manifesting as changes in transcription factor binding sites. Additionally, 4 SNPs located in both the UTR and exons were predicted to influence the secondary structure of KLF6 mRNA using the RNAfold web server. Furthermore, we performed the genotype-phenotype association analysis using SAS 9.2 which found all the 12 SNPs were significantly correlated to milk yield, fat yield, fat percentage, protein yield and protein percentage within both the first and second lactations (P < 0.0001 ~ 0.0441). Also, with Haploview 4.2 software, we found the 12 SNPs linked closely and formed a haplotype block, which was strongly associated with five milk traits (P < 0.0001 ~ 0.0203).

CONCLUSIONS

In summary, our study represented the KLF6 gene has significant impacts on milk yield and composition traits in dairy cattle. Among the identified SNPs, 7 were implicated in modulating milk traits by impacting transcriptional activity, 4 by altering mRNA secondary structure, and 1 by affecting the protein secondary structure of KLF6. These findings provided valuable molecular insights for genomic selection program of dairy cattle.

Methylation of lncSHGL promotes adipocyte differentiation by regulating miR-149/Mospd3 axis

Obesity poses significant health risks and can negatively impact an individual's quality of life. The human obesity phenotype results from the differentiation of pre-adipocytes into adipocytes, which leads to hypertrophy and hyperplasia in adipose tissue. The molecular mechanisms by which long non-coding RNAs (lncRNAs) modulate adipocyte differentiation, a process implicated in obesity development, remain poorly characterized. A lncRNA which suppressed the hepatic gluconeogenesis and lipogenesis (lncSHGL) was newly identified. Our research aims to elucidate the functional role and mechanistic underpinnings of suppressor of lncSHGL in adipocyte differentiation. We observed that lncSHGL expression progressively diminished during 3T3-L1 differentiation and was downregulated in the liver and perirenal adipose tissue of ob/ob mice. lncSHGL acts as a molecular sponge for miR-149, with Mospd3 identified as a target of miR-149.Overexpression of lncSHGL and inhibition of miR-149 led to suppressed 3T3-L1 proliferation, decreased lipid droplet accumulation, and attenuated promoter activity of PPARγ2 and C/EBPα. These changes consequently resulted in reduced expression of Cyclin D1, LPL, PPARγ2, AP2, and C/EBPα, as well as inhibited the PI3K/AKT/mTOR signaling pathway. In contrast, lncSHGL suppression yielded opposing outcomes. Moreover, the effects of lncSHGL overexpression and miR-149 inhibition on reduced expression of Cyclin D1, LPL, PPARγ2, AP2, and C/EBPα were reversible upon miR-149 overexpression and Mospd3 suppression. These findings were further validated in vivo. We also discovered a significant increase in methylation levels during 3T3-L1 differentiation, with lncSHGL highly expressed in the presence of a methylation inhibitor. In conclusion. lncSHGL methylation facilitates adipocyte differentiation by modulating the miR-149/Mospd3 axis. Targeting lncSHGL expression may represent a promising therapeutic strategy for obesity-associated adipogenesis, particularly in the context of fatty liver disease.

Bioinformatics and genetic variants analysis of FGF10 gene promoter with their association at carcass quality and body measurement traits in Qinchuan beef cattle

The fibroblast growth factor 10 (FGF10) gene regulates adipogenesis and myogensis. In this study, sequencing of FGF10 prompter region identified three SNPs at loci g.78G > A, g.116C > T and g.201A > T. Each SNP yields three genotypes as GG, GA and AA at loci g.78G > A, CC, CT and TT at loci g.116C > T and AA, AT and TT at loci g.201A > T. Allelic and genotypic frequencies of all three SNPs deviated from the Hardy-Weinberg equilibrium (HWE) (P < 0.05) and were found highly polymorphic as PIC (0.25 < PIC < 0.50). Moreover, we found highest LD (D'/γ2) between SNP2 and SNP3 (0.989/0.909), followed by SNP1 and SNP3 (0.944/0.796). Moreover, three variants of FGF10 gene promoter exhibited significant (P < 0.05) association with body measurement and carcass quality traits in Qinchuan beef cattle. At loci g.78G > A, the genotype GG showed significantly (P < 0.01) larger body length (BL), rump length (RL), chest depth (CD), chest circumference (CC) and ultrasound loin area (ULA). The genotype TC at loci g.116C > T showed significantly (P < 0.01 and 0.05) larger body measurement and intramuscular fat, and ultrasound loin area (ULA). In addition to that, at loci g.201A > T, genotype TT showed significantly (P < 0.01 and P < 0.05) larger body length (BL), rump length (RL), hip width (HW), chest circumference (CC) and ultrasound loin area (ULA). Additionally, screening of promoter sequence of FGF10 gene explored loss of four TFs binding sites (KLF3, ZNF37α, GLIS2 and BCL11A) at g.116C > T because of SNP2. However, a single TF binding site was lost at g.202A > T due to SNP3. Interestingly, none of TF binding site was lost at g.78G > A in SNP1; however, one new TF binding site was gained at this location due to SNP1. These findings conclude that genotype GG, TC and TT could be used as genetic markers of FGF10 gene for body measurement and carcass quality traits in Qinchuan beef cattle.

