Improvements to the HITS-CLIP protocol eliminate widespread mispriming artifacts.
Ontology highlight
ABSTRACT: 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: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.
Project description:RNA-based regulatory mechanisms play important roles in the development and plasticity of neural circuits and neurologic disease. Developing axons provide a well suited model to study RNA-based regulation, and contain specific subsets of mRNAs that are locally translated and have roles in axon pathfinding. However, the RNA-binding proteins involved in axon pathfinding, and their corresponding mRNA targets, are still largely unknown. Here we find that the RNA-binding protein IMP2 (Igf2bp2) is strikingly enriched in developing axon tracts, including in spinal commissural axons. We used the HITS-CLIP approach to perform a genome-wide identification of RNAs that interact directly with IMP2 in the native context of developing brain. This IMP2 interactome was highly enriched for mRNA targets related to axon guidance. Accordingly, IMP2 knockdown in the developing spinal cord led to strong defects in commissural axon trajectories at the midline intermediate target. These results reveal a highly distinctive axonal enrichment of IMP2, show that it interacts with a network of axon guidance-related mRNAs, and reveal its requirement for normal axon pathfinding during vertebrate development. CLIP-seq
Project description:We used a genome-wide approach (High-throughput sequencing of RNA isolated by crosslinking immunoprecipitation, or HITS-CLIP) to define direct miRNA-mRNA interactions in three breast cancer subtypes (estrogen receptor positive, Her2 amplified and triple negative). Focusing on steroid receptor signaling, we identified two novel regulators of the ER pathway (miR-9-5p and miR-193a/b-3p), which together target multiple genes involved in ER signaling. Moreover, this approach enabled the definition of miR-9-5p as a global regulator of steroid receptor signaling in breast cancer. Finally, we show that miRNA targets and networks defined by our analysis are predictive of patient outcomes and provide global insight into miRNA regulation in breast cancer. Argonaute HITS-CLIP on three representative breast cancer cell lines (each in triplicate).
Project description:We have identified Mbnl2 mediated splicing events and mRNA expression regulation by comparing WT and Mbnl2 ΔE2/ΔE2 mouse hippocampii using Affymetrix Mouse Exon Junction Array and mRNA sequencing. The splicing microarray data has already been submitted under GSE37908 which also includes a re-analysis of RNA-seq data. The TableS1.xls contains Splicing microarray analysis data of Mbnl2+/+ vs. MBNL2 ΔE2/ΔE2 knockout hippocampus. The TableS2.xls files contain RNA-Seq, Gene Ontology, HITS-CLIP and CIMS summary of Mbnl2+/+ vs. MBNL2 ΔE2/ΔE2 knockout hippocampus. The file contents are descibed in the 'TableS1_S2_readme.pdf' and data processing details are included in the 'data_processing_readme.pdf' file. The Mbnl2_TableS2.xls contains data from exon junction microarrays for splicing analysis between WT and Mbnl2 delta2 mice. It also contains RNA-seq based splicing analysis between WT and Mbnl2 delta2 mice. Mbnl2_TableS2 further contains common targets between the two analyses, Gene Ontology and finally the HITS-CLIP data. CLIP tag summary describes read numbers for the three biological replicates. CLIP sig peaks contains significant HITS-CLIP unique reads/peaks after processing the data (BED files). Finally, CIMS analysis describes the Mbnl2 binding motif.