Identification of targets of tumor suppressor microRNA-34a using a reporter library system

Proc Natl Acad Sci U S A. 2017 Apr 11;114(15):3927-3932. doi: 10.1073/pnas.1620019114. Epub 2017 Mar 29.


miRNAs play critical roles in various biological processes by targeting specific mRNAs. Current approaches to identifying miRNA targets are insufficient for elucidation of a miRNA regulatory network. Here, we created a cell-based screening system using a luciferase reporter library composed of 4,891 full-length cDNAs, each of which was integrated into the 3' UTR of a luciferase gene. Using this reporter library system, we conducted a screening for targets of miR-34a, a tumor-suppressor miRNA. We identified both previously characterized and previously uncharacterized targets. miR-34a overexpression in MDA-MB-231 breast cancer cells repressed the expression of these previously unrecognized targets. Among these targets, GFRA3 is crucial for MDA-MB-231 cell growth, and its expression correlated with the overall survival of patients with breast cancer. Furthermore, GFRA3 was found to be directly regulated by miR-34a via its coding region. These data show that this system is useful for elucidating miRNA functions and networks.

Keywords: breast cancer; miR-34a; microRNA target screening; reporter library system.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Breast Neoplasms / genetics*
  • Breast Neoplasms / pathology
  • Cell Line, Tumor
  • Female
  • Gene Expression Regulation, Neoplastic
  • Gene Library*
  • Genes, Reporter
  • Glial Cell Line-Derived Neurotrophic Factor Receptors / genetics*
  • Glial Cell Line-Derived Neurotrophic Factor Receptors / metabolism
  • Humans
  • MicroRNAs / genetics*
  • MicroRNAs / metabolism
  • RNA Helicases / genetics
  • Trans-Activators / genetics


  • GFRA3 protein, human
  • Glial Cell Line-Derived Neurotrophic Factor Receptors
  • MIRN34 microRNA, human
  • MicroRNAs
  • Trans-Activators
  • RNA Helicases
  • UPF1 protein, human