Genome-wide association study on abdomen depth, head width, hip width, and withers height in native cattle of Guilan (Bos indicus)

Native breeds in any country are a national capital, and their preservation is of great importance. Native Cattle of Guilan (NCG) is one of the few pure native breeds in Iran and the West Asia region. During the last decade, NCG population has decreased by more than 40%. This study aimed to identify significant single nucleotide polymorphisms (SNPs) and candidate genes associated with meat production traits in NCG using a genome-wide association study (GWAS). The blood and hair samples were collected from 72 NCG individuals and genotyped using the Illumina Bovine SNP50 chip. The results of the genomic scan showed that several SNPs were associated with abdominal depth, head width, hip width, and withers height in NCG. Several candidate genes were identified, including multiple epidermal growth factor-like domains 11 (MEGF11), Methionine Sulfoxide Reductase A (MSRA), chondroitin sulfate synthase 3 (CHSY3), Cyclin-Dependent Kinase 7 (CDK7), and Parkin (PRKN) genes, which are involved in muscle growth, meat tenderness, differentiation of fat cells, fat metabolism, and adipogenesis. These genes can contribute to meat quantity and quality in NCG. This study provided valuable insights into the genetics of NCG and the identification of effective genes associated with meat production traits. The results of this study could be used for the preservation and sustainable use of this breed of native cattle, as an important genetic resource in Iran.

New insight into copy number variations of goat SMAD2 gene and their associations with litter size and semen quality

Copy number variations (CNV) contribute significantly to genetic variations. Numerous studies have shown that CNV affects phenotypic traits in livestock. The SMAD family member 2 (SMAD2) is a leading candidate gene in reproduction and has a crucial effect on litter size. Additionally, SMAD2 is also required for male reproduction and influences male germ cell development. However, there are no reports on investigating the effect of CNVs in the SMAD2 gene on reproductive traits in goat. Therefore, the goal of this study was to explore associations between CNV of the SMAD2 gene and litter size and semen quality in Shaanbei white cashmere (SBWC) goats. In this study, two CNVs within the SMAD2 were identified in 352 SBWC goats (50 males and 302 females). The association analysis revealed that only CNV2 was significantly associated with female goat first-born litter size (P = 3.59 × 10^-4), male semen concentration (P < 0.01), ejaculation volume, live sperm count, and sperm deformity rate (P < 0.05). In terms of phenotypic performance, the individuals with loss genotypes outperformed those with other genotypes. CNV1 and CNV2 genotype combinations containing their dominant genotypes were also associated with goat litter size (P = 1.7 × 10^-5), but no differences in semen quality were found. In summary, CNV2 of the SMAD2 gene is useful for molecular marker-assisted selection breeding, as it is associated with essential goat reproductive traits.

Genome-Wide Analysis of the KLF Gene Family in Chicken: Characterization and Expression Profile

The kruppel-like factor (KLF) gene family is a group of transcription factors containing highly conserved zinc-finger motifs, which play a crucial role in cell proliferation and differentiation. Chicken has been widely used as a model animal for analyzing gene function, however, little is known about the function of the KLF gene family in chickens. In this study, we performed genome-wide studies of chicken KLF genes and analyzed their biological and expression characteristics. We identified 13 KLF genes from chickens. Our phylogenetic, motif, and conserved domain analyses indicate that the KLF gene family has remained conserved through evolution. Synteny analysis showed the collinear relationship among KLFs, which indicated that they had related biomolecular functions. Interaction network analysis revealed that KLFs worked with 20 genes in biological processes. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that KLF2 was involved in Apelin and Forkhead Box O (FOXO) signaling pathways. Moreover, qPCR showed that 13 KLF genes were expressed in the nine selected tissues and displayed various gene expression patterns in chickens. RNA-seq showed that KLF3 and KLF10 genes were differentially expressed in the normal and high-fat diet fed groups, and KLF4, KLF5, KLF6, KLF7, KLF9, KLF12, and KLF13 genes were differentially expressed between undifferentiated and differentiated chicken preadipocytes. Besides, RNA-seq also showed that KLF genes displayed different expression patterns in muscle at 11 and 16 embryonic days old, and in 1-day-old chickens. These results indicated that the KLF genes were involved in the development of muscle and fat in chickens. Our findings provide some valuable reference points for the subsequent study of the function of KLF genes.

