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How Complementary Targets Expose the microRNA 3' End for Tailing and Trimming during Target-Directed microRNA Degradation. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2020; 84:179-183. [PMID: 32019864 DOI: 10.1101/sqb.2019.84.039321] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
microRNAs (miRNAs) are crucial for posttranscriptional regulation of messenger RNAs. "Classical" miRNA targets predominantly interact with the miRNA seed sequence located near the miRNA 5' end. Interestingly, certain transcripts that exhibit extensive complementarity to the miRNAs 3' region, instead of being subjected to regulation, induce miRNA decay in a process termed target-directed miRNA degradation (TDMD). Here, we review recent advances in understanding the molecular mechanisms of TDMD. Specifically, we discuss how extensive miRNA complementarity to TDMD-inducing targets results in displacement of the miRNA 3' end from its protective pocket in the Argonaute protein. Unprotected miRNA 3' ends are then available for enzymatic attack by still-unidentified cellular enzymes. Identification of these cellular enzymes and discovery of additional TDMD-inducing transcripts are subjects for future research.
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Withers JB, Mondol V, Pawlica P, Rosa-Mercado NA, Tycowski KT, Ghasempur S, Torabi SF, Steitz JA. Idiosyncrasies of Viral Noncoding RNAs Provide Insights into Host Cell Biology. Annu Rev Virol 2019; 6:297-317. [PMID: 31039329 PMCID: PMC6768742 DOI: 10.1146/annurev-virology-092818-015811] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Like their host cells, many viruses express noncoding RNAs (ncRNAs). Despite the technical challenge of ascribing function to ncRNAs, diverse biological roles for virally expressed ncRNAs have been described, including regulation of viral replication, modulation of host gene expression, host immune evasion, cellular survival, and cellular transformation. Insights into conserved interactions between viral ncRNAs and host cell machinery frequently lead to novel findings concerning host cell biology. In this review, we discuss the functions and biogenesis of ncRNAs produced by animal viruses. Specifically, we describe noncanonical pathways of microRNA (miRNA) biogenesis and novel mechanisms used by viruses to manipulate miRNA and messenger RNA stability. We also highlight recent advances in understanding the function of viral long ncRNAs and circular RNAs.
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Affiliation(s)
- Johanna B Withers
- Department of Molecular Biophysics and Biochemistry, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, Connecticut 06536, USA; , , , , , , ,
- Howard Hughes Medical Institute, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, Connecticut 06536, USA
| | - Vanessa Mondol
- Department of Molecular Biophysics and Biochemistry, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, Connecticut 06536, USA; , , , , , , ,
| | - Paulina Pawlica
- Department of Molecular Biophysics and Biochemistry, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, Connecticut 06536, USA; , , , , , , ,
| | - Nicolle A Rosa-Mercado
- Department of Molecular Biophysics and Biochemistry, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, Connecticut 06536, USA; , , , , , , ,
| | - Kazimierz T Tycowski
- Department of Molecular Biophysics and Biochemistry, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, Connecticut 06536, USA; , , , , , , ,
- Howard Hughes Medical Institute, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, Connecticut 06536, USA
| | - Salehe Ghasempur
- Department of Molecular Biophysics and Biochemistry, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, Connecticut 06536, USA; , , , , , , ,
| | - Seyed F Torabi
- Department of Molecular Biophysics and Biochemistry, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, Connecticut 06536, USA; , , , , , , ,
| | - Joan A Steitz
- Department of Molecular Biophysics and Biochemistry, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, Connecticut 06536, USA; , , , , , , ,
- Howard Hughes Medical Institute, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, Connecticut 06536, USA
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