Posttranscriptional modulation of TERC by PAPD5 inhibition rescues hematopoietic development in dyskeratosis congenita

Blood. 2019 Mar 21;133(12):1308-1312. doi: 10.1182/blood-2018-11-885368. Epub 2019 Feb 6.


Reduced levels of TERC, the telomerase RNA component, cause dyskeratosis congenita (DC) in patients harboring mutations in TERC, PARN, NOP10, NHP2, NAF1, or DKC1. Inhibition of the noncanonical poly(A) polymerase PAPD5, or the exosome RNA degradation complex, partially restores TERC levels in immortalized DKC1 mutant cells, but it remains unknown if modulation of posttranscriptional processing of TERC could improve hematopoietic output in DC. We used human embryonic stem cells (hESCs) with a common dyskerin mutation (DKC1_A353V), which have defective telomere maintenance and reduced definitive hematopoietic potential, to understand the effects of reducing EXOSC3 activity, or silencing PAPD5-mediated oligoadenylation, on hematopoietic progenitor specification and function in DC. Reduction of EXOSC3 or PAPD5 levels in DKC1 mutant hESCs led to functional improvements in TERC levels and telomerase activity, with concomitant telomere elongation and reduced levels of DNA damage signaling. Interestingly, the silencing of PAPD5, but not EXOSC3, significantly restored definitive hematopoietic potential in DKC1 mutant cells. Mechanistically, we show that PAPD5 inhibition is sustained in differentiated CD34+ cells, with a concomitant increase in mature, functional, forms of TERC, indicating that regulation of PAPD5 is a potential strategy to reverse hematologic dysfunction in DC patients.

Publication types

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

MeSH terms

  • Cell Cycle Proteins / genetics
  • Dyskeratosis Congenita / metabolism
  • Dyskeratosis Congenita / pathology
  • Dyskeratosis Congenita / prevention & control*
  • Embryonic Stem Cells / cytology*
  • Embryonic Stem Cells / metabolism
  • Exosome Multienzyme Ribonuclease Complex / genetics
  • Exosome Multienzyme Ribonuclease Complex / metabolism
  • Hematopoiesis*
  • Humans
  • Mutation*
  • Nuclear Proteins / genetics
  • RNA / genetics
  • RNA / metabolism*
  • RNA Nucleotidyltransferases / antagonists & inhibitors*
  • RNA Nucleotidyltransferases / genetics
  • RNA Nucleotidyltransferases / metabolism
  • RNA Processing, Post-Transcriptional*
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism
  • Telomerase / genetics
  • Telomerase / metabolism*
  • Telomere


  • Cell Cycle Proteins
  • DKC1 protein, human
  • EXOSC3 protein, human
  • Nuclear Proteins
  • RNA-Binding Proteins
  • telomerase RNA
  • RNA
  • RNA Nucleotidyltransferases
  • TENT4B protein, human
  • Telomerase
  • Exosome Multienzyme Ribonuclease Complex