Chanchao Lorthongpanich1,*,†, Lih Feng Cheow2,†, Sathish Balu1, Stephen R. Quake2,3, Barbara B. Knowles1,4, William F. Burkholder2,5,6,#, Davor Solter1,7and Daniel M. Messerschmidt 1,8,#.
1 - Mammalian Development Group, Institute of Medical Biology (IMB), A*STAR, Singapore.
2 - Microfluidics Systems Biology Lab, Institute of Molecular and Cell Biology (IMCB), A*STAR, Singapore.
3 - Department of Bioengineering and Department of Applied Physics, Stanford University and Howard Hughes Medical Institute, Stanford, CA, USA.
4 - The Jackson Laboratory, Bar Harbor, ME, USA.
5 - Genome Institute of Singapore, A*STAR, Singapore.
6 - Nanyang Technological University, Singapore.
7 - Duke - National University of Singapore, Graduate Medical School, Singapore.
8 - Developmental Epigenetics and Disease, IMCB, A*STAR, Singapore.
* Present address: Siriraj Center of Excellence for Stem Cell Research (SISR), Faculty of Medicine Siriraj Hospital, Mahidol University, Thailand.
† These authors contributed equally to this work.
# Corresponding authors: Daniel M. MESSERSCHMIDT: firstname.lastname@example.org
William BURKHOLDER: email@example.com
Published in Science on 6 September 2013.
Epigenetic alterations are increasingly recognized as cause of human cancers and disease. These aberrations are likely to arise during genomic reprogramming in mammalian preimplantation embryos, when their epigenomes are most vulnerable. However, this process is only partially understood because of the experimental inaccessibility of early-stage embryos. Here, we introduce a methodologic advance, probing single cells for various DNA-methylation errors at multiple loci, to reveal failed maintenance of epigenetic mark results in chimeric mice, which display unpredictable phenotypes leading to developmental arrest. Yet we show that mouse pronuclear transfer can be used to ameliorate such reprogramming defects. This study not only details the epigenetic reprogramming dynamics in early mammalian embryos but also suggests diagnostic and potential future therapeutic applications.
Figure legend: (A-B) Illustration of the single-cell DNA methylation detection assay: DNA methylation (lollipops) prevents BstUI restriction digest; both primer combinations will generate PCR products (red/black) (A). If unmethylated, BstUI cuts and the large amplicon (red) cannot be generated (B). (C-D) Mosaic demethylation defects in maternal Trim28 mutants: Preimplantation embryos lacking maternal TRIM28 (C) or control embryos (D) were dissected and individual blastomeres subjected to analysis (see above). The methylation state for six loci in single blastomeres is shown. (Black dot indicates DNA methylation, both amplicons were detected after BstUI digest; white dot, no DNA methylation, only the small amplicon was detected; X, neither amplicon was detected.)
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