Effects of Probiotics Supplementation on the Intestinal Metabolites, Muscle Fiber Properties, and Meat Quality of Sunit Lamb

The development of animal husbandry is closely related to the meat quality of small ruminants. Intestinal metabolites and the muscle fiber types of lambs are important factors that affect their meat quality, but few studies have examined the regulation of the "intestinal muscle axis" by probiotics. In this study, 12 Sunit lambs were divided into a control group (C) and a probiotics group (P). The gene expressions of the myosin heavy chain, metabolic enzyme activity, and short-chain fatty acids in the intestines were analyzed using gas chromatography-mass spectrometry (GC-MS) and quantitative real-time PCR. The results showed that levels of propionic acid and butyric acid in the intestines of group P were significantly higher than in group C (p < 0.05). In addition, probiotics increased the number and area ratio of type I muscle fibers. They also increased the mRNA expression of MyHC IIA and the activity of malate dehydrogenase (MDH) and succinate dehydrogenase (SDH). Propionic acid was negatively correlated with the number ratio of type IIB muscle fibers. Butyric acid was found to be significantly positively correlated with the number ratio of type IIA muscle fibers. Cooking loss, pH_24h, and shear force decreased significantly in group P. In conclusion, intestinal metabolites (SCFAs) altered the activity of oxidative-myofibril-metabolizing enzymes and the expression of myosin heavy-chain type IIA, reduced the meat shear values, and improved meat tenderness. This study provides a new basis for improving the production and meat quality of small ruminants.

Deciphering the Key Regulatory Roles of KLF6 and Bta-miR-148a on Milk Fat Metabolism in Bovine Mammary Epithelial Cells

MicroRNAs (miRNAs) are non-coding RNAs that regulate the expression of their target genes involved in many cellular functions at the post-transcriptional level. Previously, bta-miR-148a showed significantly high expression in bovine mammary epithelial cells (BMECs) of Chinese Holstein cows producing high milk fat compared to those with low milk fat content. Here, we investigated the role of bta-miR-148a through targeting Krüppel-like factor 6 (KLF6) and further analyzed the role of KLF6 in regulating fat metabolism through targeting PPARA, AMPK/mTOR/PPARG, and other fat marker genes in BMECs of Chinese Holstein. The bioinformatics analysis showed that the 3’ UTR of KLF6 mRNA possesses the binding sites for bta-miR-148a, which was further verified through dual-luciferase reporter assay. The BMECs were transfected with bta-miR-148a-mimic, inhibitor, and shNC, and the expression of KLF6 was found to be negatively regulated by bta-miR-148a. Moreover, the contents of triglyceride (TG), and cholesterol (CHO) in BMECs transfected with bta-miR-148a-mimic were significantly lower than the contents in BMECs transfected with bta-miR-148a-shNC. Meanwhile, the TG and CHO contents were significantly increased in BMECs transfected with bta-miR-148a-inhibitor than in BMECs transfected with bta-miR-148a-shNC. In addition, the TG and CHO contents were significantly decreased in BMECs upon the down-regulation of KLF6 through transfection with pb7sk-KLF6-siRNA1 compared to the control group. Contrarily, when KLF6 was overexpressed in BMECs through transfection with pBI-CMV3-KLF6, the TG and CHO contents were significantly increased compared to the control group. Whereas, the qPCR and Western blot evaluation of PPARA, AMPK/mTOR/PPARG, and other fat marker genes revealed that all of the genes were considerably down-regulated in the KLF6-KO-BMECs compared to the normal BMECs. Taking advantage of deploying new molecular markers and regulators for increasing the production of better-quality milk with tailored fat contents would be the hallmark in dairy sector. Hence, bta-miR-148a and KLF6 are potential candidates for increased milk synthesis and the production of valuable milk components in dairy cattle through marker-assisted selection in molecular breeding. Furthermore, this study hints at the extrapolation of a myriad of functions of other KLF family members in milk fat synthesis.

