Chromosoma

, Volume 123, Issue 1, pp 117–128

Reactivation of Х chromosome upon reprogramming leads to changes in the replication pattern and 5hmC accumulation

Authors

  • Alexandra N. Bogomazova
    • Vavilov Institute of General GeneticsRussian Academy of Sciences
    • Vavilov Institute of General GeneticsRussian Academy of Sciences
  • Alexandra V. Panova
    • Vavilov Institute of General GeneticsRussian Academy of Sciences
  • Evgueny D. Nekrasov
    • Vavilov Institute of General GeneticsRussian Academy of Sciences
  • Sergey L. Kiselev
    • Vavilov Institute of General GeneticsRussian Academy of Sciences
Research Article

DOI: 10.1007/s00412-013-0433-x

Cite this article as:
Bogomazova, A.N., Lagarkova, M.A., Panova, A.V. et al. Chromosoma (2014) 123: 117. doi:10.1007/s00412-013-0433-x

Abstract

Once set, the inactive status of the X chromosome in female somatic cells is preserved throughout subsequent cell divisions. The inactive status of the X chromosome is characterized by many features, including late replication. In contrast to induced pluripotent stem cells (iPSCs) in mice, the X chromosome in human female iPSCs usually remains inactive after reprogramming of somatic cells to the pluripotent state, although recent studies point to the possibility of reactivation of the X chromosome. Here, we demonstrated that, during reprogramming, the inactive X chromosome switches from late to synchronous replication, with restoration of the transcription of previously silenced genes. This process is accompanied by accumulation of a new epigenetic mark or intermediate of the DNA demethylation pathway, 5-hydroxymethylcytosine (5hmC), on the activated X chromosome. Our results indicate that the active status of the X chromosome is better confirmed by early replication and the reappearance of 5hmC, rather than by appearance of histone marks of active chromatin, removal of histone marks of inactive chromatin, or an absence of XIST coating.

Abbreviations

5hmC

5-hydroxymethylcytosine

5mC

5-methylcytosine

EdU

5-ethynyl-2′-deoxyuridine

ESCs

Embryonic stem cells

iPSCs

Induced pluripotent stem cells

FISH

Fluorescence in situ hybridization

Xa

Active X chromosome

Xi

Inactive X chromosome

Supplementary material

412_2013_433_MOESM1_ESM.pdf (848 kb)
ESM 1(PDF 848 kb)

Copyright information

© Springer-Verlag Berlin Heidelberg 2013