Dataset Information

Pleiotropic effects of the gene diacylglycerol-O-transferase 1 (DGAT1) polymorphism in the mammary gland tissue of dairy cows

ABSTRACT: The objective of this study was to determine the effect of the DGAT1 K232A polymorphism on the global mRNA expression pattern of genes in the mammary gland tissue of grazing dairy cows in order to get more insight into the effects of this polymorphism on the physiology of the mammary glandgland of grazing dairy cows. Microarray analysis was used to identify genes whose expression was affected by the DGAT1 polymorphism in the mammary gland biopsies of 9 A232A cows, 13 K232A cows, and 4 K232K cows. The Microarray Analysis of Variance (MAANOVA) and Factor Analysis for Multiple Testing method (FAMT) were used to associate the expression of the genes present on Affymettrix Bovine Genome Arrays with the DGAT1 polymorphism. The data was also analysed at the level of functional modules by gene set enrichment analysis. In this experimental setting, DGAT1 polymorphism did not modify milk yield and composition significantly, although changes occurred in the yields of C14:0, C16:1cis-9, and some long chain fatty acids in milk. The DGAT1 polymorphism resulted in 30 differentially expressed genes related to cell growth, proliferation and development, signalling, remodelling and immune system. At the functional level, the pathways most affected by DGAT1 polymorphism were related to lipid biosynthesis, which likely reflected counter mechanisms of mammary tissue to respond to changes in milk FA composition, signalling, as well as immune system responses.

ORGANISM(S): Bos taurus

PROVIDER: GSE33720 | GEO | 2012/12/01

SECONDARY ACCESSION(S): PRJNA148457

REPOSITORIES: GEO

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Project description:The objective of this study was to determine the effect of the DGAT1 K232A polymorphism on the global mRNA expression pattern of genes in the mammary gland tissue of grazing dairy cows in order to get more insight into the effects of this polymorphism on the physiology of the mammary glandgland of grazing dairy cows. Microarray analysis was used to identify genes whose expression was affected by the DGAT1 polymorphism in the mammary gland biopsies of 9 A232A cows, 13 K232A cows, and 4 K232K cows. The Microarray Analysis of Variance (MAANOVA) and Factor Analysis for Multiple Testing method (FAMT) were used to associate the expression of the genes present on Affymettrix Bovine Genome Arrays with the DGAT1 polymorphism. The data was also analysed at the level of functional modules by gene set enrichment analysis. In this experimental setting, DGAT1 polymorphism did not modify milk yield and composition significantly, although changes occurred in the yields of C14:0, C16:1cis-9, and some long chain fatty acids in milk. The DGAT1 polymorphism resulted in 30 differentially expressed genes related to cell growth, proliferation and development, signalling, remodelling and immune system. At the functional level, the pathways most affected by DGAT1 polymorphism were related to lipid biosynthesis, which likely reflected counter mechanisms of mammary tissue to respond to changes in milk FA composition, signalling, as well as immune system responses. A total of 28 Holstein-Friesian dairy cows in mid-lactation (DIM; 153 M-BM-1 32.8 days), milk yield (25.7 M-BM-1 3.08 kg/d) and fat content (4.3 M-BM-1 0.12%) were used in the study. Two consecutive milk samples (a.m. and p.m. milking) were obtained and pooled. One aliquot was stored at 4M-BM-0C until analysis of fat, protein and lactose percentage, and another aliquot was frozen at -20M-BM-0C until analysis for FA composition by gas chromatography. Specific details regarding the analysis of FA in milk are presented in Mach et al. (2011). Approximately 750 to 1,000 mg of mammary tissue from each cow was obtained by surgical biopsy. One part of the tissue was used for isolation of DNA and the other for extraction of the RNA. Genotyping of the DGAT1 polymorphism was performed using a TaqMan allelic discrimination method in an Applied Biosystems 7500 Real-Time PCR System (Applied Biosystems) as described by Schennink et al. (2007). The genotype at the DGAT1 locus was designated KK, KA, or AA for homozygous Lysine, heterozygous Lysine/Alanine, or homozygous Alanine, respectively. Microarray analysis was used to identify genes whose expression was affected by the DGAT1 polymorphism in the mammary gland biopsies of 11 A232A cows, 13 K232A cows, and 4 K232K cows. Total RNA from mammary gland tissue (50-100 mg) was isolated using TRIzol reagent (Invitrogen, Breda, The Netherlands), following the manufacturerM-bM-^@M-^Ys instructions. The RNA purity and concentrations were determined using a NanoDrop ND-1000 spectrophotometer (Isogen, Maarssen, the Netherlands), and the RNA quality was assessed using the BioAnalyzer 2100 (Agilent Technologies, Amsterdam, the Netherlands). The RNA of each biopsy was amplified, biotin-labeled, and hybridized to single-dye Affymetrix GeneChipM-BM-. Bovine Genome Array (#900493) by ServiceXS (Leiden, the Netherlands)

Project description:Effect of breed in mid lactation Holstein (H) and Montbéliarde (M) cows on mammary glande miRNA profile. Genetic polymorphisms are known to influence milk production and composition. However, genomic mechanisms involved in the genetic regulation of milk component synthesis are not completely understood. MicroRNAs (miRNA) regulate gene expression. The objective of the present study was to compare mammary gland miRNomes of two dairy cow breeds, Holstein and Montbéliarde, with different dairy performances. Milk, fat, protein, and lactose yields were lower in Montbéliarde than in Holstein cows. MiRNomes obtained using RNA-Seq technology from the mammary glands of Holstein (n = 5) and Montbéliarde (n = 6) lactating cows revealed 623 distinct expressed miRNAs, among which 596 were known and 27 were predicted miRNAs. The comparison of their abundance in the mammary gland of Holstein versus Montbéliarde cows showed 22 differentially expressed miRNAs (Padj ≤ 0.05). Among them, 11 presented a fold change ≥2, with 2 highly expressed miRNAs (miR-100 and miR-146b). Without taking into account the fold change, the differential miRNA with the highest abundance was miR-186, which is known to inhibit cell proliferation and epithelial-to-mesenchymal transition. Data mining showed that the 17 differentially expressed miRNAs with more than 20 reads on average, regulate mammary gland plasticity and may be related to the observed differences in milk production between Holstein and Montbéliarde, which are two breeds with different mammogenic potential. Some of the 17 miRNAs could potentially target mRNAs involved in signaling pathways (such as mTOR) and in lipid metabolism, thereby suggesting that they could influence milk composition. In conclusion, we showed differences in mammary gland miRNomes of two dairy bovine breeds. These differences suggest a potential role of miRNAs in mammary gland plasticity and in milk component synthesis related to milk production and composition.

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Pleiotropic effects of the gene diacylglycerol-O-transferase 1 (DGAT1) polymorphism in the mammary gland tissue of dairy cows

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