A dyad oct-binding sequence functions as a maintenance sequence for the unmethylated state within the H19/Igf2-imprinted control region.
DNA methylation of an imprinted control region (ICR) directs the allele-specific and reciprocal expression of the mouse H19 and the insulin-like growth factor 2 (Igf2) genes, mediated by controlling enhancer access. The ICR shows enhancer blocking activity through CTCF binding to an unmethylated sequence. The unmethylated state of the maternal ICR is maintained throughout development after establishment in the germ line; however, little is known of the molecular mechanisms that regulate DNA methylation. Hence, in this study we show that a dyad Oct-binding sequence (DOS) in the ICR mediates the demethylation of low-density methylation but not hypermethylation and is required to maintain the unmethylated state against the tendency for de novo methylation within the ICR in the embryonic carcinoma cell line P19. Furthermore, we also reveal that the unmethylated state of at least one CTCF-binding site within the ICR is under the control of DOS. Our results suggest that the ICR, as a CTCF-dependent insulator, requires DOS as well as CTCF-binding sites and that DOS maintains the maternal specific unmethylated state of the ICR at postimplantation stages.
Hori
Naohiro
N
Department of Molecular Biology, School of Life Science, Faculty of Medicine, Tottori University, Tottori 683-0853, Japan. horinao@grape.med.tottori-u.ac.jp
Nakano
Hiroshi
H
Takeuchi
Toshiyuki
T
Kato
Hiroyuki
H
Hamaguchi
Sayuri
S
Oshimura
Mitsuo
M
Sato
Kenzo
K
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D017124:Conserved Sequence; D004247:DNA / Q000235:genetics* / Q000378:metabolism; D019175:DNA Methylation; D004268:DNA-Binding Proteins / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D051863:Host Cell Factor C1; D006801:Humans; D007335:Insulin-Like Growth Factor II / Q000737:chemistry / Q000378:metabolism*; D019901:Locus Control Region / Q000235:genetics*; D051379:Mice; D008957:Models, Genetic; D008969:Molecular Sequence Data; D050811:Octamer Transcription Factor-1; D050814:Octamer Transcription Factor-3; D009838:Oligodeoxyribonucleotides; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated / Q000235:genetics*; D051381:Rats; D015183:Restriction Mapping; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D013447:Sulfites; D014157:Transcription Factors / Q000378:metabolism; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; C094335:H19 long non-coding RNA; C497692:HCFC1 protein, human; C497693:Hcfc1 protein, mouse; D051863:Host Cell Factor C1; D050811:Octamer Transcription Factor-1; D050814:Octamer Transcription Factor-3; D009838:Oligodeoxyribonucleotides; C494165:POU2F1 protein, human; C494173:POU5F1 protein, human; C494166:Pou2f1 protein, mouse; C494168:Pou2f1 protein, rat; C494174:Pou5f1 protein, mouse; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; D013447:Sulfites; D014157:Transcription Factors; D007335:Insulin-Like Growth Factor II; D004247:DNA