Polymorphisms of the Growth Hormone Releasing Hormone Receptor Gene Affect Body Conformation Traits in Chinese Dabieshan Cattle

This study was performed to expose the polymorphisms of the growth hormone-releasing hormone receptor gene in Chinese Dabieshan cattle, evaluate its effect on body conformation traits, and find potential molecular markers in Chinese cattle. The GHRHR structure and the phylogenetic tree were analyzed using bioinformatics software. The polymorphism of the GHRHR gene in 486 female cattle was genotyped by PCR-RFLP and DNA sequencing, and the association between SNPs and body conformation traits of Chinese Dabieshan cattle was analyzed by one-way ANOVA in SPSS software. GHRHR was often conserved in nine species, and its sequence of cattle was closest to sheep and goats. Six polymorphic SNPs were identified, g.10667A > C and g.10670A > C were missense mutation. The association analysis indicated that the six SNPs significantly influenced the body conformation traits of Chinese Dabieshan cattle (p < 0.05). Six haplotypes were identified and Hap1 (-CAACGA-) had the highest frequency (36.10%). The Hap3/5 (-GCCCCCGGAAGG-) exhibited a significantly greater wither height (WH), hip height (HH), heart girth (HG), and hip width (HW) (p < 0.05). Overall, the polymorphisms of GHRHR affected the body conformation traits of Chinese Dabieshan cattle, and the GHRHR gene could be used as a molecular marker in Dabieshan cattle breeding programs.

Association of variants in FABP4, FASN, SCD, SREBP1 and TCAP genes with intramuscular fat, carcass traits and body size in Chinese Qinchuan cattle

This study aimed to genotype the variants in FABP4, FASN, SCD, SREBP1 and TCAP genes, and to analyze their associations with intramuscular fat (IMF) content, carcass traits and body size in Chinese Qinchuan cattle (QC). The association studies showed that the FABP4 c.220A > G polymorphism was significantly associated with ultrasound longissimus muscle depth (ULMD) and IMF, the FASN g.16024A > G polymorphism was significantly associated with ULMD and some body size traits, the SREBP1 84 bp indel was significantly associated with back fat thickness, ULMD and some body size traits. The frequencies of well-characterized A allele in FABP4 c.220A > G in Korean cattle (KOR) and Japanese Black cattle (JB), T allele in SCD g.8586C > T in KOR, SS genotype in SREBP1 84 bp indel in KOR and JB, DELDEL genotype in TCAP g.592-597CTGCAGinsdel in KOR were significantly higher than in Chinese cattle breeds. Thus, the associated four polymorphisms were expected to be genetic selection markers for meat quality, carcass traits and body size of QC.

Genetic variants in the serum amyloid A2 (SAA2) gene as a potential marker for milk production traits in Chinese Holstein cows

Background

This study was conducted to detect potential polymorphisms of the serum amyloid A2 (SAA2) gene and explore their relationships with milk production traits in Chinese Holstein cows.

Objectives: This study used

sequencing technology conducted in 532 Chinese Holstein cows.

Methods

Three single nucleotide polymorphisms (SNPs) were identified within intron 1, named g.14061A>G, g.14072G>C and g.14819C>T. Eight estimated haplotypes were identified, of which three major haplotypes had a frequency of Hap3 (‐ACC‐), Hap5 (‐GCC‐) and Hap2 (‐AGT‐), with 17.9%, 12.30% and 8.10%, respectively.

Results

The association analysis of single markers (g.14061A>G and g.14819C>T) and combined genotypes (Hap1/5) revealed prominent effects on milk production traits in Chinese Holstein cows (p < 0.05).

Conclusions

Our results suggest that the SAA2 gene is associated with economic traits in Chinese Holstein cows and may be used as candidate gene for marker‐assisted selection and management in breeding programs.

Effect of genetic variants in the SMAD1 and SMAD5 genes promoter on growth and beef quality traits in cattle

The SMAD1 and SMAD5 genes belong to mothers against decapentaplegic proteins family, which participate in the BMP pathway to control skeletal myogenesis and growth. In the present study, we analyzed the associations between polymorphisms of SMAD1 and SMAD5 genes promoter and important economical traits in Qinchuan cattle. Four SNPs in the SMAD1 gene promoter and three SNPs in the SMAD5 promoter were identified by sequencing of 448 Qinchuan cattles. Allelic and frequency analyses of these SNPs resulted in eight haplotypes both in the promoters of the two genes promoter and identified potential cis-regulatory transcription factor (TF) components. In addition, correlation analysis showed that cattle SMAD1 promoter activity of individuals with Hap4 (P < 0.01) was stronger than that of individuals with Hap2. while the transcriptional activity of individuals with Hap3 within SMAD5 gene promoter was significantly (P < 0.01) higher followed by H2. Uniformly, diplotypes H4-H6 of SMAD1 gene and H1-H3 of SMAD5 gene performed significant (P < 0.01) associations with body measurement and improved carcass quality traits. All these results have indicated that polymorphisms in SMAD1 and SMAD5 genes promoter could impact the transcriptional regulation and then affect muscle content in beef cattle. Moreover, both the SMAD1 and SMAD5 genes were expressed ubiquitously in 10 tissues and had higher expression in the longissimus thoracis tissue from 6-month-old and 12-month-old cattle than in cattle of other ages. We can conclude that SMAD1 and SMAD5 genes may play an important role in muscle growth and development, and the variants mapped within SMAD1 and SMAD5 genes can be utilized in molecular marker-assisted selection for cattle carcass quality and body measurement traits in breed improvement programs of Qinchuan cattle.

