Triacylglycerol synthesis in goat mammary gland. Factors influencing the esterification of fatty acids synthesized de novo.
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ABSTRACT:
SUBMITTER: Hansen HO
PROVIDER: S-EPMC1153655 | biostudies-other | 1984 Jun
REPOSITORIES: biostudies-other
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Project description:BACKGROUND:Nutrition affects milk composition thus influencing its nutritional properties. Nutrition also modifies the expression of mammary genes, whose regulation is not fully understood. MicroRNAs (miRNA) are small non coding RNA which are important post-transcriptional regulators of gene expression by targeting messenger RNAs. Our goal was to characterize miRNA whose expression is regulated by nutrition in the lactating goat mammary gland, which may provide clues to deciphering regulations of the biosynthesis and secretion of milk components. METHODOLOGY/PRINCIPAL FINDINGS:Using high-throughput sequencing technology, miRNomes of the lactating mammary gland were established from lactating goats fed ad libitum or deprived of food for 48 h affecting milk production and composition. High throughput miRNA sequencing revealed 30 miRNA with an expression potentially modulated by food deprivation; 16 were down-regulated and 14 were up-regulated. Diana-microT predictive tools suggested a potential role for several nutriregulated miRNA in lipid metabolism. Among the putative targets, 19 were previously identified as differently expressed genes (DEG). The functions of these 19 DEG revealed, notably, their involvement in tissue remodelling. CONCLUSION/SIGNIFICANCE:In conclusion, this study offers the first evidence of nutriregulated miRNA in the ruminant mammary gland. Characterization of these 30 miRNA could contribute to a clearer understanding of gene regulation in the mammary gland in response to nutrition.
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Project description:Development of mammary secretory epithelium and its functional differentiation occur during pregnancy under combined actions of ovarian steroids, pituitary hormones and growth factors. If the effect of these molecules is relatively well known, effect of differentiation factors expressed locally is not enough characterized. To understand local regulation of mammary tissue development and differentiation we realized transcriptional analysis on 5 physiological stages (4 during pregnancy and 1 during lactation). An appropriate experimental design was drawn to follow gene expression profiles during differentiation of mammary tissue. Results showed that at mid-pregnancy, mammary tissue was enough defferentiated into secretory epithelium to express milk protein genes and genes of the immune response system actors. But the secretoty activation of mammary epithelium was done only after parturition and wwas characterized by the expression of lipidogenesis genes. Keywords: time course, mammary gland differentiation, goat, pregnancy 18 samples, loop design
2010-05-16 | E-GEOD-14008 | biostudies-arrayexpress
Project description:CCAAT/enhancer binding protein α (C/EBPα) is the key transcription factor involved in lipid metabolism, however, the role of C/EBPα in milk fat synthesis of dairy goats remains unknown. The objective of the present research was to clarify the function of C/EBPα in goat mammary epithelial cells (GMECs) and its impact on peroxisome proliferator-activated receptor gamma (PPARG) promoter activity. In this study, C/EBPα overexpression increased its mRNA and protein levels by 42-fold and 6-fold, respectively. In contrast, transfecting siRNA targeting C/EBPα decreased its mRNA level to 20% and protein abundance to 80% of the basal level. The contents of lipid droplets, triacylglycerol (TAG), and cholesterol were increased (P < 0.05) in C/EBPα-overexpressing GMECs, and knockdown of C/EBPα led to the opposite results. Overexpression of C/EBPα significantly increased the expression levels of genes involved in TAG synthesis (AGPAT6, DGAT2, P < 0.01), lipid droplet formation (PLIN2, P < 0.01), and fatty acid synthesis (FADS2, P < 0.05; ELOVL6, P < 0.01). Knockdown of C/EBPα decreased (P < 0.05) the expression levels of AGPAT6, DGAT1, DGAT2, PLIN2, FADS2, and ELOVL6. C/EBPα upregulated the expression level of PPARG (P < 0.05), and four C/EBPα binding regions were identified in the PPARG promoter at -1,112 to -1,102 bp, -734 to -724 bp, -248 to -238 bp, and -119 to -109 bp. Knockdown of C/EBPα reduced (P < 0.05) the PPARG promoter activity when the C/EBPα binding regions were mutated at -1,112 to -1,102 bp, -734 to -724 bp, and -248 to -238 bp locations of the promoter. However, the promoter activity did not change when the mutation was located at -119 bp. In conclusion, our results suggest that C/EBPα can promote TAG synthesis in GMECs through its effects on mRNA abundance of genes related to lipid metabolism and regulation of the PPARG promoter activity via C/EBPα binding regions.
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Project description:Development of mammary secretory epithelium and its functional differentiation occur during pregnancy under combined actions of ovarian steroids, pituitary hormones and growth factors. If the effect of these molecules is relatively well known, effect of differentiation factors expressed locally is not enough characterized. To understand local regulation of mammary tissue development and differentiation we realized transcriptional analysis on 5 physiological stages (4 during pregnancy and 1 during lactation). An appropriate experimental design was drawn to follow gene expression profiles during differentiation of mammary tissue. Results showed that at mid-pregnancy, mammary tissue was enough defferentiated into secretory epithelium to express milk protein genes and genes of the immune response system actors. But the secretoty activation of mammary epithelium was done only after parturition and wwas characterized by the expression of lipidogenesis genes. Keywords: time course, mammary gland differentiation, goat, pregnancy
2009-12-23 | GSE14008 | GEO