title: A mRNA and cognate microRNAs localize in the nucleolus.
abstract: We previously discovered that a set of 5 microRNAs are concentrated in the nucleolus of rat myoblasts. We now report that several mRNAs are also localized in the nucleoli of these cells as determined by microarray analysis of RNA from purified nucleoli. Among the most abundant of these nucleolus-localized mRNAs is that encoding insulin-like growth factor 2 (IGF2), a regulator of myoblast proliferation and differentiation. The presence of IGF2 mRNA in nucleoli was confirmed by fluorescence in situ hybridization, and RT-PCR experiments demonstrated that these nucleolar transcripts are spliced, thus arriving from the nucleoplasm. Bioinformatics analysis predicted canonically structured, highly thermodynamically stable interactions between IGF2 mRNA and all 5 of the nucleolus-localized microRNAs. These results raise the possibility that the nucleolus is a staging site for setting up particular mRNA-microRNA interactions prior to export to the cytoplasm.
authors.affiliation: a Program in Cell and Developmental Dynamics; Department of Biochemistry and Molecular Pharmacology; University of Massachusetts Medical School ; Worcester , MA USA.
authors.forename: Pablo
authors.initials: P
authors.lastname: Reyes-Gutierrez
authors.forename: Joan C
authors.initials: JC
authors.lastname: Ritland Politz
authors.forename: Thoru
authors.initials: T
authors.lastname: Pederson
mesh_terms: D000818:Animals; D001665:Binding Sites; D002454:Cell Differentiation / Q000235:genetics; D002466:Cell Nucleolus / Q000235:genetics*; D049109:Cell Proliferation / Q000235:genetics; D003593:Cytoplasm; D018507:Gene Expression Regulation, Developmental; D017404:In Situ Hybridization, Fluorescence; D007335:Insulin-Like Growth Factor II / Q000737:chemistry / Q000235:genetics*; D035683:MicroRNAs / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D032446:Myoblasts; D012326:RNA Splicing / Q000235:genetics; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D051381:Rats
chemical_list: C000599313:Igf2 protein, rat; D035683:MicroRNAs; D012333:RNA, Messenger; D007335:Insulin-Like Growth Factor II
keywords: insulin-like growth factor-2; microRNA-mRNA interactions; nucleolus