MicroRNAs direct rapid deadenylation of mRNA.

Skirball Institute of Biomolecular Medicine and Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.81). 04/2006; 103(11):4034-9. DOI: 10.1073/pnas.0510928103
Source: PubMed

ABSTRACT MicroRNAs (miRNAs) are ubiquitous regulators of eukaryotic gene expression. In addition to repressing translation, miRNAs can down-regulate the concentration of mRNAs that contain elements to which they are imperfectly complementary. Using miR-125b and let-7 as representative miRNAs, we show that in mammalian cells this reduction in message abundance is a consequence of accelerated deadenylation, which leads to rapid mRNA decay. The ability of miRNAs to expedite poly(A) removal does not result from decreased translation; nor does translational repression by miRNAs require a poly(A) tail, a 3' histone stem-loop being an effective substitute. These findings suggest that miRNAs use two distinct posttranscriptional mechanisms to down-regulate gene expression.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Crohn's disease (CD) is a major subtype of inflammatory bowel disease (IBD). Herb-partitioned moxibustion (HPM) has been proven to be effective in treating CD by a large amount of clinical and experimental researches. MiRNAs (microRNAs) are increasingly recognized as important posttranscriptional regulators of inflammatory genes. In this study, we established experimental CD rat models and investigated the miRNAs associated with the onset of experimental CD; then, we further identified CD-related miRNAs that were regulated by HPM and explored the relationship between CD and the potential target genes of involved miRNAs. We found that miR-147 and miR-205 were significantly downregulated in colons of experimental CD rats and may be closely associated with the onset of experimental CD. HPM may extenuate inflammatory responses in colons and ameliorate colonic damages in CD via upregulating the expression of miR-147 and miR-205 and then further downregulating the expression of inflammation-related mRNAs, negatively regulating inflammatory signal pathways, and reducing the production of downstream inflammatory cytokines.
    Evidence-based Complementary and Alternative Medicine 01/2015; 2015:265238. DOI:10.1155/2015/265238 · 2.18 Impact Factor
  • Source
    01/2011; DOI:10.7150/jca.2.116
  • [Show abstract] [Hide abstract]
    ABSTRACT: microRNA-449a (miR-449a) has been identified to function as a tumor suppressor in several types of cancers. However, the role of miR-449a in neuroblastoma has not been intensively investigated. We recently found that the overexpression of miR-449a significantly induces neuroblastoma cell differentiation, suggesting its potential tumor suppressor function in neuroblastoma. In this study, we further investigated the mechanisms underlying the tumor suppressive function of miR-449a in neuroblastoma. We observed that miR-449a inhibits neuroblastoma cell survival and growth through two mechanisms - inducing cell differentiation and cell cycle arrest. Our comprehensive investigations on the dissection of the target genes of miR-449a revealed that three novel targets- MFAP4, PKP4 and TSEN15 -play important roles in mediating its differentiation-inducing function. In addition, we further found that its function in inducing cell cycle arrest involves down-regulating its direct targets CDK6 and LEF1. To determine the clinical significance of the miR-449a-mediated tumor suppressive mechanism, we examined the correlation between the expression of these five target genes in neuroblastoma tumor specimens and the survival of neuroblastoma patients. Remarkably, we noted that high tumor expression levels of all the three miR-449a target genes involved in regulating cell differentiation, but not the target genes involved in regulating cell cycle, are significantly correlated with poor survival of neuroblastoma patients. These results suggest the critical role of the differentiation-inducing function of miR-449a in determining neuroblastoma progression. Overall, our study provides the first comprehensive characterization of the tumor-suppressive function of miR-449a in neuroblastoma, and reveals the potential clinical significance of the miR-449a-mediated tumor suppressive pathway in neuroblastoma prognosis.
    RNA Biology 03/2015; 12(5). DOI:10.1080/15476286.2015.1023495 · 5.38 Impact Factor


Available from