This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Wee, G. Articles by Han, Y.-M. Search for Related Content PubMed PubMed Citation Articles by Wee, G. Articles by Han, Y.-M.

Epigenetic alteration of the donor cells does not recapitulate the reprogramming of DNA methylation in cloned embryos

¹ Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701, Republic of Korea,² Korea Advanced Institute of Science and Technology (KAIST), Center for Stem Cell Differentiation, Daejeon 305-701, Republic of Korea and³ Korea Research Institute of Bioscience and Biotechnology (KRIBB), Center for Development and Differentiation, Daejeon 305-806, Republic of Korea

Correspondence should be addressed to Y-M Han; Email: ymhan{at}kaist.ac.kr

Epigenetic reprogramming is a prerequisite process during mammalian development that is aberrant in cloned embryos. However, mechanisms that evolve abnormal epigenetic reprogramming during preimplantation development are unclear. To trace the molecular event of an epigenetic mark such as DNA methylation, bovine fibroblasts were epigeneticallyaltered by treatment with trichostatin A (TSA) and then individually transferred into enucleated bovine oocytes. In the TSA-treated cells, expression levels of histone deacetylases and DNA methyltransferases were reduced, but the expression level of histone acetyltransferases such as Tip60 and histone acetyltransferase 1 (HAT1) did not change compared with normal cells. DNA methylation levels of non-treated (normal) and TSA-treated cells were 64.0 and 48.9% in the satellite I sequence (P < 0.05) respectively, and 71.6 and 61.9% in the -satellite sequence respectively. DNA methylation levels of nuclear transfer (NT) and TSA-NT blastocysts in the satellite I sequence were 67.2 and 42.2% (P < 0.05) respectively, which was approximately similar to those of normal and TSA-treated cells. In the -satellite sequence, NT and TSA-NT embryos were substantially demethylated at the blastocyst stage as IVF-derived embryos were demethylated. The in vitro developmental rate (46.6%) of TSA-NT embryos that were individually transferred with TSA-treated cells was higher than that (31.7%) of NT embryos with non-treated cells (P < 0.05). Our findings suggest that the chromatin of a donor cell is unyielding to the reprogramming of DNA methylation during preimplantation development, and that alteration of the epigenetic state of donor cells may improve in vitro developmental competence of cloned embryos.