Expression of different genotypes of bovine TRDMT1 gene and its polymorphisms association with body measures in Qinchuan cattle (Bos Taurus)

DNA methyltransferase 2 (DNMT2) was renamed as tRNA aspartic acid methyltransferase 1 (TRDMT1) by catalyzing the methylation of tRNA^Asp anti-codon loop C38. The development of sequencing of nucleic acids and protein detection techniques have prompted the demonstration that TRDMT1 mediated tRNA modification affects protein synthesis efficiency. This process affects the growth and development of animals. The DNA of 224 Qinchuan cattles aged 2-4 years old was collected in this experiment. The genetic variations of TRDMT1 exon and some intron regions were detected by mixed pool sequencing technology. qRT-PCR and Western Blot were used to detect the expression levels of mRNA and protein produced with the combination of different genetic variant loci. Three haplotypes were detected and the distribution ratios were different. Muscle tissue mRNA and protein testing showed that there were differences in mRNA expression levels among different genotypes (P < 0.05) and the protein expression levels between different genotypes show the same trend as mRNA. This study provides potential molecular materials for the improvement of Qinchuan cattle reproductivity and provides theoretical support for studying the effects of livestock TRDMT1 on animal growth and development.

Association of SNPs in AKIRIN2, TTN, EDG1 and MYBPC1 genes with growth and carcass traits in Qinchuan cattle

Growth and carcass traits are the main breeding objectives in beef cattle. The aim of this study was to confirm genetic effects of the c.*188G>A SNP of AKIRIN2, the g.231054C>T SNP of TTN, the g.1471620G>T SNP of EDG1 and the g.70014208A>G SNP of MYBPC1 on growth and carcass traits in Chinese Qinchuan (QC) cattle, as well as to compare the frequencies of the well-characterized alleles of these SNPs among six Chinese cattle populations, three Japanese cattle populations, two European cattle populations and one Korean cattle population. In this study, a total of 665 cattle samples were genotyped using MassARRAY and PCR-RFLP. Association analysis explored effects of four SNPs on growth and carcass traits including body length, wither height, hip height, hip width, rump length, chest depth, chest circumference, back fat thickness, ultrasound longissimus muscle area and ultrasound longissimus muscle depth in QC (P<0.05 to P<0.001). The well-characterized A (c.*188G>A), T (g.231054C>T) and T (g.1471620G>T) alleles in Japanese Black cattle were significantly higher than Chinese cattle breeds, on the contrary, the G allele (g.70014208A>G) was markedly higher in Chinese cattle breeds than other cattle breeds. These results suggest that the four SNPs might be useful as a molecular marker for growth-related traits in Chinese QC cattle.

Bioinformatics analysis and genetic polymorphisms in genomic region of the bovine SH2B2 gene and their associations with molecular breeding for body size traits in qinchuan beef cattle

The Src homology 2 B 2 (SH2B2) gene regulate energy balance and body weight at least partially by enhancing Janus kinase-2 (JAK2)-mediated cytokine signaling, including leptin and/or GH signaling. Leptin is an adipose hormone that controls body weight. The objective of the present study is to evaluate the association between body measurement traits and SH2B2 gene polymorphisms as responsible mutations. For this purpose, we selected four single-nucleotide polymorphisms (SNPs) in SH2B2 gene, including two in intron 5 (g.20545A>G, and g.20570G>A, one synonymous SNP g.20693T>C, in exon 6 and one in intron 8 (g.24070C>A, and genotyped them in Qinchuan cattle. SNPs in sample populations were in medium polymorphism level (0.250<PIC<0.500). Association study indicated that the g.20570G>A, g.20693T>C, and g.24070C>A, significantly (P < 0.05) associated with body length (BL) and chest circumference (CC) in Qinchuan cattle. In addition, H4H3 and H5H5 diplotype had highly significantly (P < 0.01) greater body length (BL), rump length (RL), and chest circumference (CC) than H4H2. Our investigation will not only extend the spectrum of genetic variation of bovine SH2B2 gene, but also provide useful information for the marker assisted selection in beef cattle breeding program.

