Title

MicroRNAs with a nucleolar location

UMMS Affiliation

Department of Biochemistry and Molecular Pharmacology

Publication Date

7-25-2009

Document Type

Article

Subjects

Animals; Cell Nucleolus; Cells, Cultured; MicroRNAs; Microarray Analysis; Myoblasts; Rats; Tissue Distribution

Disciplines

Life Sciences | Medicine and Health Sciences

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.

Rights and Permissions

Citation: RNA. 2009 Sep;15(9):1705-15. Epub 2009 Jul 23. Link to article on publisher's site

DOI of Published Version

10.1261/rna.1470409

Related Resources

Link to Article in PubMed

Journal/Book/Conference Title

RNA (New York, N.Y.)

PubMed ID

19628621