Heterogeneity in imprinted methylation patterns of pluripotent embryonic germ cells derived from pre-migratory mouse germ cells

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ydbio.2007.11.007 Byline: Tanya C. Shovlin, Gabriela Durcova-Hills, Azim Surani, Anne McLaren Keywords: Embryonic germ (EG) cells; Primordial germ cells (PGCs); Embryonic stem (ES) cells; DNA methylation; Germ cell development Abstract: Pluripotent stem cells, termed embryonic germ (EG) cells, have been generated from both human and mouse primordial germ cells (PGCs). Like embryonic stem (ES) cells, EG cells have the potential to differentiate into all germ layer derivatives and may also be important for any future clinical applications. The development of PGCs in vivo is accompanied by major epigenetic changes including DNA demethylation and imprint erasure. We have investigated the DNA methylation pattern of several imprinted genes and repetitive elements in mouse EG cell lines before and after differentiation. Analysed cell lines were derived soon after PGC specification, 'early', in comparison with EG cells derived after PGC colonisation of the genital ridge, 'late' and embryonic stem (ES) cell lines, derived from the inner cell mass (ICM). Early EG cell lines showed strikingly heterogeneous DNA methylation patterns, in contrast to the uniformity of methylation pattern seen in somatic cells (control), late EG cell and ES cell lines. We also observed that all analysed XX cell lines exhibited less methylation than XY. We suggest that this heterogeneity may reflect the changes in DNA methylation taking place in the germ cell lineage soon after specification. Author Affiliation: The Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK Article History: Received 3 September 2007; Revised 25 October 2007; Accepted 2 November 2007