MicroRNAs with a nucleolar location

Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
RNA (Impact Factor: 4.62). 08/2009; 15(9):1705-15. DOI: 10.1261/rna.1470409
Source: PubMed

ABSTRACT There is increasing evidence that noncoding RNAs play a functional role in the nucleus. We previously reported that the microRNA (miRNA), miR-206, is concentrated in the nucleolus of rat myoblasts, as well as in the cytoplasm as expected. Here we have extended this finding. We show by cell/nuclear fractionation followed by microarray analysis that a number of miRNAs can be detected within the nucleolus of rat myoblasts, some of which are significantly concentrated there. Pronounced nucleolar localization is a specific phenomenon since other miRNAs are present at only very low levels in the nucleolus and occur at much higher levels in the nucleoplasm and/or the cytoplasm. We have further characterized a subset of these miRNAs using RT-qPCR and in situ hybridization, and the results suggest that some miRNAs are present in the nucleolus in precursor form while others are present as mature species. Furthermore, we have found that these miRNAs are clustered in specific sites within the nucleolus that correspond to the classical granular component. One of these miRNAs is completely homologous to a portion of a snoRNA, suggesting that it may be processed from it. In contrast, the other nucleolar-concentrated miRNAs do not show homology with any annotated rat snoRNAs and thus appear to be present in the nucleolus for other reasons, such as modification/processing, or to play roles in the late stages of ribosome biosynthesis or in nonribosomal functions that have recently been ascribed to the granular component of the nucleolus.

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Available from: Joan Ritland, Aug 17, 2015
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    • "+ (Koberna et al. 2002) FC/DFC border FC, DFC, or FC/DFC border (Huang 2002) rRNA processing and ribosome subunits assembly + (Staněk et al. 2001) + (Beven et al. 1996) DFC and GC DFC and GC Viral infections + (Taliansky et al. 2011; Kim et al 2007) + (Dove et al. 2006; Emmott et al. 2008) DFC (Rakitina et al. 2011) DFC (Dove et al. 2006) HIV proteins/mRNA − + (Olson and Dundr 2005) DFC or GC Stress sensor and response Changes of morphology and composition (Stępiński 2009, 2010) + (Boulon et al. 2010) -p53 pathway − + (Olson 2004; Mayer and Grummt 2005; Suzuki et al. 2012; Krüger and Scheer 2010) nucleolar cavity (Krüger and Scheer 2010) -Without p53 pathway − + (Olausson et al. 2012) Regulation of tumor suppressor and oncogenic activity − + (Tsai and McKay 2002) Cell cycle regulation Yeast (Cockell and Gasser 1999; Visintin et al. 1999; Visintin and Amon 2000) Control of aging − + (Guarente 1997) Promotion of protein homeostasis via chaperones − + (Bański et al. 2010) Metabolism, modifications, assembly, or transport of RNAs and/or RNA-containing complexes + Brown and Shaw 2008; Shaw and Brown 2012 + (Brown and Shaw 2008; Shaw and Brown 2012) -mRNA + (Kim et al. 2009) + (Gururajan et al. 1994; Názer et al. 2012) -Signal recognition particles (SRP) RNA − + (Politz et al. 2000; Jacobson and Pederson 1998) -Small RNAs (snRNAs and snoRNAs) + (Kim et al. 2010) + (Gerbi et al. 2003) -tRNAs/RNase P proteins: Yeast (Bertrand et al. (1998) + (Jarrous et al. 1999) -Rpp14 and Rpp29 DFC -Rpp38 Allover nucleolus -Regulatory RNAs (siRNAs and miRNAs) + (Pontes et al. 2013) + (Politz et al. 2009) Nucleolar periphery and CBs -Modulation of telomerase function – + (Wang et al. 2010) Exon-junction complex (EJC) proteins in mRNA metabolism + (Brown and Shaw 2008; Pendle et al. 2005) "
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