Project description:We report the ability of the Drosha null/conditional-null mouse model to enable the identification of pri-miRNA transcripts. The conditional-null allele of Drosha phenocopies the null allele both in mESC and in mice, upon conversion to the null state with Cre.
Project description:We report the ability of the Drosha null/conditional-null mouse model to enable the identification of pri-miRNA transcripts. The conditional-null allele of Drosha phenocopies the null allele both in mESC and in mice, upon conversion to the null state with Cre. Examination of the effects of Drosha deficiency in mouse embryonic stem cells.
Project description:Maturation of canonical microRNA (miRNA) is initiated by DROSHA that cleaves the primary transcript (pri-miRNA). Over 1,800 miRNA loci are annotated in humans, but it remains largely unknown if and at which sites the pri-miRNAs are cleaved by DROSHA. Here we performed in vitro processing on a full set of human pri-miRNAs (miRBase v21) followed by sequencing. This comprehensive profiling enabled us to classify miRNAs based on DROSHA-dependence and map their cleavage sites with respective processing efficiency measures. Only 758 pri-miRNAs are confidently processed by DROSHA, while the majority may be non-canonical or false entries. Analyses of the DROSHA-dependent pri-miRNAs show key cis-elements for processing. We observe widespread alternative processing as well as unproductive cleavage events such as “nick” or “inverse” processing. SRSF3 is a broad-acting auxiliary factor modulating alternative processing and suppressing unproductive processing. The profiling data and methods developed in this study will allow systematic analyses of miRNA regulation.
Project description:MicroRNA (miRNA) biogenesis begins with Drosha cleavage, the fidelity of which is critical for downstream processing and mature miRNA target specificity. To understand how pri-miRNA sequence and structure influence Drosha cleavage, we studied the processing of pri-miR-9-1 sequence variants, which encode the same mature miRNA but differ in the surrounding scaffold. We show that, in addition to previously known features, the overall structural flexibility of pri-miRNA impacts Drosha cleavage fidelity. Internal loops and nearby G·U wobble pairs on the pri-miRNA stem induce the use of non-canonical cleavage sites by Drosha, resulting in 5’ isomiR production. Here, we report the the miRNA-seq data of HEK293T cell lines transfected with different pri-miR-9 constructs.
Project description:MicroRNA (miRNA) biogenesis begins with Drosha cleavage, the fidelity of which is critical for downstream processing and mature miRNA target specificity. To understand how pri-miRNA sequence and structure influence Drosha cleavage, we studied the processing of three pri-miR-9 paralogs (pri-miR-9-1, pri-miR-9-2 and pri-miR-9-3), which encode the same miRNA but differ in the surrounding scaffold. We show that pri-miR-9-1 has a unique Drosha cleavage profile due to its kinked tertiary structure. Cleavage of pri-miR-9-1, but not pri-miR-9-2 or pri-miR-9-3, generates an alternative-miR-9 with a shifted seed sequence that expands the scope of its target RNAs. Here, we report the the miRNA-seq data of HEK293T and HeLa cell lines transfected with different pri-miR-9 constructs.
Project description:MicroRNA (miRNA) maturation is initiated by DROSHA, a double-stranded RNA (dsRNA)-specific RNase III enzyme. By cleaving primary miRNAs (pri-miRNAs) at specific positions, DROSHA serves as a main determinant of miRNA sequences and a highly selective gate-keeper for the canonical miRNA pathway. However, the sites of DROSHA-mediated processing have not been annotated on a genomic scale, and it remains unclear to what extent DROSHA functions outside the miRNA pathway. Here we establish a protocol termed ‘formaldehyde crosslinking and immunoprecipitation followed by sequencing (fCLIP-seq)’ that allows identification of DROSHA cleavage sites at single nucleotide resolution. fCLIP identifies numerous cleavage sites that do not match the ends of annotated mature miRNAs, particularly at the 3′ termini, suggesting widespread end modifications during miRNA maturation such as trimming and tailing. fCLIP also finds many pri-miRNAs undergoing alternative processing, yielding multiple miRNA isoforms. Moreover, we discover dozens of novel substrates that are bound and cleaved by DROSHA. These substrates are processed less efficiently than canonical pri-miRNAs, and produce only minute amounts of small RNAs. Depletion of DROSHA results in an increase of the hairpin-containing transcripts. Thus, the hairpins may serve mainly as cis-elements for DROSHA-mediated gene regulation rather than as miRNA genes. fCLIP-seq not only accurately maps the cleavage sites of DROSHA and suggests noncanonical functions of DROSHA, but also could be a general tool for investigating interactions between dsRNA binding proteins and structured RNAs.
