title: Regulation of eye development by transcription control of CCCTC binding factor (CTCF).
abstract: CCCTC binding factor (CTCF), a transcriptional regulator, plays important roles in epigenetics and development. In the present study, we report that overexpression of CTCF in transgenic mice during embryonic development suppresses Pax6 gene expression. This effect causes defects in ocular development that result in microophthalmia. In eye-derived cells transfected with a tetracycline turn-on CTCF system, up-regulation of CTCF expression significantly suppressed Pax6 expression. In contrast, the knockdown of CTCF mRNA resulted in the down-regulation of CTCF protein expression, which in turn enhanced the Pax6 expression. CTCF controls Pax6 transcription by interacting with a repressor element located in the 5'-flanking region upstream of the Pax6 P0 promoter. This interaction suppressed Pax6 gene transcription by blocking the effect of an ectoderm enhancer located 3.5 kb upstream from the P0 promoter. We also found an 80-bp sequence in a region -1.2 kbp upstream from the P0 promoter that contained multiple CTCF binding sites and interacted with nuclear proteins obtained from eye-derived cells forming electrophoretic mobility shift assay complexes with CTCF. We conclude that a novel function of CTCF is to regulate Pax6 transcription by binding to the repressor element, which in turn blocks the effect of the ectoderm enhancer resulting in the inhibition of P0 promoter activity.
authors.affiliation: Division of Molecular Medicine, Harbor-UCLA Medical Center, David Geffen School of Medicine, University of California-Los Angeles, Torrance, California 90502-2006, USA.
authors.forename: Tie
authors.initials: T
authors.lastname: Li
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Lu
authors.forename: Luo
authors.initials: L
authors.lastname: Lu
mesh_terms: D000818:Animals; D001483:Base Sequence; D000076246:CCCTC-Binding Factor; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D005123:Eye / Q000196:embryology*; D005136:Eye Proteins / Q000096:biosynthesis* / Q000235:genetics; D015870:Gene Expression; D017930:Genes, Reporter / Q000235:genetics; D018398:Homeodomain Proteins / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D011401:Promoter Regions, Genetic / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D011817:Rabbits; D051381:Rats; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D013752:Tetracycline / Q000494:pharmacology; D014158:Transcription, Genetic / Q000502:physiology
chemical_list: D000076246:CCCTC-Binding Factor; C000619697:CTCF protein, human; C000619698:Ctcf protein, mouse; D004268:DNA-Binding Proteins; D005136:Eye Proteins; D018398:Homeodomain Proteins; D000071841:PAX6 Transcription Factor; C000605730:PAX6 protein, human; D051761:Paired Box Transcription Factors; C000605732:Pax6 protein, mouse; C000605733:Pax6 protein, rat; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; D012097:Repressor Proteins; D013752:Tetracycline