Depletion of human micro-RNA miR-125b reveals that it is critical for the proliferation of differentiated cells but not for the down-regulation of putative targets during differentiation

Yong Sun Lee, Hak Kyun Kim, Sangmi Chung, Kwang Soo Kim, Anindya Dutta

Research output: Contribution to journalArticle

285 Scopus citations

Abstract

Micro-RNAs are small non-coding RNAs that regulate target gene expression post-transcriptionally through base pairing with the target messenger RNA. Functional characterization of micro-RNAs awaits robust experimental methods to knock-down a micro-RNA as well as to assay its function in vivo. In addition to the recently developed method to sequester micro-RNA with 2′-O-methyl antisense oligonucleotide, we report that small interfering RNA against the loop region of a micro-RNA precursor can be used to deplete the micro-RNA. The depletion of miR-125b by this method had a profound effect on the proliferation of adult differentiated cancer cells, and this proliferation defect was rescued by co-transfected mature micro-RNA. This technique has unique advantages over the 2′-O-methyl antisense oligonucleotide and can be used to determine micro-RNA function, assay micro-RNAs in vivo, and identify the contribution of a predicted micro-RNA precursor to the pool of mature micro-RNA in a given cell. miR-125b and let-7 micro-RNAs are induced, whereas their putative targets, lin-28 and lin-41, are decreased during in vitro differentiation of Tera-2 or embryonic stem cells. Experimental increase or decrease of micro-RNA concentrations did not, however, affect the levels of the targets, a finding that is explained by the fact that the down-regulation of the targets appears to be mostly at the transcriptional level in these in vitro differentiation systems. Collectively these results reveal the importance of micro-RNA depletion strategies for directly determining micro-RNA function in vivo.

Original languageEnglish (US)
Pages (from-to)16635-16641
Number of pages7
JournalJournal of Biological Chemistry
Volume280
Issue number17
DOIs
StatePublished - Apr 29 2005

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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