MicroRNA-96 directly inhibits γ-globin expression in human erythropoiesis

PLoS One. 2011;6(7):e22838. doi: 10.1371/journal.pone.0022838. Epub 2011 Jul 28.

Abstract

Fetal hemoglobin, HbF (α(2)γ(2)), is the main hemoglobin synthesized up to birth, but it subsequently declines and adult hemoglobin, HbA (α(2)β(2)), becomes predominant. Several studies have indicated that expression of the HbF subunit γ-globin might be regulated post-transcriptionally. This could be confered by ∼22-nucleotide long microRNAs that associate with argonaute proteins to specifically target γ-globin mRNAs and inhibit protein expression. Indeed, applying immunopurifications, we found that γ-globin mRNA was associated with argonaute 2 isolated from reticulocytes that contain low levels of HbF (<1%), whereas association was significantly lower in reticulocytes with high levels of HbF (90%). Comparing microRNA expression in reticulocytes from cord blood and adult blood, we identified several miRNAs that were preferentially expressed in adults, among them miRNA-96. The overexpression of microRNA-96 in human ex vivo erythropoiesis decreased γ-globin expression by 50%, whereas the knock-down of endogenous microRNA-96 increased γ-globin expression by 20%. Moreover, luciferase reporter assays showed that microRNA-96 negatively regulates expression of γ-globin in HEK293 cells, which depends on a seedless but highly complementary target site located within the coding sequence of γ-globin. Based on these results we conclude that microRNA-96 directly suppresses γ-globin expression and thus contributes to HbF regulation.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Blotting, Western
  • Cells, Cultured
  • Enzyme-Linked Immunosorbent Assay
  • Erythropoiesis / physiology*
  • Fetal Blood / metabolism
  • Fetal Hemoglobin / genetics*
  • Fetal Hemoglobin / metabolism
  • Hemoglobin A / genetics*
  • Hemoglobin A / metabolism
  • Humans
  • Immunoprecipitation
  • Luciferases / metabolism
  • MicroRNAs / antagonists & inhibitors
  • MicroRNAs / genetics
  • MicroRNAs / metabolism
  • MicroRNAs / physiology*
  • RNA, Messenger / genetics*
  • RNA, Messenger / metabolism
  • Reticulocytes / cytology
  • Reticulocytes / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • gamma-Globins / genetics*
  • gamma-Globins / metabolism

Substances

  • MIRN96 microRNA, human
  • MicroRNAs
  • RNA, Messenger
  • gamma-Globins
  • Hemoglobin A
  • Fetal Hemoglobin
  • Luciferases