Project description:We report identification of 348 high confidence miRNA target sites in 261 genes in the bovine retina Employ Argonaute HITS-CLIP analysis to identify miRNA target sites in the bovine retina
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:To estimate transcripts levels in P13 mouse neocortex. MicroRNAs (miRNAs) play critical roles in the regulation of gene expression. Recently, high-throughput sequencing of RNAs isolated by crosslinking immunoprecipitation (HITS-CLIP) has identified functional protein-RNA interaction sites. We used HITS-CLIP to covalently crosslink native Argonaute (Ago) protein-RNA complexes in mouse brain. This produced two simultaneous datasets—Ago-miRNA and Ago-mRNA binding sites—that were combined with bioinformatic analysis to identify miRNA-target mRNA interaction sites. We validated genome-wide interaction maps for miR-124, and generated additional maps for the 20 most abundant miRNAs present in P13 mouse brain. Here we include the expression data obtained from dissected P13 mouse neocortex. These data are used for in silico CLIP simulation for normalization of Ago HITS-CLIP tags and also for selecting transcripts expressed in P13 mouse cortex.
2009-05-30 | GSE16338 | GEO
Project description:HITS-CLIP and RNA-Seq of bovine retina
Project description:microRNAs (miRNAs) are essential components of gene regulation, but identification of miRNA targets remains a major challenge. Most target prediction and discovery relies on perfect complementarity of the miRNA seed to the 3’ untranslated region (UTR). However, it is unclear to what extent miRNAs target sites without seed matches. Here, we performed a transcriptome-wide identification of the endogenous targets of a single miRNA—miR-155—in a genetically controlled manner. We found that approximately forty percent of miR-155-dependent Argonaute binding occurs at sites without perfect seed matches. The majority of these non-canonical sites feature extensive complementarity to the miRNA seed with one mismatch. These non-canonical sites confer regulation of gene expression albeit less potently than canonical sites. Thus, non-canonical miRNA binding sites are widespread, often contain seed-like motifs, and can regulate gene expression, generating a continuum of targeting and regulation. Argonaute (AGO) HITS-CLIP Libraries generated from wild type and miR-155 knockout activated T cells. AGO HITS-CLIP libraries were generated from activated wild type and miR-155 knockout T cells with two different 3' linkers. Libraries were generated and sequenced with an 11nt index read that contained both a 5nt multiplexing index and a 6nt degenerate barcode. Files have been demultiplexed and the 6nt degenerate barcode has been appended as the first 6 nucleotides of the read.
Project description:High-throughput sequencing of RNA isolated by crosslinking immunoprecipitation (HITS-CLIP) allows for high resolution, genome-wide mapping of RNA-binding proteins. We found that substantial mispriming during reverse transcription results in the overrepresentation of sequences complementary to the primer used for reverse transcription. Up to 45% of peaks in publicly available HITS-CLIP libraries are attributable to this artifact, and the majority of libraries have detectable levels of mispriming. We also found that standard techniques for validating miRNA-target interactions fail to differentiate between artifactual peaks and physiologically relevant peaks. Here, we present a modification to the HITS-CLIP protocol that effectively eliminates this artifact. Argonaute HITS-CLIP on the MCF-7 breast cancer cell line treated with 17β-estradiol for 0, 6 or 24 hours using a nested reverse transcriptions pimer and protected or unprotected reverse PCR primers for library amplification.
Project description:We performed Ago HITS-CLIP to identify targets of viral and human miRNAs in latently KSHV-infected PEL cells Ago HITS-CLIP was performed in two latently infected PEL cell lines, BCBL-1 and BC-3; Argonaute-immunoprecipitation of UV cross-linked Ago-miRNA-mRNA complexes, followed by RNA isolation, library construction, and high-throughput sequencing (Illumina GAxII); we performed 3 biological replicates for each cell line, two technical (sequencing) replicates of BCBL-1 biological replicate 1
Project description:microRNAs (miRNAs) act as sequence-specific guides for Argonaute (AGO) proteins, which mediate post-transcriptional silencing of target mRNAs. Despite their importance in many biological processes, rules governing AGO-miRNA targeting are only partially understood. We use a modified AGO HITS-CLIP strategy, termed CLEAR (Covalent Ligation of Endogenous Argonaute-bound RNAs) CLIP that enriches miRNAs ligated to their endogenous mRNA targets. CLEAR-CLIP mapped ~130,000 endogenous miRNA-target interactions in mouse brain and ~40,000 in human hepatoma cells. Motif and structural analysis define expanded pairing rules for over 200 mammalian miRNAs. Most interactions combine seed-based pairing with distinct, miRNA-specific patterns of auxiliary pairing. At some regulatory sites, this specificity confers distinct silencing functions to miRNA family members with shared seed sequences but divergent 3’ ends. This work provides a means for explicit biochemical identification of miRNA sites in vivo, leading to the discovery that miRNA 3’ end pairing is a general determinant of AGO binding specificity.
Project description:microRNAs (miRNAs) act as sequence-specific guides for Argonaute (AGO) proteins, which mediate post-transcriptional silencing of target mRNAs. Despite their importance in many biological processes, rules governing AGO-miRNA targeting are only partially understood. We use a modified AGO HITS-CLIP strategy, termed CLEAR (Covalent Ligation of Endogenous Argonaute-bound RNAs) CLIP that enriches miRNAs ligated to their endogenous mRNA targets. CLEAR-CLIP mapped ~130,000 endogenous miRNA-target interactions in mouse brain and ~40,000 in human hepatoma cells. Motif and structural analysis define expanded pairing rules for over 200 mammalian miRNAs. Most interactions combine seed-based pairing with distinct, miRNA-specific patterns of auxiliary pairing. At some regulatory sites, this specificity confers distinct silencing functions to miRNA family members with shared seed sequences but divergent 3’ ends. This work provides a means for explicit biochemical identification of miRNA sites in vivo, leading to the discovery that miRNA 3’ end pairing is a general determinant of AGO binding specificity.