Precursor miR-886, a novel noncoding RNA repressed in cancer, associates with PKR and modulates its activity (original) (raw)

  1. Nawapol Kunkeaw1,2,
  2. Sung Ho Jeon1,3,
  3. Inhan Lee4,
  4. Betty H. Johnson1,
  5. Gum-Yong Kang5,
  6. Joo Young Bang5,
  7. Hyung Soon Park5,
  8. Chanvit Leelayuwat2 and
  9. Yong Sun Lee1
  10. 1Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas 77555, USA
  11. 2The Centre for Research and Development of Medical Diagnostic Laboratories, Khon Kaen University, Khon Kaen 40002, Thailand
  12. 3Department of Life Science, Hallym University, Chuncheon 200-702, Korea
  13. 4miRcore, Ann Arbor, Michigan 48105, USA
  14. 5ProBiond Co. Ltd., Seoul 143-701, Korea

Abstract

Noncoding RNAs have drawn significant attention in biology recently. Whereas the current research is highly inclined to microRNAs, research on other noncoding RNAs has lagged behind. Here, we investigated a novel noncoding RNA that has been known as precursor microRNA miR-886 (pre-miR-886). Pre-miR-886 has been proposed also as a vault RNA, a component of the vault complex implicated in cancer drug resistance. We identified pre-miR-886 as a 102-nucleotide-long, abundant cytoplasmic RNA that is neither a genuine pre-microRNA nor a vault RNA. Pre-miR-886 is physically associated with PKR (Protein Kinase RNA-activated), an interferon-inducible and double-stranded RNA dependent kinase. The suppression of pre-miR-886 activates PKR and its downstream pathways, eIF2α phosphorylation and the NF-κB pathway, leading to impaired cell proliferation. We also found that pre-miR-886 is suppressed in a wide-range of cancer cell lines and in clinical specimens. This study is the first intense characterization of pre-miR-886 as well as the initial report on its function as a PKR regulator, which suggests a critical role in tumorigenesis.

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