Egg-specific expression of protein with DNA methyltransferase activity in the biocarcinogenic liver fluke Clonorchis sinensis

Seon Hee Kim, Hye Jeong Cho, Woon Mok Sohn, Chun Seob Ahn, Yoon Kong, Hyun Jong Yang, Young An Bae

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Despite recent reports regarding the biology of cytosine methylation in Schistosoma mansoni, the impact of the regulatory machinery remains unclear in diverse platyhelminthes. This ambiguity is reinforced by discoveries of DNA methyltransferase 2 (DNMT2)-only organisms and the substrate specificity of DNMT2 preferential to RNA molecules. Here, we characterized a novel DNA methyltransferase, named CsDNMT2, in a liver fluke Clonorchis sinensis. The protein exhibited structural properties conserved in other members of the DNMT2 family. The native and recombinant CsDNMT2 exhibited considerable enzymatic activity on DNA. The spatiotemporal expression of CsDNMT2 mirrored that of 5-methylcytosine (5 mC), both of which were elevated in the C. sinensis eggs. However, CsDNMT2 and 5 mC were marginally detected in other histological regions of C. sinensis adults including ovaries and seminal receptacle. The methylation site seemed not related to genomic loci occupied by progenies of an active long-terminal-repeat retrotransposon. Taken together, our data strongly suggest that C. sinensis has preserved the functional DNA methylation machinery and that DNMT2 acts as a genuine alternative to DNMT1/DNMT3 to methylate DNA in the DNMT2-only organism. The epigenetic regulation would target functional genes primarily involved in the formation and/or maturation of eggs, rather than retrotransposons.

Original languageEnglish
Pages (from-to)1228-1238
Number of pages11
Issue number9
StatePublished - 14 Aug 2015

Bibliographical note

Publisher Copyright:
Copyright © Cambridge University Press 2015.


  • 5-methylcytosine
  • Clonorchis sinensis
  • DNA methylation
  • DNA-dependent methyltransferase
  • DNMT2
  • egg development


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