MicroRNA knockout by genome editing technologies is promising. In order to extend the application of the technology and to investigate the function of a specific miRNA, we used CRISPR/Cas9 to deplete human miR-93 from a cluster by targeting its 5' region in HeLa cells. Various small indels were induced in the targeted region containing the Drosha processing site and seed sequences. Interestingl...

We recently found that hnRNP A1, a protein implicated in many aspects of RNA processing, acts as an auxiliary factor for the Drosha-mediated processing of a microRNA precursor, pri-miR-18a. Here, we provide the mechanism by which hnRNP A1 regulates this event. We show that hnRNP A1 binds to the loop of pri-miR-18a and induces a relaxation at the stem, creating a more favorable cleavage site for...

MicroRNAs (miRNAs) are implicated in the differentiation and function of many cell types. We provide genetic and in vivo evidence that the two RNaseIII enzymes, Drosha and Dicer, do indeed function in the same pathway. These have previously been shown to mediate the stepwise maturation of miRNAs (Lee, Y., C. Ahn, J. Han, H. Choi, J. Kim, J. Yim, J. Lee, P. Provost, O. Radmark, S. Kim, and V.N. ...

MicroRNAs (miRNAs) are noncoding small RNA of approximately 22 bases, which suppress expression of target genes through translational block or degradation of a target's transcript. Recent studies uncovered specific miRNA expression profiles in human malignancies. Nevertheless, the mechanisms underlying cancer-specific miRNA expression are largely unknown. miRNA biogenesis consists of a series o...

MicroRNAs play an important role in cancer initiation and development. The aim of this study was to investigate whether polymorphisms in miRNA machinery genes are associated with the development of colorectal cancer (CRC). RAN rs14035 CT heterozygotes and T allele carriers (CT + TT) genotypes had lower risk of CRC, while the DICER1 rs3742330, DROSHA rs10719, and XPO5 rs11077 polymorphisms were ...

Introduction It has been well known that the microRNA biogenesis is involved in the pathogenesis of various diseases. We investigated the possible association between DROSHA rs642321 variant and risk of acute lymphocytic leukemia (ALL). Materials and Methods We genotyped 75 children diagnosed with ALL and 115 age- and sex-matched children with no history of cancer of any type (as the control ...

The canonical microRNA (miRNA) pathway converts primary hairpin precursor transcripts into approximately 22 nucleotide regulatory RNAs via consecutive cleavages by two RNase III enzymes, Drosha and Dicer. In this study, we characterize Drosophila small RNAs that derive from short intronic hairpins termed "mirtrons." Their nuclear biogenesis appears to bypass Drosha cleavage, which is essential ...

A well-defined mechanism governs the maturation of most microRNAs (miRNAs) in animals, via stepwise cleavage of precursor hairpin transcripts by the Drosha and Dicer RNase III enzymes. Recently, several alternative miRNA biogenesis pathways were elucidated, the most prominent of which substitutes Drosha cleavage with splicing. Such short hairpin introns are known as mirtrons, and their study ha...

MicroRNAs (miRNAs) are central regulators of gene expression, and a large fraction of them are encoded in introns of RNA polymerase II transcripts. Thus, the biogenesis of intronic miRNAs by the microprocessor and the splicing of their host introns by the spliceosome require coordination between these processing events. This cross-talk is addressed here. We show that key microprocessor proteins...

Epstein-Barr virus (EBV) microRNAs miR-BHRF1-1, -2, and -3 have been detected in latency III-infected lymphoblasts, where they are encoded within EBNA transcripts (X. Cai, A. Schafer, S. Lu, J. P. Bilello, R. C. Desrosiers, R. Edwards, N. Raab-Traub, and B. R. Cullen, PLoS Pathog. 2:e23, 2006). In latency III-infected lymphoblasts, we have also identified a stable 1.3-kb RNA, which begins 3' to...