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.
Project description:The study aimed to identify miRNAs expression profiles associated with growth and regression of dominant-size follicles in bovine. Follicles and corpora lutea (CL, from days 1 to 4 of the estrous cycle) were collected from abattoir ovaries and their status (healthy/atretic) was assessed by measuring steroid levels and aromatase expression. Total RNA was isolated from whole follicles at different developmental stages and from CL. An heterologous microarray (Exiqon, Denmark) approach followed by RT-qPCR validation (Qiagen, UK) was used to identify and compare miRNA profiles between large healthy follicles (diameter, 13–16 mm, n=6) and each of small (4–8 mm, n=6 pools of follicles), large atretic folllicles (13-16 mm, n=6) and CL (n=6) . RNA from the above groups was hybridized to the miRCURY LNA™ microRNA Hi-Power Labeling Kit,Hy3™/Hy5™ (Exiqon) and hybridized on the miRCURY LNA™ microRNA Array (6th gen). A total of 17 and 57 microRNAs were differentially expressed (> 2 fold, adj. P-value < 0.05) between Large Healthy and each of Small and Large Atretic follicles, respectively, a fraction of which corresponded to registered bovine miRNA sequences. A subset of 5 bovine miRNAs (miR-144, miR-202,vmiR-451, miR-652, miR-873) were confirmed by qPCR to be upregulated in Large Healthy follicles, were enriched in mural granulosa cells and their predicted targets mapped to genes involved in follicular cell proliferation and differentiation, suggesting an involvemet of this subset of microRNAs in ovarian follicle development. Moreover, a total of 11 and 22 unique miRNAs were up- and down-regulated, respectively (≥ 2.5 fold; adjusted P-value < 0.01), in corpora lutea relative Large Healthy follicles, including an upregulated cluster, miR-183-96-182, which was shown to be involved in luteal cell proliferation and steroidogenesis
Project description:miRNA profile of the bovine pretransfer endometrium based on pregnancy success after in vivo and in vitro produced embryos transfer
Project description:Affymetrix Human GeneChips are used to profile gene expression of bovine tissues and embryos to identify uniquely expressed genes in bovine in-vitro fertilized embryos by comparing with seven bovine adult tissues through gene clustering
Project description:Evaluation of the miRNA Expression Profile in Bovine Mammary Glands Artificially Infected as a Tool for Identifying Candidate Genes for Mastitis Resistance.
Project description:Influence of bovine virus diarrhoea virus on the transcriptome profile of bovine endometrium in response to bacterial lipopolysaccharide.
Project description:Bene expression profile of Angus bovine testis tissue at 2, 4 and 8 weeks of age using Affymetrix Bovine GeneChip Experiment Overall Design: Samples obtained from Angus bull calves at 2, 4 and 8 weeks of age. Two replicates at each age, 6 total samples.