Journal Article

Negative regulation of lncRNA GAS5 by miR-21

Xu, M, Bai, C, Mo, Y-Y, Wu, F, Zhu, Z, Watabe, K, Zhang, X, Zhang, Z

2013

Overview

In addition to protein-coding genes, the human genome makes a large amount of noncoding RNAs, including microRNAs and long noncoding RNAs (lncRNAs). Both microRNAs and lncRNAs have been shown to have a critical role in the regulation of cellular processes such as cell growth and apoptosis, as well as cancer progression and metastasis. Although it is well known that microRNAs can target a large number of protein-coding genes, little is known whether microRNAs can also target lncRNAs. In the present study, we determine whether miR-21 can regulate lncRNA expression. Using the lncRNA RT-PCR (reverse transcription-polymerase chain reaction) array carrying 83 human disease-related lncRNAs, we show that miR-21 is capable of suppressing the lncRNA growth arrest-specific 5 (GAS5). This negative correlation between miR-21 and GAS5 is also seen in breast tumor specimens. Of interest, GAS5 can also repress miR-21 expression. Whereas ectopic expression of GAS5 suppresses, GAS5–siRNA increases miR-21 expression. Importantly, there is a putative miR-21-binding site in exon 4 of GAS5; deletion of the miR-21-binding site abolishes this activity. Experiments with in vitro cell culture and xenograft mouse model suggest that GAS5 functions as a tumor suppressor. We further show that the biotin-labeled GAS5–RNA probe is able to pull down the key component (AGO2) of the RNA-induced silencing complex (RISC) and we subsequently identify miR-21 in this GAS5–RISC complex, implying that miR-21 and GAS5 may regulate each other in a way similar to the microRNA-mediated silencing of target mRNAs. Together, these results suggest that miR-21 targets not only tumor-suppressive protein-coding genes but also lncRNA GAS5.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 631/337/384/2568 / 631/337/384/331 / 631/67/395 / 631/67/581 / Animals / Apoptosis / Binding sites / Biochemistry / Biomedical and Life Sciences / Cancer / Cell Biology / Cell culture / Cell Cycle Analysis / Cell death / Cell growth / Cell Line, Tumor / Female / Genes / Genes, Tumor Suppressor / Genomes / Heterografts / Hospitals / Humans / In Situ Hybridization / Life Sciences / MCF-7 Cells / Metastasis / Mice / Mice, Nude / MicroRNAs / MicroRNAs - genetics / MicroRNAs - metabolism / Original Paper / Plasmids - genetics / Polymerase chain reaction / Proteins / RNA, Long Noncoding - genetics / RNA, Long Noncoding - metabolism / Stem Cells / Toxicology / Transfection / Up-Regulation