title: Egg-specific expression of protein with DNA methyltransferase activity in the biocarcinogenic liver fluke Clonorchis sinensis.
abstract: 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.
authors.affiliation: Department of Microbiology,Graduate School of Medicine,Gachon University,191 Hambakmoe-ro,Yeonsu-gu,Incheon 406-799,Republic of Korea.
authors.forename: Seon-Hee
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Microbiology,Graduate School of Medicine,Gachon University,191 Hambakmoe-ro,Yeonsu-gu,Incheon 406-799,Republic of Korea.
authors.forename: Hye-Jeong
authors.initials: HJ
authors.lastname: Cho
authors.affiliation: Department of Parasitology and Institute of Health Sciences,Gyeongsang National University College of Medicine,Jinju,Republic of Korea.
authors.forename: Woon-Mok
authors.initials: WM
authors.lastname: Sohn
authors.affiliation: Department of Molecular Parasitology,Sungkyunkwan University School of Medicine and Center for Molecular Medicine,Samsung Biomedical Research Institute,Suwon,Republic of Korea.
authors.forename: Chun-Seob
authors.initials: CS
authors.lastname: Ahn
authors.affiliation: Department of Molecular Parasitology,Sungkyunkwan University School of Medicine and Center for Molecular Medicine,Samsung Biomedical Research Institute,Suwon,Republic of Korea.
authors.forename: Yoon
authors.initials: Y
authors.lastname: Kong
authors.affiliation: Department of Parasitology,Ewha Womans University School of Medicine,Seoul,Republic of Korea.
authors.forename: Hyun-Jong
authors.initials: HJ
authors.lastname: Yang
authors.affiliation: Department of Microbiology,Graduate School of Medicine,Gachon University,191 Hambakmoe-ro,Yeonsu-gu,Incheon 406-799,Republic of Korea.
authors.forename: Young-An
authors.initials: YA
authors.lastname: Bae
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000909:Antibodies, Helminth; D003004:Clonorchis sinensis / Q000201:enzymology*; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D051379:Mice; D008969:Molecular Sequence Data; D010063:Ovum / Q000201:enzymology*; D011487:Protein Conformation
chemical_list: D000909:Antibodies, Helminth; D004248:DNA (Cytosine-5-)-Methyltransferases
keywords: 5-methylcytosine; Clonorchis sinensis; DNA methylation; DNA-dependent methyltransferase; DNMT2; egg development