Novel mutations in the signal transducer and activator of transcription 3 gene are associated with sheep body weight and fatness traits

The signal transducer and activator of transcription 3 (STAT3) gene plays a crucial role in leptin-mediated energy metabolism, upon which the growth and development of animals depend. Nevertheless, no studies have reported the effects of STAT3 gene polymorphisms on body weight and fatness modulation in sheep. This study aimed to illustrate STAT3 mRNA expression across tissues and various developmental stages of sheep and to highlight the association of STAT3 gene polymorphisms with body weight and fat-related traits in sheep, in order to identify a genetic marker that may conceivably be of value for marker-assisted selection (MAS). This study revealed that STAT3 was differentially expressed across age and sex (p < 0.05), with higher expression in the ram liver. The abundant expression of STAT3 in the liver of male sheep and increased expression in the hypothalamus and longissimus dorsi muscle from birth to six months of age may indicate the vital role of the STAT3 gene in animal growth and development. Moreover, SNP association analysis also revealed that the novel SNPs of the STAT3 gene detected in this study showed a significant association with body weight and fatness traits (p < 0.05). In conclusion, the significant genetic effects of the STAT3 gene polymorphisms on sheep growth and development revealed that STAT3 could be a marker gene for the selection of growth-related traits in sheep.

Transcriptional regulation of adipogenic marker genes for the improvement of intramuscular fat in Qinchuan beef cattle

The intramuscular fat content plays a crucial role in meat quality traits. Increasing the degree of adipogenesis in beef cattle leads to an increase in the content of intramuscular fat. Adipogenesis a complex biochemical process which is under firm genetic control. Over the last three decades, the Qinchuan beef cattle have been extensively studied for the improvement of meat production and quality traits. In this study, we reviewed the literature regarding adipogenesis and intramuscular fat deposition. Then, we summarized the research conducted on the transcriptional regulation of key adipogenic marker genes, and also reviewed the roles of adipogenic marker genes in adipogenesis of Qinchuan beef cattle. This review will elaborate our understanding regarding transcriptional regulation which is a vital physiological process regulated by a cascade of transcription factors (TFs), key target marker genes, and regulatory proteins. This synergistic action of TFs and target genes ensures the accurate and diverse transmission of the genetic information for the accomplishment of central physiological processes. This information will provide an insight into the transcriptional regulation of the adipogenic marker genes and its role in bovine adipogenesis for the breed improvement programs especially for the trait of intramuscular fat deposition.

The role of BAMBI in regulating adipogenesis and myogenesis and the association between its polymorphisms and growth traits in cattle

Bone morphogenic protein and activin membrane-bound inhibitor (BAMBI) is a transmembrane protein that affects the growth, development and muscle regeneration of the body by regulating the TGF-β, BMP and Wnt signaling pathways. Studies have found that BAMBI has important regulatory functions in skeletal muscle and preadipocytes in vivo and in vitro. However, research on this protein in cattle is lacking. In this study, to determine the role of BAMBI in the growth and development of cattle, we first found that the expression of BAMBI in adipose tissue and longissimus muscle of newborn and adult Qinchuan beef cattle was significantly different. Then we showed that BAMBI knockdown promoted the differentiation of bovine preadipocytes and suppressed myoblast myogenesis, as indicated by the increased lipid droplets and the decreased myotubes, as well as the corresponding significant changes in the expression of PPARγ, C/EBPα, C/EBPβ, FABP4, MyoD, MyoG and Myf6. Finally, to further verify the effect of BAMBI on the growth performance of cattle, we identified seven novel SNPs in the BAMBI genomic region, which were significantly correlated with one or more growth traits (p < 0.05). Furthermore, individuals with haplotype H1H4 (TC-GA-CT-CA-AT-AT-AG) had a higher body and carcass quality than those with other haplotypes (p < 0.05). In brief, BAMBI may be a functional gene for the differentiation of bovine preadipocytes and myoblasts, and variations in the BAMBI genomic region, especially the combined haplotype H1H4, may benefit marker-assisted selection in cattle.

Role of promoting inflammation of Krüppel-like factor 6 in acute kidney injury

Background

Krüppel-like factor 6 (KLF6) is a transcription factor that participate in various pathophysiological processes, but its contribution in ischemia acute kidney injury (AKI) is lacking so far. The study aimed to investigate the expression and the role of KLF6 in kidney ischemia–reperfusion (IR) injury.

Method

Microarray data were collected from GSE58438 and GSE52004. The rat IR model was established to evaluate the mRNA and protein expression of KLF6 and inflammatory cytokines in serum and kidney tissues. SiRNA-KLF6 was transfected with HK-2 cells, and then a cell-based hypoxia-reoxygenation (HR) model was established.

