Negative regulation of lncRNA GAS5 by miR-21.
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.
Department of Pharmacology/Toxicology and Cancer Institute, University of Mississippi Medical Center, Jackson, MS, USA.
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Z
Zhang
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Zhu
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K
Watabe
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Zhang
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Bai
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Xu
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Wu
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Mo
D000818:Animals; D045744:Cell Line, Tumor; D005260:Female; D016147:Genes, Tumor Suppressor; D064593:Heterografts; D006801:Humans; D017403:In Situ Hybridization; D061986:MCF-7 Cells; D051379:Mice; D008819:Mice, Nude; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics; D062085:RNA, Long Noncoding / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D015854:Up-Regulation
C561567:GAS5 long non-coding RNA, human; C524940:MIRN21 microRNA, human; D035683:MicroRNAs; D062085:RNA, Long Noncoding