Project description:Background: The mammary gland is a dynamic organ that undergoes important physiological changes during reproductive cycles. Until now, data regarding the characterisation of miRNA in the mammary gland have been scarce and mainly focused on their abnormal expression in breast cancer. Our goal was to characterise the microRNA (miRNA) involved in mechanisms regulating the mammary function, with particular focus on the lactation stage Methodology/principal findings: Using high-throughput sequencing technology, an exhaustive repertoire of miRNA (miRNome) expressed in mouse and bovine mammary glands during established lactation was identified, characterised and compared. Furthermore, in order to obtain more information on miRNA loading in the RNA-induced silencing complex (RISC), the miRNome was compared with that obtained from RNA associated with the AGO2 protein (AGO2-miRNome) in mouse lactating mammary gland. This study enabled the identification of 164 and 167 miRNA in mouse and bovine, respectively. Among the 30 miRNA most highly expressed in each species, 24 were common to both species and six of them tended to be more highly expressed in lactating than in non-lactating mammary gland. The potential functional roles of these 24 miRNA were deduced using DIANA-miRPath software, based on miRNA/mRNA interactions. Moreover, seven putative novel miRNA were identified. Using DAVID analysis, it was concluded that the predicted targets of two of these putative novel miRNA are involved in mammary gland morphogenesis. Conclusion/significance: Our study provides an overview of the characteristics of lactating mouse and bovine mammary gland miRNA expression profiles. Moreover, species-conserved miRNA involved in this fundamental biological function were identified. These miRNomes will new be used as references for further studies during which the impact of animal breeding on the miRNA expression will be analysed. microRNA profiles of mammary glands from 2 FVB/N mice at lactation day-12 and mammary biopsies from 4 Holstein dairy cows at mid-lactation, generated by deep sequencing, using Illumina HiSeq 2000.
Project description:Background: The mammary gland is a dynamic organ that undergoes important physiological changes during reproductive cycles. Until now, data regarding the characterisation of miRNA in the mammary gland have been scarce and mainly focused on their abnormal expression in breast cancer. Our goal was to characterise the microRNA (miRNA) involved in mechanisms regulating the mammary function, with particular focus on the lactation stage Methodology/principal findings: Using high-throughput sequencing technology, an exhaustive repertoire of miRNA (miRNome) expressed in mouse and bovine mammary glands during established lactation was identified, characterised and compared. Furthermore, in order to obtain more information on miRNA loading in the RNA-induced silencing complex (RISC), the miRNome was compared with that obtained from RNA associated with the AGO2 protein (AGO2-miRNome) in mouse lactating mammary gland. This study enabled the identification of 164 and 167 miRNA in mouse and bovine, respectively. Among the 30 miRNA most highly expressed in each species, 24 were common to both species and six of them tended to be more highly expressed in lactating than in non-lactating mammary gland. The potential functional roles of these 24 miRNA were deduced using DIANA-miRPath software, based on miRNA/mRNA interactions. Moreover, seven putative novel miRNA were identified. Using DAVID analysis, it was concluded that the predicted targets of two of these putative novel miRNA are involved in mammary gland morphogenesis. Conclusion/significance: Our study provides an overview of the characteristics of lactating mouse and bovine mammary gland miRNA expression profiles. Moreover, species-conserved miRNA involved in this fundamental biological function were identified. These miRNomes will new be used as references for further studies during which the impact of animal breeding on the miRNA expression will be analysed.
Project description:Milk protein is one of the most important economic traits in the dairy industry. Yet, the miRNA gene regulatory network for the synthesis of milk protein in mammary is poorly understood. In this study, the hypothesis was that miRNAs have potential roles in bovine milk protein production. Using miRNA-seq and RNA-seq, we investigated the miRNAs profiles of mammary glands from 12 Chinese Holstein cows with six cows at peak of lactation and six in non-lactating period, from which three cows were in high and three in low milk protein percentage.
Project description:A series of experiments to establish a bovine developing mammary gland gene expression signature, identify genes differentially expressed in bovine lactating mammary gland, and to establish the false positive rate of the BMAM microarray Keywords = gene expression, differential expression, lactation, development, physiology, bovine, mammary, microarray, EST, cDNA Keywords: repeat sample
Project description:Nutrition affects milk composition influencing its nutritional properties. Nutrition also modifies the expression of mammary genes, whose regulation is not completely known. MicroRNAs (miRNA) are small non-coding RNA that work as important post-transcriptional gene expression regulators by targeting messenger RNAs. Our goal was to characterize miRNA whose expression is regulated by nutrition in the lactating goat mammary gland, and which may give clues to decipher the regulations of milk components biosynthesis and secretion. Using high-throughput sequencing technology, miRNomes of the lactating mammary gland have been established from 4 goats fed ad libitum and 6 goats food deprived during 48h. Food deprivation affected the expression of 30 miRNA (padj<0.1), 16 were downregulated and 14 were upregulated. Prediction tools Diana-microT suggests a potential role of several nutriregulated miRNA in the lipid metabolism. Among putative targets 19 differently expressed genes (DEG) previously identified in the same sample, were found. Functions of these 19 DEG revealed their involvement in tissue remodeling. This study constitutes the first evidence of nutriregulated miRNA in the ruminant mammary gland. The characterization of these 30 miRNA could contribute to a better understanding of genes regulations in the mammary gland in response to nutrition. MicroRNA profiles of mammary glands from 10 Alpine goats at the peak of lactation (48 ± 2 days post-partum) generated by a HiSeq 2500 using Illumina Solexa technic.
Project description:Analysis of key genes and gene networks determining milk productivity of the dairy HF cows Transcriptomes were compared of in the mammary glands of the healthy lactating Holstein Friesian cows of the high- (average 11097 kg milk/lactation) and low- (average 6956 kg milk/lactation) milk yield.
Project description:With regulatory roles in development, cell proliferation and disease, micro-RNA (miRNA) biology is of great importance and a potential key to novel RNA-based therapeutic regimens. Biochemically based sequencing approaches have provided robust means of uncovering miRNA binding landscapes on transcriptomes of various species. However, a current limitation to the therapeutic potential of miRNA biology in cattle is the lack of validated miRNAs targets. Here, we use cross-linking immunoprecipitation (CLIP) of the Argonaute (AGO) proteins and unambiguous miRNA-target identification through RNA chimeras to define a regulatory map of miRNA interactions in the cow (Bos taurus). The resulting interactome is the deepest reported to date for any species, demonstrating that comprehensive maps can be empirically obtained. We observe that bovine miRNA targeting principles are consistent with those observed in other mammals. Motif and structural analyses define expanded pairing rules with most interactions combining seed-based pairing with distinct, miRNA-specific patterns of auxiliary pairing. Further, miRNA-target chimeras had predictive value in evaluating true regulatory sites of the miR-17 family. Finally, we define miRNA-specific targeting for >5000 mRNAs and determine gene ontologies (GO) for these targets. This confirmed repression of genes important for embryonic development and cell cycle progress by the let-7 family, and repression of those involved in cell cycle arrest by the miR-17 family, but it also suggested a number of unappreciated miRNA functions. Our results provide a significant resource for transcriptomic understanding of bovine miRNA regulation, and demonstrate the power of experimental methods for establishing comprehensive interaction maps.