Results

Bioinformatics showed KLF6 mRNA in kidney tissue is up-regulated in 3 h after IR in rat kidney, which involved in cell activation, leukocyte activation, and response to hydrogen peroxide after IR. The rat IR model results showed that KLF6 expression was peaking at 6 h, and the expression of pro-inflammatory cytokines MCP-1 and TNF-α was increased both in serum and kidney tissues, while anti-inflammatory cytokine IL-10 was decreased after IR. Furthermore, in vitro results showed that KLF6 knock-down reduced the pro-inflammatory cytokines expression.

Conclusion

These results suggest that (1) KLF6 might be a novel biomarker for early diagnosis of AKI and (2) KLF6 may play a role in promoting inflammation in AKI.

Polymorphism of the PLIN1 gene and its association with body measures and ultrasound carcass traits in Qinchuan beef cattle

The PLIN1 gene produces a phosphorylated protein wrapped in lipid droplets in adipocytes. This phosphorylation assists the mobilization of fat into adipose tissue. The purpose of the experiment was to study the polymorphism of the PLIN1 gene and its relationship with the body and carcass characteristics of Qinchuan cattle to find molecular genetic markers that can be used for breeding. The expression level of the PLIN1 gene was determined in various tissues by qRT-PCR. The results showed that the highest level of PLN1 expression was found in subcutaneous fat, followed by the heart and longissimus muscle, and the lowest level was found in the kidney. Five SNP loci of the PLIN1 gene were identified in 510 Qinchuan cattle, including g.3580T>C (SNP1), g.3898G>A (SNP2), g.8333G>A (SNP3), g.10517T>C (SNP4), and g.10538G>T (SNP5). The results show that SNP1, SNP2, SNP3, and SNP4 were moderately polymorphic (0.25 < PIC < 0.5), while SNP5 was minimally polymorphic (PIC < 0.25). SNP2, SNP3, and SNP5 were within Hardy-Weinberg equilibrium (P > 0.05), but SNP1 and SNP4 were not (P < 0.05). Correlation analysis showed that the five SNPs of the PLIN1 gene were correlated with back-fat depth, intramuscular fat, and chest depth of Qinchuan cattle. The double haplotype H2H4 in Qinchuan beef was associated with body and carcass traits. We conclude that variants mapped within PLIN1 can be used in marker-assisted selection for carcass quality and body traits in breed improvement programs for Qinchuan cattle.

Genetic variants in MYF5 affected growth traits and beef quality traits in Chinese Qinchuan cattle

Myogenic factor 5 plays actively roles in the regulation of myogenesis. The aims of this study are to identify the evolution information of MYF5 protein among 10 domestic and mammalian animals, to uncover the expression patterns of MYF5 gene in calves and adults of Qinchuan cattle, and to expose the genetic variants of the MYF5 gene and explore its effect on cattle growth traits and beef quality traits in Qinchuan cattle. The bioinformatics results showed that the MYF5 proteins highly conserved in different mammalian or domestic animals apart from chicken. The expression level of MYF5 gene in the heart, muscle, lung, large intestine and liver was greater than that of other tissues. PCR amplicons sequencing identified four novel SNPs at g.5738A>G, g.5785C>T and g.5816A>G in the 3rd exon region and g.6535A>G in the 3' UTR. Genotypic frequencies of g.5785C>T was harshly deviated from the HWE (P < .05). Genetic diversity was low or intermediate for the four SNPs and those SNPs were in the weak linkage disequilibrium. Association analysis results indicated g.5785C>T, g.5816A>G and g.6535A>G significant effect on growth performance and beef quality traits of Qinchuan cattle. H1H3 diplotype had greater body size and better beef quality. All the results implicate that the MYF5 gene might be applied as a promising candidate gene in Qinchuan cattle breeding.

Genetic variants in the TORC2 gene promoter and their association with body measurement and carcass quality traits in Qinchuan cattle

