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Abnormal DNA methylation of the Oct‐4 enhancer region in cloned mouse embryos
Author(s) -
Kawasumi Miyuri,
Unno Yuichi,
Matsuoka Toshiki,
Nishiwaki Megumi,
Anzai Masayuki,
Amano Tomoko,
Mitani Tasuku,
Kato Hiromi,
Saeki Kazuhiro,
Hosoi Yoshihiko,
Iritani Akira,
Kishigami Satoshi,
Matsumoto Kazuya
Publication year - 2009
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.20966
Subject(s) - biology , enhancer , dna methylation , embryo , methylation , genetics , dna , cloning (programming) , microbiology and biotechnology , gene , transcription factor , gene expression , computer science , programming language
Oct‐4 is essential for normal embryonic development, and abnormal Oct‐4 expression in cloned embryos contributes to cloning inefficiency. However, the causes of abnormal Oct‐4 expression in cloned embryos are not well understood. As DNA methylation in regulatory regions is known to control transcriptional activity, we investigated the methylation status of three transcriptional regulatory regions of the Oct‐4 gene in cloned mouse embryos—the distal enhancer (DE), the proximal enhancer (PE), and the promoter regions. We also investigated the level of Oct‐4 gene expression in cloned embryos. Immunochemistry revealed that 85% of cloned blastocysts expressed Oct‐4 in both trophectoderm and inner cell mass cells. DNA methylation analysis revealed that the PE region methylation was greater in cloned morulae than in normal morulae. However, the same region was less methylated in cloned blastocysts than in normal blastocysts. We found abnormal expression of de novo methyltransferase 3b in cloned blastocysts. These results indicate that cloned embryos have aberrant DNA methylation in the CpG sites of the PE region of Oct‐4 , and this may contribute directly to abnormal expression of this gene in cloned embryos. Mol. Reprod. Dev. 76: 342–350, 2009. © 2008 Wiley‐Liss, Inc.