title: Non-germ Line Restoration of Genomic Imprinting for a Small Subset of Imprinted Genes in Ubiquitin-like PHD and RING Finger Domain-Containing 1 (Uhrf1) Null Mouse Embryonic Stem Cells.
abstract: The underlying mechanism for the establishment and maintenance of differential DNA methylation in imprinted genes is largely unknown. Previous studies using Dnmt1 knock-out embryonic stem (ES) cells demonstrated that, although re-expression of DNMT1 restored DNA methylation in the non-imprinted regions, the methylation patterns of imprinted genes could be restored only through germ line passage. Knock-out of Uhrf1, an accessory factor essential for DNMT1-mediated DNA methylation, in mouse ES cells also led to impaired global DNA methylation and loss of genomic imprinting. Here, we demonstrate that, although re-expression of UHRF1 in Uhrf1(-/-) ES cells restored DNA methylation for the bulk genome but not for most of the imprinted genes, it did rescue DNA methylation for the imprinted H19, Nnat, and Dlk1 genes. Analysis of histone modifications at the differential methylated regions of the imprinted genes by ChIP assays revealed that for the imprinted genes whose DNA methylation could be restored upon re-expression of UHRF1, the active histone markers (especially H3K4me3) were maintained at considerably low levels, and low levels were maintained even in Uhrf1(-/-) ES cells. In contrast, for the imprinted genes whose DNA methylation could not be restored upon UHRF1 re-expression, the active histone markers (especially H3K4me3) were relatively high and became even higher in Uhrf1(-/-) ES cells. Our study thus supports a role for histone modifications in determining the establishment of imprinting-related DNA methylation and demonstrates that mouse ES cells can be a valuable model for mechanistic study of the establishment and maintenance of differential DNA methylation in imprinted genes.
authors.affiliation: From the Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241 and.
authors.forename: Shankang
authors.initials: S
authors.lastname: Qi
authors.affiliation: From the Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241 and.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Wang
authors.affiliation: From the Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241 and.
authors.forename: Pishun
authors.initials: P
authors.lastname: Li
authors.affiliation: From the Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241 and.
authors.forename: Qihan
authors.initials: Q
authors.lastname: Wu
authors.affiliation: From the Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241 and.
authors.forename: Tieliu
authors.initials: T
authors.lastname: Shi
authors.affiliation: From the Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241 and jwli@bio.ecnu.edu.cn.
authors.forename: Jiwen
authors.initials: J
authors.lastname: Li
authors.affiliation: From the Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai 200241 and the Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China jmweng@bio.ecnu.edu.cn.
authors.forename: Jiemin
authors.initials: J
authors.lastname: Wong
mesh_terms: D000483:Alleles; D000818:Animals; D022762:CCAAT-Enhancer-Binding Proteins; D002135:Calcium-Binding Proteins; D047369:Chromatin Immunoprecipitation; D002851:Chromatography, High Pressure Liquid; D018899:CpG Islands; D019175:DNA Methylation; D053595:Embryonic Stem Cells / Q000166:cytology; D018392:Genomic Imprinting; D006657:Histones / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D062085:RNA, Long Noncoding / Q000378:metabolism; D013447:Sulfites / Q000737:chemistry; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases
chemical_list: D022762:CCAAT-Enhancer-Binding Proteins; D002135:Calcium-Binding Proteins; C512925:Dlk1 protein, mouse; C094335:H19 long non-coding RNA; D006657:Histones; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C490239:Nnat protein, mouse; D009687:Nuclear Proteins; D062085:RNA, Long Noncoding; D013447:Sulfites; D014157:Transcription Factors; D044767:Ubiquitin-Protein Ligases; C117054:Uhrf1 protein, mouse; C042345:hydrogen sulfite
keywords: DNA methylation; embryonic stem cell; epigenetics; gene expression; histone methylation