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Science. 2017 May 5;356(6337):503-508. doi: 10.1126/science.aag3260.

Integration of CpG-free DNA induces de novo methylation of CpG islands in pluripotent stem cells.

Author information

1
Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
2
Life Science Center, Tsukuba Advanced Research Alliance, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8577, Japan.
3
Universidad Católica San Antonio de Murcia (UCAM) Campus de los Jerónimos, N° 135 Guadalupe 30107, Murcia, Spain.
4
King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
5
Integrative Genomics and Bioinformatics Core, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
6
Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA. belmonte@salk.edu.

Abstract

CpG islands (CGIs) are primarily promoter-associated genomic regions and are mostly unmethylated within highly methylated mammalian genomes. The mechanisms by which CGIs are protected from de novo methylation remain elusive. Here we show that insertion of CpG-free DNA into targeted CGIs induces de novo methylation of the entire CGI in human pluripotent stem cells (PSCs). The methylation status is stably maintained even after CpG-free DNA removal, extensive passaging, and differentiation. By targeting the DNA mismatch repair gene MLH1 CGI, we could generate a PSC model of a cancer-related epimutation. Furthermore, we successfully corrected aberrant imprinting in induced PSCs derived from an Angelman syndrome patient. Our results provide insights into how CpG-free DNA induces de novo CGI methylation and broaden the application of targeted epigenome editing for a better understanding of human development and disease.

PMID:
28473583
PMCID:
PMC5654639
DOI:
10.1126/science.aag3260
[Indexed for MEDLINE]
Free PMC Article

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