Project description:Targeted sequencing at Microprocessor cleavage sites in pri-miRNAs to determine processing efficiency of several pri-miRNAs in vivo in one experiment
Project description:Targeted sequencing at Microprocessor cleavage sites in pri-miRNAs to determine processing efficiency of several pri-miRNAs in vivo in one experiment
Project description:To investigate the precise processing mechanism of pri-miRNA, we prepared 38,880 pri-miRNA variants which contain unique barcode sequences (Fang and Bartel, Mol Cell, 60: 131) and performed high-throughput processing experiments.
Project description:The in vitro high-throughput human pri-miRNA processing assays were conducted to check whether mismatches and wobble base pairs in the upper stem of pri-miRNAs affects the DROSHA cleavage.
Project description:The microRNA (miRNA) biogenesis is responsible for the production of miRNAs that play critical roles in gene expression and numerous human diseases. The adequate biogenesis of miRNAs is largely determined by the efficiency and fidelity of primary microRNA (pri-miRNA) processing by Microprocessor. Here, we investigated the roles of a secondary RNA element, an RNA bulge, in pri-miRNA processing. We discovered that the 3p-strand bulges in positions 7-9 from the Microprocessor cleavage sites (midB_7-9) contributes to determining the cleavage sites of Microprocessor, the 5p- and 3p-strand bugles in positions 10-12 (midB_10-12) blocked the unproductive cleavage, and the 3p-strand bulges in positions 6-7 (seedB) inhibited the productive cleavage of Microprocessor. The 5p-strand midB_10-12 was found enriched and conserved in many pri-miRNAs of humans and other organisms. In addition, by analyzing the published Microprocessor-RNA structure and doing mutagenesis, we identified several amino acid residues of Microprocessor that explains a structure basis for the processing inhibition caused by seedB. The revealed functions of bulges in our study improves our understanding of the pri-miRNA processing by Microprocessor and implies their roles in regulating miRNA expression.
Project description:MicroRNA biogenesis is known to be modulated by a variety of RNA binding proteins (RBPs), but in most cases, individual RBPs appear to influence the processing of a small number of selective targets. We herein report binding of the NONO/PSF heterodimer to hundreds of expressed pri-miRNAs in HeLa cells to globally enhance pri-miRNA processing by the Drosha/DGCR8 Microprocessor. As NONO/PSF are key components of paraspeckles organized by the lncRNA NEAT1, we find that NEAT1 also has profound effects on global pri-miRNA processing. Mechanistic dissection reveals that NEAT1 broadly interacts with NONO/PSF as well as many other RBPs, and that multiple RNA segments in NEAT1, including a “pseudo pri-miRNA” near its 3’ end, help attract the Microprocessor. These findings suggest a bird nest model for a large lncRNA to orchestrate efficient processing of an entire class of small RNAs in the nucleus.we used small RNA-seq to identify miRNA level in response to secific knockdowns relative to siGFP treatment control
Project description:We investigate the role of a long ncRNA transcribed from an ultraconserved region (T-UCR) in the control of post-transcriptional pri-miRNA processing. The regulation is based on complementarity between the lower stem region in pri-miR-195 transcript and the ultraconserved sequence in Uc.283+A, which prevents pri-miRNA cleavage by Drosha. Mutation of the site in either RNA molecule uncouples regulation in vivo and in vitro. We propose a model in which lower-stem strand invasion by Uc.283+A impairs microprocessor recognition and efficient pri-miRNA cropping. In this work, we characterize a new role for Uc.283+A as a direct interactor and regulator of pri-miRNA-195 maturation at the level of Drosha processing. We combine cellular assays with in vitro biochemical analyses to reveal the first case of RNA-directed downregulation of miRNA biogenesis by a T-UCR In the study presented here, a colorrectal cancer cell line (HCT-116) was transiently transfected with Uc.283+A in order to identify putative miRNA targets for Uc.283+A. Variant 1 represents a SNP variant (8x(T) repeat in the sequence). Variant 2 represents a SNP variant (9x(T) repeat in the sequence).
Project description:We investigate the role of a long ncRNA transcribed from an ultraconserved region (T-UCR) in the control of post-transcriptional pri-miRNA processing. The regulation is based on complementarity between the lower stem region in pri-miR-195 transcript and the ultraconserved sequence in Uc.283+A, which prevents pri-miRNA cleavage by Drosha. Mutation of the site in either RNA molecule uncouples regulation in vivo and in vitro. We propose a model in which lower-stem strand invasion by Uc.283+A impairs microprocessor recognition and efficient pri-miRNA cropping. In this work, we characterize a new role for Uc.283+A as a direct interactor and regulator of pri-miRNA-195 maturation at the level of Drosha processing. We combine cellular assays with in vitro biochemical analyses to reveal the first case of RNA-directed downregulation of miRNA biogenesis by a T-UCR