Project description:MicroRNA (miRNA) maturation is initiated by DROSHA, a double-stranded RNA (dsRNA)-specific RNase III enzyme. By cleaving primary miRNAs (pri-miRNAs) at specific positions, DROSHA serves as a main determinant of miRNA sequences and a highly selective gate-keeper for the canonical miRNA pathway. However, the sites of DROSHA-mediated processing have not been annotated on a genomic scale, and it remains unclear to what extent DROSHA functions outside the miRNA pathway. Here we establish a protocol termed ‘formaldehyde crosslinking and immunoprecipitation followed by sequencing (fCLIP-seq)’ that allows identification of DROSHA cleavage sites at single nucleotide resolution. fCLIP identifies numerous cleavage sites that do not match the ends of annotated mature miRNAs, particularly at the 3′ termini, suggesting widespread end modifications during miRNA maturation such as trimming and tailing. fCLIP also finds many pri-miRNAs undergoing alternative processing, yielding multiple miRNA isoforms. Moreover, we discover dozens of novel substrates that are bound and cleaved by DROSHA. These substrates are processed less efficiently than canonical pri-miRNAs, and produce only minute amounts of small RNAs. Depletion of DROSHA results in an increase of the hairpin-containing transcripts. Thus, the hairpins may serve mainly as cis-elements for DROSHA-mediated gene regulation rather than as miRNA genes. fCLIP-seq not only accurately maps the cleavage sites of DROSHA and suggests noncanonical functions of DROSHA, but also could be a general tool for investigating interactions between dsRNA binding proteins and structured RNAs.
Project description:Maturation of canonical microRNA (miRNA) is initiated by DROSHA that cleaves the primary transcript (pri-miRNA). Over 1,800 miRNA loci are annotated in humans, but it remains largely unknown if and at which sites the pri-miRNAs are cleaved by DROSHA. Here we performed in vitro processing on a full set of human pri-miRNAs (miRBase v21) followed by sequencing. This comprehensive profiling enabled us to classify miRNAs based on DROSHA-dependence and map their cleavage sites with respective processing efficiency measures. Only 758 pri-miRNAs are confidently processed by DROSHA, while the majority may be non-canonical or false entries. Analyses of the DROSHA-dependent pri-miRNAs show key cis-elements for processing. We observe widespread alternative processing as well as unproductive cleavage events such as “nick” or “inverse” processing. SRSF3 is a broad-acting auxiliary factor modulating alternative processing and suppressing unproductive processing. The profiling data and methods developed in this study will allow systematic analyses of miRNA regulation.
Project description:Maturation of canonical microRNA (miRNA) is initiated by DROSHA that cleaves the primary transcript (pri-miRNA). Over 1,800 miRNA loci are annotated in humans, but it remains largely unknown if and at which sites the pri-miRNAs are cleaved by DROSHA. Here we performed in vitro processing on a full set of human pri-miRNAs (miRBase v21) followed by sequencing. This comprehensive profiling enabled us to classify miRNAs based on DROSHA-dependence and map their cleavage sites with respective processing efficiency measures. Only 758 pri-miRNAs are confidently processed by DROSHA, while the majority may be non-canonical or false entries. Analyses of the DROSHA-dependent pri-miRNAs show key cis-elements for processing. We observe widespread alternative processing as well as unproductive cleavage events such as “nick” or “inverse” processing. SRSF3 is a broad-acting auxiliary factor modulating alternative processing and suppressing unproductive processing. The profiling data and methods developed in this study will allow systematic analyses of miRNA regulation.
Project description:The Ewing Sarcoma protein (EWS) is a multifaceted RNA binding protein (RBP) with established roles in transcription, pre-mRNA processing, and DNA damage response. By generating high quality EWS-RNA interactome, we uncovered its specific and prevalent interaction with a large subset of primary microRNAs (pri-miRNA). Depletion of EWS reduced, while overexpression enhanced, the expression of its target miRNAs. Biochemical analysis revealed that multiple elements in target pri-miRNAs, including the sequences flanking the stem-loop region, contribute to EWS binding and sequence swap between target and non-target demonstrated that the flanking sequences provide the specificity for enhanced pri-miRNA processing by the Microprocessor Drosha/DGCR8. Interestingly, as previously reported and we confirmed, EWS appears to repress Drosha expression, and we further demonstrated that EWS is able to enhance the recruitment of Drosha to the chromatin. Together, these findings suggest that EWS may positively and negatively regulate miRNA biogenesis, but via distinct mechanisms, thus providing a new foundation to understand the function of EWS in development and disease.