The TORC2 gene is responsible for nutrient metabolism, gluconeogenesis, myogenesis and adipogenesis through the PI3K-Akt, AMPK, glucagon and insulin resistance signaling pathways. Sequencing of PCR amplicons explored three novel SNPs at loci g.16534694G>A, g.16535011C>T, and g.16535044A>T in the promoter region of the TORC2 gene in the Qinchuan breed of cattle. Allelic and genotypic frequencies of these SNPs deviated from Hardy-Weinberg equilibrium (HWE) (P < 0.05). SNP1 genotype GG, SNP2 genotype CT and SNP3 genotype AT showed significantly (P <0.05) larger body measurement and improved carcass quality traits. Haplotype H1 (GCA) showed significantly (p<0.01) higher transcriptional activity (51.44%) followed by H4 (ATT) (34.13%) in bovine preadipocytes. The diplotypes HI-H3 (GG-CC-AT), H1-H2 (GG-CT-AT) and H3-H4 (GA-CT-TT) showed significant (P<0.01) associations with body measurement and improved carcass quality traits. Analysis of the relative mRNA expression level of the TORC2 gene in different tissues within two different age groups revealed a significant increase (P<0.01) in liver, small intestine, muscle and fat tissues with growth from calf stage to adult stage. We can conclude that variants mapped within TORC2 can be used in marker-assisted selection for carcass quality and body measurement traits in breed improvement programs of Qinchuan cattle.

The Molecular Characteristics of the FAM13A Gene and the Role of Transcription Factors ACSL1 and ASCL2 in Its Core Promoter Region

The gene family with sequence similarity 13 member A (FAM13A) has recently been identified as a marker gene in insulin sensitivity and lipolysis. In this study, we first analyzed the expression patterns of this gene in different tissues of adult cattle and then constructed a phylogenetic tree based on the FAM13A amino acid sequence. This showed that subcutaneous adipose tissue had the highest expression in all tissues except lung tissue. Then we summarized the gene structure. The promoter region sequence of the gene was successfully amplified, and the -241/+54 region has been identified as the core promoter region. The core promoter region was determined by the unidirectional deletion of the 5' flanking promoter region of the FAM13A gene. Based on the bioinformatics analysis, we examined the dual luciferase activity of the vector constructed by the mutation site, and the transcription factors ACSL1 and ASCL2 were found as transcriptional regulators of FAM13A. Moreover, electrophoretic mobility shift assay (EMSA) further validated the regulatory role of ACSL1 and ASCL2 in the regulation of FAM13A. ACSL1 and ASCL2 were finally identified as activating transcription factors. Our results provide a basis for the function of the FAM13A gene in bovine adipocytes in order to improve the deposition of fat deposition in beef cattle muscle.

Advances of Molecular Markers and Their Application for Body Variables and Carcass Traits in Qinchuan Cattle

This review considers the unique characteristics of Chinese cattle and intramuscular fat content (IMF) as factors influencing meat quality, including tenderness, flavor, and juiciness of meat. Due to its nutritional qualities, meat contributes to a healthy and balanced diet. The intramuscular fat content and eating quality of beef are influenced by many factors, which can generally be divided into on-farm and pre-slaughter factors (breed, sex of cattle, age at slaughter, housing system, diet, and pre-slaughter handling) and postmortem factors (post-slaughter processing, chilling temperature, and packaging). Meat quality traits can also be influenced by the individual genetic background of the animal. Worldwide, the function of genes and genetic polymorphisms that have potential effects on fattening of cattle and beef quality have been investigated. The use of DNA markers is recognized as a powerful and efficient approach to achieve genetic gain for desirable phenotypic characteristics, which is helpful for economic growth. The polymorphisms of the SIRT4, SIRT6, SIRT7, CRTC3, ABHD5, KLF6, H-FABP, and ELOVL6 genes for body and growth characteristics of cattle, and also for beef quality, are considered with the aim of highlighting the significance of beef intramuscular fat content, and that growth, body, and meat quality characteristics are polygenically regulated.

The effect of haplotypes in the promoter region of SIRT4 gene on the ultrasound traits in Qinchuan cattle

Sirtuin 4 (SIRT4) belongs to the mitochondrial sirtuin class of NAD⁺-dependent protein deacylases. This gene plays an important role in the regulation of lipid metabolism, cellular growth, and metabolism in mammals. Here, potential polymorphisms were sought in the bovine SIRT4 gene, and the relationships between the detected polymorphisms and carcass quality in Qinchuan cattle were assessed. Four single nucleotide polymorphisms (SNPs) were identified in the promoter region of the SIRT4 gene from the sequencing results of 452 individual cattle. A total of 8 different haplotypes were identified. Of these, the 3 most frequently observed haplotypes had frequencies of 35.0% (-CTG-), 18.3% (-CTA-), and 12.9% (-CCG-). The frequencies of g.-311C > T, g.-771C > T, and g.-1022G > A conformed to Hardy-Weinberg equilibrium in all the samples (chi-square test, P < 0.05). The association analysis indicated that these 3 polymorphisms were significantly associated with subcutaneous fat depth and intramuscular fat content (at P < 0.01 or P < 0.05). Interestingly, the Hap1/2 (-CAG-CAA-) diplotype was more highly associated with desirable ultrasound than other haplotype combinations.