“The ontogeny of cKIT+ human primordial germ cells proves to be a resource for human germ line reprogramming, imprint erasure and in vitro differentiation”
Research into embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) has allowed a greater understanding of the development and differentiation of specific cellular lineages and the molecular mechanisms which control them. However, our lack of understanding of human foetal development translates to a lack of details to validate, guide and quality control differentiation in vitro. Germ cell development from pluripotent sources could aid research and therapeutics in human fertility (Hayashi et al, Ohinata et al and Reijo et al). Development is understood to begin in primordial germ cells expressing the tyrosine protein kinase receptor cKIT (see paper for extended references), but how these cells progress is relatively less understood, although widespread changes to epigenetic modifications are key to this process (Hajkova et al 2008, Hajkova et al 2010, Popp et al and Seki et al). Now, in a study from researchers from the laboratory of Amander T. Clark from the University of California, Los Angeles, USA, cKIT-positive PGCs have been tracked from 6 to 20 developmental weeks through the analysis of human embryonic and fetal samples allowing the identification of the temporal nature of alterations in multiple epigenetic modifications and, additionally, they show that established hESC lines are not equivalent to human PGCs (Gkountela et al).